Population Genetic Analysis of Plasmodium falciparum from Lake Victoria Islands Using a Novel Single Fluorescent Labeled Microsatellite Assay

Abstract

Despite unprecedented efforts to control Plasmodium falciparum over decades, it remains entrenched in Africa, accounting for 90% of global malaria deaths. Control efforts have been difficult due in part to high levels of P. falciparumgenetic diversity, drug resistance, poor vector management, poor drug access drug due to poverty. Attempts to understand the genetic structure and transmission dynamics of this parasite are underway in different regions prior to implementation of interventions. However, to date, few studies have examined the genetic diversity of malaria parasites in Lake Victoria islands where malaria transmission is stable. In order to examine population genetics, the current genotyping platforms based on laser induced fluorescence detectionare relied on. The cost, however, of producing a new fluorescently labeled primer is prohibitive to many laboratories. To overcome such challenges a novel genotyping assay was adopted.The sensitive, specificity and reproducibility of the assay in typingP. falciparumcultures was determined. The assay proved to be highly reproducible withhave detection sensitivityof up to 50parasites/µL. The validated assay was used to genotype 188 P. falciparumsamples from Lake Victoria basin in order to measure the extent of genetic diversity and population structure. High levels of genetic diversity were measured throughout the region (Mean He= 0.84)and low levels of population structure. Overall FST value was 0.044 indicating that approximately 5% of the overall allelic variation is due to differences between the populations. Based on these results, the study concludes that parasite population structure in the studied islands is shaped by human migration patterns that maintain extensive parasite gene flow between the sites. Consequently, any malaria elimination and interventions strategies in the study area will have to be carried out broadly on all four islands and adjoining mainland region.