疟疾控制和消除

Background: In developing countries, malaria is still a leading cause of morbidity and mortality and children are the most affected individuals. In order to strengthen malaria control, new intervention such as Seasonal Malaria Chemoprevention (SMC) has been developed. This strategy is very effective in preventing malaria clinical episodes but its effect on children’s immunity is not well documented. This study aimed to evaluate the effects of SMC on the acquisition of anti-AMA1 and anti-MSP1_42 antibodies among children fewer than 10 years living in the southern part of Senegal (Velingara). Patients and methods: The study was nested in a cluster randomized trial assessing the impact of SMC with a single dose of Sulfadoxine-Pyrimethamine (SP) and 3 doses of Amodiaquine (AQ). Two cross-sectional surveys were carried out (October 2010) and (September 2011) to assess the effect of SMC on children’s immunity. Thick and thin blood smears were performed to assess malaria parasiteamia prevalence. Blood was collected on filter paper for serological measurement by ELISA to measure IgG anti-MSP1_42 and anti-AMA1. Logistic regression analysis was performed to assess factors associated with the production of antibodies. Results: A total number of 1611 children under 10 years old were included in two surveys (866 children in 2010 and 745 children in 2011). Malaria prevalence was 10.39% at baseline (2010) and 5.03% one year after intervention (2011). The seroprevalence of anti-MSP1_42 anti-AMA1 antibodies was higher in 2010 compared to 2011 providing a significant reduction of IgG production at 11.4 AU (95%CI ⦋8.3-14.4⦌) for MSP1_42 and 7.2 AU (95%CI ⦋4.5-9.9⦌) for AMA1. Seroprevalence increased with age and Plasmodium falciparum carriage while it decreased according to the area and study period. Conclusion: SMC is an effective strategy for malaria prevention in children under 10 years. The strategy can as well induce a decrease of IgG anti-AMA1 and anti-MSP1_42 which are protective against malaria. Consequently, this strategy needs to be renewed each year in areas where malaria is highly seasonal to avoid a resurgence of malaria, while promoting the use of other antimalarial interventions.

Cerebral malaria is a clinical manifestation of the brain during Plasmodium falciparum infection, which may lead to fatal outcomes if left unattended or delayed in therapeutic management. It is often accompanied by multi-organ complications such as renal failure, respiratory distress, jaundice, severe anemia etc., further raising the degree of mortality. Over the years, the management of severe and cerebral malaria has improved radically but still the mortality rate in severe malaria is worrysome. An extremely uncommon case is demonstrated here, which is a classical illustration of malarial death due to CM and multi-organ dysfunction; complicated due to an episode of Oleander poisoning amidst. Falciparum malaria can have myriads of clinical presentations which may co-exist with other pathologies which is challenging for the clinicians, therefore, a high degree of suspicion followed by early diagnosis of malaria, may be more frequently pronounced in healthcare settings in malaria endemic areas to improve overall outcome and better management of malaria control programs.

Background: Polymorphism and antigenic variation of malaria parasites determine malaria episode and its outcome. The aim of this study was to determine Plasmodium falciparum genetic diversity over time in population with uncomplicated malaria under ACT exposure in Senegal. Method: P. falciparum isolates collected from 300 individuals with uncomplicated malaria infection living in a rural area of Senegal from 2004 to 2008 were analyzed by a nested PCR amplification of msp1 and msp2 genes to compare P. falciparum allelic families’ diversity. Results: Allelic variation in both msp1 and msp2 genes were identified in the samples analyzed. For msp1 gene, 10 different alleles were found (3 msp1_K1, 4 msp1_Mad20 and 3 msp1_Ro33). Among them msp1_k1 allelic family was predominant (>70%) over year. Regarding msp2 gene, 7.0 different alleles were found (3 msp2_3D7, 4 msp2_FC27). However msp2_FC27 strain was predominant, especially in 2006 and 2007. Monoclonal infections were more frequent for msp1 gene, in 2004 (48.78%) and 2005 (45.05%) and for msp2 gene than polyclonal ones. Conclusion: This study demonstrated some differences in the P. falciparum diversity between symptomatic subjects over years living in rural area in Senegal and this should be taken into account when designing msp1 or msp2 malaria vaccine.