Nishizawa Tsutomu, Takahashi Masaharu, Tsatsralt-Od Bira, Nyamdavaa Khurelbaatar, Dulmaa Nyamkhuu, Osorjin Byankhuu, Tseren-Ochir Erdene-Ochir, Sharav Tumenjargal, Bayasgalan Chimedtseren, Sukhbaatar Boldbaatar, Nagashima Shigeo, Murata Kazumoto, Okamoto Hiroaki
Division of Virology, Department of Infection and Immunity, Jichi Medical University School of Medicine, Shimotsuke, Tochigi, 329-0498, Japan.
National Center for Communicable Diseases, Ministry of Health Mongolia, Ulaanbaatar, 210648, Mongolia.
Virus Res. 2021 Jul 2;299:198355. doi: 10.1016/j.virusres.2021.198355. Epub 2021 Mar 1.
Hepatitis E virus (HEV) infects humans and a wide variety of other mammalian hosts. Recently, HEV strains belonging to genotype 8 (G8) within the Orthohepevirus A species of the Hepeviridae family, were identified in Bactrian camels (Camelus bactrianus) in China. The Bactrian camel (also known as the Mongolian camel) is native to the steppes of Central Asia. However, the HEV strains of Mongolian camels have not been examined. Among 200 serum samples from domestic Bactrian camels raised on 6 farms, in 6 soums in 3 provinces; 71 (35.5 %) were positive for anti-HEV IgG, with prevalence differing by farm (soum) (4.2-75.0 %); and 2 camels (1.0 %) that had been raised in Bogd, Bayankhongor Province, which had the highest seroprevalence among the six studied areas, were positive for HEV RNA. The two HEV strains (BcHEV-MNG140 and BcHEV-MNG146) obtained from the viremic camels in the present study shared 97.7 % nucleotide identity. They were closest to the reported G8 Chinese camel HEV strains but differed from them by 13.9-14.3 % over the entire genome, with a nucleotide difference of 24.0-26.5 % from the reported G1-G7 HEV strains. A phylogenetic tree indicated that the BcHEV-MNG140 and BcHEV-MNG146 strains were located upstream of a clade consisting of the Chinese camel HEV strains and formed a cluster with them, with a bootstrap value of 100 %, suggesting that they may represent a novel subtype within G8. These results indicate a high prevalence of HEV infection in Mongolian camels and suggest that the variability of camel HEV genomes is markedly high.
戊型肝炎病毒（HEV）可感染人类及多种其他哺乳动物宿主。最近，在中国双峰驼（Camelus bactrianus）中鉴定出了属于戊型肝炎病毒科正戊型肝炎病毒属A种基因型8（G8）的HEV毒株。双峰驼（也称为蒙古骆驼）原产于中亚草原。然而，尚未对蒙古骆驼的HEV毒株进行检测。在来自3个省份6个苏木的6个养殖场饲养的200份双峰驼血清样本中，71份（35.5%）抗HEV IgG呈阳性，不同养殖场（苏木）的流行率有所不同（4.2%-75.0%）；在研究的6个地区中血清阳性率最高的巴彦洪戈尔省博格德饲养的2峰骆驼（1.0%）HEV RNA呈阳性。本研究中从病毒血症骆驼获得的2株HEV毒株（BcHEV-MNG140和BcHEV-MNG146）核苷酸同一性为97.7%。它们与已报道的G8中国骆驼HEV毒株最为接近，但在整个基因组上与它们的差异为13.9%-14.3%，与已报道的G1-G7 HEV毒株的核苷酸差异为24.0%-26.5%。系统发育树表明，BcHEV-MNG140和BcHEV-MNG146毒株位于由中国骆驼HEV毒株组成的一个进化枝的上游，并与它们形成一个簇，自展值为100%，表明它们可能代表G8内的一个新亚型。这些结果表明蒙古骆驼中HEV感染率很高，并提示骆驼HEV基因组的变异性明显很高。
