Department of Biology, University of North Dakota, Grand Forks, North Dakota, United States of America.
Virology Division, US Army Medical Research Institute of Infectious Diseases, Fort Detrick, Maryland, United States of America.
PLoS Negl Trop Dis. 2022 Oct 6;16(10):e0010835. doi: 10.1371/journal.pntd.0010835. eCollection 2022 Oct.
The transmission cycle of West Nile virus (WNV) involves multiple species of birds. The relative importance of various bird species to the overall transmission is often inferred from the level and duration of viremia that they experience upon infection. Reports utilizing in vitro feeding techniques suggest that the source and condition of blood in which arboviruses are fed to mosquitoes can significantly alter the infectiousness of arbovirus to mosquitoes. We confirmed this using live hosts. A series of mosquito feedings with Culex pipiens was conducted on WNV-infected American robins and common grackles over a range of viremias. Mosquitoes were assayed individually by plaque assay for WNV at 3 to 7 days after feeding. At equivalent viremia, robins always infected more mosquitoes than did grackles. We conclude that the infectiousness of viremic birds cannot always be deduced from viremia alone. If information concerning the infectiousness of a particular bird species is important, such information is best acquired by feeding mosquitoes directly on experimentally infected individuals of that species.
西尼罗河病毒（WNV）的传播周期涉及多种鸟类。各种鸟类对整体传播的相对重要性通常是根据它们感染后出现的病毒血症水平和持续时间来推断的。利用体外饲养技术的报告表明，向蚊子提供黄病毒的血液来源和状况可以显著改变黄病毒对蚊子的感染力。我们使用活体宿主证实了这一点。在一系列的实验中，用库蚊属的蚊子对不同病毒血症的感染西尼罗河病毒的美洲知更鸟和普通八哥进行了多次喂食。在喂食后 3 到 7 天，通过噬菌斑测定法对每只蚊子进行西尼罗河病毒检测。在同等的病毒血症水平下，知更鸟感染的蚊子总是比八哥多。我们的结论是，病毒血症鸟类的感染力不能仅仅从病毒血症来推断。如果有关特定鸟类感染性的信息很重要，那么最好通过直接在该物种的实验感染个体上喂养蚊子来获取该信息。
