PANNA: DDT and Malaria Resource Center

DDT and Malaria Resource Center

The following is a compilation of selected articles related to the use of the pesticide DDT to control malaria. For each article, we provide a full citation, our own brief summary, the original abstract, and a direct link to the original source when available.

The articles cover a range of issues and perspectives, and are grouped in the following categories:

DDT's Impact on Human Health and the Environment
The Debate over DDT
Malaria Control: Asia
Malaria Control: Africa
Malaria Control: The Americas
Malaria Control: General and Multi-Regional

This compilation will be updated periodically and it is by no means comprehensive. We hope it will prove to be a useful tool in the ongoing discussion among policymakers, advocacy groups and the media regarding the use of DDT and the need to improve efforts to effectively control malaria.

For detailed information on the toxicity, health effects and regulatory status of DDT, visit PANNA's on-line Pesticide Database.

For a list of additional web resources, click here.

This resource was last updated January 26, 2006.

BASIC FACTS ABOUT DDT

DDT is a pesticide that was used heavily worldwide in the 1950s and 1960s both in agricultural production and for malaria control. Concerns about impacts on wildlife populations - particularly predatory birds - led to the phase out of DDT in many countries in the 1970s. Use of the pesticide for malaria control has continued in some regions, though most countries now rely on combinations of other control methods.

DDT has been in the news in recent years as an international treaty, the Stockholm Convention, raised the possibility of global elimination of DDT and its "loss" as a tool for malaria control. At the same time, much more is now known about the human health effects of exposure to DDT and its breakdown products. To learn more basic information about DDT, including where it continues to be used and produced, see " DDT and Malaria: Answers to Common Questions." To learn more about DDT and the Stockholm Convention, see the debate section below as well as World Wildlife Fund's series of reports on DDT.

A) DDT’S EFFECTS ON HEALTH AND THE ENVIRONMENT

1) Longnecker, M. P., M. A. Klebanoff, H. Zhou, J. W. Brock. Association between maternal serum concentration of the DDT metabolite DDE and pre-term and small-for-gestational-age babies at birth. The Lancet 2001; 358: 110-114.

PANNA summary: This 2001 landmark study by the National Institute of Environmental Health Sciences and three other organizations found a strong relationship between prematurely delivered and low birth weight babies and mothers' blood levels of DDE, the metabolic breakdown product of DDT. The study took its data from children born between the years 1959 and 1966, a time when DDT was still being used in the United States and so average blood levels of DDE were much higher than they are in the U.S. today, but still lower than what they are in other countries where DDT is still being used to control malaria. The researchers conclude that the ties between premature birth rates, a major factor in infant mortality, and blood levels of DDE should lead to the reassessment of the costs and benefits of DDT-based malaria control strategies around the world.

Abstract:

Background DDT (1,1,1-trichloro-2,2-bis (p-chlorophenyl) ethane) is highly effective against most malaria-transmitting mosquitoes and is being widely used in malaria-endemic areas. The metabolite, DDE (1,1-dichloro-2,2-bis (p-chlorophenyl) ethylene), has been linked to pre-term birth in small studies, but these findings are inconclusive. Our aim was to investigate the association between DDE exposure and pre-term birth.

Methods Our study was based on the U.S. Collaborative Perinatal Project (CPP). From this study we selected a subset of more than 44,000 eligible children born between 1959 and 1966 and measured the DDE concentration in their mothers' serum samples stored during pregnancy. Complete data were available for 2,380 children, of whom 361 were born pre-term and 221 were small-for-gestational age.

Findings The median maternal DDE concentration was 25 µg/L (range 3-178)--several fold higher than current US concentrations. The adjusted odds ratios (OR) of pre-term birth increased steadily with increasing concentrations of serum DDE (ORs=1, 1·5, 1·6, 2·5, 3·1; trend p<0·0001). Adjusted odds of small-for-gestational-age also increased, but less consistently (ORs=1, 1·9, 1·7, 1·6, 2·6; trend p=0·04). After excluding pre-term births, the association of DDE with small-for-gestational-age remained.

Interpretation The findings strongly suggest that DDT use increases pre-term births, which is a major contributor to infant mortality. If this association is causal, it should be included in any assessment of the costs and benefits of vector control with DDT.

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2) van Wendel de Joode B, Wesseling C, Kromhout H, Monge P, Garcia M, Mergler D. Chronic nervous system effects of long-term occupational exposure to DDT. Lancet 2001 Mar 31; 357(9261): 1014-16.

PANNA summary: This study found that retired malaria-control workers who had worked spraying DDT did worse on tests of neurobehavioral functions than control groups, and that the longer they had worked with DDT, the poorer the test results. These results indicate that long-term exposure to DDT is measurably harmful.

Abstract: Dichlorodiphenyltrichloroethane (DDT) is a compound with moderate toxicity that is judged to be safe for occupational use, although little is known about its long-term effects on the human nervous system. We investigated chronic nervous-system effects of long-term occupational exposure to DDT by comparing the neurobehavioral performance of retired malaria-control workers with a reference group of retired guards and drivers. DDT-exposed workers did worse on tests assessing various neurobehavioral functions than controls; performance significantly deteriorated with increasing years of DDT application. Our results could not be explained by exposure to cholinesterase-inhibiting pesticides or other potential confounding factors.

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3) Longnecker, MP, MA Klebanoff, JW Brock, H Zhou, KA Gray, LL Needham and AJ Wilcox. Maternal serum level of 1,1-Dichloro-2,2-bis (p-chlorophenyl) ethylene and risk of cryptorchidism, hypospadias, and polythelia among male offspring. American Journal of Epidemiology Vol. 155, No. 4 : 313-322.

PANNA summary: In light of recent findings that the metabolic byproduct of DDT, DDE, blocks receptors for androgens (male hormones) in rats, scientists undertook this study to see if there is some similar effect in humans. They looked at data for mothers' blood levels of DDE (see article #1) and the frequency of birth defects in male babies from the same set of children born between 1959 and 1966. They found that elevated DDE levels in the mother's blood serum correlated with increased incidence of undescended testicles, penis abnormalities, and extra nipples in male children.

Abstract: 1,1-Dichloro-2,2-bis (p-chlorophenyl) ethylene (p,p'-DDE) is a metabolite of the insecticide 2,2-bis (p-chlorophenyl) -1,1,1-trichloroethane (DDT) and is a ubiquitous environmental contaminant. Nearly everyone in the United States has a detectable serum level of DDE. DDE was recently found to inhibit binding of androgen to its receptor and to block androgen action in rodents. Normal development of male genitalia in mammals depends on androgen action. The authors used stored serum samples to examine the relation between maternal DDE levels during pregnancy and adjusted odds of cryptorchidism (n = 219), hypospadias (n = 199), and polythelia (extra nipples) (n = 167) among male offspring, using a nested case-control design with one control group (n = 552). Subjects were selected from the Collaborative Perinatal Project, a US birth cohort study begun in 1959-1966, when DDE levels were much higher than they are at present. Compared with boys whose mother's recovery-adjusted serum DDE level was less than 21.4 microg/liter, boys with maternal levels greater than or equal to 85.6 microg/liter had adjusted odds ratios of 1.3 (95% confidence interval (CI): 0.7, 2.4) for crypt-orchidism, 1.2 (95% CI: 0.6, 2.4) for hypospadias, and 1.9 (95% CI: 0.9, 4.0) for polythelia. For cryptorchidism and polythelia, the results were consistent with a modest-to-moderate association, but in no instance was the estimate very precise. The results were inconclusive. (Epidemiology Branch, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA. longnecker@niehs.nih.gov)

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4) Bouwman, H. DDT levels in serum, breast-milk and infants in various populations in malaria and non-malaria controlled areas of KwaZulu. Medical Research Council. 1991:1-38.

Abstract: The World Health Organization (WHO) considers 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) safe to man and the environment when applied intra-domiciliary for malaria control. Research into the possible health effects under prevailing conditions and taking social customs into account, have, however, been lacking. This study was undertaken to determine levels of DDT in serum and breast-milk and possible risks posed by the insecticide to the health of lactating mothers and their infants. The aims of the study were: (1) To determine the levels of DDT and its metabolites, DDD and DDE, in the serum of members of families from a sprayed and a non-sprayed area, as well as changes caused by indoor application of DDT; (2) To determine the levels of DDT and its metabolites in the breast-milk of mothers from a sprayed and a non-sprayed area, as well as changes caused by indoor application of DDT; (3) To determine the uptake of DDT and its metabolites by the infant via breast-milk, and to develop a statistical model that describes the dynamics; and (4) To determine the risk to the health of mother and infant posed by exposure to DDT and its metabolites.

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5) Bouwman, H.; Becker, P. J.; Cooppan, R. M., and Reinecke, A. J. Transfer of DDT used in malaria control to infants via breast milk. Bulletin of the World Healt Organization. 1992; 70(2):241-50. ISSN: 0042-9686.

PANNA summary: This is a study of the levels of DDT and its metabolites in the blood of infants and the breast milk of their mothers in KwaZulu, South Africa where DDT is used to control malaria. It was found that breastfeeding is the primary source of DDT in babies' blood, and that it accumulates with age. DDT in the environment is a secondary source.

Abstract: The transfer of p,p'-DDT (1,1,1-tricholoro-2,2-bis(4-chlorophenyl)ethane) and its metabolites to infants via breast-feeding was studied in an area of KwaZulu, South Africa, where DDT is used to interrupt malaria transmission. Samples of whole blood were collected from 23 infants, together with samples of breast milk from their respective mothers. The mean sigma DDT (total DDT) in the whole blood was 127.03 micrograms.l-1 and that in the breast milk, 15.06 mg.kg-1 (milk fat). The % DDT (% DDT of sigma DDT) was significantly higher in the infant blood than in the breast milk (P less than 0.05). A multiplicative regression analysis indicated that sigma DDT increased significantly (P less than 0.01) in infant whole blood with infant age. Multiple regression showed that 70.0% of the variation in sigma DDT was due to the variation in parity of the mother, age of the infant, and the sigma DDT in breast milk. These variables accounted also for 76.3% of the variation in p,p'-DDE but only for 38.2% of that in p,p'-DDT. Organochlorines were therefore largely transferred to the infant from the mother, with DDT in the environment playing a secondary role. (Department of Zoology, University for Christian Higher Education, Potchefstroom, South Africa.)

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6) Bouwman, H.; Cooppan, R. M.; Botha, M. J., and Becker, P. J. Serum levels of DDT and liver function of malaria control personnel. S Afr Med J. 1991; 79(6):326-329. ISSN: 0038-2469.

PANNA summary: This study found that blood levels of DDT and its metabolites are higher in people who work as DDT sprayers than for the general population in KwaZulu, South Africa, where DDT is used for malaria control. Possible health risks to the sprayers from these elevated levels, including evidence of reduced liver function, were identified.

Abstract: The levels of DDT and metabolites in serum of 23 applicators involved in malaria control operations in Natal were determined using gas chromatography with electron capture detection. The mean levels (microgram/l, ppb) were 61.7 DDT, 129.3 DDE, 11.0 DDD and 202.0 sigma DDT. Percentage DDT was 33.4%. These levels were higher than for an age matched sample of the general population in KwaZulu, who are protected by DDT against malaria. Percentage DDT correlated negatively with age (P less than 0.05) for the applicators, suggesting a change in pharmacodynamics with age. Mean serum albumin, alkaline phosphatase, aspartate transferase and gamma-glutamyltransferase (GGT) levels did not differ significantly from an age-matched control group, but the mean GGT value for the applicators was higher than the maximum of the laboratory normal range. Although not clinically significant, the alanine transferase was significantly higher in the applicators than in the control group. These higher levels suggest a possible risk to the health of the sprayers, but uncertainties remain. (Research Institute for Environmental Diseases of the South African Medical Research Council, Pretoria.)

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7) Gladen, B. C. and Rogan, W. J. DDE and shortened duration of lactation in a northern Mexican town. American Journal of Public Health. 1995; 85(4):504-508.

PANNA summary: The authors found that DDE (a metabolite of DDT) levels in the breast milk of mothers in an agricultural town in northern Mexico is strongly linked to the length of time that they breastfeed their infants. Mothers with the highest levels of DDE breastfed for only 3 months on average, while mothers with the lowest DDE levels breastfed for an average of 7.5 months. The authors conclude that DDT exposure may be contributing to the trend toward decreasing lengths of lactation world wide.

Abstract: OBJECTIVES. Worldwide declines in the duration of lactation are cause for public health concern. Higher levels of dichlorodiphenyl dichloroethene (DDE) have been associated with shorter durations of lactation in the United States. This study examined whether this relationship would hold in an agricultural town in northern Mexico. METHODS. Two hundred twenty-nine women were followed every 2 months from childbirth until weaning or until the child reached 18 months of age. DDE was measured in breast milk samples taken at birth, and women were followed to see how long they lactated. RESULTS. Median duration was 7.5 months in the lowest DDE group and 3 months in the highest. The effect was confined to those who had lactated previously, and it persisted after statistical adjustment for other factors. These results are not due to overtly sick children being weaned earlier. Previous lactation lowers DDE levels, which produces an artifactual association, but simulations using best estimates show that an effect as large as that found here would arise through this mechanism only 6% of the time. CONCLUSIONS. DDE may affect women's ability to lactate. This exposure may be contributing to lactation failure throughout the world. (Statistics and Biomathematics Branch, National Institute of Environmental Health Sciences, Mail Drop A3-03 POB 12233, Research Triangle Park, NC 27709, USA.)

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8) Rogan, W. J.; Gladen, B. C.; McKinney, J. D.; Carreras, N.; Hardy, P.; Thullen, J.; Tingelstad, J., and Tully, M. Polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in human milk: Effects on growth, morbidity, and duration of lactation. American Journal of Public Health. 1987; 77(10):1294-1297.

PANNA summary: This study determined the effects of PCBs and DDE (DDT metabolite) in breast milk on infant growth and health. Its most significant finding was that higher levels of DDE are associated with markedly shorter duration of breast feeding, indicating that DDE is somehow interfering with mothers’ ability to breastfeed their children.

Abstract: We followed 858 children from birth to one year of age to determine whether the presence of polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in breast milk affected their growth or health. Neither chemical showed an adverse effect on weight or frequency of physician visits for various illnesses, although differences were seen between breast-fed and bottle-fed children, with bottle-fed children being heavier and having more frequent gastroenteritis and otitis media. Children of mothers with higher levels of DDE were breast-fed for markedly shorter times, but adjustments for possible confounders and biases did not change the findings. In absence of any apparent effect on the health of the children, we speculate that DDE may be interfering with the mother's ability to lactate, possibly because of its estrogenic properties.

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9) Douthwaite, R J, ed. DDT in the Tropics: The impact on wildlife in Zimbabwe of ground-spraying for tsetse fly control. Canterbury, UK: R J Douthwaite and Associates, Environmental Management Consultants, 1999. (see the International Centre for Pesticide Safety's Review at: http://www.icps.it/english/bollettino/psn97/970307.htm)

PANNA summary: A report on studies funded by the UK's Department for International Development looking at the recovery of local wildlife known to have been affected after DDT spraying for tsetse fly control in northwestern Zimbabwe 10 years earlier. The author argues that DDT has had relatively little impact on wildlife populations in the area compared with the widespread woodland destruction by immigrant farmers and elephants. Deltamethrin, a synthetic pyrethroid that would perhaps have less impact on wildlife, has been used successfully for ground spraying instead of DDT, but it still costs too much to make it a viable solution. This report aims to inform use of DDT for tsetse fly control under the new POPs treaty that allows for limited use for vector control.

(no abstract available)

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10) Booth, William. EPA moves to cap risks of DDT on ocean floor. The Washington Post. September 5, 2000. A03.

PANNA summary: Between 1947 and 1971, Montrose Chemical's plant in Torrance, California flushed more than 100 tons of DDT into the county sewer system, where it ran into the Pacific Ocean near the cliffs of Palos Verdes. DDT remains on the ocean floor and is the nation's deepest and largest Superfund site. DDT levels in the bodies of fish caught in this area and sold in Los Angeles are much higher than government safety standards. EPA is filing suit against Montrose Chemical to pay for the cost of cleaning up and restoring the waters off Palos Verdes.

(no abstract available)

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11) Wiktelius, S and CA Edwards. Organochlorine Insecticide Residues in African Fauna: 1971-1995. Review of Environmental Contamination and Toxicology 151: 1-37.

PANNA summary: Traces the use of organochlorine insecticides (including DDT) in Africa and the levels of organochlorines subsequently found in the tissues of terrestrial and aquatic animals. The authors found that levels, especially of DDT and diedrin, were "high enough to have considerable potential for chronic toxicity, for causing behavioral changes, or even for killing wild animals, particularly fish and birds and possibly crocodiles." The author warns against possible long-term population effects on the fauna of Africa if the use of organochlorines is not restricted.

Abstract: Organochlorine insecticides (OCLs), which were introduced in the decade following World War II, were used extensively in Europe, the U.S., and other developed countries into the 1970s. However, data began to accumulate on their persistence in soils and aquatic sediments, their potential to be taken up into animal tissues and to bioconcentrate in birds and mammals in the higher tropic levels of food chains and even in humans. As a result, registration authorities phased out their use progressively, in Europe and the U.S., from 1973 onward. However, the production of OCLs in developed countries and their use in developing countries continued through the 1970s and 1980s into the 1990s because they were no longer under patent agreement, were inexpensive to manufacture, and were very effective in pest control. In Africa, the use of OCLs continued well into the 1990s for the control of mosquitoes, tsetse flies, and desert locusts as well as to combat various crop, animal, and human pests. Some of these uses involved extensive spraying of large areas of nonagricultural land, thereby exposing many groups and species of wildlife to their residues. Although there is some evidence of a gradual decline in the use of OCLs in Africa, they are still being used in appreciable quantities. During the past 25 years, there have been 50 published reports of OCL residues in the various groups of invertebrate and vertebrate animals constituting the African fauna. These have been based on a diverse range of surveys, target animals, sampling methods, and analytical techniques. Moreover, they are extremely regionally-biased, the most intense surveys being in Zimbabwe, Kenya, Egypt, and South Africa. DDT was the most commonly used OCL, accounting for about half the total use, followed closely by dieldrin and HCH. Birds and fish have been sampled most intensively, with relatively few studies on other taxa. We reviewed the OCL residue data on African fauna from these reports and summarized the maximum and mean residues in the various groups of terrestrial and aquatic invertebrates and vertebrates. Overall, residues in the fauna were the greatest for DDT, followed in turn by those of dieldrin, HCH, endosulfan, and endrin, with small amounts of aldrin and toxaphene being found in some animals. There were relatively few reports of OCL residues in terrestrial invertebrates and virtually none in aquatic invertebrates. Only a few reports demonstrated OCL residues in terrestrial vertebrates, although high levels of DDT, dieldrin, and HCH were found in crocodile eggs and large residues of dieldrin occurred in bats, squirrels, and monkeys. Considerable OCL residues were reported in a few species of fish, especially Barbus, Clarias, Hydrocynus, Labeo, Sarotherodon, Epiplatys, and Synodontis. These residues were at levels that could have caused chronic toxicity or behavioral changes. The calculated maximum and mean OCL residues in the various elements of the African fauna until 1995 were compared with those calculated for corresponding faunal groups in Europe and the U.S. from their development and introduction up to 1973. The OCL residues reported in African fauna between 1971 and 1975 tended to be significantly higher overall than those published for Europe and the U.S. In particular, residues of DDT and dieldrin in African birds and their eggs were greater than those that had been incriminated as causing significant eggshell thinning and reproductive failure in European and U.S. aquatic and terrestrial birds up to 1973. Additionally, high DDT and dieldrin residues were reported from some species of African fish at levels that could potentially affect their reproduction, have chronic toxic and behavioral effects, and even drastically affect populations. Holistic case studies on the use of OCLs to control tsetse flies and desert locusts were discussed. OCL levels in trophic levels of fauna associated with Lake Kariba (between Zambia and Zimbabwe) were summarized. (Swedish University of Agricultural Sciences, Uppsala, Sweden)

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12) Toxicological Profile for DDT, DDE, and DDD. Prepared by Syracuse Research Corporation for US Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry. September 2002. http://www.atsdr.cdc.gov/toxprofiles/tp35.html

PANNA summary: This report is concerned solely with DDT in the USA, so there is very little attention paid to malaria or DDT’s use for vector control. The profile provides clear explanations of why DDT is still in the U.S. environment when it was banned for use in this country in 1972, how it persists in the soil and water, and how it moves from one place to another. The report cites many possible dangers of the toxin to public health. Health effects cited in this report include: nervous system effects, changes in liver enzymes, and “harmful effects” on reproduction and adrenal gland function. EPA has classified DDT and its metabolites as probable human carcinogens, though this report says that there is no evidence of increased cancer risk in humans.

