National Institute of Malariology, Parasitology and Entomology, Hanoi, Vietnam.
Health Poverty Action Vietnam, Hanoi, Vietnam.
Malar J. 2023 Jul 5;22(1):204. doi: 10.1186/s12936-023-04631-1.
Despite recent reductions in Vietnam, malaria transmission persists in some areas in forests and farmlands where a high density of Anopheles mosquitoes relative to other environments occurs. To inform effective malaria control measures, it is important to understand vector bionomics and the malaria transmission role of Anopheles spp. in the highland regions of Vietnam. This study was conducted to quantify the abundance, composition and biting behaviour of the Anopheles mosquito population, and the proportion of Plasmodium spp. infected mosquitoes collected from forest and agricultural farm sites in Gia Lai province, Vietnam.
Forest and agricultural farm sites in Gia Lai province were selected for mosquito collections (total eight sites). Mosquito collection was performed by Human-baited Double Net Trap (HDNT), animal-baited traps (ABT) using cattle, and CDC light traps. Captured mosquitoes were identified morphologically, and salivary glands of Anopheles mosquitoes were examined for sporozoites using microscopy. Plasmodium infection was determined by Polymerase Chain Reaction (PCR), and identification of blood meal type was determined by PCR and diffuse serum agglutination assay.
A total of 1815 Anopheles mosquitoes belonging to 19 species were collected by ABT (n = 1169), HDNT (n = 471) and CDC light trap (n = 175). Anopheles abundance and diversity varied by district and environment. Capture by HDNT of Anopheles of vectorial concern was observed between early evening and early morning. Plasmodium vivax infection was determined by PCR in two Anopheles dirus specimens captured by HDNT in forest sites. Blood from a range of hosts could, including human blood, could be detected in species considered primary and secondary vectors An. dirus, and Anopheles aconitus, and Anopheles maculatus, respectively.
A low number of Anopheles spp. considered primary vectors of concern and very low numbers of Plasmodium spp. infected Anopheles mosquitoes were captured at the end of the rainy season in the Central Highlands of Vietnam. However, capture species of vectorial concern by HDNT throughout the early to late evening demonstrates that use of additional personal protective measures could supplement current preventative measures, such as bed nets to prevent exposure to vectors of concern in this region.
尽管越南最近有所减少，但在森林和农田等某些地区，疟疾病媒依然存在，那里的按蚊密度相对其他环境较高。为了制定有效的疟疾控制措施，了解按蚊的媒介生物学特性以及在越南高原地区的疟疾病媒传播作用非常重要。本研究旨在量化采集自越南嘉莱省森林和农业农田的按蚊种群的丰度、组成和叮咬行为，以及感染疟原虫的按蚊比例。
选择嘉莱省的森林和农业农田进行蚊子采集（共 8 个地点）。蚊子采集通过人诱双层帐（HDNT）、使用牛的动物诱捕器（ABT）和 CDC 诱蚊灯进行。捕获的蚊子通过形态学进行鉴定，并用显微镜检查按蚊的唾液腺是否有孢子。通过聚合酶链反应（PCR）确定疟原虫感染情况，通过 PCR 和弥散血清凝集试验确定血餐类型。
共采集到 1815 只属于 19 个种的按蚊，其中 ABT（n=1169）、HDNT（n=471）和 CDC 诱蚊灯（n=175）分别采集到 1815 只、471 只和 175 只。蚊子的数量和多样性因地区和环境而异。HDNT 捕捉到的有传播意义的按蚊，其活动时间在傍晚至清晨之间。在森林地区的 HDNT 中捕获到的两只按蚊迪蚊中检测到间日疟原虫感染。在被认为是主要和次要媒介的按蚊迪蚊、按蚊库蚊和按蚊斑蚊中，检测到了包括人血在内的多种宿主的血液。
在越南中部高地的雨季末期，只捕获到少量被认为是主要传播媒介的按蚊和非常少量感染疟原虫的按蚊。然而，HDNT 整个傍晚到深夜都在捕捉到有传播意义的物种，这表明在该地区使用额外的个人防护措施可以补充当前的预防措施，如蚊帐，以防止接触到有传播意义的病媒。
