Extensive genetic diversity in Plasmodium vivax from Sudan and its genetic relationships with other geographical isolates

Abstract

Plasmodium vivax malaria is a neglected tropical disease in Africa due to low occurrence rates and lack of accurate diagnosis. Recently, there has been a dramatic increase in P. vivax cases in East Africa and reportedly spreading to western countries. This study investigated the geographical origin and genetic diversity of P. vivax in Sudan by 14 microsatellite markers. A total of 113 clinical P. vivax samples were collected from two districts, New Halfa and Khartoum in Sudan. In addition, data from 841 geographical samples retrieved from the database for global genetic analysis were included in the analysis to further the genetic relationships among the P. vivax isolates at regional and worldwide scales. On a regional scale, we observed 91 unique and 8 shared haplotypes amongst the Sudan samples. Such a high genetic diversity compared to other geographical isolates lends support to hypothesis that P. vivax was originated from Africa. On a global scale, as already demonstrated, we observed distinct genetic clustering of P. vivax isolates from Africa, South America, and Asia (including Papua New Guinea and Solomon Island) with limited admixture in all three clusters. The principal component analysis and phylogenetic tree showed similar clustering patterns and highlighted the contribution of the African isolates to the genetic variation observed globally. The East African P. vivax showed similarity with some of the Asian isolates suggesting potential recent introductions. Our results show extensive genetic diversity co-occurring with significant multi-locus linkage disequilibrium, demonstrating the effectiveness of using microsatellite markers to implement effective control measures.