Sleeping space matters: LLINs usage in Ghana.

Long Lasting Insecticidal Net (LLIN) is an effective malaria prevention mechanism. However, ownership of LLIN does not imply its use among households. The availability of enough sleeping space is a natural prerequisite to install and use LLINs. The objective of this study was to explore the effect of sleeping space and other socio-demographic factors of households' heads on LLINs usage among households. A cross-sectional household-based study was conducted using a quantitative approach. Data was collected exclusively from households that received LLINs at no direct financial cost to them in a mass malaria campaign conducted in the study area using a structured questionnaire. A total of 383 households sampled for the study received 1,181 LLINs with a range of 1 to 15 LLINs per household. Less than 16% of households that received more than 2 LLINs installed all the LLINs they received during the distribution. Among households that received LLINs, 45% of them did not use them at all and 36% of them used them every night including the night before data collection. The number of bedrooms, children and members per household, and the number of occupants per bedroom were also found statistically associated with the use of LLINs among households. The study used a quantitative approach to investigate sleeping space in relation to LLINs usage and malaria control, an area and topic that has not been adequately covered in the literature.

Knowledge of malaria prevention among pregnant women and non-pregnant mothers of children aged under 5 years in Ibadan, South West Nigeria.

BACKGROUND: Adequate knowledge of malaria prevention and control can help in reducing the growing burden of malaria among vulnerable groups, particularly pregnant women and children aged under 5 years living in malaria endemic settings. Similar studies have been conducted but with less focus on these vulnerable groups. This study assessed knowledge of malaria prevention and control among the pregnant women and non-pregnant mothers of children aged under 5 years in Ibadan, Oyo State, South West Nigeria. METHODS: In this cross sectional study, data on socio-demographic, clinical and knowledge on malaria prevention was collected using interviewer administered questionnaires from consenting study participants attending Adeoyo maternity hospital between May and November 2016. Data was described using percentages and compared across the two maternal groups in the study population. Knowledge scoring from collected data was computed using the variables on causes, symptoms and prevention of malaria and thereafter dichotomised. Multivariate analyses were used to assess the interactive effect of socio demographic and clinical characteristics with malaria knowledge. Level of statistical significance was set at p < 0.05. RESULTS: Of the 1373 women in the study, 59.6% (818) were pregnant women while 40.4% (555) were mothers of children aged under 5 years. The respondents mean age was 29 years ± 5.2. A considerable proportion of both the pregnant women (n = 494, 60.4%) and the non-pregnant mothers of children aged under 5 years (n = 254, 45.8%) did not have correct knowledge on malaria prevention measures based on our assessment threshold (p < 0.001). Having a tertiary level education was associated with better knowledge on malaria (4.20 ± 1.18, F = 16.80, p < 0.001). Multivariate analyses showed that marital status, educational attainment, gravidity, and HIV status were significantly associated with knowledge of malaria prevention and control. CONCLUSION: The findings indicate that socio-demographic factors such as marital and educational status greatly influence knowledge on malaria prevention and control measures. Key health stakeholders and authorities need to implement strategies and direct resources to improve the knowledge of mothers on malaria prevention and control. This would stem the tides of malaria related deaths among pregnant women and children aged under 5 years.

Malaria knowledge and bed net use in three transmission settings in southern Africa.

BACKGROUND: Insecticide-treated nets (ITNs) reduce malaria morbidity and mortality in endemic areas. Despite increasing availability, the use of ITNs remains limited in some settings. Poor malaria knowledge is a barrier to the widespread use of ITNs. The goal of this study was to assess the levels of malaria knowledge and evaluate factors associated with bed net use among individuals residing in three regions of southern Africa with different levels of malaria transmission and control. METHODS: A cross-sectional study was conducted on a sample of 7535 residents recruited from 2066 households in Mutasa District, Zimbabwe (seasonal malaria transmission), Choma District, Zambia (low transmission) and Nchelenge District, Zambia (high transmission), between March 2012 and March 2017. A standardized questionnaire was used to collect data on demographics, malaria-related knowledge and use of preventive measures. Multivariate logistic regression analyses were used to assess determinants of bed net use. RESULTS: Most of the 3836 adult participants correctly linked mosquito bites to malaria (85.0%), mentioned at least one malaria symptom (95.5%) and knew of the benefit of sleeping under an ITN. Bed net ownership and use were highest in Choma and Nchelenge Districts and lowest in Mutasa District. In multivariate analyses, knowledge of ITNs was associated with a 30-40% increased likelihood of bed net use after adjusting for potential confounders across all sites. Other factors significantly associated with bed net use were age, household size and socioeconomic status, although the direction, strength and size of association varied by study site. Importantly, participants aged 5-14 years had reduced odds of sleeping under a bed net compared to children younger than 5 years. CONCLUSION: Relevant knowledge of ITNs translated into the expected preventive behaviour of sleeping under a bed net, underscoring the need for continued health messaging on malaria prevention. The implementation and delivery of malaria control and elimination interventions needs to consider socioeconomic equity gaps, and target school-age children to ensure access to and improve utilization of ITNs.

