Data from: Venereal Transmission of Vesicular Stomatitis Virus by Culicoides sonorensis Midges

Culicoides sonorensis biting midges are well-known agricultural pests and transmission vectors of arboviruses such as vesicular stomatitis virus (VSV). The epidemiology of VSV is complex and encompasses a broad range of vertebrate hosts, multiple routes of transmission, and diverse vector species. In temperate regions, viruses can overwinter in the absence of infected animals through unknown mechanisms, to reoccur the next year. Non-conventional routes for VSV vector transmission may help explain viral maintenance in midge populations during inter-epidemic periods and times of adverse conditions for bite transmission. In this study, we examined whether VSV could be transmitted venereally between male and female midges. Our results showed that VSV-infected females could venereally transmit virus to uninfected naïve males at a rate as high as 76.3% (RT-qPCR), 31.6% (virus isolation) during the third gonotrophic cycle. Additionally, VSV-infected males could venereally transmit virus to uninfected naïve females at a rate as high as 76.6% (RT-qPCR), 49.2% (virus isolation). Immunofluorescent staining of micro-dissected reproductive organs, immunochemical staining of midge histological sections, examination of internal reproductive organ morphology, and observations of mating behaviors were used to determine relevant anatomical sites for virus location and to hypothesize the potential mechanism for VSV transmission in C. sonorensis midges through copulation.

索诺兰库蠓（Culicoides sonorensis）是一类广为人知的农业害虫，同时也是水泡性口炎病毒（vesicular stomatitis virus, VSV）等虫媒病毒的传播媒介。水泡性口炎病毒的流行病学特征极为复杂，涵盖广泛的脊椎动物宿主、多元的传播路径以及多样的媒介物种。在温带区域，即便无感染宿主动物存在，病毒仍可通过未知机制越冬，并于次年再度暴发。非传统的媒介传播途径或可解释病毒在流行间期以及叮咬传播条件不利时，在库蠓种群中的维持机制。本研究探究了VSV是否可通过交配途径在雌雄库蠓间传播。研究结果显示，在第三次生殖营养周期中，感染VSV的雌蠓可将病毒经交配途径传播给未接触过病毒的易感雄蠓，传播率经实时荧光定量聚合酶链反应（RT-qPCR）检测可达76.3%，经病毒分离检测可达31.6%。此外，感染VSV的雄蠓也可经交配途径将病毒传播给未接触过病毒的易感雌蠓，传播率经RT-qPCR检测可达76.6%，经病毒分离检测可达49.2%。本研究通过对显微解剖的生殖器官进行免疫荧光染色、库蠓组织切片的免疫化学染色、内部生殖器官形态学观察以及交配行为观测，明确了病毒定位的相关解剖部位，并推测了C. sonorensis库蠓通过交配传播VSV的潜在机制。