诺如病毒在沿海地区人群和环境中的循环传播路径研究

Circulation routes of norovirus among population and environment in coastal area

目的了解沿海地区环境和人群中诺如病毒的污染状况,分析该病毒的传播路径。方法在2013年12月至2014年12月期间,定期逐月采集广东长沙湾牡蛎养殖区内的牡蛎、养殖水样本和沿岸居民的急性胃肠炎病例粪便或呕吐物样本。采用实时荧光定量RT-PCR与半巢式PCR相结合的方法检测诺如病毒,并采用Sanger法进行测序,绘制系统发育树。结果共检测331份牡蛎样本、110份养殖水样本和75份急性胃肠炎病例样本。牡蛎样本中诺如病毒阳性率为32.6%（108/331）,养殖水样本中诺如病毒阳性率为11.8%（13/110）,急性胃肠炎病例样本中诺如病毒阳性率为20.0%（15/75）,牡蛎和养殖水样本冬春季诺如病毒阳性率高于夏秋季（P〈0.05或P〈0.01）。牡蛎中检出的诺如病毒基因型最多,共9种,病例和养殖水中分别检出5种和4种基因型。不同样本间存在相一致的基因型。从病例、牡蛎和养殖水样本中检出的诺如病毒均具有较高的序列一致度（95.8%~99.7%）。结论诺如病毒普遍流行于广东长沙湾养殖区内,持续存在且型别多样。诺如病毒在人群和环境中很可能存在循环传播路径,控制牡蛎养殖水域的诺如病毒污染对保障贝类产品的食品卫生十分必要。

Objective To investigate the prevalence of norovirus in environment and population in coastal area and explore the virus transmission route. Methods Samples of cultivated oysters, aquaculture water, and vomitus/faeees of patients with acute gastroenteritis were collected in Changsha Bay each month from December 2013 to December 2014. Noroviruses were detected by both real time RT-PCR and semi- nested RT-PCR. The partial capsid gene was amplified and sequenced by Sanger approach to conduct phy- logenetic analysis. Results A total of 331 samples of cultivated oysters, 110 samples of aquaculture water and 75 samples of vomitus/faeces from diarrhea patients were detected. Norovirus positive rates were 32. 6% （108/331）, 11.8% （13/110）, and 20.0% （15/75） in samples of cultivated oysters, aquacul- ture water, and diarrhea patients, respectively. Positive percentage of norovirus was higher in winter-spring season than that in summer-autumn season for the samples of oysters and aquaculture water （ P 〈 0.05 or P 〈0.01 ）. Nine genotypes were detected in cultivated oysters, 5 in diarrhea patients, and 4 in aquacul- ture water. Identical genotypes were found in different samples. High sequence identities of norovirus were observed in the three types of samples （95.8% -99.7% ）. Conclusion Noroviruses prevailed and per-sisted in Changsha Bay with high genetic diversity. There would be a circulation route of noroviruses among the population and environment. It is necessary to control the contamination of norovirus in aquaculture wa- ter for shellfish food hygiene.