2014年广西北海市养殖环境与牡蛎中诺如病毒污染相关性调查

Correlation between oyster production environment and norovirus contamination in Beihai City,Guangxi,2014

目的调查广西北海市养殖场牡蛎、沉积物、水样中诺如病毒的污染状况及养殖场水温变化与诺如病毒检出率之间的关系,了解养殖环境与牡蛎中诺如病毒污染的相关性,为采取有效措施降低牡蛎中诺如病毒污染程度提供建议。方法 2014年1-12月,在广西北海市两个养殖场连续采集牡蛎、沉积物、水样共336份,同时监测养殖场水温,采用荧光RT-PCR法对样本中诺如病毒进行检测,确定诺如病毒污染状况及基因型分布。结果 336份样本中诺如病毒总检出率为12.50%(42/336),牡蛎、沉积物样本诺如病毒检出率分别为15.83%(38/240)、8.33%(4/48),水样未检出诺如病毒;基因分型结果显示检出的诺如病毒均为GⅡ型。牡蛎及沉积物诺如病毒检出率差异无统计学意义(P>0.05),但牡蛎诺如病毒检出率显著高于水样(P<0.01)。诺如病毒总检出率随着养殖场水温的降低而升高。结论 2014年广西北海市养殖场牡蛎及沉积物诺如病毒污染严重,污染的诺如病毒基因型均为GⅡ型,养殖环境水温及沉积物与牡蛎中诺如病毒的污染密切相关,而养殖环境水样与牡蛎中诺如病毒污染的相关性需进一步确认。

Objective To investigate the relationship between the contamination status of norovirus in oyster farms, sediment and water samples, the relationship between water temperature in oyster farms and detection rate of norovirus in Beihai City, Guan- gxi, so as to explore the correlation between oyster production environment and norovirus contamination and to put forward sugges- tions for taking effective measures to reduce norovirus contamination in oysters. Methods A total of 336 oyster, sediment and water samples were collected from 2 oyster farms in Beihai City, Guangxi between January and December in 2014, and water tem- perature at the sampling sites was simultaneously monitored. Real-time reverse transcription polymerase chain reaction （RT-PCR） assay was used to detect the presence of norovirus RNA and genogroups. Results The overall detection rate of norovirus in the 336 samples was 12.50% （42/336}. The detection rates of norovirus in oyster and sediment samples were 15.83% （38/240） and 8.33% （ 4/48 } respectively, and no norovirus was detected in water samples. Norovirus genotyping revealed that the detected noro- viruses all belonged to genogroup II （ GII）. No statistically significant difference was observed in the detection rate of norovirus in oyster and sediment samples （ P〉0.05 }, but the detection rate of norovirus was significantly higher in oyster samples than in water samples { P〈0.01 ）. The overall detection rate of norovirus increased with the decrease of water temperature in the oyster farms. Conclusions The oysters and sediment in the oyster farms in Beihai City, Guangxi in 2014 are heavily contaminated with noro- virus GII. The norovirus contamination in oyster and sediment is closely correlated with water temperature in the oyster farms. The correlation between norovirus contamination in oyster and in water environment at production sites needs further analysis.