(no abstract available)

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13) Altshul, L., C. Chen, L. Fu, W.Guang, A. Huang , S. Korrick, M. Perry,

S. A. Venners, X. Wang, and X. Xu. Preconception Serum DDT and Pregnancy Loss: A Prospective Study Using a Biomarker of Pregnancy. American Journal of Epidemiology Advance Access. August 2005. Vol. 162, No. 8.

PANNA summary: The authors investigated the effect of DDT on pregnancy losses in a group of women in Anhui , China . The researchers found a positive exposure-response association between DDT traces found within the body and the risk of successive early pregnancy losses.

Abstract: Previous studies of pregnancy losses and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) were limited because they did not include losses prior to clinical detection of pregnancy and because exposures were measured after the pregnancies of interest. The authors examined the association of preconception serum total DDT (sum of DDT isomers and metabolites) concentration and subsequent pregnancy losses in 388 newly married, nonsmoking, female textile workers in China between 1996 and 1998. Upon stopping contraception, subjects provided daily urine specimens and records of vaginal bleeding for up to 1 year or until clinical pregnancy. Daily urinary human chorionic gonadotropin was assayed to detect conception and early pregnancy losses, and pregnancies were followed to detect clinical spontaneous abortions. There were 128 (26%) early pregnancy losses in 500 conceptions and 36 (10%) spontaneous abortions in 372 clinical pregnancies. Subjects were grouped in tertiles by preconception serum total DDT concentration (group 1: 5.5�22.9 ng/g; group 2: 23.0�36.5 ng/g; group 3: 36.6� 113.3 ng/g). Compared with group 1, group 2 had adjusted relative odds of early pregnancy losses of 1.23 (95% confidence interval (CI): 0.72, 2.10), and group 3 had adjusted odds of 2.12 (95% CI: 1.26, 3.57). The relative odds of early pregnancy losses associated with a 10-ng/g increase in serum total DDT were 1.17 (95% CI: 1.05, 1.29). The small number of spontaneous abortions following clinical detection of pregnancy were not associated with serum total DDT. In this population, there was a positive, monotonic, exposure-response association between preconception serum total DDT and the risk of subsequent early pregnancy losses.

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14) Aimin, C. and W.J. Rogan. Health risks and benefits of bis (4-chlorophenyl)-1,1,1trichloroethane (DDT). US National Institute of Environmental Health Sciences. 2005 Lancet 2005; 366: 763�73

PANNA summary: This article traces the health impacts and effectiveness or lack of effectiveness for countries continuing to use DDT for malaria control after its inclusion in the Stockholm Convention list of chemicals targeted for a global ban in 2001. Due to a lack of controlled testing and conflicting or inconclusive data it was impossible to determine the specific negative health effects of DDT. The authors call for more research to determine if the health risks outweigh the health benefits.

Abstract: DDT (bis[4-chlorophenyl]-1,1,1-trichloroethane) is a persistent insecticide that was used worldwide from the mid-1940s until its ban in the USA and other countries in the 1970s. When a global ban on DDT was proposed in 2001, several countries in sub-Saharan Africa claimed that DDT was still needed as a cheap and effective means for vector control. Although DDT is generally not toxic to human beings and was banned mainly for ecological reasons, subsequent research has shown that exposure to DDT at amounts that would be needed in malaria control might cause preterm birth and early weaning, abrogating the benefit of reducing infant mortality from malaria. Historically, DDT has had mixed success in Africa ; only the countries that are able to find and devote substantial resources towards malaria control have made major advances. DDT might be useful in controlling malaria, but the evidence of its adverse effects on human health needs appropriate research on whether it achieves a favourable balance of risk versus benefit. (Epidemiology Branch, USNational Institute of Environmental Health Sciences, P O Box 12233, Research Triangle Park, NC 27709, USA. rogan@niehs.nih.gov)

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15) Bouwman, H., and C. H. J. Schutte. Effects of Sibship on DDT Residue Levels in Human Serum from a Malaria Endemic Area in Northern KwaZulu . Bulletin of Environmental Contaminants and Toxicology. 1993; 50: 300-7.

PANNA Summary: This study analyzes serum levels of DDT and its metabolites of siblings in eight homesteads. The authors conclude that there is a strong correlation between siblings under malaria control conditions and serum levels of DDT. They recommend that children always be included in environmental exposure studies and that separate risk assessments be done, since the young experience different environmental circumstances and are especially vulnerable during development.

(no abstract available)

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16) Bouwman, H., R. M. Cooppan, P. J. Becker, et al. Malaria Control and Levels of DDT in Serum of Two Populations in KwaZulu. Journal of Toxicology and Environmental Health. 1991; 33(3): 141-55.

PANNA Summary: The authors established that the average level of DDT and its metabolites was higher in the population exposed to in-house DDT application for malaria control than in the control group. The researchers also discovered that the levels of DDT and its metabolites decreased between the ages of three and twenty-nine years, yet following age twenty-nine, the levels began to increase again. Based on these results, the authors suggest that different processes govern DDT dynamics with relation to age. They also tested liver function and found that, although DDT metabolite levels correlate with levels of the liver protein, alcohol consumption better predicted liver protein levels. Thus, the authors conclude that �DDT as used for malaria control does not adversely affect the liver function.�

Abstract: Concentrations of p,p'-DDT, p,p'-DDE, and p,p'-DDD were determined in serum of members of households of two different areas of KwaZulu. Annual intradomiciliary application of DDT is used for the interruption of malaria transmission in one area (the exposed group) while the other served as the control. Demographic differences between the two groups resulted in significantly more females in the control group. The two groups were comparable with respect to age. Serum from household members living in DDT-treated dwellings had significantly higher (p < .005) levels of ?DDT and metabolites (mean ?DDT 140.9 µg/l) than those from the control area (mean ?DDT 6.04 µg/l). Percentage DDT was also significantly higher (p < .05) in the exposed group (28.9%) than the control group (8.3%). ?DDT for the 3-10 yr age interval (168.6 µg/l) was significantly higher (p < .05) than the 20-29 (60.5 µg/l) and 30-39 (84.2 µg/l) yr age intervals. There seemed to be two groups with regard to accumulation and elimination. The age group 3-29 appeared to be eliminating DDT, most likely accumulated from contaminated breast milk, faster than they accumulated it. From around 29 yr of age accumulation predominated as the levels increased with age. Regression analysis suggested pharmacokinetic differences for DDE and DDT between the two groups. Liver function parameters between the two groups only differed significantly for gamma-glutamyl transferase ( g GT) (p < .005), but the influence of difference in alcohol consumption, which was significantly higher in the exposed group (p < .0001), offered a better explanation. Those of the exposed group that consumed alcohol had a significantly higher (p < .05) mean g GT level (41.5 IU/l) than those that did not (20.2 IU/l), but were not significantly different for ?DDT (p > .05). The safety of DDT used in malaria control for subjects aged 3 and older was confirmed by the levels of DDT in serum when compared with other studies, which showed lack of any negative effects associated with these levels in adults, and an apparently normal liver function in the exposed and control groups. ( Research Institute for Environmental Diseases, Medical Research Council, Pretoria , Republic of South Africa .)

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17) Bouwman, H., P. J. Becker, and C. H. J. Schutte. Malaria Control and Longitudinal Changes in Levels of DDT and Its Metabolites in Human Serum from KwaZulu. Bulletin of the World Health Organization. 1994; 72(6): 921-30.

(Regional: Africa )

PANNA Summary: Based on previous research, the authors propose that uptake and elimination, two coexisting processes, control the changes in serum levels of DDT and its metabolites; and that these two processes switch with age. To confirm this, the authors compared the rates of change in addition to the change in levels. They found an increase in DDT metabolites for the older group (=21 years) and a decrease in serum levels for the younger group (3 to 20 years) over a 12-month period. Their data indicate that DDT levels increased faster in the older group than in the younger group, and that there is a more rapid reduction in serum DDT in the younger group. The authors' findings and analyses support the proposition that the body's rate and, perhaps, process of eliminating DDT is different in children than in adults.

Abstract: Blood samples were obtained on four occasions over a 12-month period from individuals living in KwaZulu , South Africa , who had been exposed to DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) as a consequence of its use in their homes to control transmission of malaria. The longitudinal changes in serum DDT and its major metabolities, DDE and DDD, were determined. No additional risk was considered to have been presented by the increases that occurred following application of the pesticide. There were significant increases in DDT, DDE and ?DDT (DDT + its metabolites) for the age group =21 years, but for the age group 3-20 years a reduction in serum levels occurred over 12 months. Two concurrent processes probably govern the increase and decrease in serum levels, and the relative contributions of each interchange as the individual becomes older. The results suggest that children in KwaZulu experience conditions that differ from those of their parents, as well as from those that affect children in developed countries. In consequence, it is desirable that risk assessments of vector control chemicals consider all sectors of a population. ( Department of Zoology, Potchefstroom University for Christian Higher Education, South Africa .)

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B) THE DEBATE OVER DDT

1) Roberts, D. R. DDT is still needed for disease control. Pesticide Safety News. V. 5, No. 4, 1st trimester 2002. http://www.icps.it/english/bollettino/psn02/05020401.htm

Liroff, R. DDT's future under the Stockholm Convention. Pesticide Safety News. V. 5, No. 4, 1st trimester 2002. http://www.icps.it/english/bollettino/psn02/05020402.htm

PANNA summary: The closing remarks of two authors after an extended debate in this publication.

Roberts argues that DDT use should not be eliminated under the Stockholm Convention, and its additional reduction should not be a goal. Agricultural use, the main source of DDT that has built up in the environment, has already been eliminated by most nations and is banned under the Stockholm Convention. DDT levels in the environment are already falling and will continue to fall once it is banned for agricultural use worldwide. So, the much less harmful public health uses of DDT should be allowed to continue uninhibited.

Liroff summarizes findings on DDT's health and environmental impacts since Stockholm treaty negotiations began in 1998, and also indicates successes with alternatives to DDT in Latin American countries. He points out that access to DDT will not be denied outright, and that countries still using it for malaria control will be allowed to continue doing so. However, he argues that the over-arching goal should be a reduction of reliance on DDT and other pesticides for any and all uses, and so efforts should be made toward the development and implementation of less harmful and more integrated alternative approaches to malaria control.

(no abstract available)

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2) Article: Politically Incorrect U.N. July 12, 2001. Review & Outlook, The Wall Street Journal. available at: http://www.junkscience.com/july01/wsj-UN.htm

PANNA summary: The Wall Street Journal applauds the U.N for its "politically incorrect" stance in the report Making New Technologies Work for Human Development, which supports the use of DDT for malaria control (and criticizes environmental and public health groups concerned about genetically modified foods).

(no abstract available)

Full text of response: Your July 12 editorial "Politically Incorrect U.N." congratulates the U.N. for supporting use of DDT for malaria control. In so doing, the Journal is perpetuating the myth that environmentalists want DDT banned regardless of its usefulness in combating malaria. The World Wildlife Fund supports reduced reliance on DDT for malaria control primarily because of the hazards it poses to human health when it is sprayed indoors and the demonstrated success of alternative approaches. DDT contaminates food and mothers' milk. Just this week, the British medical journal The Lancet reports that DDE -- a breakdown product of DDT -- is associated with pre-term deliveries and low birth weights. Mexico and Vietnam are among the countries that have successfully controlled malaria while eliminating DDT, showing the promise of alternative methods. The World Health Organization's Roll Back Malaria program emphasizes use of bed nets treated with other chemicals. The new Stockholm Convention on Persistent Organic Pollutants (POPs) -- negotiated under U.N. auspices -- provides for DDT's continued use for malaria control, increased investments in and periodic evaluations of alternatives, and the ultimate elimination of DDT when countries are satisfied the alternatives are workable. WWF and the many other environmental and public health organizations who were observers at the treaty negotiations endorse this prudent approach. (Richard A. Liroff, Ph.D, Director, Alternatives to DDT Project, World Wildlife Fund,Washington)

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3) Roberts, D.R. DDT Risk Assessments Environmental Health Perspectives, Correspondence. Volume 109, Number 7, July 2001. p. A 302-3.

Liroff, R. DDT Risk Assessments: Response. Environmental Health Perspectives, Correspondence. Volume 109, Number 7, July 2001. p. A 302-3.

PANNA summary: Roberts contends that environmentalists bent on eliminating DDT and its subsequent ban in many countries have caused the resurgence of diseases previously controlled by DDT, as well as diverted research attention and funds from the development of insecticidal methods of disease control into research on the adverse effects of DDT. Roberts in essence blames environmentalists for “spiraling increases in disease rates” he says are preventable by DDT.

Liroff points out that the language of the Stockholm treaty, while recognizing a total elimination of DDT as an end goal, provides for the slow phase-out of the insecticide for vector control. He counters Roberts’ claims by pointing to Roberts’ own history of staunch defense of DDT and downplay of the toxicological risks. Liroff concludes that while DDT is very effective, less risky alternatives should be sought out and used.

Full text: DDT Risk Assessments

Two recent articles in EHP (1,2) and the latest Agency for Toxic Substances and Disease Registry toxicologic profile for DDT (3) make repeated references to DDT risks. These statements of risk, like so many others, are one-sided and give no consideration to colossal increases in diseases previously controlled with DDT. Behind disease statistics are grievous human tragedies, as with the case of a little girl who died of an infection that could have been prevented if her house had been sprayed with DDT. She lived in a village in the Andes and was 8 years old in 1998 when she died of bartonellosis. Bartonellosis was previously controlled through malaria housespray programs, but without DDT, the disease returned.

One-sided and narrowly focused risk assessments form the bedrock of anti-DDT advocacy (4,5), but advocacy for global elimination of DDT through United Nations Environment Programme (UNEP) treaty negotiations failed (6). Countries can continue using DDT for disease control, and DDT is not listed for global elimination. This outcome was possible only through efforts of hundreds of scientists on behalf of hundreds of millions of people at risk of illness and death from malaria (7).

Environmental activists who still want DDT eliminated and who are surprised by the lack of cost-effective alternatives should understand that global vilification of DDT eliminated almost all research on public health insecticides. Lack of research support persists and contrasts sharply with the richness of funds for research on adverse health effects of DDT; 29 major projects are presently funded by the National Institutes of Health (National Institute of Environmental Health Sciences, National Cancer Institute, National Institute of General Medical Sciences, and the National Institute of Child Health and Human Development) (3). The evidence of DDT efficacy in controlling diseases is irrefutable. In just 3 years, house spraying in Guyana reduced maternal and infant mortalities by 56% and 39%, respectively, and reduced malaria cases by 99% (8). Similar evidence from other geographic areas persuaded delegates to UNEP treaty negotiations that DDT is still needed. Yet, and in spite of all contrary evidence, the UN program to phase out DDT is unabated (9,10). The current “phase-out” program by the World Health Organization’s Roll Back Malaria initiative and the Global Environment Facility (Washington, DC) includes no publicized disease control performance standards and does not include appropriate on-site studies or tests to determine, under varying epidemiologic and environmental conditions, that DDT alternatives will provide adequate and sustained protection of rural populations.

After years of successful efforts, the modus operandi of DDT elimination remains the same: apply political and economic pressures, convince country politicians that DDT is not needed, pass laws banning its use, and let impoverished rural populations quietly suffer spiraling increases in disease rates (11,12). Even short-term commitments of funds for purchasing the more expensive and less effective DDT alternatives are a continuation of past practices: in the end, disease rates will increase. The Andean girl’s death is one of millions of preventable deaths that occurred as national and international regulations, trade barriers, international policies, and UN resolutions were applied to stop public health uses of DDT (13). With absolute certainty, the best measures of success in the anti-DDT campaign are increases in disease and death from malaria, leishmaniasis, bartonellosis, dengue fever, and dengue hemorrhagic fever. We can add to this list the renewed threat that urban yellow fever will once again ravage populations of the Americas. Even this emerging threat is linked to past failures to continue appropriate public health uses of DDT. The Andean girl’s unrecognized but precious stake in the DDT issue was her life, now lost. How many millions more must die because of hypothetical risks from minute quantities of DDT sprayed on internal house walls? (Donald R. Roberts, Uniformed Services University of the Health Sciences, Bethesda, Maryland, droberts@usuhs.mil)

Full Text: DDT Risk Assessments: Response

Donald Roberts contends that organizations such as the World Wildlife Fund (WWF) failed in efforts to eliminate DDT under the recently negotiated persistent organic pollutants (POPs) treaty. To the contrary, the WWF strongly supports the treaty’s language on DDT. Throughout the negotiations, the WWF recognized that DDT should not be banned immediately and that uncertainties about the cost and effectiveness of alternatives required flexibility in treaty language (1,2). Reflecting this, the new treaty proclaims ultimate elimination of DDT as a goal while establishing a mechanism for reducing reliance on DDT and promoting alternatives (3). As a result of the treaty, new funds are being provided by the Global Environment Facility to develop malaria control programs that reduce use of DDT.

Roberts has been an outspoken defender of DDT. He has prolifically and passionately downplayed the toxicologic risks of DDT while emphasizing its effectiveness for malaria control (4–6). He frequently argues that external political pressures drive poorer nations to abandon DDT, thereby endangering millions of the world’s most impoverished people. Malaria-endemic countries have had ample scientific justification for seeking alternatives. For example, in the mid-1990s, Mexican public health researchers expressed concern about high human exposures to DDT as a result of malaria control operations (7,8).

Mexico has since eliminated DDT while successfully combating malaria. South Africa also sought to reduce use of DDT in the mid-1990s because of concern about elevated levels in mothers’ milk (9). One species of mosquito was resistant to alternative sprays, so South Africa resumed using DDT. South Africa concluded that the hazards from malaria outweigh those associated with DDT exposure.

South Africa’s experience underscores the importance of the flexibility provided by the POPs treaty. Brazil and India offer important lessons about limits to DDT’s effectiveness. During the late 1980s and early 1990s, malaria rates in Brazil went up even as spraying of houses with DDT increased, but dropped after Brazil shifted strategies (10). With assistance from the World Bank, India is reducing its reliance on DDT. The main rural malaria vector (responsible for 65% of India’s malaria) is resistant to DDT (11). Indian researchers found elevated levels of DDT in buffalo milk, soil, water, and human blood where DDT had been sprayed to control malaria (12,13).

The ATSDR’s 2000 update of its toxicologic profile for DDT/DDE (14) reflects major concerns raised by the WWF and other environmental and public health groups during the POPs negotiations. In contrast to the previous profile published in the early 1990s, the update contains a large section, “Health Effects in Wildlife Potentially Relevant to Human Health,” reminding readers that animals are sentinels for health effects in humans. A new section captioned “Children’s Susceptibility” reiterates a central message from the U.S. National Academy of Sciences’ landmark 1993 report on pesticides in the diets of infants and children (15): children are not little adults, but may be uniquely susceptible and exposed to pesticides. The data in the toxicologic profile support the logic of the POPs treaty: DDT can be valuable for controlling malaria, but it is prudent to reduce human exposures.

Recent studies on humans, too late to be included in the toxicologic profile, further support such caution. For example, Longnecker et al. (16) found that DDE concentrations in mothers are associated with increased risk of pre-term delivery and lowered birth weight. Roberts takes EHP’s contributors to task for their “one-sided” references to DDT’s risks and their failures to account for DDT’s benefits. Roberts’ encomium to DDT is itself one-sided. Why expose humans to hazards from DDT when less risky strategies might be employed? The POPs treaty encourages development of alternatives and provides a new funding mechanism to support malaria control. (Richard A. Liroff, Alternatives to DDT Project, World Wildlife Fund, Washington, D.C., Rich.Liroff@wwfus.org)

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4) Attaran, A. and R. Maharaj. Doctoring malaria, badly: The global campaign to ban DDT. British Medical Journal. V 321, 2 December 2000.

Liroff, Rich. Commentary: Reduction and elimination of DDT should proceed slowly. British Medical Journal. V 321, 2 December 2000.