Effects of artesunate-mefloquine combination on incidence of Plasmodium falciparum malaria and mefloquine resistance in western Thailand: a prospective study.

BACKGROUND: Worsening drug resistance in Plasmodium falciparum malaria is a major threat to health in tropical countries. We did a prospective study of malaria incidence and treatment in an area of highly multidrug-resistant P. falciparum malaria. METHODS: We assessed incidence of P. falciparum malaria and the in-vivo responses to mefloquine treatment over 13 years in two large camps for displaced Karen people on the northwest border of Thailand. During this time, the standard mefloquine dose was first increased, and then combined artesunate and mefloquine was introduced as first-line treatment for uncomplicated P. falciparum malaria. FINDINGS: Early detection and treatment controlled P. falciparum malaria initially while mefloquine was effective (cure rate with mefloquine [15 mg/kg] and sulphadoxine-pyrimethamine in 1985, 98% [95% CI 97-100]), but as mefloquine resistance developed, the cure rate fell (71% [67-77] in 1990). A similar pattern was seen for high-dose (25 mg/kg) mefloquine monotherapy from 1990-94. Since the general deployment of the artesunate-mefloquine combination in 1994, the cure rate increased again to almost 100% from 1998 onwards, and there has been a sustained decline in the incidence of P. falciparum malaria in the study area. In-vitro susceptibility of P. falciparum to mefloquine has improved significantly (p=0.003). INTERPRETATION: In this area of low malaria transmission, early diagnosis and treatment with combined artesunate and mefloquine has reduced the incidence of P. falciparum malaria and halted the progression of mefloquine resistance. We recommend that antimalarial drugs should be combined with artemisinin or a derivative to protect them against resistance.

DDT house spraying and re-emerging malaria.

PIP: This article discusses the role of DDT in the re-emerging cases of malaria worldwide. It is noted that malaria is reappearing in urban areas and in countries that previously eradicated the disease, including the Amazon Basin, South and North Korea, Armenia, Azerbaijan, and Tajikistan. In addition, the frequency of imported malaria has also increased in industrial countries. Although many factors contribute to such a phenomenon, the strongest correlation is with decreasing numbers of houses sprayed with DDT. Early studies of DDT showed repellent, irritant, and toxic actions that worked against malaria vector mosquitoes. Sprayed on house walls, DDT exerted powerful control over indoor transmission of malaria. However, since the ban of DDT in the 1970s and the implementation of alternative malaria-control programs there has been a global outburst of malaria epidemics. In view of this, it is recommended that the global response to burgeoning malaria rates allow for DDT residual house spraying where it is known to be effective and necessary. Regulations and policies of industrialized countries and international agencies that block financial assistance to countries that use DDT for malaria control should be eliminated.^ieng

How do rural households perceive and prioritise malaria and mosquito nets? A study in five communities of Nigeria.

The aim of this study was to determine households' levels of prioritization and perception of malaria, ordinary mosquito nets and insecticide-treated nets (ITNs). A cross-sectional survey was conducted in five malaria holo-endemic communities in Enugu State, South-eastern Nigeria. The household heads or the representatives from randomly selected households were interviewed, using a pre-tested interviewer-administered questionnaire. The majority of the respondents had a good knowledge about malaria and the use of ordinary mosquito nets to prevent malaria. However, few knew about the existence of ITNs. Most respondents also stated that malaria was a priority problem and perceived some risk of contracting it. Despite the high level of knowledge about the use of mosquito nets, only 14.0%, 15.7%, 9.6% and 8.0% of the respondents from four of the communities had ever purchased any type of mosquito nets, except in Orba where the proportion was 50.3%. However, more than 80% in all the communities expressed a desire to buy insecticide-treated mosquito nets for the prevention of mosquito bites. There was considerable knowledge about malaria and the use of mosquito nets to prevent it. There were also high levels of prioritization of the disease, mosquito nets and ITNs which signalled the possibility of establishing sustainable community-based ITN programmes, especially as households wanted to buy the ITNs.

