Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan.
Department of Microbiology, Faculty of Medicine and Research Center for Global and Local Infectious Diseases, Oita University, Yufu, Oita 879-5593, Japan.
Virus Res. 2024 Oct;348:199438. doi: 10.1016/j.virusres.2024.199438. Epub 2024 Jul 19.
Previous studies have emphasized the necessity of surveillance and control measures for hepatitis E virus (HEV) infection in wild boars, an important reservoir of HEV. To assess the current situation of HEV infection in wild boars in Japan, this study investigated the prevalence and genetic diversity of HEV among wild boars captured in 16 prefectures of Japan during 2018-2023. Serum samples from 968 wild boars were examined for anti-HEV IgG antibodies and HEV RNA. The prevalence of anti-HEV IgG varied geographically from 0 % to 35.0 %. HEV RNA was detected in 3.6 % of boars, with prevalence varying by prefecture from 0 % to 22.2 %. Genotype 3 was the most prevalent genotype (91.9 %), followed by genotype 4 (5.4 %), with one strain closely related to genotype 6. The prevalence of HEV infection among wild boars decreased from 2018/2019 to 2022/2023 with significant declines in levels of anti-HEV IgG antibodies (14.5 % vs. 6.2 %, P < 0.0001) and HEV RNA (7.6 % vs. 1.5 %, P < 0.0001). Regional analysis showed varying trends, with no HEV RNA-positive boars found in several regions in recent years. A plausible factor contributing to the decline in HEV infection is the application of countermeasures, including installing fences to prevent intrusion into pig farms, implemented in response to the emergence of classical swine fever virus (CSFV) infection in wild boars and domestic pigs, with incidents reported annually since 2018. Further investigation is warranted to explore the association between countermeasures to CSFV infection and the decrease in HEV infection among wild boars.
先前的研究强调了监测和控制野猪（戊型肝炎病毒 [HEV] 的重要储存宿主）中 HEV 感染的必要性。为评估日本野猪中 HEV 感染的现状，本研究调查了 2018 年至 2023 年间在日本 16 个县捕获的野猪中 HEV 的流行率和遗传多样性。对 968 头野猪的血清样本进行了抗-HEV IgG 抗体和 HEV RNA 检测。抗-HEV IgG 的流行率在地域上从 0%到 35.0%不等。HEV RNA 在 3.6%的野猪中被检测到，各地区的流行率从 0%到 22.2%不等。基因型 3 是最常见的基因型（91.9%），其次是基因型 4（5.4%），其中一个毒株与基因型 6 密切相关。野猪中 HEV 感染的流行率从 2018/2019 年到 2022/2023 年下降，抗-HEV IgG 抗体（14.5%比 6.2%，P<0.0001）和 HEV RNA（7.6%比 1.5%，P<0.0001）水平显著下降。区域分析显示出不同的趋势，近年来在几个地区未发现 HEV RNA 阳性野猪。HEV 感染下降的一个可能因素是针对野猪和家猪中经典猪瘟病毒（CSFV）感染采取的对策的应用，自 2018 年以来每年都有报道。需要进一步调查以探讨 CSFV 感染对策与野猪中 HEV 感染减少之间的关系。
