Medical and Veterinary Entomology Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
Medical Laboratory, Institut Pasteur du Cambodge, Phnom Penh, Cambodia.
Med Vet Entomol. 2023 Dec;37(4):737-744. doi: 10.1111/mve.12678. Epub 2023 Jul 5.
In Southeast Asia, despite the use of Japanese encephalitis vaccines and vaccination coverage, Japanese encephalitis (JE) transmission is still a major public health issue. The main vectors of this virus are mosquitoes from the genus Culex, which diversity and density are important in Southeast Asia. The main vector species of Japanese encephalitis virus (JEV) in Cambodia belong to the Vishnui subgroup. However, their morphological identification solely based on the adult stage remains challenging, making their segregation and detection difficult. In order to identify and describe the distribution of the three main JEV vector species in Cambodia, namely Culex vishnui, Cx. pseudovishnui and Cx. tritaeniorhynchus, mosquito samplings were carried out throughout the country in different environments. Phylogenetic analysis of the cytochrome c oxidase subunit I (coI) gene using maximum-likelihood tree with ultrafast bootstrap and phylogeographic analysis were performed. The three main Culex species are phylogenetically separated, and represent two distinct clades, one with Cx. tritaeniorhynchus and the second with Cx. vishnui and Cx. pseudovishnui, the latter appearing as a subgroup of Cx. vishnui. The phylogeographic analysis shows a distribution of the Vishnui subgroup on the entire Cambodian territory with an overlapped distribution areas leading to a sympatric distribution of these species. The three JEV vector species are geographically well-defined with a strong presence of Cx. pseudovishnui in the forest. Combined with the presence of Cx. tritaeniorhynchus and Cx. vishnui in rural, peri-urban, and urban areas, the presence of JEV-competent vectors is widespread in Cambodia.
在东南亚，尽管使用了日本脑炎疫苗并且接种率很高，但日本脑炎（JE）仍然是一个主要的公共卫生问题。该病毒的主要传播媒介是库蚊属的蚊子，其多样性和密度在东南亚很重要。柬埔寨日本脑炎病毒（JEV）的主要媒介种属于 Vishnui 亚群。然而，仅基于成虫阶段对它们进行形态学鉴定仍然具有挑战性，这使得它们的分离和检测变得困难。为了鉴定和描述柬埔寨三种主要 JEV 媒介种，即库蚊属的 Culex vishnui、Cx. pseudovishnui 和 Cx. tritaeniorhynchus 的分布，在不同环境中对全国的蚊子进行了采样。使用最大似然树法进行了细胞色素 c 氧化酶亚基 I（coI）基因的系统发育分析，采用超快自举和系统地理学分析。这三种主要的库蚊种在系统发育上是分开的，代表两个不同的分支，一个分支是 Cx. tritaeniorhynchus，另一个分支是 Cx. vishnui 和 Cx. pseudovishnui，后者是 Cx. vishnui 的一个亚群。系统地理学分析显示，Vishnui 亚群在整个柬埔寨领土上的分布情况，其分布区域重叠，导致这些物种的同域分布。三种 JEV 媒介种在地理上有明确的界限，在森林中 Cx. pseudovishnui 的存在很强。结合 Cx. tritaeniorhynchus 和 Cx. vishnui 在农村、城郊和城市地区的存在，JEV 有能力的媒介在柬埔寨广泛存在。