Antimalarials dispensing pattern by patent medicine dealers in rural settlements in Nigeria.

The pattern of antimalarial dispensing by Patent Medicine Dealers (PMD) was studied in 17 villages of Gokana (Ogoni Land) in Rivers State of Nigeria. Of the 40 PMDs studied only eight (20%) had had formal health training and only eight could understand doctor's prescriptions. In total, 19 different types of antimalarials could be obtained from the individual ranges of antimalarials displayed by the 40 PMDs in the study. Chloroquine phosphate was the most frequently available. Twenty-three (57.5%) of PMDs administered Chloroquine at below the recommended dose of this drug. Twelve (30%) PMDs, eight with formal training and four others, administered the correct dose whilst five (12.5%) gave too much. All 40 of the PMDs studied knew how to dispense Daraprim and Fansidar correctly. We conclude that malaria control through prevention and treatment would be more effective if PMDs were to receive training on antimalarial dispensing alongside Community Health Workers.

Antimalarial drug combination policy: a caveat.

PIP: This paper presents facts on malaria epidemiology and historical perspectives of antimalarial drug use in Thailand. It also suggests that the use of an artesunate-mefloquine combination for treating falciparum malaria may be one of the factors responsible for the success of the country's control strategies. It is noted that in Thailand Plasmodium falciparum has evolved resistance to chloroquine, sulfadoxine-pyrimethamine, and mefloquine in succession. In view of this, administration of oral artesunate plus mefloquine became the standard treatment for microscopically confirmed uncomplicated falciparum malaria in 1995. The regimen requires administration of 300 mg/day of artesunate for 2 days plus 750 mg mefloquine on the first day, followed by 500 mg on the second day. Overall, it is too early to assume that the addition of artesunate has halted the progression of mefloquine resistance in Thailand. In terms of applicability of the regimen worldwide, the complexity of the factors involved makes it impossible to predict the useful lifespan of the artesunate-mefloquine combination on the Thai-Myanmar border. Further research is needed into the determination and validation of the most suitable antimalarial regimens for each epidemiologically distinct area and each operationally different circumstance.^ieng

Malaria chemoprophylaxis with tafenoquine: a randomised study.

BACKGROUND: Tafenoquine is an analogue of primaquine with an improved therapeutic and safety profile. It has a long half-life and activity against liver-stage malaria parasites, so may be useful for chemoprophylaxis. In this randomised, double-blind study we assessed the efficacy and safety of tafenoquine in different doses. METHODS: 2144 individuals aged 12-20 years living in Lambaréné, Gabon, an endemic area for Plasmodium falciparum malaria, were invited to take part. 535 attended, and 426 eligible participants were randomly assigned tafenoquine (250 mg, 125 mg, 62.5 mg, or 31.25 mg) or placebo daily for 3 days. 417 received initial curative treatment with halofantrine, and 410 completed the assigned prophylaxis regimen. During follow-up of 70 days, adverse events were recorded and thick blood smears were examined weekly. The primary and secondary endpoints were the number of individuals with positive blood smears by day 56 and day 77, respectively. Analyses were per-protocol. FINDINGS: Eight positive blood smears were recorded by day 56 (four/82 participants in the placebo group; four/79 tafenoquine 31.25 mg group). By day 77, 34 positive blood smears had been recorded (14/82 placebo; 16/79 tafenoquine 31.25 mg; three/86 tafenoquine 62.5 mg; one/79 tafenoquine 125 mg; none/84 tafenoquine 250 mg). Numbers of adverse events did not differ significantly between the treatment groups. INTERPRETATION: Tafenoquine is effective and well tolerated. It has the potential to replace currently used drugs for malaria chemoprophylaxis.

African heads of state promise action against malaria.

