[No influence of season of transmission nor age of patients on the complexity and genetic diversity of Plasmodium falciparum infection in Cotonou, Benin].

The aim of the present study was to determine the genetic diversity and allelic frequencies of the genes encoding for the merozoite surface protein-1 (MSP-1) and protein-2 (MSP-2) of P. falciparum collected from Beninese patients during the high and low transmission seasons in Cotonou, in South Benin. Sixty and twenty-four patients were sampled during the dry and wet seasons, respectively Parasite DNA was analysed using allele-specific primers to amplify block2 of MSP-1 and central variable region of MSP-2. A total of 12 (K1, Mad20, Ro33) MSP-1 and 23 (3D7, FC27 and hybrids) MSP-2 alleles were detected. Neither age nor transmission season modified the genetic diversity of P. falciparum nor the distribution of MSP-1 and MSP-2 alleles. Combining the results of MSP-1 and MSP-2 genotyping, multiple P. falciparum infections were observed in 57% and 70% of isolates during the wet and dry seasons, respectively. The complexity of infections defined as the number of parasite genotype per isolate was 2.4 and it was not affected either by the season or by the age of the host. We conclude that change of season did not influence the permanent turn-over of parasites and the complexity of infections. Data obtained here will serve as a baseline for future studies, such as the impact of malaria control measures on parasite populations, to be conducted in Cotonou.