Department of Dermatology, Asahikawa Medical University, Asahikawa, Japan.
Department of Parasitology, Asahikawa Medical University, Asahikawa, Japan.
J Dermatol. 2021 Jul;48(7):1094-1097. doi: 10.1111/1346-8138.15865. Epub 2021 Mar 23.
A tick infestation is one of the most common arthropod-related skin diseases in Hokkaido, the northernmost island of Japan. Ticks also act as an infectious disease vector for humans. Tick-borne encephalitis (TBE), a highly mortal central nervous system infection caused by TBE virus (TBEV), has sporadically occurred there recently. However, there have been no epidemiological data on the current surveillance of human tick bites and the prevalence of TBEV in human-feeding ticks. This study was performed to clarify those indeterminate issues. One hundred and fifty-three ixodid ticks feeding on humans were collected from 150 outpatients in Hokkaido during the season of April to August 2018. None of the cases showed any infectious symptoms. These ticks were morphologically identified to species, and a cytopathic assay on baby hamster kidney cells was carried out to detect TBEV from each tick. The tick collection consisted of 108 Ixodes persulcatus (one nymph and 107 adult females), 44 female Ixodes ovatus, and one female Haemaphysalis japonica. No tick extracts showed positive results of the cytopathic assay, suggesting the non-existence of TBEV in the present specimens. However, the survey to detect TBEV from human-feeding ticks is still important to monitor the occurrence of TBE, because human tick bites by I. ovatus, a possible vector of TBEV, are increasing even in the northern and eastern areas of Hokkaido.
在日本最北部的岛屿北海道，蜱虫感染是最常见的节肢动物相关皮肤病之一。蜱虫还充当人类传染病的媒介。近年来，那里偶尔会发生由蜱传脑炎病毒（TBEV）引起的致死率极高的中枢神经系统感染——蜱传脑炎（TBE）。然而，目前还没有关于人类被蜱叮咬的监测和人类吸食蜱虫中 TBEV 流行情况的流行病学数据。本研究旨在澄清这些不确定的问题。2018 年 4 月至 8 月期间，从北海道的 150 名门诊患者中采集了 153 只吸食人类血液的硬蜱。这些患者均无任何感染症状。对这些蜱虫进行形态学鉴定，并在乳仓鼠肾细胞上进行细胞病变测定，以检测来自每只蜱虫的 TBEV。蜱虫采集包括 108 只 Ixodes persulcatus（1 只若虫和 107 只成年雌性）、44 只雌性 Ixodes ovatus 和 1 只雌性 Haemaphysalis japonica。没有蜱虫提取物在细胞病变测定中呈阳性结果，表明目前标本中不存在 TBEV。然而，从吸食人类血液的蜱虫中检测 TBEV 的调查对于监测 TBE 的发生仍然很重要，因为 TBEV 的可能媒介 I. ovatus 引起的人类蜱虫叮咬在北海道的北部和东部地区也在增加。