PIP: Heads of state of Africa signed a pledge to reduce the continent's malaria mortality by 50% by 2110 at an international summit of Malaria in Abuja, Nigeria. The primary focus of the malaria control program will be insecticide-treated bednets. The WHO wants a 30-fold increase in the availability of bednets in the next 5 years, as well as immediate access to cheap and effective antimalarial combination therapy for families at risk of malaria, including pregnant women. Malaria control requires annual donations of US$1 billion from industrialized countries. However, donations alone will be insufficient unless there is immediate debt cancellation, says Jeffrey Sachs, director of the Center for International Development at Harvard. The World Bank also raised criticisms concerning the US$150 million annual donation. In response, Ok Pannenborg of the World Bank stated that there are 100 World Bank operations all over Africa and its US$150 million annual donation for African malarial control projects is money they can use, but whether they use it is another matter.^ieng

Randomised trial of alternative malaria chemoprophylaxis strategies among pregnant women in Kigoma, Tanzania: I. Rationale and design.

OBJECTIVE: The objective of the study was to assess the effectiveness of alternative strategies of malaria chemoprophylaxis on the reduction of malaria episodes and prevalence of parasitaemia among pregnant women in Kigoma urban district in western Tanzania. DESIGN: Randomised antimalarial prophylactic trial. SETTING: The study was conducted in an urban maternal and child health (MCH) clinic in Kigoma town. SUBJECTS: All pregnant women attending antenatal care services at Kigoma urban MCH clinic were eligible. Informed consent was sought from each pregnant woman for participation in the study. INTERVENTION MEASURES: The intervention measures were intermittent and continuous malaria chemoprophylaxis using chloroquine and proguanil. MAIN OUTCOME MEASURES: Reduction of malaria episodes and parasitaemia and haemoglobin levels among participating pregnant women in Kigoma urban district. RESULTS: Baseline data indicates that the overall mean haemoglobin concentrations among the primigravidae and multigravidae women were similar within the intervention and comparison groups (F-test (df = 5, N = 701) = 1.27, P = 0.27). Similarly, no significant difference was observed in the prevalence of malaria parasitaemia within the primigravidae intervention and comparison groups (chi 2 test (df = 5, N = 701) = 5.4, P = 0.4). Hence, the process of randomisation produced comparable intervention and comparison groups with balanced characteristics. Specific results of the baseline studies are presented in the companion paper. CONCLUSION: We conclude that the process of randomisation resulted in comparable intervention and comparison groups. As malaria is a common cause of considerable morbidity and mortality among pregnant women in Tanzania, the present study provided useful data for improving reproductive health in Kigoma region, western Tanzania.

PIP: This randomized antimalarial prophylactic trial assessed the effectiveness of alternative malaria chemoprophylaxis strategies on the reduction of malaria episodes and prevalence of parasitemia among pregnant women in urban Kigoma, Tanzania. All pregnant women attending antenatal care services at an urban maternal and child health clinic were randomly exposed to either intermittent or continuous malaria chemoprophylaxis using chloroquine and proguanil. The main outcome measures of the study were reduction of malaria episodes and parasitemia and hemoglobin levels among pregnant women. Baseline findings suggest that the overall mean hemoglobin concentrations among primigravida and multigravida women were similar within the intervention and comparison groups (P = 0.27). Similarly, no significant difference was observed in the prevalence of malaria parasitemia within the primigravida intervention and comparison groups (P = 0.4). Hence, the process of randomization produced comparable intervention and comparison groups with balanced characteristics. As malaria is a common cause of morbidity and mortality among pregnant women in Tanzania, this study provided useful data for improving reproductive health in the Kigoma region.

Randomised trial of alternative malaria chemoprophylaxis strategies among pregnant women in Kigoma, Tanzania: II. Results from baseline studies.

