Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, South Africa.
Parasit Vectors. 2024 Aug 13;17(1):341. doi: 10.1186/s13071-024-06416-0.
Rift Valley fever virus (RVFV) is a zoonotic mosquito-borne virus with serious implications for livestock health, human health, and the economy in Africa, and is suspected to be endemic in north-eastern KwaZulu-Natal (KZN), South Africa. The vectors of RVFV in this area are poorly known, although several species, such as Aedes (Neomelaniconion) mcintoshi, Aedes (Neomelaniconion) circumluteolus, Aedes (Aedimorphus) durbanensis, and Culex (Lasioconops) poicilipes may be involved. The aim of the study was to determine the vertebrate blood meal sources of potential RVFV mosquito vectors in north-eastern KZN and to characterize the host-biting network.
Blood-fed mosquitoes were collected monthly from November 2019 to February 2023 using a backpack aspirator, CO-baited Centers for Disease Control and Prevention (CDC) miniature light traps and tent traps, in the vicinity of water bodies and livestock farming households. The mosquitoes were morphologically identified. DNA was extracted from individual mosquitoes and used as templates to amplify the vertebrate cytochrome c oxidase I (COI) and cytochrome b (cytb) genes using conventional polymerase chain reaction (PCR). Amplicons were sequenced and queried in GenBank and the Barcode of Life Data systems to identify the vertebrate blood meal sources and confirm mosquito identifications. All mosquitoes were screened for RVFV using real time reverse transcription (RT)-PCR.
We identified the mammalian (88.8%) and avian (11.3%) blood meal sources from 409 blood-fed mosquitoes. Aedes circumluteolus (n = 128) made up the largest proportion of collected mosquitoes. Cattle (n = 195) and nyala (n = 61) were the most frequent domestic and wild hosts, respectively. Bipartite network analysis showed that the rural network consisted of more host-biting interactions than the reserve network. All mosquitoes tested negative for RVFV.
Several mosquito species, including Ae. circumluteolus, and vertebrate host species, including cattle and nyala, could play a central role in RVFV transmission. Future research in this region should focus on these species to better understand RVFV amplification.
裂谷热病毒（RVFV）是一种人畜共患的蚊媒病毒，对非洲的牲畜健康、人类健康和经济造成严重影响，并且疑似在南非夸祖鲁-纳塔尔省东北部（KZN）流行。该地区 RVFV 的媒介蚊子知之甚少，尽管有几种物种，如 Aedes（Neomelaniconion）mcintoshi、Aedes（Neomelaniconion）circumluteolus、Aedes（Aedimorphus）durbanensis 和 Culex（Lasioconops）poicilipes 可能参与其中。本研究旨在确定 KZN 东北部潜在 RVFV 蚊媒的脊椎动物血液来源，并描述宿主叮咬网络。
2019 年 11 月至 2023 年 2 月，使用背包式吸气器、带有二氧化碳诱饵的疾病控制与预防中心（CDC）微型诱捕器和帐篷诱捕器，在水体和牲畜养殖家庭附近每月收集吸食血液的蚊子。对蚊子进行形态学鉴定。从单个蚊子中提取 DNA，并使用常规聚合酶链反应（PCR）将脊椎动物细胞色素 c 氧化酶 I（COI）和细胞色素 b（cytb）基因作为模板进行扩增。扩增子在 GenBank 和生命数据条形码系统中进行测序和查询，以确定脊椎动物的血液来源，并确认蚊子的鉴定。使用实时逆转录（RT）-PCR 对所有蚊子进行 RVFV 筛查。
我们从 409 只吸食血液的蚊子中确定了哺乳动物（88.8%）和鸟类（11.3%）的血液来源。Aedes circumluteolus（n=128）是采集到的蚊子中比例最大的物种。牛（n=195）和黑角马（n=61）分别是最常见的家养和野生宿主。二分网络分析表明，农村网络的宿主叮咬相互作用比保护区网络多。所有蚊子的 RVFV 检测均为阴性。
几种蚊子物种，包括 Ae. circumluteolus，以及牛和黑角马等脊椎动物宿主，可能在 RVFV 传播中发挥核心作用。该地区的未来研究应集中在这些物种上，以更好地了解 RVFV 的扩增。
