Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL, United States.
Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, United States.
Front Cell Infect Microbiol. 2022 Jul 1;12:923914. doi: 10.3389/fcimb.2022.923914. eCollection 2022.
The Asian longhorned tick, , is an ixodid tick native to East Asia that was first detected in North America outside a port of entry in 2017. This invasive species has since been detected in 17 states. As the invasive range of the tick continues to expand, the vector competence of for pathogens native to North America must be assessed. Here, we evaluate the vector competence of for Powassan virus (POWV) under laboratory conditions. POWV is a North American tick-borne flavivirus that is typically transmitted through the bite of species ticks. The invasive range of is expected to overlap heavily with the geographic range of and POWV cases, highlighting the potential for this invasive tick species to amplify POWV transmission in natural foci should the native tick vectors and share similar hosts. In these studies, adult female ticks were infected with POWV anal pore microinjection. Viral RNA and infectious virions were detected in tick tissues q-RT-PCR and focus-forming assay, respectively. POWV-injected female ticks were infested on mice, and virus was transmitted to mice during tick feeding, as shown by clinical signs of disease and seroconversion in the tick-exposed mice, as well as the detection of viral RNA in various mouse tissues. A POWV-injected female tick transmitted virus to her larval progeny, indicating that can vertically transmit POWV. These naturally-infected larval ticks were also able to transmit POWV to the mouse on which they fed and to the nymphal stage after molting, further demonstrating that s can transmit POWV in the horizontal and transstadial modes. Larval and nymphal ticks were also orally infected with POWV while feeding on viremic mice. Additionally, this study provides the first report of POWV neuropathology based on a natural tick transmission model of POWV. Together, our results suggest that the invasive tick is a competent vector of POWV. These findings underline the growing danger this tick may pose to human health in the United States. Additional scholarship on the tick's biology, ecology, and pathogen transmission dynamics in nature will be important towards understanding the full public health impact of this invasive species.
亚洲璃眼蜱，是一种原产于东亚的革蜱属蜱，于 2017 年在一个入境港外的北美的一个非入境港首次被发现。自此，该入侵物种已在 17 个州被发现。随着蜱虫的入侵范围不断扩大，必须评估其对北美的病原体的媒介能力。在这里，我们在实验室条件下评估了亚洲璃眼蜱对 Powassan 病毒（POWV）的媒介能力。POWV 是一种北美的蜱传黄病毒，通常通过吸血的璃眼蜱属蜱的叮咬传播。亚洲璃眼蜱的入侵范围预计将与 和 POWV 病例的地理范围严重重叠，这凸显了如果本地的蜱虫媒介和亚洲璃眼蜱属蜱共享相似的宿主，这种入侵的蜱种可能会在自然疫源地放大 POWV 的传播。在这些研究中，成年雌性亚洲璃眼蜱通过肛门微注射感染 POWV。通过 q-RT-PCR 和焦点形成测定法，分别在蜱组织中检测到病毒 RNA 和传染性病毒粒子。感染 POWV 的雌性蜱虫在感染小鼠后被寄生，在蜱虫叮咬期间，病毒传播给了小鼠，这从暴露于蜱虫的小鼠出现疾病和血清转化的临床症状，以及在各种小鼠组织中检测到病毒 RNA 中得到了证明。感染 POWV 的雌性蜱虫将病毒传播给她的幼虫后代，表明亚洲璃眼蜱属蜱可以垂直传播 POWV。这些自然感染的幼虫蜱也能够将 POWV 传播给它们所寄生的小鼠，以及在蜕皮后的若虫阶段，进一步证明了它们可以通过水平和转期两种方式传播 POWV。幼虫和若虫蜱在吸食携带病毒的小鼠时也通过口服感染了 POWV。此外，本研究提供了基于 POWV 自然传播模型的 POWV 神经病理学的首次报道。总之，我们的研究结果表明，入侵的亚洲璃眼蜱是 POWV 的一种有能力的媒介。这些发现强调了这种蜱虫对美国人类健康构成的日益严重的威胁。对该蜱虫的生物学、生态学和病原体传播动力学的进一步研究，对于了解该入侵物种的全部公共卫生影响将是重要的。