PANNA summary: Attaran and Maharaj argue that attempts to ban DDT are not only naïve, but unethical. DDT is the cheapest and the most effective method of vector control, and no other method has come close—integrated vector management is still being tested and has never been used successfully in a nation-wide program, and other insecticides are often more expensive, less effective, and run into problems of vector resistance. While DDT may be hazardous to human health, there have been no conclusive studies to that effect. The authors find the precautionary principle ridiculous in this instance—removing the best malaria-fighting chemical because it might be carcinogenic, and thereby allowing malaria to spread and take more lives hardly seems cautious. (Center for International Development, Harvard University: amir_attaran@harvard.edu, South Africa Department of Health, Communicable Disease Control)

Liroff's response addresses the fears of a medical establishment that he feels is unreasonably frightened of the Stockholm Convention. The convention does not ban DDT outright, but provides for its continued use where necessary, and eventual phase out. Liroff cites the US National Academy of Sciences and Agency for Toxic Substances and Disease Registry reports to the effect that DDT has adverse effects on the immune, endocrine, and reproductive systems, and that exposure to DDT at certain crucial stages of fetal and/or child development could lead to consequences later in life. While the global burden of malaria is a serious problem, especially on the poorest nations, some countries such as Mexico have had a great deal of success in moving to alternatives, and so it is not unreasonable to expect that a move away from DDT could not only protect human and environmental health but also improve the effectiveness of malaria control. The POPs convention needs to ensure that DDT is still available and affordable to countries that need it, and that supplies are tightly monitored so they cannot be used illegally for agriculture. (World Wildlife Fund, Alternatives to Malaria Project)

(no abstract available)

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5) Attaran, Amir. DDT saves lives. The Globe, Canada. December 5, 2000.

Watt-Cloutier, S.; R. Charlie, and J. Crump. We can all win. The Globe, Canada. December 11, 2000.

Attaran, PANNA summary: Attaran targets the Canadian government's support of the Stockholm Convention on the eve of the Johannesburg meeting in December, 2000. The environmentalists, he says, are being naïve. DDT may kill birds, but it saves people. The amount of DDT used for malaria control has little or no environmental impact compared to the amounts that were being applied for agricultural uses in Rachel Carson's day, so why make it harder and more expensive for "world's poorest, most disease-ridden countries to obtain?" Attaran says calling on the precautionary principle in this instance is tantamount to "stepping into speeding traffic as a "precaution" against tripping on a crack in the sidewalk." He scolds the Chretien government for their strong support of global elimination of DDT.

Watt-Cloutier et al, Full Text:

Amir Attaran's portrayal of Canada's position on global management of chemicals (DDT Saves Lives – Dec. 5), currently being negotiated in Johannesburg, misrepresents what is going on.

Indigenous peoples from Northern Canada here in Johannesburg are replying not only to defend Canada but also to set the record straight. We do so because Mr. Attaran's widely reported views sow mistrust between delegations from the developed and developing worlds, thus undermining the efforts of us all to achieve a global convention on 12 persistent organic pollutants (POPs), including DDT.

Mr. Attaran says: "Not only is Environment Canada arguing in the Johannesburg treaty negotiations that DDT should be eliminated once and for all, it has also proposed that the treaty not include a financial aid mechanism to help poor countries finance the alternatives. Canada is alone among wealthy countries in advocating this parsimony. Such policies literally kill."

The government of Canada has pressed for a global POPs convention as have Northern indigenous peoples who have attended all five international negotiating sessions over the last two years. Many POPs used in tropical and temperate countries end up in the Arctic, contaminating the food web and subsequently Inuit and other indigenous peoples who eat traditional food.

When used to control malaria, DDT saves the lives of thousands of people every year. While phasing out the use of DDT is an objective of the international negotiations, nobody supports a ban that puts lives at risk. When this issue surfaced in negotiations in 1999, Canadian indigenous peoples said they would refuse to be party to an agreement that threatened the health of others, notwithstanding the threat of POPs to their own health.

The view of Northern indigenous peoples is also the fundamental position of all countries participating in the negotiations and all non-governmental organizations observing the debate. Any phase-out of DDT will be conditional upon the availability of cost-effective alternatives.

Mr. Attaran's contention that Canada refuses to help finance the convention including development of alternatives to DDT is demonstrably untrue. The Minister of Finance announced $20 million in his February budget for exactly this purpose. Canada was the first nation to provide such support and is effectively advocating additional financial and technical assistance to developing countries and "economies in transition" (the old Soviet bloc).

A global POPs convention will not be finalized and ratified unless both developing and developed countries conclude that it helps them. There is no alternative to a "win-win" convention, notwithstanding Dr. Attaran's view from Harvard University. (Sheila Watt-Cloutier, President, Inuit Circumpolar Conference (Canada), Robert Charlie, Council for Yukon First Nations, and John Crump, Executive Director, Canadian Arctic Resources Committee)

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6) Roberts, D.R.; S. Manguin, and J. Mouchet. DDT house spraying and re-emerging malaria. Lancet 2000; 356: 330-332.

Smith, A. G. How toxic is DDT? Lancet, 22 July 2000. Commentary Volume 356, Number 9226.

PANNA summary: Roberts et.al. highlight the many accomplishments of DDT in malaria control over the last 55 years. A worldwide ban on DDT that would require malaria-endemic nations to reduce house spraying programs, and in turn lead to an increased malaria burden in those countries. Especially now as malaria is on the rise again and re-invading areas where it had previously been eradicated, the authors recommend that “the global response to burgeoning malaria rates should allow for DDT residual house spraying where it is known to be effective and necessary.”

In response to the Roberts, Manguin, and Mouchet article, Smith surveys studies of DDT’s effects on human health and notes that considering the great quantities of DDT that have been used and the depth that the chemical has been studied, relatively few incidences of adverse effects on humans have been found. However, “the perceived rather than the calculated risks from DDT use are an important consideration in maintaining public confidence.” For this reason, Smith advises that DDT use continue to be tightly controlled and effects closely monitored.

(no abstract available)

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7) Roberts, D.R. DDT and the global threat of reemerging malaria. Pesticide Safety News, vol. 3 no. 4, December 1999. http://www.icps.it/english/bollettino/psn99/990404.htm

Liroff, R. Balancing risks of DDT and malaria in the global POPs treaty. Pesticide Safety News, vol 4, no 2, June 2000. http://www.icps.it/English/Bollettino/Index-boll.htm

PANNA summary: Roberts argues that DDT has not been convincingly linked to public health problems, and that pressure not to use DDT for malaria control are unwarranted and irresponsible. He challenges the use of Mexico as a model for controlling malaria without DDT, saying that "only time will tell" whether the alternative approaches adopted by the country will be successful in the long run. He highlights data from several countries in South America showing a link between falling DDT use and rising incidence of malaria.

Liroff responds to Roberts' arguments with information on the current status of the international negotiations on POPs and the case for phasing out DDT. He identifies ways to strengthen malaria control programs, and h argues that the implementation of an effective integrated strategy of malaria control combined with DDT rollbacks would be a "win-win" situation.

(no abstract available)

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8) McGinn, Anne Platt. Malaria, Mosquitoes, and DDT: A toxic war against a global disease. WorldWatch. May/June 2002, pp.16., http://www.worldwatch.org/mag/2002/15-03.html

PANNA summary: A well-balanced article, interesting for its current statistics on the prevalence of malaria worldwide and comparisons with other diseases of global concern like AIDS. Briefly describes malaria—the history of the disease and its phases and symptoms. Includes comments on the Stockholm Convention and a list of the four guiding principles of WHO's Roll Back Malaria program. McGinn concludes that there is no place for DDT in modern malaria control efforts—it’s simply obsolete, and half a century of experience has shown that there is little justification for its continued use.

(no abstract available)

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9) Gladwell, Malcolm. The Mosquito Killer: Millions of people owe their lives to Fred Soper - Why isn’t he a hero? The New Yorker: Annals of Public Health. July 2, 2001. pp. 42-51.

PANNA summary: A rich historical piece that brings a unique perspective to the present debates, this article traces the history of DDT’s use for malaria control, with special attention to Fred Soper. Soper worked for the Rockefeller Foundation in the days before the WHO and UN. “With DDT as his weapon, Soper almost saved the world from one of its most lethal afflictions. Had he succeeded, we would not today be writing DDT’s obituary. We would view it in the same heroic light as penicillin and the polio vaccine.” Gladwell traces the history of Soper’s and DDT’s successes and failures, from the discovery of DDT’s miraculous insecticidal capability in the early forties, through the rise and fall of the global malaria eradication campaign of the sixties, which Soper led, to the post-Silent Spring environmentalists’ movement to limit and ban use of DDT.

(no abstract available)

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10) Attaran, A. In praise of DDT. Pesticide Outlook. June 2001; p. 83.

PANNA summary: The author "argues the case for the retention of DDT in the battle against malaria as the POPs Convention reaches the signing stage." He points to incidences in Africa and Asia where malaria was almost completely under control until the country started phasing out DDT, at which time there were huge rebounds in the numbers of malaria cases. It is, in his eyes, a case of pitting speculative though unproven health risks of DDT as a toxin against the definite health risks of malaria if DDT, the cheapest and still most effective solution, is not used.

(no abstract available)

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11) Attaran, A.; D.R. Roberts, C.F. Curtis, and W.L. Kilama. Balancing risks on the backs of the poor. Nature Medicine 2000 Jul; 6(7): 729-31. http://www.malaria.org/attarannaturemed.html

PANNA summary: Attaran, Roberts, et al are quite forceful in presenting their case as to why the Stockholm Convention and "First World Environmentalists" should not continue with their campaign to "reduce and/or eliminate" the use of DDT for malaria control. They argue that studies of the harmful effects of DDT on humans and the environment either are inconclusive, haven't been replicated, or were due to large scale agricultural use of DDT in the past, while DDT's effectiveness as a tool for malaria control is undeniable and backed by decades of experience. Environmentalists in industrialized countries have the luxury of placing environmental concerns above poverty alleviation, while developing countries do not have the same luxury. Malaria is one of the major factors keeping underdeveloped nations in poverty, and environmentalists' attempts to take DDT, the most powerful and effective weapon in the arsenal, away from those nations for their own environmental concerns amounts to eco-imperialism.

Abstract: Malaria kills over one million people, mainly children, in the tropics each year, and DDT remains one of the few affordable, effective tools against the mosquitoes that transmit the disease. Attaran et al. explain that the scientific literature on the need to withdraw DDT is unpersuasive, and the benefits of DDT in saving lives from malaria are well worth the risks. (Center for International Development, Kennedy School of Government, Harvard University, Cambridge, Massachussetts 02138, USA amir_attaran@harvard.edu)

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12) Raloff, Janet. The case for DDT: What do you do when a dreaded an environmental pollutant saves lives? Science News, Vol. 158, No. 1, July 1, 2000, p. 12. http://www.sciencenews.org/20000701/bob8.asp

PANNA summary: Raloff summarizes recent findings and arguments around the push to ban DDT, citing Roberts and Liroff, among others. She finds that arguments for continued use of DDT are very strong—although our eventual goal should be elimination, it would be disastrous to abandon DDT prematurely, and it should be brought back in areas where its decreased use has caused malaria infection rates to surge, especially in Latin America. It would, however, be unwise to rely on only one tool, and so many scientists advocate increased research into the development of new methods as well.

(no abstract available)

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13) Curtis, C.F. and J.D. Lines. Should DDT be banned by international treaty? Parasitology Today 2000 Mar; 16(3): 119-21.

Abstract: The insecticide DDT has been an effective and affordable means of malaria control in many countries, but pressure for its use to be banned is mounting. Here, Chris Curtis and Jo Lines take a critical look at evidence that links house spraying by DDT with harm to the environment and human health, and stress the need for resources for alternatives to DDT to be made available to countries that would be affected by a DDT ban. (London School of Hygiene and Tropical Medicine, Keppel Street, London, UK WC1E 7HT. chris.curtis@lshtm.ac.uk)

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14) Roberts, D., C. Curtis, R. Tren, et al. Malaria Control and Public Health . Emerging Infectious Diseases [letter]. 2004; 10(6): 1170-1.

Response: Chen, A., and W. J. Rogan. Malaria Control and Public Health . Emerging Infectious Diseases. 2004; 10(6): 1172.

Available Online at:

http://www.cdc.gov/ncidod/EID/vol10no6/03-0787_03-1116.htm

PANNA Summary: Roberts et al. refute the arguments Chen and Rogan made in their article �Nonmalarial infant death and DDT use for malaria control,� published in 2003. Roberts et al. claim that Chen and Rogan's conclusions require �substantial evidence of a causal relationship between DDT and adverse consequences of DDT [indoor residue spraying] for malaria control,� and that no adverse effects on maternal health or infant survival are attributable to DDT. They assert that DDT spraying is still the cheapest, most effective malaria control method. (Department of Preventive Medicine and Biometrics, Uniformed Services University of the Health Sciences, Bethesda , Maryland ; droberts@usuhs.mil.)

In response, Chen and Rogan admit that causality has not been demonstrated between DDT and shortened lactation or preterm birth, but claim �the evidence is sufficiently strong that the possibility of causality cannot be dismissed.� They insist that we should proceed with caution regarding the use of DDT because its safety has not been �demonstrated absolutely.� (Epidemiology Branch, National Institute of Environmental Health Sciences ( niehs ), Research Triangle Park , North Carolina ; rogan@niehs.nih.gov .)

(no abstracts available)

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C) MALARIA CONTROL: ASIA

1) Henley, David. Malaria past and present: The case of North Sulawesi, Indonesia. Southeast Asian Journal of Tropical Medicine and Public Health. Sept 2001, vol. 32, no. 3, p. 595-607.

PANNA summary: According to the author, the most likely source of the long-term decline of malaria in North Sulawesi is large-scale conversion of forest to permanent farmland. DDT was being sprayed until the last of the national stock was used up in 1993 after a ban that started in 1990, then other more expensive chemicals were used until about 1997. During that period, malaria rates went down steadily. But in 1997 with the economic downturn in Asia, the government of Indonesia cut back spending on malaria control significantly and since then, malaria has made a small though significant resurgence. The author concludes that it is unlikely for environmental management, bed nets, or anti-malaria medication to be as effective as insecticide spraying in controlling malaria in North Sulawesi.

Abstract: The incidence and impact of malaria in North Sulawesi have declined both in the short term during the 1990s, and over a much longer timespan (though perhaps less continuously) since the end of the colonial period. The improvement already seems to have been well underway before deliberate vector control activities became extensive in the second half of the 1970s, and environmental changes affecting the Anopheles mosquito fauna, in particular the replacement of primary and secondary forest by permanent farmland, are probably the principal reasons for the long-term trend; other possible factors include the increasing use of antimalarial drugs. The well-documented decline in malaria incidence over the years 1991-1997, nevertheless, probably reflects the unprecedented scale of residual insecticide spraying in the province during that period, while the slight resurgence of the disease in the last three years corresponds to the subsequent cessation of house spraying as a result of the current economic crisis. Despite the evident importance of environmental change as a factor ameliorating the malaria situation in the long term, experience from the colonial era suggests that the prospects for deliberate environmental management (species sanitation) as an alternative malaria control strategy are poor. (Royal Institute for Linguistics and Anthropology (KITLV), Leiden, The Netherlands. henley@kitlv.nl)

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2) Barcus, Mazie J., F. Laihad, M. Sururi, P. Sismadi, H. Marwoto, M. J. Bangs, and J. K. Baird. Epidemic malaria in the Menoreh Hills of central Java. American Journal of Tropical Medicine and Hygiene. 60(3). 2002 pp. 281-292.

PANNA summary: DDT spraying and the introduction of chloroquine medication for malaria starting in the 1950s virtually eradicated endemic malaria from the island of Java. DDT spraying was abandoned by the Republic of Indonesia in the late 1980s and stocks were depleted by the early 1990s. Spraying of less effective and more expensive pesticides continued through the early 1990s. This study shows that the sharp decline in government spending on malaria control since the economic downturn of the late 1990s, especially the curtailment of indoor spraying, has lead to a real epidemic of malaria in the hills of central Java. The authors call for a revival of residual indoor spraying programs as the only proven effective solution to the outbreak.

Abstract: After more than 50 years of effective management, resurgent malaria threatens residents in the Menoreh Hills and the foothills of the Dieng Plateau of Central Java, Indonesia. The Dieng Plateau dominates the highland center of Central Java. The steep Menoreh Hills, surrounded by rice paddy habitats, cover approximately 500 km2 with no peaks greater than 1,000 m. We studied epidemic malaria in Purworejo district, one of the three districts containing the Menoreh Hills. Between 1986 and 1995, the annual parasite incidence (API) in Purworejo ranged from 2 to 11 cases per 1,000 residents per year and was typically approximately 5 per 1,000. In 2000 the API was 44.5. This sharp increase was confined to subdistricts in and around the Menoreh Hills and Dieng Plateau foothills. The primary vectors of malaria, those favoring steep, forested hillsides on Java, were Anopheles maculatus and Anopheles balabacensis. Deterioration of vector control activity, followed by a severe economic downturn in 1997, may explain the epidemic. Malaria in the Menoreh Hills and lower Dieng Plateau threatens surrounding areas of rice paddy inhabited by Anopheles aconitus as well as a nearby coastal habitat where the even more efficient vector Anopheles sundaicus occurs in abundance. Most of the 130 million people living on Java never experienced the hyper- and holoendemic malaria that occurred throughout most of the island before the effective DDT spraying and chloroquine treatment campaigns of the 1950s. Reintroduced endemic malaria threatens the island of Java. (U.S. Naval Medical Research Unit # 2, Jakarta, Indonesia)

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3) Sharma, V.P. Current scenario of malaria in India. Parassitologia 41: 349-53, 1999.

PANNA summary: The author reviews statistics of malaria incidence and control in India. DDT is the insecticide most widely used for malaria control, followed by HCH, malathion, and synthetic pyrethroids, and they are all used for residual indoor spraying in rural areas and anti-larva operations in urban areas. The major vector species has become resistant to DDT and HCH in most of the country. At the same time, malaria rates are increasing in many parts of the country because of man-made environmental changes like irrigation projects and piped-in water supplies—anywhere rapid development is happening, malaria is invading. Indian national and state governments continue to pour resources and energy into the problem, with help from the World Bank.

Abstract: The Indian National Malaria Eradication Programme (NMEP) is reporting 2.5 to 3 million malaria cases, and about 1,000 malaria deaths annually. Malaria in the northeastern states is stable and in the peninsular India unstable. There are six major and three minor malaria vectors, of which Anopheles culicifacies transmits malaria in rural areas and An. stephensi in the towns. Other vectors are of local importance. Plasmodium vivax is the dominant infection and accounts for 60-65% cases whereas P. falciparum contributes 30-35% cases. Field operations to control malaria are impeded by resistance and/or exophilic vector behavior, parasite resistance to antimalarial drugs, operational problems in spraying, failure to search breeding of mosquitoes at weekly intervals, staff shortages and financial constraints. Resurgent malaria invaded new ecotypes created by green revolution, industrial growth and urban development resulting in paradigm shift towards man-made malaria. NMEP has launched a world bank-assisted enhanced malaria control project with primary emphasis to protect 62.2 million high risk population in 7 states. (Malaria Research Centre, Delhi, India. vps@icmrmrc.ren.nic.in)

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4) Agarwal, Ravi. No Future in DDT: A case study of India. Pesticide Safety News, May 2001.

PANNA summary: India is an important case study to understand that DDT is becoming obsolete, not only owing to concerns over its toxicity, but also because it is losing its effectiveness in treating malaria. India has been manufacturing and using DDT for more than 50 years. Use for agriculture was banned in 1989, and use for malaria has been declining in favor of more multi-sector approaches to the problem, since unsafe levels of DDT are turning up in food supplies and the egg shells of large predatory birds, and its effectiveness is waning anyway. India currently spends 35% of its health budget on malaria control each year. The current strategy is based on prioritizing control in high-risk areas, reducing the use of chemical insecticides, and the prevention and control of epidemics through community participation, the use of bed nets, and early diagnosis and treatment. The use of DDT in urban areas has halted completely.

(no abstract available)

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5) Sharma, V.P. Environmental management in malaria control in India. In Malaria: waiting for the vaccine. Targett, GAT. Ed. England: John Wiley & Sons Ltd, 1991.

