Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
Institute for Bacterial Infections and Zoonoses, Friedrich-Loeffler-Institut, Naumburger Str. 96a, 07743 Jena, Germany.
Viruses. 2019 Jul 22;11(7):669. doi: 10.3390/v11070669.
Tick-borne encephalitis virus (TBEV) is an important arbovirus, which is found across large parts of Eurasia and is considered to be a major health risk for humans. Like any other arbovirus, TBEV relies on complex interactions between vectors, reservoir hosts, and the environment for successful virus circulation. Hard ticks are the vectors for TBEV, transmitting the virus to a variety of animals. The importance of these animals in the lifecycle of TBEV is still up for debate. Large woodland animals seem to have a positive influence on virus circulation by providing a food source for adult ticks; birds are suspected to play a role in virus distribution. Bank voles and yellow-necked mice are often referred to as classical virus reservoirs, but this statement lacks strong evidence supporting their highlighted role. Other small mammals (e.g., insectivores) may also play a crucial role in virus transmission, not to mention the absence of any suspected reservoir host for non-European endemic regions. Theories highlighting the importance of the co-feeding transmission route go as far as naming ticks themselves as the true reservoir for TBEV, and mammalian hosts as a mere bridge for transmission. A deeper insight into the virus reservoir could lead to a better understanding of the development of endemic regions. The spatial distribution of TBEV is constricted to certain areas, forming natural foci that can be restricted to sizes of merely 500 square meters. The limiting factors for their occurrence are largely unknown, but a possible influence of reservoir hosts on the distribution pattern of TBE is discussed. This review aims to give an overview of the multiple factors influencing the TBEV transmission cycle, focusing on the role of virus reservoirs, and highlights the questions that are waiting to be further explored.
蜱传脑炎病毒（TBEV）是一种重要的虫媒病毒，广泛分布于欧亚大陆的大部分地区，被认为是人类的主要健康威胁之一。与其他虫媒病毒一样，TBEV 的成功传播依赖于媒介、储存宿主和环境之间的复杂相互作用。硬蜱是 TBEV 的媒介，将病毒传播给多种动物。这些动物在 TBEV 生命周期中的重要性仍存在争议。大型林地动物似乎通过为成年蜱虫提供食物来源对病毒传播产生积极影响；鸟类被怀疑在病毒分布中发挥作用。田鼠和黄胸鼠通常被称为经典的病毒储存宿主，但这一说法缺乏强有力的证据支持其突出作用。其他小型哺乳动物（如食虫动物）也可能在病毒传播中发挥关键作用，更不用说在非欧洲地方性流行地区缺乏任何可疑的储存宿主了。强调共食传播途径重要性的理论甚至将蜱虫本身命名为 TBEV 的真正储存宿主，而哺乳动物宿主只是传播的桥梁。对病毒储存宿主的更深入了解可以更好地理解地方性流行地区的发展。TBEV 的空间分布受到某些地区的限制，形成了仅 500 平方米大小的自然焦点。其发生的限制因素很大程度上未知，但储存宿主对 TBE 分布模式的可能影响正在讨论中。本综述旨在概述影响 TBEV 传播周期的多种因素，重点关注病毒储存宿主的作用，并强调有待进一步探索的问题。
