Department of Veterinary Science, National Institute of Infectious Diseases, Tokyo, Japan.
Laboratory of Veterinary Microbiology, Joint Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi, Japan.
J Vet Med Sci. 2022 Jul 10;84(7):982-991. doi: 10.1292/jvms.22-0236. Epub 2022 May 31.
The present study investigated severe fever with thrombocytopenia syndrome virus (SFTSV) infection in raccoons in Wakayama Prefecture from 2007 to 2019. To perform surveillance, an enzyme-linked immunosorbent assay (ELISA) was established, and the sensitivity and specificity of the ELISA were 100% in comparison with a 50% focus-reduction neutralization assay. Using the established ELISA, we performed serosurveillance of SFTSV infection in 2,299 raccoons in Tanabe region, Wakayama Prefecture from 2007 to 2019. The first anti-SFTSV-positive raccoon was captured in October 2009. The seroprevalence of SFTSV infection was <10% between April 2009 and March 2013, 23.9% between April 2013 and March 2014, 37.5% between April, 2014 and March 2015, and over 50% from April 2015. Next, we performed detection of SFTSV genes in sera of raccoons captured in Wakayama Prefecture after April 2013. The results indicated that 2.4% of raccoons were positive for SFTSV genes and that the frequency of SFTSV infection among raccoons between January and March (0.7%) was lower than that between April and June (3.4%). In addition, virus genes were detected from many specimens, including sera and feces of two raccoons, and viral antigens were detected in lymphoid cells in lymphoid follicles in the colon by immunohistochemical staining. In conclusion, SFTSV had recently invaded the area and had rapidly spread among wild animals. The first patient in this area was reported in June 2014, indicating that raccoons are good sentinels for assessing the risk of SFTSV in humans.
本研究调查了 2007 年至 2019 年日本和歌山县浣熊中严重发热伴血小板减少综合征病毒（SFTSV）的感染情况。为了进行监测，建立了酶联免疫吸附试验（ELISA），与 50%的焦点减少中和试验相比，该 ELISA 的灵敏度和特异性均为 100%。使用建立的 ELISA，我们对 2007 年至 2019 年和歌山县田边地区的 2299 只浣熊进行了 SFTSV 感染的血清学监测。第一只抗 SFTSV 阳性浣熊于 2009 年 10 月捕获。SFTSV 感染的血清阳性率在 2009 年 4 月至 2013 年 3 月期间<10%，2013 年 4 月至 2014 年 3 月期间为 23.9%，2014 年 4 月至 2015 年 3 月期间为 37.5%，从 2015 年 4 月开始超过 50%。接下来，我们对 2013 年 4 月后在和歌山县捕获的浣熊血清中 SFTSV 基因进行了检测。结果表明，有 2.4%的浣熊 SFTSV 基因呈阳性，1 月至 3 月（0.7%）感染 SFTSV 的浣熊频率低于 4 月至 6 月（3.4%）。此外，从许多标本中检测到病毒基因，包括两只浣熊的血清和粪便，并且通过免疫组织化学染色在结肠的淋巴滤泡中检测到淋巴样细胞中的病毒抗原。总之，SFTSV 最近已入侵该地区，并在野生动物中迅速传播。该地区的第一例患者于 2014 年 6 月报告，这表明浣熊是评估 SFTSV 感染人类风险的良好哨兵。
