Patterns of malaria indices across three consecutive seasons in children in a highly endemic area of West Africa: a three times-repeated cross-sectional study.

OBJECTIVES: To study the manifestations of Plasmodium infection, and its relations with the malaria disease, especially when comparing dry and rainy seasons in a hyperendemic area of West Africa. METHODS: The study was carried out in an area where malaria transmission is high, showing important seasonal variations. One thousand children, representing the total child population (1-12 year old), were observed transversally at the end of three consecutive seasons (dry/rainy/dry). The usual indicators, such as parasite density, splenomegaly, anaemia, or febrile disease were recorded and analysed. RESULTS: The prevalence of Plasmodium falciparum was high in all age groups and seasons, constantly around 60%. The high transmission season (rainy) showed higher rates of anaemia and spleen enlargement and, in the youngest children only, higher parasite densities. There were also differences between the two dry seasons: in the first one, there was a higher rate of fever than in the second one (p < 0.001). Low parasite density (<2,000 p/µl) was never associated with fever during any season, raising some concern with regard to the usefulness of parasite detection. The possible origins of fever are discussed, together with the potential usefulness of analyzing these indices on a population sample, at a time when fever incidence rises and malaria is one potential cause among others. The distinction to be made between the Plasmodium infection and the malaria disease is highlighted. CONCLUSIONS: These data confirm previous hypotheses of a strong difference in malaria infection and disease between dry and rainy seasons. The most relevant seasonal indicator was not mainly parasite rate and density but anaemia, spleen enlargement, prevalence and possible origin of fever. RECOMMENDATIONS: In any situation (i.e. fever or not) and especially during the dry season, one must consider that detection of parasites in the blood is only evidence of a Plasmodium infection and not necessarily of a malaria disease. In such a situation, it seems suitable to obtain, through national malaria teams, a well-defined situation of transmission and prevalence of Plasmodium infection following zones and seasons, in order to adapt control strategies. For researchers, a systematic management of data separately for dry and rainy season appears mandatory.

The implementation of malaria intermittent preventive trialtreatment with sulphadoxine-pyrimethamine in infants reduced all-cause mortality in the district of Kolokani, Mali: results from a cluster randomized control.

BACKGROUND: Malaria intermittent preventive treatment of malaria in infant with sulphadoxine-pyrimethamine (IPTi-SP) reduced the incidence of malaria and anaemia by 30% and 20% respectively. The strategy is now a recommended policy for malaria control. However, there was no published study on the impact of the strategy on mortality. The present study assessed the impact of the implementation of IPTi-SP in health services in Mali on all-cause mortality. METHODS: The 22 health sub-districts of the district of Kolokani were randomized at a 1:1 ratio to either receive IPTi-SP or to serve as a control. The IPTi-SP was implemented for two years starting December 2006. Information on births and deaths through 31 March, 2009 was collected on all children who reached four months of age on 1 December, 2006, likely to be exposed to the intervention in 75 localities randomly selected in each zone. RESULTS: A total of 5,882 children (2,869 from the intervention zone and 3,013 from the nonintervention zone) who reached four months of age between 1 December, 2006 and 1 December, 2008 were surveyed between the age of four months to the age of 18 months from 1 December, 2006 to 31 March, 2009. In the cohort of four to 18 months of age, the mortality rate per 1,000 children was 2.53 in the intervention zone compared to 3.46 in the nonintervention zone, gender and season adjusted mortality rate ratio (MRR) = 0.73 (95% CI 0.55-0.97, p = 0.029). In the cohort of the four to 12 months of age, mortality rates per 1,000 children were 2.22 in the intervention zone and 3.13 in the non-intervention zone, MRR = 0.71 (95% CI 0.49-1.02, p = 0.064) adjusted for gender and season. CONCLUSION: The implementation of the IPTi-SP resulted in a substantial reduction in all-cause mortality in children. The results of this study support the adoption and the implementation of IPTi-SP as malaria control strategy. TRIAL REGISTRATION: ClinicalTrials.govNCT00766662.