Hata Akihiko, Katayama Hiroyuki, Kitajima Masaaki, Furumai Hiroaki
Research Center for Environmental Quality Management, Kyoto University, Shiga, Japan
Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo, Japan.
Appl Environ Microbiol. 2015 Aug;81(15):4932-9. doi: 10.1128/AEM.00563-15. Epub 2015 May 15.
Human astroviruses (HAstVs) are a common etiological agent of infantile gastroenteritis. Recent studies revealed that novel astrovirus (AstV) strains of the MLB clade (MLB-AstVs) and VA clade (VA-AstVs), which are genetically distinct from the classic HAstVs, are circulating in the human population. In the present study, we quantified classic HAstVs as well as carried out a genetic analysis of classic and novel HAstVs in wastewater in Japan. The concentration of classic HAstVs in the influent water samples ranged from 10(4) to 10(5) copies per liter, and the amount removed by wastewater treatment was determined to be 2.4 ± 0.3 log10. Four types of classic HAstV strains (HAstV types 1, 2, 5, and 4/8) as well as novel AstV strains belonging to the MLB-2, VA-1, and VA-2 clades were identified using reverse transcription-PCR (RT-PCR) assays, including assays newly developed for the detection of strains of the MLB and VA clades, followed by cloning and nucleotide sequencing. Our results suggest that genetically diverse AstV strains are circulating among the human population in Japan. The newly developed (semi)nested RT-PCR assays for these novel AstV clades are useful to identify and characterize the novel AstVs in environmental waters.
人星状病毒（HAstVs）是婴幼儿肠胃炎的常见病原体。最近的研究表明，与经典人星状病毒在基因上不同的新型星状病毒（AstV）毒株，即MLB进化枝（MLB-AstVs）和VA进化枝（VA-AstVs），正在人群中传播。在本研究中，我们对日本废水中的经典HAstVs进行了定量，并对经典和新型HAstVs进行了基因分析。进水水样中经典HAstVs的浓度范围为每升10⁴至10⁵拷贝，经污水处理去除的量确定为2.4±0.3 log10。使用逆转录-聚合酶链反应（RT-PCR）检测方法，包括新开发的用于检测MLB和VA进化枝毒株的检测方法，随后进行克隆和核苷酸测序，鉴定出四种经典HAstV毒株（HAstV 1型、2型、5型和4/8型）以及属于MLB-2、VA-1和VA-2进化枝的新型AstV毒株。我们的结果表明，基因多样的AstV毒株正在日本人群中传播。针对这些新型AstV进化枝新开发的（半）巢式RT-PCR检测方法，对于鉴定和表征环境水体中的新型AstVs很有用。