PANNA summary: Malaria fell sharply in India during the malaria eradiation campaign of the 1960s due to DDT spraying, the success of which overshadowed the small successes of other methods. However, malaria resurged following the close out of the eradication program, peaking in 1976. A new government control campaign initiated in 1977 brought the numbers back down, but there has been a plateau since the early 1980s. The effectiveness of residual pesticide spraying was waning. For this reason, environmental management as part of an integrated control strategy has become necessary, and India began to implement it in the 1980s. The scheme includes breeding control by environmental manipulation (filling in small stagnant water holes and creating channels for water to run off) and biological means (introducing larval predators to breeding sites), both of which have been quite effective. Environmental management as a control strategy requires a great deal of scientific understanding and attention, and is not cost effective in sparsely populated areas, but has few of the negative side effects of insecticides.

(no abstract available)

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6) Kidson, C. and K. Indaratna. Ecology, economics, and political will: The vicissitudes of malaria strategies in Asia. Parassitologia 40: 39-46, 1998.

PANNA summary: Though malaria is currently more prevalent in Africa than Asia, Asia is the epicenter of the multi-drug resistant strain of malaria, P. falciparum, that is currently overtaking much of the tropical world. This is probably due to the huge changes in economics, social and natural environments, and the huge migrations of people that have taken place on the continent over the past few decades. Some nations have come close to complete malaria control, such as China, Thailand, and Malaysia, but fail near national borders, especially those that are forested, as this is where the movement of people in search of economic opportunities has lead to weakness in control. In light of the enormous economic influences on and impacts of malaria, the author asks nations not to keep malaria in the public health sector, but bring its control into the realm of economic planning as well.

Abstract: The documented history of malaria in parts of Asia goes back more than 2,000 years, during which the disease has been a major player on the socioeconomic stage in many nation states as they waxed and waned in power and prosperity. On a much shorter time scale, the last half century has seen in microcosm a history of large fluctuations in endemicity and impact of malaria across the spectrum of rice fields and rain forests, mountains and plains that reflect the vast ecological diversity inhabited by this majority aggregation of mankind. That period has seen some of the most dramatic changes in social and economic structure, in population size, density and mobility, and in political structure in history: all have played a part in the changing face of malaria in this extensive region of the world. While the majority of global malaria cases currently reside in Africa, greater numbers inhabited Asia earlier this century before malaria programs savored significant success, and now Asia harbors a global threat in the form of the epicenter of multidrug resistant Plasmodium falciparum which is gradually encompassing the tropical world. The latter reflects directly the vicissitudes of economic change over recent decades, particularly the mobility of populations in search of commerce, trade and personal fortunes, or caught in the misfortunes of physical conflicts. The period from the 1950s to the 1990s has witnessed near "eradication" followed by resurgence of malaria in Sri Lanka, control and resurgence in India, the influence of war and postwar instability on drug resistance in Cambodia, increase in severe and cerebral malaria in Myanmar during prolonged political turmoil, the essential disappearance of the disease from all but forested border areas of Thailand where it remains for the moment intractable, the basic elimination of vivax malaria from many provinces of central China. Both positive and negative experiences have lessons to teach in the debate between eradication and control as alternative strategies. China has for years held high the goal of "basic elimination", eradication by another name, in sensible semi-defiance of WHO dictates. The Chinese experience makes it clear that, given community organization, exhaustive attention to case detection, management and focus elimination, plus the political will at all levels of society, it is possible both to eliminate malaria from large areas of an expansive nation and to implement surveillance necessary to maintain something approaching eradication status in those areas. But China has not succeeded in the international border regions of the tropical south where unfettered population movement confounds the program. Thailand, Malaysia and to an extent Vietnam have also reached essential elimination in their rice field plains by vigorous vertical programs but fall short at their forested borders. Economics is central to the history of the rise and fall of nations, and to the history of disease in the people who constitute nations. The current love affair with free market economics as the main driving force for advance of national wealth puts severe limitations on the essential involvement of communities in malaria management. The task of malaria control or elimination needs to be clearly related to the basic macroeconomic process that preoccupies governments, not cloistered away in the health sector Historically malaria has had a severe, measurable, negative impact on the productivity of nations. Economic models need rehoning with political aplomb and integrating with technical and demographic strategies. Recent decades in Chinese malaria history carry some lessons that may be relevant in this context. (Centre for Health Economics, Faculty of Economics, Chulalongkorn University, Bangkok, Thailand)

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7) Panvisavas, S., S. Dendoung, and N. Dendoung. Social and cultural aspects of malaria. Southeast Asian Journal of Tropical Medicine and Public Health. Dec 2001, vol. 32, no. 4. 727-732.

PANNA summary: Malaria eradication programs in the 1950's failed to remove the disease from rural Thailand, and so the authors want to advise WHO's current "Roll Back Malaria" campaign that only an integrated socio-cultural approach to malaria control in this area will be effective. The real causes of malaria persistence in rural areas, they contend, are poverty and discrimination. The political situation in Southeast Asia has led to a concentration of poor people--indigenous people turned wage laborers, poor farmers, refugees from neighboring countries, and soldiers--on the borders in the forests where malaria has the most potential to spread and health care is the least developed. Traditional systems of knowledge about malaria and its prevention are discredited and ignored. Only an approach that respects traditional knowledge and aims to alleviate poverty and involve communities will be effective.

Abstract: This paper examines the impact of social and cultural factors on malaria control in rural Thailand. It contends that standard vertical malaria control programs tend to ignore local workplace and living conditions instead of recruiting traditional practices into the planning scenario for more effective control. Careful attention to these practices in the context of local economic capacity can serve to offset the common failure to take the major causative factor of poverty into account. (Faculty of Social Sciences and Humanities, Mahidol University at Salaya, Nakhon Pathom, Thailand)

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8) Kamolratanakul, P., P. Butraporn, M. Prasitisuk, C. Prasittisuk, and K. Indaratna. Cost-effectiveness and sustainability of lambdacyhalothrin-treated mosquito nets in comparison to DDT spraying for malaria control in western Thailand. American Journal of Tropical Medicine and Hygiene 2001, 65(4), 279-84.

PANNA summary: In a highly endemic region along the forested border between Thailand and Myanmar, the researchers conducted a relatively small-scale (~2300 people) comparative study of the cost-effectiveness of insecticide-treated bed nets and residual indoor spraying of DDT. Calculated on a "per case of malaria prevented" basis, they found that the treated bed nets were more cost-effective than DDT spraying. As DDT spraying is not particularly popular or practical in this region anyway, they recommend that pyrethroid-treated bed nets be used in this region, and considered for other regions in the future.

Abstract: The cost-effectiveness of lambdacyhalothrin-treated nets in comparison with conventional DDT spraying for malaria control among migrant populations was evaluated in a malaria hyperendemic area along the Thai-Myanmar border. Ten hamlets of 243 houses with 948 inhabitants were given only treated nets. Twelve hamlets of 294 houses and 1,315 population were in the DDT area, and another 6 hamlets with 171 houses and 695 inhabitants were in the non-DDT-treated area. The impregnated net program was most cost-effective (US$1.54 per 1 case of prevented malaria). Spraying with DDT was more cost-effective than malaria surveillance alone ($1.87 versus $2.50 per 1 case of prevented malaria). These data suggest that personal protection measures with insecticide-impregnated mosquito net are justified in their use to control malaria in highly malaria-endemic areas in western Thailand. (Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand)

9) H.N. Saiyed, V.K. Bhatnagar, Rekha Kashyap. Impact of pesticide use in India. Asian Pacific Newsletter. http://www.occuphealth.fi/e/info/asian/ap399/india05.htm

PANNA summary: A brief article on the health effects of pesticide production and use in India, both on people working with those pesticides and on the general population.

(no abstract available)

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10) Bhatia, M.R., J. Fox-Rushby, and A. Mills. Cost-Effectiveness of Malaria Control Interventions When Malaria Mortality is Low: Insecticide-Treated Nets Versus In-House Residual Spraying in India . Social Science and Medicine. 2004; 59(2004): 525-39.

Available Online at: http://www.sciencedirect.com/

PANNA Summary: In India , a low malaria mortality region, both insecticide-treated nets and in-house residual spraying are effective in preventing malaria. Nets are more effective and more efficient than residual spraying, although nets cost more. Additionally, the amount of insecticide used for treated nets was much less than that used for spraying. Although unlikely, residual spraying may become more cost-effective than treated nets under certain circumstances.

Abstract: Malaria is one of the leading causes of morbidity and mortality in the developing world and a major public health problem in India . Disillusioned by in-house residual spraying (IRS), and increasingly aware that insecticide-treated nets (ITNs) have proved to be effective in reducing malaria mortality and morbidity in various epidemiological settings, policy-makers in India are keen to identify which is the more cost-effective malaria control intervention. A community randomized controlled trial was set up in Surat to compare the effectiveness and efficiency of IRS and ITNs. Both control strategies were shown to be effective in preventing malaria over the base-case scenario of early diagnosis and prompt treatment. The mean costs per case averted for ITNs was statistically lower (Rs. 1848, 1567-2209; US$ 52) than IRS (Rs. 3121, 2386-4177, US$ 87). The conclusions were robust to changes in assumptions. This study expands the scope of recent comparative economic evaluations of ITNs and IRS, since it was carried out in a low mortality malaria endemic area. (Department of Social Policy, London School of Economics , Houghton Street , London WC2A 2AE , UK .)

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D) MALARIA CONTROL: AFRICA

1) Bouwman, Henk. Malaria control and the paradox of DDT. Africa--Environment and Wildlife. vol. 8, no. 4, May 2000. http://www.icps.it/english/bollettino/psn00/000303.htm

PANNA summary: A balanced look at the helpful-harmful paradox of DDT use against malaria in Africa. The author's pointers for future use of insecticides against malaria are especially interesting, as they include environmental monitoring and investigation of alternatives to spraying in houses where women's and children's exposure can be greatest.

(no abstract available)

2) Cox, J.S.H., J. Mouchet, and D.J. Bradley. Determinants of malaria in Africa. In Contextual Determinants of Malaria, and also presented at an International Workshop, Lausanne, Switzerland, May 14-18, 2000.

PANNA summary: Malaria is more endemic in Sub-Saharan Africa than anywhere else in the world. There is nonetheless some variation that can be helpful to understand for predicting outbreaks. In some areas, the spread of malaria varies because of factors like rainfall, altitude, and latitude. This malaria is unstable and highly susceptible to small environmental variation. In other areas, malaria is highly endemic and stable and so the effects of environmental and social changes are less pronounced.

(no abstract available)

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3) Fontenille, D and L Lochouarn. The complexity of the malaria vectorial system in Africa. Parassitologia 41: 267-271, 1999.

PANNA summary: There are as many as five different mosquito species that transmit malaria in Africa; sometimes more than one species will transmit the disease in one place at one time, and sometimes different species will transmit the disease in the same place, but at different times of year. The authors stress that vector control strategies should take the diversity of the vectors into account and plan accordingly, as the control of one or two of the vector species will not be as effective as the control of all five.

Abstract: The malaria vectorial system in Africa is very complex. Five very efficient vector species transmit malaria: Anopheles gambiae, An. arabiensis, An. funestus, and the sometimes overlooked An. nili and An. moucheti. This paper focuses on morphological, behavioural and genetic differences observed among populations within each vector species. It emphasizes that future strategies for controlling vectors should take into account this heterogeneity.

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4) Goodman, C.A., P.G. Coleman, and A.J. Mills. Cost-effectiveness of malaria control in sub-Saharan Africa. The Lancet 354: July 31, 1999, 378-85.

PANNA summary: In an attempt to inform WHO's Roll Back Malaria campaign, the authors used mathematical models to calculate the costs of various malaria control strategies in a very low income sub-Saharan African country, like residual insecticide spraying and the use of insecticide-treated bed nets, drugs like chloroquine given during pregnancy and during early childhood, and making improvements upon current malaria treatments. The costs were calculated per disability-adjusted life year, and ranged from $4-10. While this is relatively affordable when compared with health interventions aimed at other health problems, the authors point out that governments of the poorest nations will not be able to supply this money to their most impoverished populations without help from the international community.

Abstract: Antimalarial chemoprophylaxis during pregnancy significantly increases the birth weight of babies born to primigravidae, but coverage in sub-Saharan Africa is very limited. This analysis assessed whether increasing coverage is justified on cost-effectiveness grounds. A standardized modeling framework was used to estimate ranges for the cost per discounted year of life lost averted by weekly chloroquine chemoprophylaxis and intermittent sulfadoxine-pyrimethamine (SP) treatment for primigravidae in an operational setting with moderate to high malaria transmission. The SP regimen was found to be more cost-effective than the chloroquine regimen, because of both lower costs and higher compliance. Both regimens appear to be a good value for money in comparison with other methods of malaria control and based on rough cost-effectiveness guidelines for low-income countries, even with high levels of drug resistance. However, extending the SP regimen to all gravidae and increasing the number of doses per pregnancy could make the intervention significantly less cost-effective. (Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, United Kingdom. catherine.goodman@lshtm.ac.uk)

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5) Greenwood, B. Malaria mortality and morbidity in Africa. Bulletin of the World Health Organization.1999, 77(8), 617-8.

PANNA summary: The author argues that though it is difficult to obtain accurate information on malaria mortality and morbidity in Africa, this information is crucially important for the national Ministries of Health, who must prioritize their spending and need to know how big a threat the various diseases of the region really are. Malaria is only one of the major killers of African children--in various regions, diseases like measles and pneumonia can claim as many lives as malaria. What's more, the symptoms of some of these diseases appear similar to those of malaria, and in such poor areas many of the cases are never admitted to hospitals for treatment, so accurate data is hard to come by.

(editorial, no abstract available)

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6) Toure, YT. The malaria challenge in the 21st century: Perspectives for Africa. Parassitologia 41: 507-9. 1999.

PANNA summary: The author pinpoints the main causes for the failure of malaria control campaigns in Africa in the past: resistance to drugs on the part of the parasites and to insecticides on the part of the vectors, inadequate health infrastructure, and lack of trained health professionals and scientists. The main goals for the 21st century are the same as they have always been, to reduce morbidity and mortality due to malaria, and to reduce malaria transmission. The problem is not necessarily in the research, but in the implementation—the best strategies are often underutilized and applied inefficiently. It has become clear that malaria is irrevocably connected to rural poverty, and the author makes the powerful statement that: “Provision of basic health care centers, schools, and safe water supplies to the rural areas may contribute much more to malaria (…) control than most of the activities which have been undertaken up to the present time.”

Abstract: Malaria control has had little success in Africa despite the achievements in malaria research. It is time to put more emphasis on sustainable control measures through local commitment to diagnose and treat malaria in order to prevent illness and death. This goal can be best achieved through basic health care centers, schools and safe water supplies to rural areas. Complementary actions through research and international support will be strongly needed. (Departement d'Epidemiologie des Affections Parasitaires, Ecole Nationale de Medecine, de Pharmacie et d'Odonto-Stomatologie, Bamako, Mali. yeya@mrtcbko.malinet.ml)

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7) Teklehaimanot, A, and A Bosman. Opportunities, problems and perspectives for malaria control in sub-Saharan Africa. Parassitologia 41: 335-8, 1999.

PANNA summary: This article focuses on the malaria problem in sub-Saharan Africa: the factors that have contributed to it over the years, current efforts to control malaria, and warnings for the future of those efforts. Malaria has persisted in the region because of environmental conditions conducive to the spread of malaria and widespread poverty. While the current growth of new programs with an interest in controlling malaria is heartening, the author warns that when control efforts have been interrupted in the past, resilient malaria has always come back with devastating consequences. Effective malaria control in sub-Saharan Africa can only come in the form of long-term, sustained action that is firmly rooted in the social development of the country.

Abstract: Environments conducive to high malaria transmission and widespread poverty are at the roots of the 'malaria giant', which affects 46 countries in Africa. The recent interest in and momentum of work on malaria, in endemic countries and the international community, is unprecedented and opens new perspectives for controlling the disease. Significant steps included: (i) the allocation of US$20 million by WHO for accelerated implementation of malaria control in 34 African countries in 1997-98; (ii) the Declaration on Malaria by the Heads of States of the Organization of African Unity and the establishment of the African Initiative for Malaria Control in 1997; (iii) the concomitant mobilisation of the research community in the Multilateral Initiative on Malaria; (iv) the G8 Summit in 1998 in Birmingham asking for higher commitment to malaria control, particularly in Africa; and (v) the Roll Back Malaria initiative set as a WHO priority project in 1998. However, experiences have proved the alarming 'resilience' of the malaria system in Africa, showing devastating consequences when malaria returns to the original levels after intensive control is interrupted. Effective malaria control in Africa requires long-term action, firmly rooted in the social development of the country. (World Health Organization, Communicable Diseases Prevention and Control, Geneva, Switzerland)

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8) Lindsay, S.W., and W.J.M. Martens. Malaria in the African highlands: Past, present, and future. Bulletin of the World Health Organization. 1998, 76, pp. 33-45.

PANNA summary: There has been a steady rise in malaria in the African highlands over the past fifty years due to environmental changes and deteriorating health care. The highlands were once considered a safe haven from diseases that have always been widespread in the plains, but no longer. Because highland populations don’t have the natural resistance to malaria that plains people have developed over generations, epidemics in these regions can hit particularly hard. This study maps out the most epidemic-prone regions and projects their spread with global warming. The author recommends that special attention be paid to preventing malaria epidemics in the highland regions.

Abstract: Many of the first European settlers in Africa sought refuge from the heat and diseases of the plains by moving to the cool and salubrious highlands. Although many of the highlands were originally malaria free, there has been a progressive rise in the incidence of the disease over the last 50 years, largely as a consequence of agroforestry development, and it has been exacerbated by scarce health resources. In these areas of fringe transmission where the malaria pattern is unstable, epidemics may be precipitated by relatively subtle climatic changes. Since there is little immunity against the disease in these communities, outbreaks can be devastating, resulting in a substantial increase in morbidity and death among both children and adults. We present here the results obtained using a mathematical model designed to identify these epidemic-prone regions in the African highlands and the differences expected to occur as a result of projected global climate change. These highlands should be recognized as an area of special concern. We further recommend that a regional modeling approach should be adopted to assess the extent and severity of this problem and help improve disease surveillance and the quality of health care delivered in this unstable ecosystem. (Department of Biological Sciences, University of Durham, England)

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9) Killeen, Gerry F., U. Fillinger, and B. G. J. Knols. Advantages of larval control for African malaria vectors: Low mobility and behavioral responsiveness of immature mosquito stages allow high effective coverage. Malaria Journal June 21, 2002, 1:8.

PANNA summary: This study starts with the hypothesis that targeting adult mosquitoes with strategies like pyrethrin-treated bed nets and indoor residual spraying is less effective because adult mosquitoes avoid those kinds of obstacles. In the egg and larval stages of development, mosquitoes are confined to a marine habitat and are much less mobile, so absolute coverage is more viable. The authors encourage African nations where malaria is endemic to make larval control a high priority, since the mosquito species that cause most malaria in Africa breed near human settlements and so should be easy to find and control in the larval stages.

Abstract:
BACKGROUND: Based on sensitivity analysis of the MacDonald-Ross model, it has long been argued that the best way to reduce malaria transmission is to target adult female mosquitoes with insecticides that can reduce the longevity and human-feeding frequency of vectors. However, these analyses have ignored a fundamental biological difference between mosquito adults and the immature stages that precede them: adults are highly mobile flying insects that can readily detect and avoid many intervention measures whereas mosquito eggs, larvae and pupae are confined within relatively small aquatic habitats and cannot readily escape control measures.

PRESENTATION OF THE HYPOTHESIS: We hypothesize that the control of adult but not immature mosquitoes is compromised by their ability to avoid interventions such as excito-repellant insecticides.

TESTING THE HYPOTHESIS: We apply a simple model of intervention avoidance by mosquitoes and demonstrate that this can substantially reduce effective coverage, in terms of the proportion of the vector population that is covered, and overall impact on malaria transmission. We review historical evidence that larval control of African malaria vectors can be effective and conclude that the only limitations to the effective coverage of larval control are practical rather than fundamental.

