Genetic diversity of Plasmodium vivax malaria in China and Myanmar

Daibin Zhong,Mariangela Bonizzoni,Guofa Zhou,Guangze Wang,Bin Chen,Anne Vardo-Zalik,Liwang Cui,Guiyun Yan,Bin Zheng

doi:10.1016/j.meegid.2011.05.009

Abstract

Genetic diversity and population structure of Plasmodium vivax parasites are valuable to the prediction of the origin and spread of novel variants within and between populations, and to the program evaluation of malaria control measures. Using two polymorphic genetic markers, the merozoite surface protein genes PvMSP-3α and PvMSP-3β, we investigated the genetic diversity of four Southeast Asian P. vivax populations, representing both subtropical and temperate strains with dramatically divergent relapse patterns. PCR amplification of PvMSP-3α and PvMSP-3β genes detected three and four major size polymorphisms among the 235 infections examined, respectively, while restriction analysis detected 15 and 19 alleles, respectively. Samples from different geographical areas differed dramatically in their PvMSP-3α and PvMSP-3β allele composition and frequency. Samples tended to cluster on the basis of their PCR-RFLP polymorphism. These results indicated that different parasite genotypes were circulating in each endemic area, and that geographic isolation may exist. Multiple infections were detected in all four parasite populations, ranging from 20.5% to 31.8%, strongly indicating that P. vivax populations were highly diverse and multiple clonal infections are common in these malaria-hypoendemic regions of Southeast Asia.

Highlights

Plasmodium vivax is the most common and globally widespread of four human malaria species
The aim of this study was to assess the level of genetic polymorphism of the PvMSP-3α and PvMSP-3β in P. vivax infections from China and Myanmar
It is important to note that the mixed-strain infections were defined by instances when the summed size of the DNA fragments in RFLP analysis was greater than the size of the uncut PCR product, or when more than one size PCR product was seen in the initial amplification

Summary

Introduction

Plasmodium vivax is the most common and globally widespread of four human malaria species. It accounted for at least 70–80 million clinical cases annually (Mendis et al, 2001; Hay et al, 2004; Prajapati et al, 2006). It is the most important species causing human malaria outside of Africa, and is especially prevalent in Southeast Asia and Central and South America (WHO, 2006). As many countries in Southeast Asia including China are entering the phase of malaria elimination (http://apmen.org/), they are facing the challenge of eliminating vivax malaria

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