Investigation of zoonotic infection of hepatitis E virus among mammalians and birds

1. 在日本从北海道到冲绳的20个县饲养的1425头猪中，794头（56%）检测出抗HEV IgG，表明HEV感染在日本猪中广泛存在。鉴定出55株与日本急性戊型肝炎患者分离株密切相关的猪戊型肝炎分离株。鉴定和鉴定了两株基因3型HEV分离株，它们与同一基因型的已知分离株的同源性仅为81-83%。血清抗HEV IgA阳性与HEV病毒血症相关。在日本12个县捕获的87只野猪中，有两只检测到HEV RNA。测定了从这两个地区（山口和德岛）和先前在佐贺县发现的病毒血症野猪分离的三株HEV株的全基因组序列。它们与日本从肝炎患者和猪中分离出的HEV密切相关。在蒙古243头猪中，223头（92%）和89头（37%）抗HEV IgG和HEV RNA阳性。鉴定出似乎是本土的基因3型HEV分离株。在印度尼西亚巴厘岛的101头猪中，58头（57%）抗戊肝病毒IgG阳性，5头（5%）戊肝病毒血症。鉴定出4株基因4型葡萄酒HEV分离株，其核苷酸序列与巴厘岛戊型肝炎患者分离株的同源性为97 ~ 98%。这些结果表明，即使在发展中国家也存在人畜共患戊型肝炎。基因型4的HEV分离株是从日本爱知县食用捕获的野猪肉后感染急性戊型肝炎的4名患者身上分离到的。由于从同一地区捕获的野猪中分离出两株鉴定率为bbbb99 %的HEV分离株，因此强烈认为HEV是由野猪传染给人的。建立了一种检测1-4基因型人和动物hev的高灵敏度RT-PCR系统。

1. Seven-hundred ninety-four (56%) of 1,425 farm pigs that were raised in 20 prefectures from Hokkaido to Okinawa, Japan had detectable anti-HEV IgG, indicating that HEV infection is widespread among Japanese pigs. Fifty-five swine HEV isolates that were closely related to HEV isolates obtained from Japanese patients with acute hepatitis E were identified. Two genotype 3 HEV isolates that shared only 81-83% identities with known isolates of same genotype were identified and characterized. Positivity of serum anti-HEV IgA was correlated to HEV viremia.2. Two of 87 wild boars caught in 12 prefectures in Japan had detectable HEV RNA. Full-genome sequences of three HEV isolates from these two (Yamaguchi and Tokushima) and previously found viremic boar in Saga were determined. They were closely related to HEV isolates recovered from hepatitis patients and pigs in Japan.3. Among 243 pigs in Mongolia, 223 (92%) and 89 (37%) were positive for anti-HEV IgG and HEV RNA, respectively. HEV isolates of genotype 3 that appeared to be indigenous were identified. Among 101 pigs in Bali, Indonesia, 58 (57%) were positive for anti-HEV IgG and five(5%) were viremic for HEV. Fours wine HEV isolates of genotype 4 whose nucleotide sequence showed 97-98% identities to HEV isolate recovered from a patient with hepatitis E in Bali were identified. These results indicate that zoonotic hepatitis E is present even in developing countries.4. The HEV isolates of genotype 4 were recovered from four patients who contracted acute hepatitis E after eating meat from wild boars caught in Aichi, Japan. Since two HEV isolates that had an identity of >99% were recovered from wild boars caught in the same area, HEV infection from boars to humans was strongly suggested.5. A highly sensitive RT-PCR system to detect human and animal HEVs of genotypes 1-4 was developed.