IMPLICATIONS OF THE HYPOTHESIS: Larval control strategies against the vectors of malaria in sub-Saharan Africa could be highly effective, complementary to adult control interventions, and should be prioritized for further development, evaluation and implementation as an integral part of Rolling Back Malaria. (Department of Tropical Medicine, School of Public Health and Tropical Medicine,Tulane University Health Sciences Centre, 1430 Tulane Avenue, New Orleans, Louisiana 70112, USA, gerrykilleen@hotmail.com)

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10) Guyatt, H.L.; S.A. Ochola, and R.W. Snow. Too poor to pay: Charging for insecticide-treated bednets in highland Kenya. Tropical Medicine and International Health: v 7, no 10, pp 846-850. October 2002.

PANNA summary: The authors conducted surveys in areas of rural highland Kenya where Medical Emergency Relief International (MERLIN) initiated the provision of insecticide treated bed nets in 1999. Survey respondents included homes with nets provided by the MERLIN program and those without. They were asked how much they would pay for a bed net and if they didn't have one, why not. The results showed that while the vast majority of households are willing to pay for a bed net, most can not afford to pay the full cost or even a subsidized price. The authors conclude that bed nets should be provided free of charge during WHO's initiative to increase bed nets in homes in order to eliminate the bias toward wealthier families.

Abstract: WHO has proposed malaria control as a means to alleviate poverty. One of its targets includes a 30-fold increase in insecticide-treated nets (ITNs) in the next 5 years. How this service will be financed remains unclear. In July 2000, 390 homesteads in rural highland Kenya were interviewed on their willingness to pay for ITNs. The costs to a household of protecting themselves with ITNs were compared with current household expenditure. Homesteads expressed a willingness to pay for ITNs, but the amounts offered were not sufficient to cover the costs of providing this service without donor support to meet the difference. Furthermore, as most household expenditure was allocated to basic needs these interventions were 'unaffordable'. The cost of protecting a household with ITNs would be equivalent to sending three children to primary school for a year. The aspiration by poor rural homesteads to protect themselves with ITNs is not compatible with their ability to pay. One option to have an immediate equitable impact on ITN coverage and break the cycle between malaria and poverty is to provide this service free of charge. (Wellcome Trust Research Laboratories/KEMRI, Nairobi, Kenya, hguyatt@wtnairobi.mimcom.net)

11) Guyatt, H.L., J. Kinnear, M. Buruni, and R.W. Snow. A comparative cost analysis of insecticide-treated nets and indoor residual spraying in highland Kenya. Health Policy and Planning 2002; 17(2): 144-153.

PANNA summary: Indoor residual spraying is more cost-effective than insecticide-treated nets in the highlands of Kenya. This conclusion was reached through a cost analysis for both methods, in terms of cash expenditures and also in broader economic terms including the opportunity costs of using staff for these purposes and capital costs.

Abstract: The relative cost of indoor residual house-spraying (IRS) versus insecticide-treated bednets (ITNs) forms part of decisions regarding selective malaria prevention. This paper presents a cost comparison of these two approaches as recently implemented by Merlin, a UK emergency relief organization funded through international donor support and working in the highland districts of Gucha and Kisii in Kenya. The financial costs (cash expenditures) and the economic costs (including the opportunity costs of using existing staff and volunteers, and an annualized cost for capital items) were assessed. The financial cost for IRS was US$0.86 per person protected, compared with $4.21 for ITNs (reducing to $3.42 to the provider assuming cost recovery). The economic cost per person protected for IRS was $0.88, compared with $2.34 for ITNs. The costs for ITNs were sensitive to the number of nets sold per community group ('efficiency'), as the delivery costs constituted upwards of 40% of the total cost. However, even marked increases in efficiency of these groups could not reduce the costs of ITNs to that comparable with IRS, except if more than one cycle of IRS was needed. The implications of predicted reductions in the cost of insecticide for both IRS and ITNs are also explored. The provision of itemized cost data allows predictions to be made on changes in the design of these programmes. Under almost all design scenarios, IRS would appear to be a more cost-efficient means of vector control in the Kenyan highlands. (Kenya Medical Research Institute/Wellcome Trust Collaborative Programme, Nairobi, Kenya, Centre for Tropical Medicine, University of Oxford, Oxford, UK, Hguyatt@wtnairobi.mimcom.net)

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12) Guyatt, H.L., S.K. Corlet, T.P. Robinson, S.A. Ochola, and R.W. Snow. Malaria prevention in highland Kenya: Indoor residual house-spraying vs. insecticide-treated bednets. Tropical Medicine and International Health. April 2002. vol. 7 no. 4: pp. 298-303.

PANNA summary: This study finds that indoor residual spraying (IRS) is both more effective and less expensive than insecticide-treated bed nets (ITN) for controlling malaria in the highlands of Kenya. In blood tests of the residents of homes where IRS and ITN were used after a malaria outbreak, it was found that IRS-treated homes had a lower percentage of residents with malaria parasites still in their blood than ITN-treated homes, and that the cost had also been significantly lower.

Abstract: This study compares the effectiveness and cost-effectiveness of indoor residual house-spraying (IRS) and insecticide-treated bednets (ITNs) against infection with Plasmodium falciparum as part of malaria control in the highlands of western Kenya. Homesteads operationally targeted for IRS and ITNs during a district-based emergency response undertaken by an international relief agency were selected at random for evaluation. Five hundred and ninety homesteads were selected (200 with no vector control, 200 with IRS and 190 with ITNs). In July 2000, residents in these homesteads were randomly sampled according to three age-groups: 6 months-4 years, 5-15 years, and > 15 years for the presence of P. falciparum antigen (Pf HRP-2) using the rapid whole blood immunochromatographic test (ICT). The prevalence of P. falciparum infection amongst household members not protected by either IRS or ITN was 13%. Sleeping under a treated bednet reduced the risk of infection by 63% (58-68%) and sleeping in a room sprayed with insecticide reduced the risk by 75% (73-76%). The economic cost per infection case prevented by IRS was US$ 9 compared to US$ 29 for ITNs. This study suggests that IRS may be both more effective and cheaper than ITNs in communities subjected to low, seasonal risks of infection and as such should be considered as part of the control armamentarium for malaria prevention. (Wellcome Trust Research Laboratories/KEMRI, Nairobi, Kenya, hjuyatt@wtnairobi.mimcom.net)

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13) Romi, R., M.C. Razaiarimanga, R. Raharimanga, E.M. Rakotondraibe, L.H. Ranaivo, V. Pietra, A. Raveloson, and G. Majori. Impact of the Malaria Control Campaign (1993-1998) in the highlands of Madagascar: Parasitological and entomological data. American Journal of Tropical Medicine and Hygiene. 66(1), 2002, pp. 2-6.

PANNA summary: The study tracks malaria prevalence in the highlands of Madagascar through five years of an Italian-run and World Bank funded control program (1993-1998), a response to the reappearance of epidemic malaria in the region in the late 1980s. The program used annual indoor spraying of DDT and improved availability of chloroquine, and appears to have been effective, with significant decreases in the number of malaria cases and the abundance of the main vector species in villages throughout the region.

Abstract: Malaria transmission in the central highlands of Madagascar was interrupted in the 1960s by a national control program that used DDT indoor spraying and mass treatment with chloroquine. At the end of the 1980s in this region, epidemic malaria reappeared. Italian health authorities provided technical assistance to the National Malaria Control Program since the beginning of the resurgence of malaria in the central highlands. Yearly residual house spraying performed for 5 years (1993-1998) and the availability of antimalarial drugs reduced malaria transmission to very low levels, with improvement in parasitologic and entomologic indexes. A significant reduction of malaria prevalence was observed in the villages located at altitudes of 1,000-1,500 m, corresponding to the stratum of unstable malaria that was the main target of the antivector interventions. A significant reduction of malaria prevalence was also observed in the villages located at altitudes of 900-1,000 m, where malaria transmission is stable. The main vector Anopheles funestus was dramatically reduced in abundance and distribution in the sprayed areas. (Laboratorio di Parassitologia, Istituto Superiore di Sanita, Roma, Italy. romi@iss.it)

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14) Jambou R., Ranaivo L., Raharimalala L., Randrianaivo J., Rakotomanana F., Modiano D., Pietra V., Boisier P., Rabarijaona L., Rabe T., Raveloson N., De Giorgi F. Malaria in the highlands of Madagascar after five years of indoor house spraying of DDT. Transactions of the Royal Society of Tropical Medicine and Hygiene (2001) 95, 14-18.

PANNA summary: This article reports on a study of the prevalence of malaria parasites in the blood of school children in the highlands of Madagascar, in regions where DDT spraying campaigns to eliminate the vector Anopheles funestus were carried out between December 1993 and January 1998. Parasite prevalence in children was generally found to decline with increasing altitude, but below 1,500 meters, the impact of the spraying campaigns was clear. Below 1,000 meters, parasite prevalence was 2.7% in villages that had been sprayed and 20% in those that hadn’t; between 1,000 and 1,500 meters, the difference was .8% to 4.5%. However, the presence of antibodies to the parasite was much more common than the parasite itself, appearing in 22-63% of children in each school, indicating that the parasite is still in active circulation. The authors warn against the high potential for rapid re-infection of the area from lower neighboring areas and suggest bolstering current surveillance efforts with continued spraying of DDT in the marginal zones.

Abstract: The central region of Madagascar is a vast area of highlands (altitude 700-2000 m). Malaria transmission has re-established itself here since the last epidemic of 1985-90 and has caused the deaths of 40,000 persons according to the Minister of Health. To combat the main malaria vector in the region, Anopheles funestus, annual programmes of indoor house spraying of DDT were carried out between December 1993 and January 1998 in most rural areas at altitude 1000-1500 m. A parasitological and serological study was then conducted in the highland schools to evaluate the impact of the programme and set up a database on the region. Using a cluster-sampling method 2 independent selections were conducted (one of 130 sites, the other of 40 sites). During the study, 13,462 schoolchildren were examined, 71% living in sprayed villages. Parasite prevalence among schoolchildren declined as altitude increases, from 11% at 700-900 m to 0.4% at > 1500 m. Below 1500 m, the impact of the spraying on the prevalence of the parasite was very clear (an average decrease of from 20% to 2.7% below 1000 m and of from 4.5% without spraying to 0.8% at 1000-1500 m). Geographical analysis of the data showed that the marginal regions remained the most affected by malaria (especially outside spraying zones), and persistence of 'pockets of transmission' at 1000-1500 m, essentially in areas where spraying has never been used. In 9 schools, anti-Plasmodium antibodies were sought by indirect immunofluorescence on thick smears of parasitized red blood cells. The seroprevalence ranged from 22% to 63%, which suggests that the parasite is still circulating in the region. Even though our data show that vector control continues to be very successful in the Madagascan highlands, rapid reinfection could occur and must be monitored following spraying. To this end, the Minister for Health, with the support of the Italian Co-operation, has placed the region under epidemiological surveillance since 1997. An alert system for the timely detection of the sources of epidemics and the targeting of the antivectoral campaign is also in operation. Our study suggests that this strategy should be reinforced by the spraying of DDT in the marginal zones in order to consolidate the results obtained at higher altitudes. (Pasteur Institute of Madagascar, Madagascar. rjambou@pasteur.sn)

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15) Mnzava, A.E.P., B.L. Sharp, D.J. Mthembu, D. le Sueur, S.S. Dlamini, J.K. Gumede, and I. Kleinschmidt. Malaria control: Two years' use of insecticide-treated bednets compared with insecticide house spraying in KwaZulu-Natal. South African Medical Journal, November 2001. Vol. 91, No. 11, pp. 978-983.

PANNA summary: This study found that use of insecticide-treated bed nets was more effective for preventing malaria than indoor spraying of the insecticide deltamethrin over the course of two years (1997-'99) in KwaZulu-Natal. However, they warn that cost-effectiveness has varied in studies in different countries around the world, and so encourage the South African Department of Health to consider more data on cost and long-term effectiveness of treated bed nets.

Abstract:

OBJECTIVES: The objective of this study was to produce data indicating whether insecticide-treated bednets should replace insecticide house spraying as a malaria control method in South Africa. We report 2 years of preliminary data on malaria incidence comparing areas receiving insecticide-treated bednets and those subjected to house spraying in northern KwaZulu-Natal.

DESIGN, SETTING AND SUBJECTS: In order to measure significant reductions in malaria incidence between the two interventions, a geographical information system (GIS) was used to identify and create seven pairs of geographical blocks (areas) in the malaria high-risk areas of Ndumu and Makanis in Ingwavuma magisterial district, KwaZulu-Natal. Individual blocks were then randomly allocated to either insecticide-treated bednets or house spraying with deltamethrin. Malaria cases were either routinely recorded by surveillance agents at home or were reported to the nearest health facility.

RESULTS AND CONCLUSIONS: The results show that 2 years' use of insecticide-treated bednets by communities in Ndumu and Makanis, KwaZulu-Natal, significantly reduced the malaria incidence both in 1997 (rate ratio (RR) = 0.879, 95% confidence interval (CI) 0.80-0.95, P = 0.04) and in 1998 (RR = 0.667, CI 0.61-0.72, P = 0.0001). Using a t-test, these significant reductions were further confirmed by an assessment of the rate of change between 1996 and 1998, showing a 16% reduction in malaria incidence in blocks using treated bednets and an increase of 45% in sprayed areas (t = 2.534, P = 0.026 (12 df)). In order to decide whether bednets should replace house spraying in South Africa, we need more data on the efficacy of treated bednets, their long-term acceptability and the cost of the two interventions. (Malaria Research Lead Programme, South African Medical Research Council, Durban)

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16) Utzinger, J., Y. Tozan, F. Doumani, and B.H. Singer. The economic payoffs of integrated malaria control in the Zambian copperbelt between 1930 and 1950. Tropical Medicine and International Health. August 2002, vol. 7. no. 8, pp.657-677.

PANNA summary: In this analysis of the economic benefits of integrated malaria control efforts in copper-mining communities of Zambia between 1930 and 1950, the authors show that integrated methods can be highly effective. As DDT and other chemical insecticides were not in use yet at the time, control strategies included environmental management, improvement in living conditions, improvement of hospital facilities, use of bed nets, and improved availability of anti-malarial drugs. The number of lives, malaria attacks, work shift losses, disability adjusted life years, direct treatment costs, and lost work hours saved more than made up for the cost of implementing the program because of the dramatic increase in copper production and revenues in the area.

Abstract: It has long been suggested that malaria is delaying the economic development of countries that are most severely affected by the disease. Several studies have documented the economic consequences of malaria at the household level, primarily in communities engaged in subsistence farming. A missing element is the appraisal of the economic impact of malaria on the industrial and service sectors that will probably become the backbone of many developing economies. We estimate the economic effects of integrated malaria control implemented during the colonial period and sustained for 20 years in four copper mining communities of the former Northern Rhodesia (now Zambia). Integrated malaria control was characterized by strong emphasis on environmental management, while part of the mining communities also benefited from rapid diagnosis and treatment and the use of bednets. The programmes were highly successful as an estimated 14,122 deaths, 517,284 malaria attacks and 942,347 work shift losses were averted. Overall, 127,226 disability adjusted life years (DALYs) were averted per 3-year incremental period. The cumulative costs of malaria control interventions were US$ 11,169,472 (in 1995 US$). Because the control programmes were so effective, the mining companies attracted a large reservoir of migrant labourers and sustained healthy work forces. The programmes averted an estimated US$ 796,622 in direct treatment costs and US$ 5,678,745 in indirect costs as a result of reduced work absenteeism. Within a few years of programme initiation, Northern Rhodesia became the leading copper producer in Africa, and mining generated the dominant share of national income. Copper production and revenues, which increased dramatically during malaria control interventions, amounted to the equivalent of US$ 7.1 billion (in 1995 US$). Integrated malaria control in copper mining communities was a sound investment. It had payoff for public and occupational health, generally, and without it copper extraction and social and economic development would have been impossible. (Office of Population Research, Princeton University, Princeton, NJ, USA, Woodrow Wilson School of Public and International Affairs, Princeton University, Princeton, NJ, USA, World Bank, Washington, DC, USA)

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17) Schellenberg, D., C. Menendez, E. Kahigwa, J. Aponte, J. Vidal, M. Tanner, H. Mshinda, P. Alonso. Intermittent treatment for malaria and anemia control at time of routine vaccinations in Tanzanian infants: A randomized, placebo-controlled trial. Lancet 2001; 357: 1471-77.

PANNA summary: In this study of seven hundred infants in Ifakara, Tanzania, children were given weight-appropriate doses of the anti-malarial and anti-anemia drug sulphadoxine-pyrimethamine (or a placebo pill) at the time of immunization by WHO's Expanded Program on Immunization: two, three, and nine months old. Incidence of malaria in the first year of life was 59% less in the group who received the medication than in the group who received the placebo, and incidence of anemia was 50% less, even though both groups received iron supplements. This method of malaria control shows potential for delaying first malaria incidence in young children to a time when their immune systems are better equipped to deal with the disease.

Abstract:

BACKGROUND: Clinical malaria and severe anaemia are major causes of paediatric hospital admission and death in many malaria-endemic settings. In the absence of an effective and affordable vaccine, control programmes continue to rely on case management while attempting the large-scale deployment of insecticide-treated nets. We did a randomised, placebo-controlled trial to assess the efficacy and safety of intermittent sulphadoxine-pyrimethamine treatment on the rate of malaria and severe anaemia in infants in a rural area of Tanzania.

METHODS: We randomly assigned 701 children living in Ifakara, southern Tanzania, sulphadoxine-pyrimethamine or placebo at 2, 3, and 9 months of age. All children received iron supplementation between 2 and 6 months of age. The intervention was given alongside routine vaccinations delivered through WHO's Expanded Program on Immunisation (EPI). The primary outcome measures were first or only episode of clinical malaria, and severe anaemia in the period from recruitment to 1 year of age. Morbidity monitoring through a hospital-based passive case-detection system was complemented by cross-sectional surveys at 12 and 18 months of age. Results were expressed in terms of protective efficacy (100 [1-hazard ratio]%) and analysis was by intention to treat.

FINDINGS: 40 children dropped out (16 died, 11 migrated, 12 parents withdrew consent, and one for other reasons). Intermittent sulphadoxine-pyrimethamine treatment was well tolerated and no drug-attributable adverse events were recorded. During the first year of life, the rate of clinical malaria (events per person-year at risk) was 0.15 in the sulphadoxine-pyrimethamine group versus 0.36 in the placebo group (protective efficacy 59% [95% CI 41-72]), and the rate of severe anaemia was 0.06 in the sulphadoxine-pyrimethamine group versus 0.11 in the placebo group (50% [8-73]). Serological responses to EPI vaccines were not affected by the intervention.

INTERPRETATION: This new approach to malaria control reduced the rate of clinical malaria and severe anaemia by delivering an available and affordable drug through the existing EPI system. Data are urgently needed to assess the potential cost-effectiveness of intermittent treatment in areas with different patterns of malaria endemicity. (Unidad de Epidemiologia, Hospital Clinic, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Villarroel 170, 08036, Barcelona, Spain)

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18) Coetzee, M., D.W.K. Horne, B.D. Brooke, and R.H. Hunt. DDT, dieldrin, and pyrethroid insecticide resistance in African malaria vector mosquitoes: An historical review and implications for future malaria control in southern Africa. South African Journal of Science 95, May 1999, p 215-8.

PANNA summary: This paper reviews articles on vector resistance to the insecticides DDT, dieldrin, and pyrethroids, mapping them out over the history of their use and over Southern Africa. As control programs have been moving away from DDT and dieldrin and toward pyrethroids and other alternative insecticides in more recent years, resistances to pyrethroids have also been developing among vector populations.

Abstract: Historical records of dieldrin and DDT insecticide resistance in the African malaria vectors Anopheles gambiae and An. arabiensis have been mapped. Policy changes to the malaria control programmes in South Africa have resulted in DDT being phased out as the insecticide of choice and replaced with pyrethroids. Recent records of resistance to pyrethroids in An. gambiae in West Africa raise concern about the future usefulness of pyrethroids for malaria control in southern Africa.

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19) Curtis, C.F., C.A. Maxwell, R.J. Finch, and K.J. Njunwa. A comparison of use of a pyrethroid either for house spraying or for bednet treatment against malaria vectors. Tropical Medicine and International Health. 3(8) 619-31, August 1998.

