Research Centre of Infection and Immunity, The University of Hong Kong, Hong Kong SAR.
Department of Microbiology, The University of Hong Kong, Hong Kong SAR.
J Gen Virol. 2011 Aug;92(Pt 8):1888-1898. doi: 10.1099/vir.0.030817-0. Epub 2011 Apr 20.
The genus Mamastrovirus belongs to the family Astroviridae and consists of at least six members infecting different mammalian hosts, including humans, cattle and pigs. In recent years, novel astroviruses have been identified in other mammalian species like roe deer, bats and sea lions. While the bovine astrovirus was one of the earliest astroviruses to have been studied, no further research has been performed recently and its genome sequence remains uncharacterized. In this report, we describe the detection and genomic characterization of astroviruses in bovine faecal specimens obtained in Hong Kong. Five of 209 specimens were found to be positive for astrovirus by RT-PCR. Two of the positive specimens were found to contain sequences from two different astrovirus strains. Complete genome sequences of approximately 6.3 kb in length were obtained for four strains, which showed similar organization of the genome compared to other astroviruses. Phylogenetic analysis confirmed their identities as members of the genus Mamastrovirus, and showed them to be most closely related to the Capreolus capreolus astrovirus. Based on the pairwise genetic distances among their full-length ORF2 sequences, these bovine astroviruses may be assigned into at least three different genotype species. Sequence analysis revealed evidence of potential recombination in ORF2. In summary, we report the first genome sequences of bovine astroviruses and clearly establish the species status of the virus. Additionally, our study is among the first to report co-infection by different astrovirus genotypes in the same host, which is an essential step for recombination to occur.
Mamastrovirus 属属于星状病毒科，由至少六个成员组成，感染不同的哺乳动物宿主，包括人类、牛和猪。近年来，在其他哺乳动物物种中，如狍、蝙蝠和海狮中也发现了新型星状病毒。虽然牛星状病毒是最早研究的星状病毒之一，但最近没有进一步的研究，其基因组序列仍未得到描述。在本报告中，我们描述了在香港从牛粪便标本中检测和鉴定星状病毒的情况。通过 RT-PCR 检测，在 209 个标本中有 5 个呈星状病毒阳性。在两个阳性标本中发现了两种不同的星状病毒株序列。我们获得了四个毒株约 6.3kb 长的完整基因组序列，与其他星状病毒相比，它们的基因组具有相似的组织。系统发育分析证实了它们作为 Mamastrovirus 属成员的身份，并表明它们与 Capreolus capreolus 星状病毒最为密切相关。根据其全长 ORF2 序列之间的成对遗传距离，这些牛星状病毒可能至少分为三个不同的基因型种。序列分析显示在 ORF2 中存在潜在重组的证据。总之，我们报告了牛星状病毒的第一个基因组序列，并明确建立了该病毒的种属地位。此外，我们的研究是首次在同一宿主中报告不同星状病毒基因型的共同感染，这是重组发生的必要步骤。
