Department of Molecular Tropical Medicine and Genetics, Mahidol University, Bangkok, Thailand.
Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
J Infect Dis. 2019 Feb 15;219(5):695-702. doi: 10.1093/infdis/jiy519.
In Southeast Asia, Plasmodium knowlesi, a parasite of long-tailed macaques (Macaca fascicularis), is an important cause of human malaria. Plasmodium cynomolgi also commonly infects these monkeys, but only one naturally acquired symptomatic human case has been reported previously.
Malariometric studies involving 5422 subjects (aged 6 months to 65 years) were conducted in 23 villages in Pailin and Battambang, western Cambodia. Parasite detection and genotyping was conducted on blood samples, using high-volume quantitative PCR (uPCR).
Asymptomatic malaria parasite infections were detected in 1361 of 14732 samples (9.2%). Asymptomatic infections with nonhuman primate malaria parasites were found in 21 individuals living close to forested areas; P. cynomolgi was found in 11, P. knowlesi was found in 8, and P. vivax and P. cynomolgi were both found in 2. Only 2 subjects were female, and 14 were men aged 20-40 years. Geometric mean parasite densities were 3604 parasites/mL in P. cynomolgi infections and 52488 parasites/mL in P. knowlesi infections. All P. cynomolgi isolates had wild-type dihydrofolate reductase genes, in contrast to the very high prevalence of mutations in the human malaria parasites. Asymptomatic reappearance of P. cynomolgi occurred in 2 subjects 3 months after the first infection.
Asymptomatic naturally acquired P. cynomolgi and P. knowlesi infections can both occur in humans.
NCT01872702.
在东南亚，长尾猕猴（Macaca fascicularis）体内的疟原虫（Plasmodium knowlesi）是人类疟疾的一个重要病因。食蟹猕猴（Macaca fascicularis）也通常会感染这种疟原虫，但之前仅报告过一例自然感染并出现症状的人类病例。
在柬埔寨西部的拜林省和马德望省的 23 个村庄，对 5422 名 6 个月至 65 岁的对象进行了疟疾学研究。采用高容量定量 PCR（uPCR）对血样进行寄生虫检测和基因分型。
在 14732 份样本中的 1361 份（9.2%）中检测到无症状疟原虫感染。在靠近森林地区生活的 21 名个体中发现了非人类灵长类动物疟原虫的无症状感染；发现 11 例感染食蟹猕猴疟原虫，8 例感染 knowlesi 疟原虫，2 例同时感染 vivax 疟原虫和食蟹猕猴疟原虫。仅有 2 名女性和 14 名年龄在 20-40 岁之间的男性感染。食蟹猕猴疟原虫感染的几何平均寄生虫密度为 3604 个/毫升，knowlesi 疟原虫感染的几何平均寄生虫密度为 52488 个/毫升。所有食蟹猕猴疟原虫分离株均具有野生型二氢叶酸还原酶基因，而人类疟原虫的突变则非常普遍。2 例食蟹猕猴疟原虫感染的个体在初次感染后 3 个月再次出现无症状感染。
无症状的自然获得性食蟹猕猴疟原虫和 knowlesi 疟原虫感染均可在人类中发生。
NCT01872702。
