Congpuong Kanungnit, Ubalee Ratawan
Department of Medical Technology, Faculty of Science and Technology, Bansomdejchaopraya Rajabhat University, Bangkok 10600, Thailand.
Department of Entomology, Armed Forces Research Institute of Medical Sciences, Bangkok 10400, Thailand.
Korean J Parasitol. 2017 Oct;55(5):465-472. doi: 10.3347/kjp.2017.55.5.465. Epub 2017 Oct 31.
Recent trends of malaria in Thailand illustrate an increasing proportion of Plasmodium vivax, indicating the importance of P. vivax as a major causative agent of malaria. P. vivax malaria is usually considered a benign disease so the knowledge of this parasite has been limited, especially the genetic diversity and genetic structure of isolates from different endemic areas. The aim of this study was to examine the population genetics and structure of P. vivax isolates from 4 provinces with different malaria endemic settings in Thailand using 6 microsatellite markers. Total 234 blood samples from P. vivax mono-infected patients were collected. Strong genetic diversity was observed across all study sites; the expected heterozygosity values ranged from 0.5871 to 0.9033. Genetic variability in this study divided P. vivax population into 3 clusters; first was P. vivax isolates from Mae Hong Son and Kanchanaburi Provinces located on the western part of Thailand; second, Yala isolates from the south; and third, Chanthaburi isolates from the east. P. vivax isolates from patients having parasite clearance time (PCT) longer than 24 hr after the first dose of chloroquine treatment had higher diversity when compared with those having PCT within 24 hr. This study revealed a clear evidence of different population structure of P. vivax from different malaria endemic areas of Thailand. The findings provide beneficial information to malaria control programme as it is a useful tool to track the source of infections and current malaria control efforts.
泰国疟疾的近期趋势表明间日疟原虫的比例在增加，这表明间日疟原虫作为疟疾主要病原体的重要性。间日疟通常被认为是一种良性疾病，因此对这种寄生虫的了解有限，特别是来自不同流行地区的分离株的遗传多样性和遗传结构。本研究的目的是使用6个微卫星标记物，研究泰国4个疟疾流行情况不同的省份中间日疟原虫分离株的群体遗传学和结构。共收集了234份间日疟单感染患者的血样。在所有研究地点均观察到较强的遗传多样性；预期杂合度值范围为0.5871至0.9033。本研究中的遗传变异性将间日疟原虫群体分为3个簇；第一个是来自泰国西部湄宏顺府和北碧府的间日疟原虫分离株；第二个是来自南部的也拉分离株；第三个是来自东部的尖竹汶分离株。与首次服用氯喹治疗后寄生虫清除时间（PCT）在24小时内的患者相比，PCT超过24小时的患者的间日疟原虫分离株具有更高的多样性。这项研究揭示了泰国不同疟疾流行地区间日疟原虫不同群体结构的明确证据。这些发现为疟疾控制计划提供了有益信息，因为它是追踪感染源和当前疟疾控制工作的有用工具。
