Department of Parasitology, Institute of Tropical Medicine, Antwerp, Belgium.
Malar J. 2010 Jun 3;9:151. doi: 10.1186/1475-2875-9-151.
Peru is one of the Latin American countries with the highest malaria burden, mainly due to Plasmodium vivax infections. However, little is known about P. vivax transmission dynamics in the Peruvian Amazon, where most malaria cases occur. The genetic diversity and population structure of P. vivax isolates collected in different communities around Iquitos city, the capital of the Peruvian Amazon, was determined.
Plasmodium vivax population structure was determined by multilocus genotyping with 16 microsatellites on 159 P. vivax infected blood samples (mono-infections) collected in four sites around Iquitos city. The population characteristics were assessed only in samples with monoclonal infections (n = 94), and the genetic diversity was determined by calculating the expected heterozygosity and allelic richness. Both linkage disequilibrium and the genetic differentiation (theta) were estimated.
The proportion of polyclonal infections varied substantially by site (11% - 70%), with the expected heterozygosity ranging between 0.44 and 0.69; no haplotypes were shared between the different populations. Linkage disequilibrium was present in all populations (IAS 0.14 - 0.61) but was higher in those with fewer polyclonal infections, suggesting inbreeding and a clonal population structure. Strong population differentiation (theta = 0.45) was found and the Bayesian inference cluster analysis identified six clusters based on distinctive allele frequencies.
The P. vivax populations circulating in the Peruvian Amazon basin are genetically diverse, strongly differentiated and they have a low effective recombination rate. These results are in line with the low and clustered pattern of malaria transmission observed in the region around Iquitos city.
秘鲁是拉丁美洲疟疾负担最重的国家之一，主要是由于间日疟原虫感染。然而，人们对发生大多数疟疾病例的秘鲁亚马逊地区间日疟原虫的传播动态知之甚少。本研究旨在确定伊基托斯市（秘鲁亚马逊地区首府）周围不同社区采集的间日疟原虫分离株的遗传多样性和种群结构。
对伊基托斯市周围四个地点采集的 159 份间日疟原虫感染血液样本（单感染）进行了 16 个微卫星的多位点基因分型，以确定间日疟原虫的种群结构。仅对具有单克隆感染的样本（n = 94）评估种群特征，并通过计算预期杂合度和等位基因丰富度来确定遗传多样性。同时估计连锁不平衡和遗传分化（theta）。
不同地点的多克隆感染比例差异很大（11% - 70%），预期杂合度在 0.44 至 0.69 之间；不同人群之间没有共享的单倍型。所有人群都存在连锁不平衡（IAS 0.14 - 0.61），但在多克隆感染较少的人群中更高，这表明存在近亲繁殖和克隆种群结构。发现了强烈的种群分化（theta = 0.45），贝叶斯推断聚类分析根据独特的等位基因频率确定了六个聚类。
在秘鲁亚马逊盆地循环的间日疟原虫种群具有遗传多样性，分化强烈，有效重组率低。这些结果与在伊基托斯市周围地区观察到的低而聚类的疟疾传播模式一致。