OBJECTIVE: To determine baseline data among pregnant women consenting to participate in a randomised trial of alternative strategies of malaria chemoprophylaxis in Kigoma urban district, western Tanzania. DESIGN: Cross-sectional study. SETTING: The study was conducted in an urban MCH clinic in Kigoma town in western Tanzania. SUBJECTS: All consenting pregnant women who fulfilled entry criteria were recruited into the study. BASELINE STUDIES: Baseline data were collected prior to randomisation of women to antimalarial prophylactic regimens. Baseline measurements included examination for blood depleting parasitic infections (stool and urine examinations), haemoglobin levels, haematocrit, sickling test, and blood slide for malaria parasites. RESULTS: A total of 728 pregnant women consented to participate in the interview and of these 705 participated in baseline studies constituting a participation rate of 96.8%. The age of participating women ranged from 14 to 45 years with a mean age of 23.7 years (standard deviation [SD] = 5.4) while the mean number of pregnancies ranged from 1 to 13 with a mean of 3.2 (SD = 2.2). The prevalence of malaria parasitaemia among the pregnant women examined was 9.4% (N = 705) while the prevalence of anaemia (defined as Hb < 8.5 gdl-1) was 12.4% (N = 579). No significant difference was observed in prevalence proportions of malaria parasitaemia in relation to age, parity, marital status and use of mosquito bednets. However the prevalence of anaemia among women in the age group 31-45 years was significantly lower than that observed among women in the age group 14-20 years (2.9% versus 18.9%; crude odds ratio [OR] = 0.13; 95% confidence interval [CI], 0.02-0.55). Sickle cell disease (HbAS) was found in 2.3% (N = 564) of the pregnant women examined. CONCLUSION: It is concluded that the prevalence of malaria parasitaemia and anaemia was very high in this population suggesting the need for interventions directed at controlling these major causes of maternal morbidity and mortality in Tanzania.

PIP: This cross-sectional study conducted in Kigoma urban district, western Tanzania, determined the baseline data among pregnant women consenting to participate in a randomized trial of alternative malaria chemoprophylaxis strategies. Baseline data were obtained prior to randomization of women to antimalarial prophylactic regimens (intermittent or continuous chloroquine and proguanil). Baseline measurements included examination for blood depleting parasitic infections (stool and urine examinations), hemoglobin levels, hematocrit, sickling test, and blood slide for malaria parasites. A total of 728 pregnant women consented to participate, and of these, 705 participated in baseline studies constituting a participation rate of 96.8%. The age range was 14-45 years, while the number of pregnancies ranged from 1 to 13. The prevalence of malaria parasitemia among the subjects was 9.4% (N = 705), while the prevalence of anemia was 12.4% (N = 579). There was no significant difference in prevalence proportions of malaria parasitemia in relation to age, parity, marital status and use of mosquito bednets. However, the prevalence of anemia among women aged 31-14 years was significantly lower than among women in the age group 14-20 years (2.9% vs. 18.9%; crude odds ratio = 0.13; 95% confidence interval, 0.02-0.55). Sickle cell disease (HbAS) was found in 2.3% (N = 564) of the pregnant women examined. The prevalence of malaria parasitemia and anemia was very high in this population, suggesting the need for effective disease control interventions.

Control malaria to help defeat poverty, says WHO.

PIP: In a report by the WHO, interventions against malaria could help alleviate poverty in countries where the disease is rife, and aid in boosting economic growth. The WHO calls on the international community, private foundations, and international agencies to commit funds for malaria interventions and research. This call was made since malaria has long term effects on trade, tourism, foreign investment, and commerce. Moreover, repeated bouts of malaria add to costs through malnutrition and death among children and time off work among adults. In this light, WHO further suggests the setting up of a malaria vaccine and purchase fund to spur pharmaceutical and biotechnological companies into developing a vaccine. Furthermore, new therapeutic, preventive and diagnostic tools need to be developed, particularly drugs, insecticides and dipstick tests.^ieng

Roll Back Malaria: spotlight on Africa.

PIP: Africa is the continent most severely affected by malaria. It is for this reason that the Roll Back Malaria (RBM) initiative has Africa as its main focus. This article examines the efforts, strategies and achievements of RBM in malaria prevention in Africa. It is shown that under the RBM banner two countries from Africa were able to report, by the end of 1999, adequate preparedness for anticipated malaria epidemics in the second quarter of 2000. Four other countries have pushed forward accelerated malaria control activities to cope with the complex emergency situations, and at least 10 others are in the process of doing so. In the field of research, RBM has collaborated with the UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases (TDR) to work on a number of areas such as product research and home management of malaria. On the other hand, it is noted that the Abuja Plan of Action promotes strengthening of research in particular, development of vaccines and exploration of traditional methods for malaria.^ieng

Environmental management for vector control. Is it worth a dam if it worsens malaria?