PANNA summary: Using the pyrethroid insecticide lambdacyhalothrin to treat bed nets and using it to spray the inside walls of homes in northeast Tanzania proved to be equally effective at lowering the probability of malaria infection in children by 54-62%. However, treating bed nets used about one sixth the amount of insecticide as indoor spraying, and people in the area were much more enthusiastic about the bed nets, so the researchers conclude that pyrethroid-treated bed nets are more cost-effective than indoor spraying of the same chemicals.

Abstract: In an intensely malarious area in north-east Tanzania, microencapsulated lambdacyhalothrin was used in four villages for treatment of bednets (provided free of charge) and in another four villages the same insecticide was used for house spraying. Another four villages received neither intervention until the end of the trial but were monitored as controls. Bioassays showed prolonged persistence of the insecticidal residues. Light traps and ELISA testing showed reduction of the malaria vector populations and the sporozoite rates, leading to a reduction of about 90% in the entomological inoculation rate as a result of each treatment. Collections of blood fed mosquitoes showed no diversion from biting humans to biting animals. Incidence of re-infection was measured by weekly monitoring of cohorts of 60 children per village, after clearing preexisting infection with chlorproguanil-dapsone. The vector control was associated with a reduction in probability of re-infection per child per week by 54-62%, with no significant difference between the two vector control methods. Cross-sectional surveys for fever, parasitaemia, haemoglobin and weight showed association of high parasitaemia with fever and anaemia and beneficial effects of each intervention in reducing anaemia. However, passive surveillance by resident health assistants showed no evidence for reduced prevalence of fever or parasitaemia. Net treatment consumed only about one sixth as much insecticide as house spraying and it was concluded that the former intervention would work out cheaper and nets were actively demanded by the villagers, whereas spraying was only passively assented to. (London School of Hygiene and Tropical Medicine, UK. c.curtis@lshtm.ac.uk)

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20) Sharp, B. and P. van Wyk, J. B. Sikasote, P. Banda, and I. Kleinschmidt. Malaria control by residual insecticide spraying in Chingola and Chililabombwe, Copperbelt Province, Zambia. Tropical Medicine and International Health, Vol 7, no 9, pp 732-6. September 2002.

PANNA summary: This study surveyed parasite prevalence and the knowledge, attitudes and practices regarding malaria of Chingola and Chililabombwe towns after Konkola Copper Mines initiated a malaria control program there, spraying all houses in the area with either DDT or one of two synthetic pyrethroids, icon and deltamethrin. There was a significant reduction of malaria incidence following one round of spraying, down to 8.3 cases per 1,000 per month through the rainy season from 13 cases per month in the corresponding season the previous two years.

Abstract: Malaria is endemic in the whole of Zambia and is the leading cause of morbidity and mortality. Prior to 1980, effective malaria control was achieved in the northern mining towns of Chingola and Chililabombwe by means of annual residual spraying programmes. In the 1970s, incidence rates were as low as 20/1000 p.a., but by 2000 had increased to 68/1000 p.a. in Chingola and to 158/1000 p.a.in Chililabombwe. Konkola Copper Mines (KCM) initiated a malaria control programme in which all dwellings in the two towns and within a 10-km radius were sprayed with either dichlorodiphenyltrichloroethane or a synthetic pyrethroid (Icon by ZENECA or Deltamethrin by Aventis). Houses were sprayed in November and December 2000, at the start of the peak transmission period. There was a statistically significant reduction in malaria incidence recorded at KCM health facilities in the two towns, representing a protective incidence rate ratio of 0.65 (95% CI 0.44, 0.97) when comparing the post-spraying period with the corresponding period of the previous 2 years. This reduction followed a single round of house spraying during a year with higher rainfall than the preceding two and in an area where chloroquine was first-line treatment. This house-spraying programme is an example of private/public sector collaboration in malaria control. (Malaria Lead Programme, Medical Research Council, Congella, South Africa)

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21) Curtis, C.F., A.E.P. Mnzava. Comparison of house spraying and insecticide-treated nets for malaria control. Bulletin of the World Health Organization, 2000, 78(12): pp 1389-1400.

PANNA summary: This study of data from Africa, Asia, and Melanesia on the effectiveness of insecticide-treated bed nets compared with residual indoor spraying found that while the nets were as effective as indoor spraying in recent studies, they did not come close to the effectiveness once achieved by indoor spraying of DDT during the malaria eradication campaigns of 30+ years ago. This may be due in part to the longer duration of the early spraying projects, and to the fact that the pyrethroids most often used on the bed nets are excito-repellants, causing mosquitoes to leave, rather than non-irritants like DDT, which more often kill the mosquitoes. As bed nets are much smaller than the walls of a house and so much cheaper to retreat with insecticide, they may prove to be less expensive than spraying campaigns.

Abstract: The efficacies of using residual house spraying and insecticide-treated nets against malaria vectors are compared, using data from six recent comparisons in Africa, Asia and Melanesia. By all the entomological and malariological criteria recorded, pyrethroid-treated nets were at least as efficacious as house spraying with dichlorodiphenyltrichloroethane (DDT), malathion or a pyrethroid. However, when data from carefully monitored house spraying projects carried out between the 1950s and 1970s at Pare-Taveta and Zanzibar (United Republic of Tanzania), Kisumu (Kenya) and Garki (Nigeria) are compared with recent insecticide-treated net trials with apparently similar vector populations, the results with the insecticide-treated nets were much less impressive. Possible explanations include the longer duration of most of the earlier spraying projects and the use of non-irritant insecticides. Non-irritant insecticides may yield higher mosquito mortalities than pyrethroids, which tend to make insects leave the site of treatment (i.e. are excito-repellent). Comparative tests with non-irritant insecticides, including their use on nets, are advocated. The relative costs and sustainability of spraying and of insecticide-treated net operations are briefly reviewed for villages in endemic and epidemic situations and in camps for displaced populations. The importance of high population coverage is emphasized, and the advantages of providing treatment free of charge, rather than charging individuals, are pointed out. (London School of Hygiene and Tropical Medicine, London WC1E 7HT, England. chris.curtis@lshtm.ac.uk)

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22) Greenwood, B.M. Malaria transmission and vector control. Parasitology Today 1997, 13(3), 90-1.

PANNA summary: Arguments have been made that bed nets and other vector control strategies used in highly endemic regions such as Sub-Saharan Africa are only delaying cases of malaria, as they are slowing the population's natural process of developing immune resistance to the disease. Greenwood argues against this hypothesis, citing several studies among children in endemic regions of Africa that show children’s immunity is slower to develop, and their infection rates relate pretty directly to the number of bites received in a day. In this case, the author advocates the continued use of vector control strategies in Africa in the interest of saving children’s lives. Studies have shown that adults do not lose their natural resistance once they’ve developed it, and in a community using pesticide-treated nets the number of bites will still be high enough to ensure that resistance is maintained.

(no abstract available)

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23) Salako, LA. Malaria control priorities and constraints. Parassitologia 41: 495-6, 1999.

PANNA summary: The author argues that the top priority in malaria control should be changing attitudes of malaria control workers. Many cling to the idea that people already know all there is to know about malaria, when the reality is that certain habits persist that foster malaria transmission. Constraints include health budgets, inequities in the distribution of funds, lack of human resources, and unavailability of effective drugs.

Abstract: The capacity to prioritize correctly actions in malaria control depends on good knowledge not only of the epidemiology of the disease in the area but also of the behaviour of the people. Health policy makers frequently believe that the people already know enough about malaria and there is no need to commit further resources on finding out what the people actually know and do about the disease in order to modify their wrong habits. One of the pressing priorities for malaria control in Africa is therefore changing the attitude of malaria control policy makers. Considering the constraints to malaria control it is stressed that the health budget is usually below a level sufficient to finance an effective health care system. This is further compounded by inequities in the allocation of funds between health care institutions located in the urban areas compared with those located in the rural areas. Another important constraint is lack of manpower suitably trained to undertake the various elements of the global malaria control strategy. Finally, a very well known constraint is the unavailability of effective drugs at the locations where they are needed. (Nigerian Institute of Medical Research, Yaba, Lagos, Nigeria. nimr@scd.metrong.com)

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24) Bosman, A, Y Kassankogno, and AV Kondrachine. Implementation of malaria control. Parassitologia 41: 391-3, 1999.

PANNA summary: The deterioration of the malaria situation around the world and especially in Sub-Saharan Africa is being met with control strategies deficient in forecasting, early detection, and containment of malaria epidemics, and research and control communities that are too widely separated from one another. In order to tackle this problem and ease the economic burden of malaria on the world's poorest people, energies should be focused on guiding the money that is already being spent on malaria control in these communities into the most cost-effective medicines and vector control strategies.

Abstract: Global trends of infant and child mortality have decreased over the last 30 years, while the proportion of malaria deaths has progressively increased due to the deteriorating situation in sub-Saharan Africa. The Global Malaria Control Strategy promoted by WHO has encountered several obstacles to its implementation. Early diagnosis and prompt treatment can reduce malaria mortality, but there is still low investment on safe and effective modalities of care delivery at the periphery, where most of the malaria burden exists. Selective vector control (indoor residual spraying and insecticide-treated nets) plays a significant role outside Africa, but its wider use is limited by cost/affordability problems and operational issues (supply, delivery and logistics). Alternative methods such as environmental management and biological control are cost-effective only under very specific epidemiological situations. In most countries forecasting, early detection and containment of malaria epidemics is deficient, and there is separation between the research and control communities, particularly in Africa. Involvement of the internal agencies, strategic investments in capacity building and institutional networking are needed to strengthen capacity for malaria and research in the countries. The major responsibility is to guide the expenditure made by the communities (which far out-weigh the limited share of national health budgets) towards the most cost-effective approaches to reduce malaria mortality and morbidity. (Communicable Diseases Prevention and Control, World Health Organisation, Geneva, Switzerland. bosmana@who.ch)

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25) Lengeler, C.; M.L.H. Mabaso; B. Sharp. Historical review of malarial control in southern African with emphasis on the use of indoor residual house-spraying. Tropical Medicine and International Health. August 2004. Vol. 9 No. 8 pp 846�856.

PANNA summary: The researchers investigate the malarial situation before and after the introduction of indoor residual insecticide spraying (IRS) within several countries in Africa . Following the use of IRS within the respective countries, those that were able to develop a National Malaria Control Programme during the phase out of DDT and had strengthened their human and organizational assets made dramatic improvements in malarial control.

Abstract: Indoor residual house-spraying (IRS) mainly with dichlorodiphenyltrichloroethane (DDT) was the principal method by which malaria was eradicated or greatly reduced in many countries in the world between the 1940s and 1960s. In sub-Saharan Africa early malarial eradication pilot projects also showed that malaria is highly responsive to vector control by IRS but transmission could not be interrupted in the endemic tropical and lowland areas. As a result IRS was not taken to scale in most endemic areas of the continent with the exception of southern Africa and some island countries such as Reunion, Mayotte, Zanzibar , Cape Verde and Sao Tome . In southern Africa large-scale malarial control operations based on IRS with DDT and benzene hexachloride (BHC) were initiated in a number of countries to varying degrees. The objective of this review was to investigate the malarial situation before and after the introduction of indoor residual insecticide spraying in South Africa , Swaziland , Botswana , Namibia , Zimbabwe and Mozambique using historical malarial data and related information collected from National Malaria Control Programmes, national archives and libraries, as well as academic institutions in the respective countries. Immediately after the inception of IRS with insecticides, dramatic reductions in malaria and its vectors were recorded. Countries that developed National Malaria Control Programmes during this phase and had built up human and organizational resources made significant advances towards malarial control. Malaria was reduced from hyper- to meso-endemicity and from meso- to hypo-endemicity and in certain instances to complete eradication. Data are presented on the effectiveness of IRS as a malarial control tool in six southern African countries. Recent trends in and challenges to malarial control in the region are also discussed.

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26) Bruce-Chatt, L. J. Lessons learned from applied field research activities in Africa during the malaria eradication era. Bulletin of the World Health Organization. 1984. 62 (Suppl.). 19-29.

PANNA summary: The author presents an assessment of the various malaria eradication and prevention methods used in Africa from 1950 to 1974. The author then examines the period from 1975 to 1984, during which research and technological advances helped to reduce the number of cases of malaria.

Abstract: The Malaria Conference in Equatorial Africa, convened by the World Health Organization in 1950 in Kalpala , Uganda , was a milestone in the history of modern malaria control activities on the continent of Africa . It is presented and assessed the available international information on epidemiological aspects of this disease and attempted to coordinate the various methods of research and control of malaria. Its two main recommendations were that malaria should be controlled by all available health methods, irrespective of the degree of endemicity of the disease, and that the benefits that malaria control might bring to the indigenous population should be evaluated.

The first period of field research and pilot control projects in Africa was between 1950 and 1964. A large number of studies in several African countries showed that the use of residual insecticides such as DDT and HCH might decrease, at times considerably, the amount of malaria transmission, but interruption of transmission could not be achieves, except in two relatively small projects in the forest areas of the Cameroon and Liberia. During the second period, from 1965 to 1974, the difficulties of malaria eradication and control in Africa became more evident because of the development of resistance of Anopheles gambiae to DDT, HCH and dieldrin; moreover administrative, logistic, and financial problems had emerged. It became clear that the prospects for malaria control (let alone those for eradication) were related to the availability of a network of basic health services. A number of �pre-eradication� programmes were set up in order to develop better methods of malaria control and to improve the rural health infrastructures. Much field research on the chemotherapy of malaria was carried out and the value of collective or selective administration of antimalarial drugs was fully recognized, although it became obvious that this could not plan an important part in the decrease of transmission of malaria in Africa . The role of research as one of the ways of solving the technical problems of malaria control in tropical Africa was stressed from the early days of the global malaria eradication programs; the past ten years have seen and immense expansion of this activity.

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27) Carnevale, P.; F. Chandre; F. Darriet; D. Fontenille; P. Guillet; J.M. Hougard. Combating malaria vectors in Africa : Current directions of research. Trends in Parasitology. July 2002. Vol.18 No.7.

PANNA summary: The authors propose three interrelated research strategies to support malaria prevention: vector genetics, insecticide resistance and vector control. The strategies are discussed in regard to existing and needed research in these three areas.

Abstract: Vector control remains an important component of malaria control, particularly in Africa where most infant deaths occur. Among the different methods, insecticide treated bed nets seem to be a suitable way to reduce morbidity and child mortality in endemic areas. To facilitate their large-scale use and to investigate alternative vector control methods, the authors propose three current directions of research that are already being explored in Africa through a collaborating network involving several African countries:(1) vector genetics, (2) insecticide resistance and (3) vector control strategies.

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E) MALARIA CONTROL: THE AMERICAS

1) Singer, Burton and Caldas de Castro, Marcia. Agricultural Colonization and Malaria on the Amazon Frontier. Annals of the New York Academy of Science. December 2001, 954:184-222.

PANNA summary: This study shows that the high risk of malaria infection on the Amazonian frontier results from policies that have encouraged colonization in the region by millions of poor settlers from the northeast and south of Brazil. This mass migration and frontier expansion allow for malaria persistence through the following factors: poor drainage along rural roads that provides permanent breeding sites for mosquitoes, poor housing conditions, deforestation and expansion of cattle pasture, influx of temporary laborers with no natural immunity to the disease, deficiencies in the local health system, and low knowledge of the disease and how it is spread among migrants. Future migrations into these kinds of frontier lands anywhere in the world must be accompanied by cooperative agricultural extension and public health components if they are to avoid dire health and economic consequences.

Abstract: The purpose of this paper is to characterize the interrelationships between macropolitical, social and economic policies, human migration, agricultural development, and malaria transmission on the Amazon frontier. We focus our analysis on a recent colonization project, POLONOROESTE, in the state of Rondônia. Employing data from field surveys in 1985-1987 and 1995, we use spatial statistical methodologies linked to a geographical information system (GIS) to describe the patterns of human settlement in the area, the ecological transformations induced by forest clearance practices, and the manner in which these factors determine gradations of malaria risk. Our findings show that land use patterns, linked to social organization of the community and the structure of the physical environment, played a key role in promoting malaria transmission. In addition, the location of each occupied area is itself an important determinant of the pattern of malaria risk. Based on lessons learned from our spatial and temporal characterization of malaria risk, we propose policies for malaria mitigation in the Brazilian Amazon. (Office of Population Research, Princeton University, Princeton, New Jersey, USA)

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2) Gonzalez, Fernando Bejarano. The phasing out of DDT in Mexico. http://www.icps.it/english/bollettino/psn01/010205.htm

PANNA summary: Mexico has succeeded in both phasing out DDT and bringing down malaria rates in the country through a program of integrated vector management. Mexico applied over 4,000 tons of DDT a year in 1959, and implemented a complete ban in the year 2000. The integrated vector management strategy called "focalized treatment" was first used in the state of Oxaca, where farmers and environmental organizations were opposed to the spraying of DDT. The approach includes: identifying and classifying at-risk communities, reducing the parasite loads in those communities through 3-month intensive treatments with chlorine and primachine, complementary application of pyrethroids indoors and outdoors, and assessment of disease controls.

(no abstract available)

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3) Casas, M., J.L. Torres, D.N. Brown, M.H. Rodriguez, and J.L. Arrendondo-Jimenez. Selective and conventional house spraying of DDT and bendiocarb against Anopheles pseudopunctipennis in southern Mexico. Journal of the American Mosquito Control Association, 14(4):410-420, 1998.

PANNA summary: This study looked at mosquito behaviors in houses with two variables: 1) use of DDT or bendiocarb (another pesticide), and 2) was the whole wall covered with insecticide (conventional method), or only a band over the mosquitoes' preferred resting area (selective method). The study found that DDT was a more effective mosquito repellant than bendiocarb, and that the actual number of bites was substantially less in DDT-treated houses. It also found that though mosquitoes tended to rest for longer on the walls of houses that had been selectively sprayed, the actual number of bites was about the same as a house that had been conventionally sprayed. The authors recommend using selective spraying to improve cost effectiveness.

Abstract: Indoor feeding behaviors and mortalities of Anopheles pseudopunctipennis females were evaluated following contact with selective (bands covering mosquitoes' preferred resting areas) and full applications of DDT and bendiocarb on indoor sprayable surfaces. The DDT residues provoked strong avoidance behavior. To a lesser degree, mosquitoes were also repelled by bendiocarb-sprayed surfaces. Because of strong irritancy/repellency, unfed mosquitoes were driven outdoors in proportionally higher numbers. The resting time on selectively or fully DDT-sprayed huts was greatly reduced in comparison to bendiocarb-sprayed huts. Although unfed mosquitoes tended to rest on non-DDT-sprayed surfaces in the selectively treated hut, the man-biting rate was similar with both types of treatments. Unfed mosquitoes were repelled less from selectively bendiocarb-treated surfaces. Similar reductions in postfed resting times were observed on all surfaces suggesting that once fed, mosquitoes rested on sprayed surfaces for shorter intervals of time. Engorged mosquitoes had normal resting behavior (pre- and postspray) within the range of preferred resting heights in both DDT- and bendiocarb-sprayed huts, but the proportion of mosquitoes fed in the DDT-treated huts was lower. Selective spraying of walls was as effective as spraying the complete walls with both insecticides, but DDT was more effective in reducing mosquito-human contact. These studies show that by more effectively targeting vector behavior, a cost-effective alternative to traditional control techniques can be achieved. (Centro de Investigacion de Paludismo, Instituto Nacional de Salud Publica, Chiapas, Mexico)

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4) Gusamo, R. d’A. Overview of malaria control in the Americas. Parassitologia 41: 355-60, 1999.

PANNA summary: In the malaria-endemic nations of the Americas, there has been a false perception that malaria can only be controlled by insecticide spraying, which can only be implemented by centralized institutions. This perception, along with the push for decentralization of health services in the region, has made implementation of WHO's Global Malaria Control Strategy was more difficult. There has been a recent switch in policy away from eradicating malaria and toward eliminating death and illness from the disease. Thus far it has been successful, with a 60% reduction in mortality due to malaria. A new strategy developed in Mexico is now being implemented which simultaneously applies anti-parasitic measures to human and vectorial reservoirs in regions of newly formed settlements on the outskirts of urban areas. This approach is within the budgets of most effected nations.

