Yanase Tohru, Hayama Yoko, Shirafuji Hiroaki, Tsutsui Toshiyuki, Terada Yutaka
Kyushu Research Station, National Institute of Animal Health, NARO, 2702, Chuzan, Kagoshima 891-0105, Japan.
Viral Disease and Epidemiology Research Division, National Institute of Animal Health, NARO, 3-1-5, Kannondai, Tsukuba, Ibaraki 305-0856, Japan.
J Vet Med Sci. 2019 Oct 24;81(10):1496-1503. doi: 10.1292/jvms.19-0303. Epub 2019 Aug 23.
A surveillance of Culicoides biting midges with light suction traps was conducted in the northern region of Honshu, main island of Japan, during the summers and autumns of 2009 and 2010. A total of 106 trap collections across 37 cattle farms were investigated for the structure and distribution of Culicoides species. Forty-thousand and one hundred forty-nine specimens of Culicoides biting midges were identified at the species level, and ≥19 species were included in the specimens. Culicoides oxystoma, which is a known major vector of Akabane virus (AKAV), appeared not to have expanded in northern Honshu during the surveillance. Of the potential AKAV vectors suggested by a previous laboratory experiment, C. tainanus and C. punctatus widely infested cowsheds across northern Honshu. The AKAV circulation was confirmed by serological surveillance of sentinel cattle in northern Honshu during the summer and autumn of 2010 and, consequently, >200 calves affected by the virus were identified as of spring 2011. Our surveillance demonstrated that C. tainanus and C. punctatus were widely spread and often dominated at cattle farms in/around the seroconverted regions, and our results thus suggest that these species played a critical role in the AKAV transmission in 2010. Because the distribution ranges of C. tainanus and C. punctatus cover almost all of mainland Japan, a potential risk of AKAV transmission might be expected even in areas outside the range of C. oxystoma.
2009年和2010年的夏秋季节，在日本主岛本州岛北部地区，使用灯光诱捕器对库蠓属蠓虫进行了监测。对37个养牛场的总共106次诱捕采集样本进行了调查，以研究库蠓属物种的结构和分布。在物种水平上鉴定出40149只库蠓属蠓虫标本，标本中包含≥19个物种。尖喙库蠓是赤羽病毒（AKAV）的已知主要传播媒介，在监测期间似乎并未在本州岛北部扩散。根据先前的实验室实验推测，台南库蠓和点滴库蠓广泛侵扰本州岛北部的牛舍。通过对2010年夏秋季节本州岛北部哨兵牛的血清学监测，证实了AKAV的传播，因此，截至2011年春季，已鉴定出>200头受该病毒感染的小牛。我们的监测表明，台南库蠓和点滴库蠓广泛传播，并且在血清转化地区内/周边的养牛场中经常占主导地位，因此我们的结果表明，这些物种在2010年的AKAV传播中起了关键作用。由于台南库蠓和点滴库蠓的分布范围几乎覆盖了整个日本本土，即使在尖喙库蠓分布范围以外的地区，也可能存在AKAV传播的潜在风险。
