Horizontal and Vertical Transmission of Powassan Virus by the Invasive Asian Longhorned Tick, Haemaphysalis longicornis, Under Laboratory Conditions.
Horizontal and Vertical Transmission of Powassan Virus by the Invasive Asian Longhorned Tick, Haemaphysalis longicornis, Under Laboratory Conditions.
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DOI：
10.3389/fcimb.2022.923914
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发表时间：
2022
影响因子：
5.7
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中科院分区：
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亚洲长角蜱 (Haemaphysalis longicornis) 是一种原产于东亚的蜱类蜱，于 2017 年首次在北美入境口岸外发现。此后，这种入侵物种已在 17 个州被发现。随着蜱的入侵范围不断扩大，必须评估长角蜱对北美本土病原体的媒介能力。在这里，我们在实验室条件下评估了 H. longicornis 对 Powassan 病毒 (POWV) 的载体能力。 POWV 是一种北美蜱传黄病毒，通常通过硬蜱叮咬传播。预计长角蜱的入侵范围将与肩胛硬蜱和 POWV 病例的地理范围严重重叠，这突出表明，如果本地蜱媒介和长角蜱拥有相似的宿主，这种入侵蜱种就有可能在自然疫源地放大 POWV 传播。在这些研究中，成年雌性长角蜱蜱通过肛门孔显微注射感染 POWV。分别通过 q-RT-PCR 和病灶形成测定在蜱组织中检测到病毒 RNA 和感染性病毒粒子。注射POWV的雌性蜱虫感染在小鼠身上，病毒在蜱虫喂养过程中传播给小鼠，这可以从暴露于蜱虫的小鼠的疾病临床症状和血清转化以及在小鼠各种组织中检测到病毒RNA中看出。注射了 POWV 的雌性蜱将病毒传播给其幼虫后代，表明长角蜱可以垂直传播 POWV。这些自然感染的幼虫蜱也能够将 POWV 传播给它们喂养的小鼠以及蜕皮后的若虫阶段，进一步证明 H. longicornis 可以以水平和跨斯塔迪尔模式传播 POWV。幼虫和若虫蜱在喂食病毒血症小鼠时也经口感染 POWV。此外，本研究首次基于 POWV 自然蜱传播模型提供了 POWV 神经病理学报告。总之，我们的结果表明，入侵性长角蜱是 POWV 的有效载体。这些发现强调了这种蜱虫可能对美国人类健康造成的日益严重的危险。关于蜱在自然界中的生物学、生态学和病原体传播动力学的额外学术研究对于了解这种入侵物种对公共健康的全面影响非常重要。
The Asian longhorned tick, Haemaphysalis longicornis, 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 H. longicornis for pathogens native to North America must be assessed. Here, we evaluate the vector competence of H. longicornis for Powassan virus (POWV) under laboratory conditions. POWV is a North American tick-borne flavivirus that is typically transmitted through the bite of Ixodes species ticks. The invasive range of H. longicornis is expected to overlap heavily with the geographic range of Ixodes scapularis and POWV cases, highlighting the potential for this invasive tick species to amplify POWV transmission in natural foci should the native tick vectors and H. longicornis share similar hosts. In these studies, adult female H. longicornis ticks were infected with POWV via anal pore microinjection. Viral RNA and infectious virions were detected in tick tissues via 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 H. longicornis 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 H. longicornis 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 H. longicornis 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.