Abstract: The malaria endemic countries of the Americas have adopted in 1992 the WHO Global Malaria Control Strategy whose difficulties of implementation have been compounded to a major reform in the health sector, as the countries adjust to conform to financial scarcity and new economic policies. Most countries of the Region have reoriented its control program from eradication of malaria to the elimination of malaria mortality and morbidity. The Region has advanced towards these objectives having already reduced its mortality by 60% and is now in the final stages of applying new tools to control transmission and rapidly advance to reduce the incidence of malaria in the Americas. (Pan American Health Organization/World Health Organization, Washington, DC 20037, USA. gusmaore@paho.org)

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5) Gusamo, R. The control of malaria in Brazil. In The Contextual Determinants of Malaria. ed. Casman, E.A. and H. Dowlatabadi. Washington D.C.: Resources for the Future, 2002. pp 59-65.

PANNA summary: This chapter details the factors leading to the current resurgence of malaria in Brazil. In recent years, however, the situation has begun to improve. With WHO’s switch to the Global Malaria Control Strategy in 1992 (Brazil was the first nation in the Americas to switch over), priorities for control changed to more local and individually focused strategies, including early diagnosis and immediate treatment, small-scale preventative vector control measures, early detection and control of epidemics, and analysis of ecological, social, and economic determinants of the disease in order to develop new integrated control strategies. The result was a massive amount of energy poured into the implementation of the new strategy in effected communities. The results were very good, with over 8 million disability-adjusted life years saved due to preventative measures and improved diagnosis and treatment.

(no abstract available)

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6) Killeen, G.F. and U. Fillinger, I. Kiche, L.C. Gouagna, and B.G.J. Knols. Eradication of Anopheles gambiae from Brazil: Lessons for malaria control in Africa? The Lancet, Infectious Diseases, vol 2, October 2002, p. 618-627.

PANNA summary: Ever since the development of DDT as a tool for vector control, the focus of control efforts has been on controlling populations of adult mosquitoes. The authors argue that given the limitations of current methods—indoor spraying, bed nets, etc.—greater attention should be paid to successful control strategies from the past, especially larval control methods that successfully eradicated A. gambiae from northeast Brazil and the Nile River valley of Egypt in the 1930s and 40s. Though there were other types of spraying involved in the campaigns, the bulk of efforts were on spraying and dusting Anopheles breeding sites with Paris Green. Though the toxicity of Green has since been established, the authors argue that the success of this focus on control at the larval stage of development should serve as a lesson to current control efforts in Africa, and an impetus for researchers to continue investigating this approach where they left off over fifty years ago.

Abstract: Current malaria-control strategies emphasise domestic protection against adult mosquitoes with insecticides, and improved access to medical services. Malaria prevention by killing adult mosquitoes is generally favoured because moderately reducing their longevity can radically suppress community-level transmission. By comparison, controlling larvae has a less dramatic effect at any given level of coverage and is often more difficult to implement. Nevertheless, the historically most effective campaign against African vectors is the eradication of accidentally introduced Anopheles gambiae from 54000 km(2) of largely ideal habitat in northeast Brazil in the 1930s and early 1940s. This outstanding success was achieved through an integrated programme but relied overwhelmingly upon larval control. This experience was soon repeated in Egypt and another larval control programme successfully suppressed malaria for over 20 years around a Zambian copper mine. These affordable approaches were neglected after the advent of dichlorodiphenyl trichloroethane (DDT) and global malaria-control policy shifted toward domestic adulticide methods. Larval-control methods should now be re-prioritised for research, development, and implementation as an additional way to roll back malaria. (Department of Public Health and Epidemiology, Swiss Topical Institute, Basel, Switzerland. gerry.killeen@unibas.ch)

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7) Charlwood, J.D., W.D. Alecrim, N. Fe, J. Mangabeira, and V.J. Martins. A field trial with Lambda-cyhalothrin (ICON) for the intradomiciliary control of malaria transmitted by Anopheles darlingi root in Rhondonia, Brazil. Acta Tropica, 60(1995): 3-13, 1995.

PANNA summary: This field trial compared the effectiveness of residual indoor spraying of ICON and DDT in Rhondonia in 1987 and 1988 and found that ICON was more effective than DDT, with drops of as much as 76% in malaria cases in treated areas. ICON lasts longer than DDT, is cheaper, and appears more lethal to insects, killing and driving away insects during the study that DDT would have only irritated. Based on these results, the authors recommend ICON as a replacement for DDT in malaria control campaigns.

Abstract: A two stage field trial comparing the effects of Lambdacyhalothrin (ICON) and DDT when used as residual sprays on the inside surfaces of houses, was conducted in the Machadinho and Jaru areas of Rhondonia, Brazil, in 1987 and 1988. In 1987 houses along two 16 km contiguous stretches of a main and a side road were sprayed and the effects on malaria vectors monitored for the succeeding year. In the second stage approximately 55,000 houses in both districts were sprayed with ICON and the effect on malaria incidence measured by passive case detection. Of the eleven species of Anopheles caught in indoor and peridomiciliary collections A. darlingi was the commonest and is recognised as the most important vector in Brazil. ICON at either of two concentrations in bioassays killed more mosquitoes than DDT at each test from seven to twelve months after spraying. A rise in the number of A. darlingi collected eight months after spraying with DDT was not so marked in the ICON areas. Side effects of the insecticide were limited. The number of reported Plasmodium falciparum cases in the second phase declined 76% in Machadinho after spraying with ICON to 2851 cases. In Jaru there was a 28% reduction. The observed efficacy of the insecticide, its ready acceptance by the local populace, and its cost effectiveness make it a more useful insecticide for anti-malaria campaigns than DDT. (Liverpool School of Tropical Medicine, UK)

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8) Grieco, J.P., N.L. Achee, R.G. Andre, and D.R. Roberts. A comparison study of house entering and exiting behavior of Anopheles vestitipennis (Diptera: Culicidae) using experimental huts sprayed with DDT or deltamethrin in the southern district of Toledo, Belize, C. A. Journal of Vector Ecology 25(1):52-73.

PANNA summary: This study looked at how and when mosquitoes entered and exited houses in the Toledo district of Belize in unsprayed houses, houses sprayed with deltamethrin, and houses sprayed with DDT. Deltamethrin was repellant, leading to 66% fewer mosquitoes entering the house, and it shifted the mosquitoes’ peak house leaving time to five hours earlier than before the house was sprayed. DDT’s repellant effect was even more pronounced, with 97% fewer mosquitoes entering the hut at all, and thus the authors believe it is a more effective tool against malaria in this region.

Abstract: An investigation of the house entering and exiting behavior of Anopheles vestitipennis Dyar and Knab was undertaken in the Toledo District of Belize, Central America, between March and December of 1998. Three untreated experimental huts were either fitted with exit or entrance interception traps or used as a control for human landing collections. Human landing collections showed that An. vestitipennis exhibited a high level of biting activity shortly after sunset and continued biting at high levels throughout the night. Under unsprayed conditions, the use of exit and entrance interception traps demonstrated that doors, windows, and eaves were the primary mode of entry; whereas, cracks in the walls served a secondary role. The peak entrance time for An. vestitipennis occurred between 6:45 P.M. and 9:45 P.M. and a peak exit time occurred between 11:45 P.M. and 4:45 A.M. Additional trials were conducted after spraying one of the huts with DDT and another with deltamethrin. The excito-repellent properties of deltamethrin did not affect entrance times but did result in a peak exiting behavior that was five hours earlier than under pre-spray conditions. Deltamethrin also exhibited a repellency effect, showing 66% fewer An. vestitipennis entering the hut two weeks post-spray. DDT had an even more powerful repellency effect resulting in a 97% post-spray reduction of An. vestitipennis females entering the hut up to two weeks post-spray. The control hut showed only a 37% reduction in An. vestitipennis as compared to pre-spray conditions. (Department of Preventive Medicine/Biometrics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA)

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9) Roberts, D.R., E. Vanzie, M.J. Bangs, J.P. Grieco, H. Lenares, P. Hshieh, E. Rejmankova, S. Manguin, R.G. Andre, and J. Polanco. Role of residual spraying for malaria control in Belize. Journal of Vector Ecology. June, 2002. 27(1): 63-69.

PANNA summary: This study of the impact of reduced residual spraying in Belize found that it is associated with increases in cases of malaria. The authors suggest that spraying technique be improved and targeted to minimize costs and negative effects, but that its practice continue at a level above 134.6 houses per thousand people in Belize. This number was determined to be the threshold for Belize, above which malaria infection rates will not grow.

Abstract: We studied the impact of reduced residual spraying in Belize by developing a logistic regression model on relationships between numbers of houses sprayed (mostly with DDT) and numbers of malaria cases. We defined the “minimum effective house spray rate” (MEHSR) as the level of spraying that will prevent increases in malaria rates for a defined population. Under the total coverage approach (all houses sprayed), the MEHSR for Belize was 134.6. The model also showed that the odds for decreasing malaria is 1.086 for each increase of 10 houses sprayed per 1000 population. In further testing, highly significant and differential changes in malaria rates were documented for paired groups of years with house spray rates that were either above or below the MEHSR. Numbers of malaria cases since 1995 are used to show how stratification methods are used in Belize to spray fewer houses (at levels below the MEHSR of 134.6).

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10) Kroeger, A., J. Ordonez-Gonzalez, and A.I. Avina. Malaria control reinvented: health sector reform and strategy development in Colombia. Tropical Medicine and International Health. May 2002, vol. 7 no. 5, pp. 450-458.

PANNA summary: In the 1990's, Colombia undertook one of the most complex health sector reform programs in Latin America, involving the decentralization of the vertical vector-borne disease control program. There were definite negative impacts from the loss of supervisory capacities that lead to a decrease in malaria control efforts over all, and also from economic limitations that weren't initially expected by reformers. Malaria rates increased over that period. However, the transformed system is stronger in certain ways and has not yet been exploited to its fullest potential, so there is some promise for success in the future.

Abstract: The consequences of health sector reforms on control of malaria were analysed using Colombia as an example. One of the most complex health sector reform programmes in Latin America took place in the 1990s; it included transferring the vertical vector-borne disease control (VBDC) programme into health systems at state and district levels. A series of studies was undertaken in 1998-2000 at the national level (Ministry of Health Study), at the state level (Departamento Study) and at the health district level (District Study) using formal and informal interviews among control staff and document analysis as data collection tools. A government-financed national training programme for VBDC staff - which included direct observation of control operations - was also used to analyse health workers' performance in the postreform period (longitudinal study). The results showed that some shortcomings of the old vertical system, such as the negative aspects of trade union activity, have not been overcome while some positive aspects of the old system, such as capacity building, operational planning and supervision have been lost. This has contributed to a decrease in control activity which, in turn, has been associated with more malaria cases. Malaria control had to be reinvented at a much larger scale than anticipated by the reformers caused by a whole series of problems: complex financing of public health interventions in the new system, massive staff reductions, the difficulty of gaining access to district and state budgets, redefining entire organizations and - in addition to the reforms - introducing alternative strategies based on insecticide-treated materials and the growth of areas of general insecurity in many parts of Colombia itself. However, positive signs in the transformed system include: the strengthening of central control staff (albeit insufficient in numbers) when transferred from the Ministry of Health to the National Institute of Health, the opportunities offered by the Basic Health Plan (PAB) for new planning initiatives and intersectoral co-operation and the integration of malaria diagnosis and treatment into the general health services (associated with a decrease of malaria mortality). The potentials of the new system have not yet been fully exploited: capacity building, communication and management skills need to be improved and it require guidance from the national level. (Liverpool School of Tropical Medicine, Liverpool, UK. a.kroeger@liverpool.ac.uk)

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11) Zapping mosquitoes with biopesticides. Pesticides News 54. December 2001. http://www.pan-uk.org/pestnews/contents/pnindex.htm

PANNA summary: Biopesticides are not chemicals but organisms, in the case of this study they are the spores of a bacterium that effects mosquito larvae in their aquatic habitat, killing them within a few days of application. This study found that this particular biopesticide used in the malarial hotspots outside Nicaragua’s capital city was highly effective, reducing malaria cases dramatically when applied several times a year. The approach was cost effective, both because the biopesticide is cheaper than fenthion powder that the government had been using and because it needed to be applied much less often. Biopesticides represent an effective alternative to chemical insecticides that is safer for people and the environment, and potentially much less expensive.

Abstract: Mosquito control can be an expensive and hazardous process relying on highly toxic and persistent insecticides. Recent experiences in Central America show that biological control is effective, safer and cheaper than chemical control.

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F) MALARIA CONTROL: GENERAL AND MULTI-REGIONAL

1) Morner, J., R. Bos and M. Fredrix. Reducing and eliminating the use of persistent organic pesticides: Guidance on alternative strategies for sustainable pest and vector management. Inter-organization Program for the Sound Management of Chemicals. Geneva, 2002. (Available for download at: http://www.chem.unep.ch/pops/pdf/redelipops/redelipops.pdf) Integrated Vector Management pp 31-39, case studies pp.57-65.

PANNA summary: Defines integrated vector control as including pathogen-targeted, vector-targeted, and contact reduction methods. Summarizes the history of malarial vector control, in the pre-DDT (before 1950), eradication (1950-69), and post-eradication (since 1969) eras. Includes information on WHO’s current position on DDT, excerpts from the Fiftieth World Health Assembly’s resolution of the promotion of chemical safety with special attention to persistent organic pollutants, more definitions and details on the elements of IVM from WHO, and the WHO’s Five Point Action Plan for reduction of reliance on DDT. Includes case studies if Integrated Vector Management programs in India, Sri Lanka, the Philippines, Viet Nam, and Mexico.

(no abstract available)

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2) Bahrambegi, R; S. Newsome, and K. Perry, compiled. The Modern Malaria Control Handbook: A PSR Guide to Sources and Strategies. Physicians for Social Responsibility, 1999. (pdf files available at http://www.psr.org)

PANNA summary: An in-depth survey of socially and environmentally responsible malaria control strategies with extensive bibliographic resources for those interested in reading the original studies.

Excerpts from Executive Summary: As public health professionals with an interest in protecting people and ecosystems from the double threat of malaria and DDT exposure, Physicians for Social Responsibility has proposed an integrated approach that combines these two important public health priorities. (…) Clearly, no single tool--whether pesticide, pharmaceutical, or other--can be relied upon to combat such a complex disease as malaria. Malaria risk management must be maintained and improved through the development and use of safe, sustainable vector control--including chemical, biological, physical, and environmental methods--as well as increased spending on malaria drug research, treatment, and public health surveillance. The following document represents an initial review of the literature on DDT health effects, alternative malaria control strategies that have shown success, and cost comparisons of switching from DDT. It is by no means exhaustive, nor does it include detailed analysis of the research that is cited. Instead, it is a collection of information sources that can be used in designing successful malaria control programs.”

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3) White, G.B. Malaria prevention by vector control: Effectiveness of insecticidal methods. Parassitologia 41: 385-7, 1999.

PANNA summary: Extensive evaluations of the use of insecticides for indoor spraying targeting adult mosquitoes finds that it is still the most popular and cost effective method of vector control, as it has been for many years. The only thing the author argues could be more effective is pyrethroid-treated bed nets, but more data is needed to determine if that is the case. “Community prevention of malaria has no alternative to rival the simple efficacy of insecticidal methods.”

Abstract: House-spraying with residual insecticides continues to be the most popular and cost-effective means of malaria prevention and control. It remains to be seen whether insecticide treated nets will prove to be more economical and sustainable. (AFYA, Richmond, Surrey, UK. grahambwhite@compuserve.com)

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4) Walker, K. Cost comparison of DDT and alternative insecticides for malaria control. Medical and Veterinary Entomology (2000) 14, 345-54.

PANNA summary: An analysis of the prices of insecticides commonly used for malaria control programs finds that DDT is still the cheapest on a cost per house basis, though the price is increasing as global production is declining. At the same time, prices for some pyrethroids are falling so that they are almost as inexpensive as DDT in some situations. The author warns, however, that a simple monetary analysis like this does not account for other costs associated with insecticide use, and since prices fluctuate quite a lot on the global market, the author recommends that a given region choose the best insecticide to use on a case-by-case basis.

Abstract: In anti-malaria operations the use of DDT for indoor residual spraying has declined substantially over the past 30 years, but this insecticide is still considered valuable for malaria control, mainly because of its low cost relative to alternative insecticides. Despite the development of resistance to DDT in some populations of malaria vector Anopheles mosquitoes (Diptera: Culicidae), DDT remains generally effective when used for house-spraying against most species of Anopheles, due to excitorepellency as well as insecticidal effects. A 1990 cost comparison by the World Health Organization (WHO) found DDT to be considerably less expensive than other insecticides, which cost 2 to 23 times more on the basis of cost per house per 6 months of control. To determine whether such a cost advantage still prevails for DDT, this paper compares recent price quotes from manufacturers and WHO suppliers for DDT and appropriate formulations of nine other insecticides (two carbamates, two organophosphates and five pyrethroids) commonly used for residual house-spraying in malaria control programmes. Based on these 'global' price quotes, detailed calculations show that DDT is still the least expensive insecticide on a cost per house basis, although the price appears to be rising as DDT production declines. At the same time, the prices of pyrethroids are declining, making some only slightly more expensive than DDT at low application dosages. Other costs, including operations (labour), transportation and human safety may also increase the price advantages of DDT and some pyrethroids vs. organophosphates and carbamates, although possible environmental impacts from DDT remain a concern. However, a global cost comparison may not realistically reflect local costs or effective application dosages at the country level. Recent data on insecticide prices paid by the health ministries of individual countries showed that prices of particular insecticides can vary substantially in the open market. Therefore, the most cost-effective insecticide in any given country or region must be determined on a case-by-case basis. Regional coordination of procurement of public health insecticides could improve access to affordable products. (American Association for the Advancement of Science Fellow, US Environmental Protection Agency, Washington DC, USA. kwalker@usaid.gov)

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5) Coosemans, M., and P. Carnevale. Malaria vector control: A critical review on chemical methods and insecticides. Annals of the Belgian Tropical Medicine Society 1995. 75, 13-31.

PANNA summary: This review of a wide range of chemical methods of malaria vector control includes different types of pesticides and various strategies for their application. The author suggests that there are both technical and social issues to consider when choosing a vector control method. On the technical side, more guidelines are needed for comparisons of the costs and benefits of using different chemicals, with the understanding that the effectiveness of any chemical in a given area will depend more on the ecology and behavior of the vector in that area than on the chemical chosen. On the social side, priority must be placed with control methods that have large-scale community involvement, and with improving the quality and efficiency of control programs—improving research so that projects are appropriate for the ecology, economy, and society they are being implemented in, and making sure equipment is available and ready.

(no abstract available)

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6) Roberts, D.R., and R.G. Andre. Insecticide resistance issues in vector-borne disease control. American Journal of Tropical Medicine and Hygiene. 50(6) Suppl. 1994, pp 21-34.

PANNA summary: Using the case of DDT and malaria control as an example, this article delves into the issues around evaluating vector resistance to insecticides. DDT sprayed on the inside walls of houses functions both as an insecticide, killing mosquitoes that land on it, and as a repellant, causing mosquitoes not to enter the house at all or to leave very quickly. For this reason, conventional studies of resistance to DDT may not be all that useful, since it is functioning perhaps more as a repellant than as an insecticide. This has implications for the use of pyrethroids, since they function largely as repellants as well.

Abstract: Vector-borne diseases are an increasing cause of death and suffering worldwide. Efforts to control these diseases have been focused on the use of chemical pesticides, but arthropod resistance (whether physiological, biochemical, or behavioral) to pesticides is now an immense practical problem. The pharmacokinetic interactions of pesticides with arthropods, mechanisms of resistance, and the strengths and shortcomings of different resistance test methods are briefly reviewed. Using malaria control as an example, the differences between the efficacy of insecticide-sprayed houses in reducing malaria transmission, and the actual effect of such treatments on vectors are discussed. Reduced malaria transmission as a result of spraying house walls occurs through some combination of killing vectors that land on sprayed walls (insecticidal effect) and by preventing vectors from entering or remaining inside long enough to bite (behavioral effects). Both insecticidal and behavioral effects of insecticides are important, but the relative importance of one versus the other is controversial. Field studies in Africa, India, Brazil, and Mexico provide persuasive evidence for strong behavioral avoidance of DDT by the primary vector species. This avoidance behavior, exhibited when malaria vectors avoid insecticides by not entering or by rapidly exiting sprayed houses, should raise serious questions about the overall value of current physiological and biochemical resistance tests. The continued efficacy of DDT in Africa, India, Brazil, and Mexico, where 69% of all reported cases of malaria occur and where vectors are physiologically resistant to DDT (excluding Brazil), serves as one indicator that repellency is very important in preventing indoor transmission of malaria. This experience with DDT has implications for future control efforts because pyrethroids also stimulate avoidance behaviors in arthropods. Each chemical should be studied early (before broad-scale use) to define types of action against vector species by geographic area, especially for impregnated bed net applications. The problems for vector control created by use of insecticides in agriculture and the potential for management of resistance in both agriculture and vector-borne disease control are discussed. (Uniformed Services University of the Health Sciences, Bethesda, Maryland)

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7) Curtis, S.F. Should DDT continue to be recommended for malaria vector control? Medical and Veterinary Entomology (1994) 8. 107-112.

