Zoonotic cases of Plasmodium knowlesi account for most malaria cases in Malaysia, and humans infected with P. cynomolgi, another parasite of macaques have recently been reported in Sarawak. To date the epidemiology of malaria in its natural Macaca reservoir hosts remains little investigated. In this study we surveyed the prevalence of simian malaria in wild macaques of three states in Peninsular Malaysia, namely Pahang, Perak and Johor using blood samples from 103 wild macaques (collected by the Department of Wildlife and National Parks Peninsular Malaysia) subjected to microscopic examination and nested PCR targeting the Plasmodium small subunit ribosomal RNA gene. As expected, PCR analysis yielded significantly higher prevalence (64/103) as compared to microscopic examination (27/103). No relationship between the age and/or sex of the macaques with the parasitaemia and the Plasmodium species infecting the macaques could be identified. Wild macaques in Pahang had the highest prevalence of Plasmodium parasites (89.7%), followed by those of Perak (69.2%) and Johor (28.9%). Plasmodium inui and P. cynomolgi were the two most prevalent species infecting the macaques from all three states. Half of the macaques (33/64) harboured two or more Plasmodium species. These data provide a baseline survey, which should be extended by further longitudinal investigations that should be associated with studies on the bionomics of the anopheline vectors. This information will allow an accurate evaluation of the risk of zoonotic transmission to humans, and to elaborate effective strategies to control simian malaria.

在马来西亚，疟疾是人畜共患病的主要原因，而在沙捞越州，最近又有人感染猕猴的另一种疟原虫。迄今为止，在其天然的猕猴水库宿主中疟疾的流行病学仍未进行调查。在这项研究中，我们使用来自103个野生猕猴（由马来西亚野生动物和国家公园部收集）的血液样本，调查了马来西亚半岛三个州彭亨，霹雳州和柔佛州的猿猴疟疾的流行情况和针对疟原虫的巢式PCR小亚基核糖体RNA基因。不出所料，与显微镜检查（27/103）相比，PCR分析的患病率（64/103）明显更高。无法确定猕猴的年龄和/或性别与寄生虫血症和感染猕猴的疟原虫种类之间的关系。彭亨州的野生猕猴患疟原虫的比例最高（89.7％），其次是霹雳州（69.2％）和柔佛州（28.9％）。疟原虫彦和P.食蟹是最普遍的两种物种感染所有三个国家的猕猴。一半的猕猴（33/64）拥有两个或多个疟原虫种类。这些数据提供了基线调查，应通过进一步的纵向调查加以扩展，该调查应与对按蚊载体的生物学研究有关。这些信息将有助于准确评估人畜共患疾病的传播风险，并拟定有效的策略来控制猿猴疟疾。