Kumazaki Makoto, Usuku Shuzo
Department of Testing and Research, Yokohama City Institute of Health, 2-7-1 Tomiokahigashi, Kanazawa-ku, Yokohama, Kanagawa, 236-0051, Japan,
Food Environ Virol. 2015 Sep;7(3):269-75. doi: 10.1007/s12560-014-9175-z. Epub 2014 Dec 5.
Rotavirus C (RVC) is detected in both sporadic cases and outbreaks of gastroenteritis worldwide. However, the epidemic dynamics of RVC in populations remain poorly understood because the detection rate is low. In this study, raw sewage samples were collected from a wastewater treatment plant in Yokohama, Japan, over 5 years, in 12-month period from September to August, to identify the RVC strains in these samples and compare them with the RVC strains circulating in the population. RVC strains were detected in 15 of the 118 raw sewage samples collected between 2007 and 2012. The highest number of positive samples detected per period (seven) was in 2008-2009. A fragment (225 nucleotides) of the VP7 gene of RVC from 14 sewage samples was sequenced. The nucleotide sequences of 11 strains were completely consistent with those of clinical strains identified in Yokohama. A phylogenetic analysis showed that 13 strains from the sewage samples clustered with several Yokohama outbreak strains and were closely related to the clinical strains (except sewage-derived strain Y11-SW0805-C). Our study demonstrates a correlation between clinical and sewage strains of RVC based on a genetic analysis, and shows that monitoring environmental samples is an effective way to study the strains circulating in a population, including in asymptomatic or mildly symptomatic patients, even when these infections are not detected in clinical samples. This is the first report of the surveillance of RVC in sewage samples in Yokohama, Japan, for molecular epidemiological analysis.
轮状病毒C（RVC）在全球范围内的散发病例和肠胃炎暴发中均有检出。然而，由于RVC的检出率较低，其在人群中的流行动态仍知之甚少。在本研究中，于5年期间（从9月至次年8月的12个月时间段）从日本横滨的一家污水处理厂采集原污水样本，以鉴定这些样本中的RVC毒株，并将其与人群中传播的RVC毒株进行比较。在2007年至2012年期间采集的118份原污水样本中，有15份检测出RVC毒株。每个时间段检测到的阳性样本数量最多（7份）的是在2008 - 2009年。对来自14份污水样本的RVC的VP7基因片段（225个核苷酸）进行了测序。11株毒株的核苷酸序列与在横滨鉴定出的临床毒株完全一致。系统发育分析表明，来自污水样本的13株毒株与几株横滨暴发毒株聚类，并且与临床毒株密切相关（污水来源的毒株Y11 - SW0805 - C除外）。我们的研究基于基因分析证明了RVC临床毒株与污水毒株之间的相关性，并表明监测环境样本是研究人群中传播的毒株的有效方法，包括无症状或症状轻微的患者，即使在临床样本中未检测到这些感染。这是日本横滨针对分子流行病学分析对污水样本中的RVC进行监测的首份报告。