PIP: This article reports a seven-fold increase in the incidence of malaria among children living close to small dams in the Tigray region of northern Ethiopia compared with children in villages distant from the dams. Despite the weakness of a case-control design, the authors of this study convincingly addressed the issue of confounders such as altitude, seasonality, and use of antimalarials. Intensity of malaria transmission does not correlate directly with morbidity and mortality because of the modulating effects of immunity and other factors. Nevertheless, increased malarial infection is likely to constitute a serious health risk to children, particularly in the region of Ethiopia. Some of the environmental management strategies for vector control, which may be applied to dam projects include locating dams at high altitude, using insecticide-treated beds for personal protection, and adopting a range of environmental manipulations. These measures, which incorporate local knowledge and fit local circumstances, are more likely to succeed than adhering to traditional methods. It is in this situation that governments and aid agencies need to make a policy commitment to minimize the adverse health risks of dam projects through the adoption of environmental management strategies for vector control and effective public interventions as part of community development activities.^ieng

Epidemiology of malaria in pregnancy in central India.

Analysis of three years of data from a malaria clinic operated by the Indian Council of Medical Research (ICMR) in the Government Medical College Hospital in Jabalpur, central India, showed a high malaria prevalence among pregnant women, which was statistically highly significant (P < 0.0001) compared with the situation among nonpregnant women. Cerebral malaria was a common complication of severe Plasmodium falciparum infection, with a high mortality during pregnancy, requiring immediate attention. The study also showed that malaria infection was more frequent in primigravidae, falling progressively with increasing parity. Mean parasite densities were significantly higher in pregnant women compared with nonpregnant women for both P. falciparum (P < 0.001; df = 137) and P. vivax (P < 0.05; df = 72) infection. Pregnant women with falciparum or vivax malaria were significantly more anaemic than noninfected pregnant women or infected nonpregnant women. The average weight of 155 neonates from infected mothers was 350 g less than that of 175 neonates from noninfected mothers. This difference in birth weight was statistically significant for both P. falciparum (P < 0.0001; df = 278) and P. vivax (P < 0.0001; df = 223) infection. Congenital malaria was not recorded. We conclude that pregnant women from this geographical area require systematic intervention owing to their high susceptibility to malaria during pregnancy and the puerperium.

PIP: A 3-year study on malarial epidemiology was conducted among 2127 pregnant women from 12 weeks' gestation up to 40 days after delivery at the Obstetrics and Gynecology Department of Government Medical College in Central India. The women either had fever or a history of fever, belonged to the lower socioeconomic groups, and worked in their homes and in the fields. Personal and reproductive histories as well as antimalarial drug intake during pregnancy were considered. Comparisons in rates of anemia and low birth weight were investigated between the two groups, which were composed, respectively, of nonpregnant women of reproductive age assessed for the prevalence of vivax/falciparum malaria and parasite density (the control group) and pregnant women from the study group who had fever, but no malarial infection. Blood smears from all neonates whose mothers were enrolled in the study were also prepared. Results showed statistically higher malaria prevalence in primigravidae, decreasing progressively with increasing parity. 33 pregnant women were infected with P. vivax, while 67% were infected with P. falciparum; 17 of these were cerebral malaria cases. Women with falciparum or vivax malaria were significantly more anemic than noninfected pregnant women or infected nonpregnant women. The average weight of 155 neonates from infected mothers was 350 g less than that of 174 neonates from noninfected mothers. These findings suggest that the high susceptibility of pregnant women to malaria requires systemic intervention.

Cost-effectiveness of malaria control in sub-Saharan Africa.

BACKGROUND: Information on the cost-effectiveness of malaria control is needed for the WHO Roll Back Malaria campaign, but is sparse. We used mathematical models to calculate cost-effectiveness ratios for the main prevention and treatment interventions in sub-Saharan Africa. METHODS: We analysed interventions to prevent malaria in childhood (insecticide-treated nets, residual spraying of houses, and chemoprophylaxis) and pregnancy (chloroquine chemoprophylaxis and sulfadoxine-pyrimethamine intermittent treatment), and to improve malaria treatment (improved compliance, improved availability of second-line and third-line drugs, and changes in first-line drug). We developed models that included probabilistic sensitivity analysis to calculate ranges for the cost per disability-adjusted life year (DALY) averted for each intervention in three economic strata. Data were obtained from published and unpublished sources, and consultations with researchers and programme managers. FINDINGS: In a very-low-income country, for insecticide treatment of existing nets, the cost-effectiveness range was US$4-10 per DALY averted; for provision of nets and insecticide treatment $19-85; for residual spraying (two rounds per year) $32-58; for chemoprophylaxis for children $3-12 (assuming an existing delivery system); for intermittent treatment of pregnant women $4-29; and for improvement in case management $1-8. Although some interventions are inexpensive, achieving high coverage with an intervention to prevent childhood malaria would use a high proportion of current health-care expenditure. INTERPRETATION: Cost-effective interventions are available. A package of interventions to decrease the bulk of the malaria burden is not, however, affordable in very-low-income countries. Coverage of the most vulnerable groups in Africa will require substantial assistance from external donors.

