A naturally occurring strain (Anga-Mali) was identified in mosquitoes of the complex collected in the Malian villages of Dangassa and Kenieroba. Phylogenetic analysis of the nucleotide sequence of two 16S rRNA regions showed thatAnga-Mali clusters with strains from supergroup A and has the highest homology to a strain isolated from cat fleas (). Anga-Mali is different from two strains previously reported in from Burkina Faso (Anga_VK5_STP and Anga_VK5_3.1a). Quantitative analysis of and sporozoite infection in field-collected mosquitoes indicates that the prevalence and intensity of sporozoite infection is significantly lower in -infected females. The presence of in females from a laboratory (, M form) colony experimentally infected with (NF54 strain) gametocyte cultures slightly enhanced oocyst infection. However, infection significantly reduced the prevalence and intensity of sporozoite infection, as observed in the field. This indicates that Anga-Mali infection does not limit early stages of infection in the mosquito, but it has a strong deleterious effect on sporozoites and reduces malaria transmission.

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SummaryWe have produced maps of Plasmodium falciparum malaria transmission in West and Central Africa using the Mapping Malaria Risk in Africa (MARA) database comprising all malaria prevalence surveys in these regions that could be geolocated. The 1846 malaria surveys analysed were carried out during different seasons, and were reported using different age groupings of the human population. To allow comparison between these, we used the Garki malaria transmission model to convert the malaria prevalence data at each of the 976 locations sampled to a single estimate of transmission intensity E, making use of a seasonality model based on Normalized Difference Vegetation Index (NDVI), temperature and rainfall data. We fitted a Bayesian geostatistical model to E using further environmental covariates and applied Bayesian kriging to obtain smooth maps of E and hence of age-specific prevalence. The product is the first detailed empirical map of variations in malaria transmission intensity that includes Central Africa. It has been validated by expert opinion and in general confirms known patterns of malaria transmission, providing a baseline against which interventions such as insecticidetreated nets programmes and trends in drug resistance can be evaluated. There is considerable geographical variation in the precision of the model estimates and, in some parts of West Africa, the predictions differ substantially from those of other risk maps. The consequent uncertainties indicate zones where further survey data are needed most urgently. Malaria risk maps based on compilations of heterogeneous survey data are highly sensitive to the analytical methodology.keywords entomological inoculation rate, kriging, malaria, markov chain monte carlo, parasite prevalence, vectorial capacity

To determine whether Lassa virus was circulating in southern Mali, we tested samples from small mammals from 3 villages, including Soromba, where in 2009 a British citizen probably contracted a lethal Lassa virus infection. We report the isolation and genetic characterization of Lassa virus from an area previously unknown for Lassa fever.