Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan.
Viruses. 2017 Jul 17;9(7):189. doi: 10.3390/v9070189.
The tick-borne encephalitis virus (TBEV) serocomplex of flaviviruses consists of arboviruses that cause important diseases in animals and humans. The transmission of this group of viruses is commonly associated with tick species such as Ixodes spp., Dermacentor spp., and Hyalomma spp. In the case of Haemaphysalis longicornis, the detection and isolation of flaviviruses have been previously reported. However, studies showing survival dynamics of any tick-borne flavivirus in H. longicornis are still lacking. In this study, an anal pore microinjection method was used to infect adult H. longicornis with Langat virus (LGTV), a naturally attenuated member of the TBEV serocomplex. LGTV detection in ticks was done by real-time PCR, virus isolation, and indirect immunofluorescent antibody test. The maximum viral titer was recorded at 28 days post-inoculation, and midgut cells were shown to be the primary replication site. The tick can also harbor the virus for at least 120 days and can successfully transmit LGTV to susceptible mice as confirmed by detection of LGTV antibodies. However, no transovarial transmission was observed from the egg and larval samples. Taken together, our results highly suggest that anal pore microinjection can be an effective method in infecting adult H. longicornis, which can greatly assist in our efforts to study tick and virus interactions.
蜱传脑炎病毒（TBEV）属黄病毒复合群，由节肢动物传播的病毒引起，可感染动物和人类。该病毒组的传播通常与硬蜱属、璃眼蜱属和革蜱属等蜱种有关。在长角血蜱中，已报道过黄病毒的检测和分离。然而，目前仍缺乏关于任何蜱传黄病毒在长角血蜱中存活动态的研究。在这项研究中，我们使用肛门口微注射法感染成年长角血蜱，使其感染 Langat 病毒（LGTV），这是 TBEV 复合群中的一种天然减毒成员。通过实时 PCR、病毒分离和间接免疫荧光抗体试验来检测蜱中的 LGTV。LGTV 的最大病毒滴度在接种后 28 天记录到，并且中肠细胞被证明是主要的复制部位。这种蜱至少可以携带病毒 120 天，并能成功地将 LGTV 传播给易感小鼠，这通过检测 LGTV 抗体得到了证实。然而，在卵和幼虫样本中没有观察到经卵传播。总之，我们的结果强烈表明肛门口微注射可以有效感染成年长角血蜱，这将极大地帮助我们研究蜱与病毒的相互作用。