PIP: This paper examines the cost-effectiveness of malaria control using an innovative modeling approach based on probabilistic sensitivity analysis in sub-Saharan Africa. The variables included in the study were interventions for preventing malaria in childhood (insecticide-treated nets, residual spraying of houses and chemoprophylaxis), preventing malaria in pregnancy (chloroquine chemoprophylaxis and sulfadoxine-pyrimethamine intermittent treatment), and improving treatment for uncomplicated malaria (better compliance, improved availability of second- and third-line drugs, and changes in first-line drugs). Effectiveness was calculated in terms of disability-adjusted life years (DALY) formula. The cost data were obtained through published and unpublished literature, program budgets, price catalogues, and consultation with researchers and program managers. Results showed that in a very-low-income country, the cost-effectiveness range of insecticide-treated nets was US$19-85. If only insecticide treatment was required, the range would be decreased to US$4-10 per DALY averted. Cost effectiveness was $32-58 for residual spraying (two rounds per year), $3-12 for children's chemoprophylaxis, $4-29 for intermittent treatment of pregnant women, and $1-8 for improvement in case management. Cost-effectiveness analysis helped identify interventions that would result in the effective use of resources, but information on total costs was also needed in order to assess affordability. Furthermore, coverage of the most vulnerable groups in Africa would require substantial assistance from external donors.

Malaria control in Nicaragua: social and political influences on disease transmission and control activities.

Throughout Central America, a traditional malaria control strategy (depending on heavy use of organic pesticides) became less effective during the 1970s. In Nicaragua, an alternative strategy, based on frequent local epidemiological assessments and community participation, was developed in the 1980s. Despite war-related social instability, and continuing vector resistance, this approach was highly successful. By the end of the contra war, there finally existed organisational and ecological conditions that favoured improved malaria control. Yet the expected improvements did not occur. In the 1990s, Nicaragua experienced its worst recorded malaria epidemics. This situation was partly caused by the country's macroeconomic structural adjustment programme. Volunteers now take fewer slides and provide less treatment, malaria control workers are less motivated by the spirit of public service, and some malaria control stations charge for diagnosis or treatment. To "roll back malaria", in Nicaragua at least, will require the roll-back of some erroneous aspects of structural adjustment.

PIP: This paper examines the social and political influences on malaria transmission and control activities in Nicaragua. In politically unstable Central America, methods that depend on community participation and planning on the basis of routine surveillance data may be sufficient to control malaria transmission. The Nicaraguan experience in the 1980s and 1990s shows how an integrated approach can prove to be effective where social stability, health education, and strong program administration exists. During the Contra war in the 1980s, implementation of the community-based strategy was limited, resulting in increasing rates of P. vivax transmission in the war zone. The loss of timely epidemiological reporting and the decrease in use of local volunteers for blood slide detection and directly observed therapy resulted in a greater epidemic. More recently, WHO has initiated "Roll Back Malaria" and "Roll Back Structural Adjustment" programs which aim to make more efficient use of limited resources in the health sector to help eradicate malaria. Several components were needed for the strategy: the technical capacity of the national staff needed strengthening, the staff needed to be re-evaluated, additional funds were needed to assure competitive salaries, and malaria control programs needed to be identified for appropriation of funds as essential components to national development planning during structural adjustment. National leadership and the establishment of public service and social solidarity will help mobilize volunteers to work toward the goal of preventing malaria transmission.

The effect of delivery mechanisms on the uptake of bed net re-impregnation in Kilifi District, Kenya.

