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.

松嫩库蠓（Culicoides sonorensis）作为吸血蠓，是公认的农业害虫，同时也是水疱性口炎病毒（vesicular stomatitis virus, VSV）等虫媒病毒（arboviruses）的传播媒介。水疱性口炎病毒的流行病学特征复杂，涵盖广泛的脊椎动物宿主、多元传播途径以及多样的媒介物种。在温带地区，病毒可在无感染动物存在的情况下，通过未知机制完成越冬，并于次年再次暴发流行。水疱性口炎病毒媒介传播的非常规途径，或可解释流行间歇期以及吸血传播条件不利时，病毒在蠓种群中的维持机制。本研究旨在探究水疱性口炎病毒是否可在雌雄蠓之间经性交途径传播。研究结果显示，在第三个生殖营养周期中，感染水疱性口炎病毒的雌蠓可将病毒经性交传播给未感染且未接触过病毒的雄蠓，传播效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，感染水疱性口炎病毒的雄蠓可将病毒经性交传播给未感染且未接触过病毒的雌蠓，传播效率经实时荧光定量聚合酶链反应检测可达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、对蠓组织切片进行免疫化学染色、观察内生殖器官形态以及交配行为，确定了病毒在宿主体内的相关解剖定位，并推测了松嫩库蠓通过交配传播水疱性口炎病毒的潜在机制。