PANNA summary: The author reviews studies from the early 1990s on DDT and alternative insecticides, both effectiveness and resistance studies, and studies on DDT’s impacts on health, including its connection with certain cancers and elevated levels in the breast milk of mothers in areas being sprayed for malaria vector control. The author concludes, after a list of stern warnings and precautions for the switch from DDT to other malaria control techniques, that DDT should no longer be the insecticide of choice for malaria vector control.

(no abstract available)

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8) Najera, J.A. The control of tropical diseases and socioeconomic development (with special reference to malaria and its control). Parassitologia 36: 17-33, 1994.

PANNA summary: The author traces the history of malaria control efforts as an example of typical cycles in tropical disease control, from large scale and ambitious schemes to interrupt transmission by eliminating the parasite and its vector, to more modest attempts at minimizing the effects of infection through health services. Malaria has been a real and widespread obstacle to development, part of a vicious cycle in which a country is less productive because so many are sick with malaria, so less money is available to spend on malaria control efforts, and so more people become sick, and so on. Malaria control is thus a perceived as a tool for economic development. Malaria control has been most successful in regions with relatively stable political and social systems in place. For this reason, the author emphasizes that the development of malaria control strategies needs to take place as part of the development of a health system, which in turn needs to be a part of socioeconomic development.

Abstract: Malaria, as the most important and widespread of the tropical diseases, is taken as representative of the approaches to their control and the perception of their influence in socioeconomic development. An analysis is presented of the evolution of the main policy orientations for malaria control, since the discovery of mosquito transmission, identifying a quasi cyclical alternance between expectations to interrupt transmission and eliminate the parasite, and more modest approaches to minimize the effects of the infection, which cannot be eradicated, except under rather special circumstances. These apparent cycles have nevertheless yielded a wealth of experience which the current global strategy of malaria control tries to assimilate, recognizing the interdependence of socioeconomic sustainable development and malaria control. (Malaria Unit, World Health Organization, Geneva, Switzerland)

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9) Packard, R.M. ‘No other logical choice’: Global malaria eradication and the politics of international health in the post-war era. Parassitologia 40: 217-29, 1998.

PANNA summary: Despite a good deal of controversy at the time, the Eighth World Health Assembly voted to initiate the program for the global eradication of malaria in 1955. This article looks at the different factors that went in to making that decision—the stake holders, the mood of global politics at the time—and finds that a global obsession with the power of newly developed insecticides coupled with a fatalistic attitude toward growing insecticide resistance led the members of the Eighth World Health Assembly to conclude that there was “no other logical choice.”

Abstract: In 1955 the Eighth World Health Assembly voted to initiate a program for the global eradication of malaria. The global eradication of malaria represented a remarkable leap of faith. Many health authorities, both within and outside the Assembly, viewed eradication as at best fool hardy, and at worst, potentially disastrous. To understand why the World Health Assembly went ahead with a Global Eradication strategy, despite these concerns, it is necessary to examine the politics of international health and development in the post-war era. This political context shaped decisions about the adoption of DDT as a primary tool in the fight against malaria, as well as the adoption of the Malaria Eradication Program. It is equally important to understand how the advocates of an eradication strategy shaped arguments and developed support for their cause in the years leading up to the Eighth World Health Assembly meeting. (Department of History, Emory University, Atlanta, Georgia, USA)

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10) Trigg, P.I., and W.H. Wernsdorfer. Malaria control priorities and constraints. Parassitologia 41: 329-32, 1999.

PANNA summary: Priorities for malaria control, according to these authors, are cost-effective use of current tools, inclusion of malaria in health sector development, mobilizing malaria control within communities, and investing in new and more effective tools. The greatest constraint on malaria control continues to be rural poverty, both from the perspective that the disease is most widespread among the rural poor of endemic nations, and that it is those same populations which don’t have access to quality health care or the resources to take care of themselves with better housing conditions and tools for personal malaria control like bed nets and their re-impregnation with insecticides.

Abstract: Each year, there are still between 300-500 million clinical cases of malaria and over one million deaths due to the disease, 90% of which occur in Africa south of the Sahara. In all continents, malaria risk is highest in remote rural areas where poverty abounds, population densities are low and the quality and coverage of the health services are poor or in existent. A sustained impact on the malaria burden can only be achieved through the cost-effective use of current tools, by including malaria in health sector development and inter-sectorial action, by mobilizing malaria control within communities and by investing in new and more effective tools. This paper highlights some of the constraints faced by countries in controlling malaria and outlines the priority activities that are being carried out to address these constraints within both communities and the health services. It aims to be set the scene for the papers of this Centenary book which address some of these issues in more detail. (Department of Prevention and Control, Communicable Diseases, World Health Organization, Geneva, Switzerland, triggp@who.ch)

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11) Arata, A.A. Difficulties facing vector control in the 1990s. American Journal of Tropical Medicine and Hygiene. 50(6) suppl., 1994, pp 6-10.

PANNA summary: The author discusses various deficiencies in malaria vector control, including the need for more coordination with other sectors to achieve greater coverage and share costs; the decrease in popularity and production of insecticides, which is making it more difficult to choose the best one for a particular vector control program; lack of trained middle-level managers in the health field; and difficulties produced by the integration of previously independent services, including vector control. The author concludes with a short list of questions advisors should be asking themselves before implementing any vector-control program.

Abstract: Financial and technical support for vector control programs in developing countries have been reduced over the past decades. The cost of insecticides and environmental concerns are given as major reasons, but competition for the same resources with other important health problems is also a factor. This paper reviews some of the difficulties, especially managerial, that presently face vector control programs in developing countries. The need for vector control to expand beyond insecticide application and to develop approaches that require collaboration with other economic sectors and governmental agencies outside the health sector are discussed. (Vector Biology and Control Project of the Office of Health, U.S. Agency for International Development, Arlington, Virginia)

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12) Bradley, D.J. Opening Lecture: The last and the next hundred years of malariology. Parassitologia 41: 11-18, 1999.

PANNA summary: The author discusses the history of the study of malaria since the discovery by an Italian scientist in 1899 that malaria was a closed cycle between humans and mosquito vectors. He traces the different tracks that the study has taken throughout the generations, and rejoices at the new interest that scientists and international organizations are showing in the disease, as there was a glut of avoidance during the 1970s and 1980s after the failure of the global eradication campaign. He notes that the early Italian malariologists of a hundred years ago worked toward solutions in many different directions—some delving deep into different areas of the science of the disease, others bringing leadership in a broader way, still others bringing political connections, a “burning social conscience,” or an interest in rural hygiene—and that it is this kind of holistic approach to malaria that will be successful.

Abstract: The founding fathers of malariology combined scientific originality, perseverance in research, strong characters, breadth of interest and social concern. A hundred years later research and understanding has made immense progress but the world still bears a huge burden of malaria. For the next century research requires both more specialism and a holistic range if it is to be used in control, requiring multidisciplinary team work. Environmental changes and interventions produce a dynamic and changing pattern of malaria, not the static one of the past. From the original parasite life cycle, research has analysed a series of other cycles at electron microscope, biochemical and genome levels on decreasing size scales and quantitative epidemiological cycles for control. Recent additions to these concepts have been stage-specific antigens, cycles of disease rather than parasites alone, considering populations of parasites rather than just cases, and also genetic variation in each component of the parasite-human host-vector triad. In this volume there emerges for the first time a coherent overall picture of the biomedical aspects of basic malariology as the interacting population genetics of malaria parasites, anophelines and people. This provides a coherent model for the new century dealing with the great biological malaria problems of drug resistance, vaccine development, insecticidal and net control and can feed, with socio-economic work, into the gathering renewal of control efforts. New work on large-scale changes of malaria in space and time enables us to be precise about effects of local and global environmental changes to predict epidemics. Future research will be as much about linking these different scales of understanding as control will be about linking different levels of the health system. The grim situation in poor holoendemic countries also requires practical support of the type that the founders of malariology were involved in. A coherent understanding needs to feed into the new control efforts, from Roll Back Malaria onwards, for the next century. (London School of Hygiene and Tropical Medicine, UK. david.bradley@lshtm.ac.uk)

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13) Bradley, D.J. Malaria—whence and whither? In Malaria: waiting for the vaccine. Targett, GAT. Ed. England: John Wiley & Sons Ltd, 1991.

PANNA summary: A detailed look at the disease and its history—how it’s transmitted, how it effects the human body, how it was thought of throughout history, and issues to consider in malaria control for different regions. Bradley ends with two appeals for malaria control. One is for outside sub-Saharan Africa: that malaria control approaches and techniques not be abandoned as soon as they are deemed less than fully effective. In sub-Saharan Africa, the author states that even though there have been some successes with new tools, especially insecticide-treated bed nets, new tools are necessary, and the new tool we might really need to solve the problem is a vaccine.

(no abstract available)

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14) Teklehaimanot, A. Organization of control. in Malaria: waiting for the vaccine. Targett, GAT. Ed. England: John Wiley & Sons Ltd, 1991.

PANNA summary: The author examines the role of organizations in malaria control efforts. There are two major organizational structures that carry out malaria control efforts in endemic countries: vertical special programs and general health services. The author lists the ideal characteristics for a malaria control organization, and then details the main types or paradigms of malaria. Understanding the paradigm of malaria that a particular area is facing can shed a lot of light on the question of what kind of control measures would be most effective, and in turn, what kind of organization would be best suited for the job.

(no abstract available)

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15) Baird, K.J. Resurgent malaria at the millennium: Control strategies in crisis. Drugs, 59(4):719-43.

PANNA summary: After the World Health Organization abandoned the malaria eradication campaign in favor of a more consistent control campaign in 1969, malaria made a rebound and has been increasing ever since. In 1993, WHO initiated a new malaria control strategy that put emphasis on diagnosis and medical care. The author argues that the new global strategy is designed to target problems with malaria control in Africa, where vector control alone has not proven effective, but that it is not appropriate on a global scale. Vector control is still useful in malarial areas of Asia and the Americas, and removing that option now would be premature given the lack of alternative methods.

Abstract: Completion of the Panama Canal in 1914 marked the beginning of an era of vector control that achieved conspicuous success against malaria. In 1955 the World Health Organization (WHO) adopted the controversial Global Eradication Campaign emphasising DDT (dichlorodiphenyltrichloroethane) spraying in homes. The incidence of malaria fell sharply where the programme was implemented, but the strategy was not applied in holoendemic Africa. This, along with the failure to achieve eradication in larger tropical regions, contributed to disillusionment with the policy. The World Health Assembly abandoned the eradication strategy in 1969. A resurgence of malaria began at about that time and today reaches into areas where eradication or control had been achieved. A global malaria crisis looms. In 1993 the WHO adopted a Global Malaria Control Strategy that placed priority in control of disease rather than infection. This formalises a policy that emphasises diagnosis and treatment in a primary healthcare setting, while de-emphasising spraying of residual insecticides. The new policy explicitly stresses malaria in Africa, but expresses the intent to bring control programmes around the world into line with the strategy. This review raises the argument that a global control strategy conceived to address the extraordinary malaria situation in Africa may not be suitable elsewhere. The basis of argument lies in the accomplishments of the Global Eradication Campaign viewed in an historical and geographical context. Resurgent malaria accompanying declining vector control activities in Asia and the Americas suggests that the abandonment of residual spraying may be premature given the tools now at hand. The inadequacy of vector control as the primary instrument of malaria control in holoendemic Africa does not preclude its utility in Asia and the Americas. (Parasitic Diseases Program, US Naval Medical Research Unit No. 2, Jakarta, Indonesia)

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16) Bradley, D.J. The particular and the general. Issues of specificity and verticality in the history of malaria control. Parassitologia 40: 5-10, 1998.

PANNA summary: This paper traces the history of malaria control efforts since the vector, the Anopheles mosquito, was discovered, and argues that historical approaches have played too large a role in determining current strategies. Insecticides, the most common and widely used being DDT, were the favored strategy during the eradication campaign which featured a "vertical" organization, nearly autonomous within the health department, leading toward a time-limited goal of malaria eradication by a particular date. When global eradication didn't happen, the strategy shifted to a more "horizontal," long-term approach emphasizing general health services, early diagnosis and treatment of the disease. The author encourages the world to break away from this either-or system of malaria control and look for other options.

Abstract: Several ideas have currency through long periods of malaria control history and important issues in controlling many communicable diseases have often been fought out over malaria. Health administrators view complex problems of malaria control through these apparently simple ideas. The most important concepts concern the need for specific methods to combat particular features of the spread of malaria and how far this is reflected by the development of specific health services. This paper follows these ideas through the last century and argues that the dead hand of history has played too large a role in determining malaria control generally, and especially over the last two decades, while the whole period provides an illuminating commentary on conceptualization in tropical health and its evolution. The two decades following discovery of the mosquito transmission of malaria saw increasingly specific knowledge about the vectors and approaches to preventing breeding. This required "odd" health workers who poured oil on water and did fresh-water biology and later special engineers who could design reservoirs and irrigation systems hostile to anopheline breeding and apply "species sanitation". The expertise required lay outside the health sector. Later, the DDT phase focused on a single highly specialized control technique, total coverage house spraying, and led on to attempted eradication, whose activities were vertically grouped. Malaria eradication became autonomous within the health department. It became the archetypal vertical programme whose funding levels and early successes made it a model to be emulated. But the need for active case surveillance to be integrated with general health services was a major reason for failure in some countries. The subsequent reaction to failed eradication emphasized horizontal or general health services, and these are very relevant to current pre-occupations with morbidity and mortality reduction by early diagnosis and prompt treatment. The future needs a complex mixture of interventions that cut across traditional views of either specificity or of the horizontal/vertical split in programmes, and development of effective control with imperfect tools requires a more sophisticated analysis of control methods and organizations than is provided by a simple vertical/horizontal debate. (London School of Hygiene and Tropical Medicine, UK)

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17) Najera, J.A. Prevention and control of malaria epidemics. Parassitologia 41: 339-47, 1999.

PANNA summary: The author examines current methods for predicting where epidemics of malaria will occur and tries to decipher what is needed to make this pre-emptive approach more effective. Epidemic risk is determined by a certain set of relatively predictable factors, such as environmental variables like temperature and rainfall and the movement of populations of people and vectors. Close attention to high-risk areas and good cooperation between local medical establishments and the national epidemiological offices promotes the kind of early detection and precise, effective control measures that are necessary, though the most important and too often lacking factor is local capability to act quickly and effectively. So, the development and support of local abilities to translate satellite data into real local information about the possibility of an epidemic and act on it are most crucial to the control of malaria epidemics.

Abstract: Malaria epidemics have recently occurred in many areas of the world, particularly in the irregular fringe, along the limits of distribution of malaria endemicity, whether the limiting factors are temperature (latitude or altitude) or relative humidity (deserts), which were the scene of the major epidemics of the past. A review is made of the current approaches to epidemic prevention and control in line with the global malaria control strategy, of which it constitutes an essential element. The different components are discussed, including the identification and study of epidemic prone areas, the search for indicators of epidemic risk, their monitoring, and the early detection and control of actual epidemics. The potential implementation of preventive and control activities depends, nevertheless, on the degree of preparedness of the health services to detect alarm signals, the real time left for action and their capacity of implementation within that time. Recent developments in geographical information systems (GIS) and satellite derived meteorological information offer most useful tools for precise and timely epidemic forecasting, although it should be recognised that such information is only useful if based on a real understanding of their local significance. There remains an urgent need to develop and support local capabilities for the ground truthing of satellite information and for translating it into preventive and control actions.

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18) Spielman A. Research priorities for managing the transmission of vector-borne disease. Preventative Medicine 23, 693-9. 1994.

PANNA summary: A review of research trends in vector-borne disease control in the past, including the era of DDT and subsequent experimentation with different pesticides and biological controls, such as genetic manipulation and competition between species. The author’s “holy grail” of the field is the study of density limitation or regulation of vector populations. It is essential to understand how and if the population density is regulated and at what phase of development before attempting to control a population, because a control measure applied at the wrong time could actually make the population stronger. Sustainable and locally adapted strategies are the most useful.

(no abstract available)

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19) Shiff, Clive. Integrated approach to malaria control. Clinical Microbiology Reviews. V. 15, No. 2. April, 2002. p 278-93.

PANNA summary: A broad-based review of malaria control strategies, tools, and techniques that advocates an integrated approach using multiple strategies. The final recommendation of this author, who worked on malaria issues in Zimbabwe for 30 years, is that large-scale malaria control programs like WHO’s Roll Back Malaria effort must focus on building local initiative—building local infrastructure and expertise on malaria control strategies, training personnel and paying them well. RBM is very well funded, but without local expertise, Shiff argues, ministries of health will not be able to implement it and efforts will dissipate.

Abstract: Malaria draws global attention in a cyclic manner, with interest and associated financing waxing and waning according to political and humanitarian concerns. Currently we are on an upswing, which should be carefully developed. Malaria parasites have been eliminated from Europe and North America through the use of residual insecticides and manipulation of environmental and ecological characteristics; however, in many tropical and some temperate areas the incidence of disease is increasing dramatically. Much of this increase results from a breakdown of effective control methods developed and implemented in the 1960s, but it has also occurred because of a lack of trained scientists and control specialists who live and work in the areas of endemic infection. Add to this the widespread resistance to the most effective antimalarial drug, chloroquine, developing resistance to other first-line drugs such as sulfadoxine-pyrimethamine, and resistance of certain vector species of mosquito to some of the previously effective insecticides and we have a crisis situation. Vaccine research has proceeded for over 30 years, but as yet there is no effective product, although research continues in many promising areas. A global strategy for malaria control has been accepted, but there are critics who suggest that the single strategy cannot confront the wide range of conditions in which malaria exists and that reliance on chemotherapy without proper control of drug usage and diagnosis will select for drug resistant parasites, thus exacerbating the problem. An integrated approach to control using vector control strategies based on the biology of the mosquito, the epidemiology of the parasite, and human behavior patterns is needed to prevent continued upsurge in malaria in the endemic areas. (The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, USA. cshiff@jhsph.edu)

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20) The Global Health Council’s 29th Annual Conference: Global Health in Times of Crisis, 2002 Conference Abstract. B3: Rolling back malaria (Part 2): Interventions in Complex Emergency Settings. 28-31 May 2002. http://www.globalhealth.org/conference_2002/abstracts/b3.php3

PANNA summary: A specific component of WHO’s Roll Back Malaria (RBM) campaign is devoted to complex emergency situations, as an estimated 40% of malaria morbidity and mortality occurs in areas that can be defined as such. RBM developed special strategies for these areas, as techniques that work in more stable regions won’t necessarily work in complex emergency situations. These special strategies include: provision of short and long-term technical support, development of new malaria control tools, situational assessments, and determination of local capacity to respond to the identified needs.

(no abstract available)

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retrieved

BASIC FACTS ABOUT DDT

A) DDT’S IMPACT ON HUMAN HEALTH AND THE ENVIRONMENT

B) THE DEBATE OVER DDT

C) MALARIA CONTROL: ASIA

D) MALARIA CONTROL: AFRICA

E) MALARIA CONTROL: THE AMERICAS

F) MALARIA CONTROL: GENERAL AND MULTI-REGIONAL

A) DDT’S EFFECTS ON HEALTH AND THE ENVIRONMENT

B) THE DEBATE OVER DDT

C) MALARIA CONTROL: ASIA

D) MALARIA CONTROL: AFRICA

E) MALARIA CONTROL: THE AMERICAS

F) MALARIA CONTROL: GENERAL AND MULTI-REGIONAL