The results of recently completed trials in Africa of insecticide-treated bed nets (ITBN) offer new possibilities for malaria control. These experimental trials aimed for high ITBN coverage combined with high re-treatment rates. Whilst necessary to understand protective efficacy, the approaches used to deliver the intervention provide few indications of what coverage of net re-treatment would be under operational conditions. Varied delivery and financing strategies have been proposed for the sustainable delivery of ITBNs and re-treatment programmes. Following the completion of a randomized, controlled trial on the Kenyan coast, a series of suitable delivery strategies were used to continue net re-treatment in the area. The trial adopted a bi-annual, house-to-house re-treatment schedule free of charge using research project staff and resulted in over 95% coverage of nets issued to children. During the year following the trial, sentinel dipping stations were situated throughout the community and household members informed of their position and opening times. This free re-treatment service achieved between 61-67% coverage of nets used by children for three years. In 1997 a social marketing approach, that introduced cost-retrieval, was used to deliver the net re-treatment services. The immediate result of this transition was that significantly fewer of the mothers who had used the previous re-treatment services adopted this revised approach and coverage declined to 7%. The future of new delivery services and their financing are discussed in the context of their likely impact upon previously defined protective efficacy and cost-effectiveness estimates.

PIP: Recent trials of insecticide-treated bednets (ITBN) in Africa sought to achieve high ITBN coverage together with high net retreatment rates. Following the completion of a randomized, controlled trial on the coast of Kenya, a series of delivery strategies were used to continue net retreatment in the area. Adherence to a free bi-annual, house-to-house retreatment schedule resulted in a more than 95% coverage of nets issued to children. During the year following the trial, sentinel dipping stations were situated throughout the community and household members informed of their locations and opening times. More than 85% of bednets were re-impregnated between October 1993 and October 1995, and 61-67% coverage of nets used by children for 3 years after the free retreatment service was launched beginning in 1996. The introduction of a social marketing approach at sentinel sites in 1997 to retrieve some of the costs of the net retreatment services caused coverage to drop to 7.1% among children still resident in the study area who had had nets since 1993. The future of new delivery services and their financing are discussed with regard to their likely impact upon previously defined protective efficacy and cost-effectiveness estimates.

Cost of malaria control in Sri Lanka.

The study provides estimates of the cost of various malaria control measures in an area of North-Central Province of Sri Lanka where the disease is endemic. We assumed that each measure was equally effective. In these terms, impregnating privately purchased bednets with insecticide was estimated to cost Rs 48 (US(40.87) per individual protected per year, less than half the cost of spraying houses with residual insecticides. Larviciding of vector breeding sites and especially the elimination of breeding habitats by flushing streams through seasonal release of water from upstream reservoirs was estimated to be cheaper than other preventive measures (Rs 27 (US$ 0.49) and Rs 13 (US$ 0.24) per individual protected, respectively). Inclusion of both operational and capital costs of treatment indicates that the most cost-effective intervention for the government was a centrally located hospital with a relatively large catchment area (Rs 71 (US$ 1.29) per malaria case treated). Mobile clinics (Rs 153 (US$ 2.78) per malaria case treated) and a village treatment centre (Rs 112 (US$ 2.04)) per malaria case treated) were more expensive options for the government, but were considerably cheaper for households than the traditional hospital facilities. This information can guide health planners and government decision-makers in choosing the most appropriate combination of curative and preventive measures to control malaria. However, the option that is cheapest for the government may not be so for the householders, and further studies are needed to estimate the effectiveness of the various preventive measures.

PIP: A large proportion of Sri Lanka's budget is spent on malaria control. Estimates are provided of the cost of various malaria control interventions in North-Central Province, Sri Lanka, where the disease is endemic and where ongoing research activities facilitated the cost-effectiveness assessment. Each measure considered was assumed to be equally effective. As such, impregnating privately purchased bednets with insecticide was estimated to cost Rs 48 (US$0.87) per person protected per year, less than half the cost of spraying houses with residual insecticides. The larviciding of vector breeding sites and eliminating breeding habitats by flushing streams through the seasonal release of water from upstream reservoirs was estimated to be cheaper than other preventive measures, at Rs 27 and Rs 13 per person protected, respectively. Including both the operational and capital costs of treatment indicates that the most cost-effective intervention for the government was a centrally located hospital with a relatively large catchment area, at Rs 71 per malaria case treated. Mobile clinics and a village treatment center approach cost Rs 153 and Rs 112, respectively, per malaria case treated. These latter 2 strategies were the more expensive options for the government, but were less expensive for households compared to the cost of treatment at traditional hospital facilities.