No influence of the transmission season on genetic diversity and complexity of infections in Plasmodium falciparum isolates from Benin.

The principal goals of the present study were to determine the genetic diversity of the merozoite surface protein-1 (MSP-1) and protein-2 (MSP-2) genes and the complexity of infections in P. falciparum isolates collected from Beninese patients during high and low transmission season at Cotonou, in South Benin. Sixty and twenty-four patients were sampled during dry and wet season respectively. Parasite DNA was analysed using allele-specific primers to amplify block 2 of MSP-1 and central variable region of MSP-2 genes. A total of 12 (K1, Mad20, Ro33) MSP-1 and 13 (3D7 and FC27) MSP-2 alleles were detected in overall samples. Neither influence of age nor transmission season was observed in the genetic diversity of parasites and in the distribution ofMSP-1 and MSP-2 alleles. Combining the results of MSP-1 and MSP-2 genotyping, we observed 57% and 70% of multiple infections during dry and wet season respectively. The complexity of infections 2.4 fragments/individual was not affected either by the season or by the age of the host. We speculate that in an area with perennial transmission, change of season did not influence the permanent turn-over of parasites and the number of parasite genotype per person. Data obtained here will be serve as a baseline for future studies which will carried out at Cotonou to analyse the impact of any malaria control measures on parasite populations.