[Seasonality and etiological characteristics of infectious diarrhea in outpatients of 18 or above-year-old in Shanghai, 2014-2017].

Objective: To understand the seasonality and etiological characteristics of infectious diarrhea in adults from Shanghai. Methods: Adult patients with diarrhea who had visited the enteric disease clinics in 22 hospitals that carrying on the Diarrhea Comprehensive Surveillance sentinel programs in Shanghai during 2014-2017, were surveyed. Stool specimens were collected according to the different intervals of sampling and detected for 12 bacteria and 5 viruses. Concentration ratio and circular distribution method were used for data analysis. Results: From 2014 to 2017, a total of 9 573 stool specimens were collected from the targeted diarrhea patients ≥18 years old (n=96 067), through the Shanghai Diarrhea Comprehensive Surveillance program. The positive rate of detection was 46.44%. Seasonal peaks of infectious diarrhea were both seen in summer (bacteria peak, diarrheagenic Escherichia coli and Vibrio parahaemolyticus, etc.) and in winter (virus peak, Norovirus, etc.). Both bacterial and viral infections presented seasonal concentration (Raleigh's test P<0.001) but more obvious with bacterial infection. Viral infection accounted for 60.19% of the cause of infectious diarrhea. The top five predominant pathogens appeared as Norovirus, Rotavirus, diarrheagenic Escherichia coli, Vibrio parahaemolyticus, and Salmonella spp.. Conclusions: Among the adult outpatients with infectious diarrhea in Shanghai, obvious seasonality was seen, with peaks in both summer and winter. Viral infection with Norovirus in particular, appeared as the predominant source of infection. Active, continuous and comprehensive diarrhea-related surveillance programs would be able to monitor the changing dynamic of pathogen spectrum, and lead to the adoption of targeted preventive measures.目的： 了解上海市成年人感染性腹泻病例的季节分布等流行特征及病原学特征。 方法： 对2014－2017年22家上海市成人腹泻病监测点医院肠道门诊的腹泻病例进行主动监测，通过访谈形式开展流行病学调查，并间隔抽样采集病例的粪便标本。由监测点医院所在区CDC开展12种细菌和5种病毒的病原学检测。分析感染性腹泻的病原谱特征，采用集中度值及圆分布方法分析不同病原感染性腹泻的季节分布特征。 结果： 2014－2017年，上海市腹泻病综合监测系统共监测≥18岁成年人腹泻病例96 067例，共采集9 573例病例的粪便标本，标本检测阳性率46.44%。流行特征上，成年人感染性腹泻共有夏、冬季2个发病高峰，夏季以致泻性大肠埃希菌和副溶血性弧菌等细菌感染为主，冬季以诺如病毒等病毒感染为主。细菌感染和病毒感染均有季节集中倾向（雷氏检验P<0.001），细菌感染季节性强于病毒感染。病原学检测显示病毒感染占比达60.19%，病原谱分析显示前5位优势病原依次为诺如病毒、轮状病毒、致泻性大肠埃希菌、副溶血性弧菌和沙门菌。 结论： 上海市成年人感染性腹泻门诊病例以病毒感染为主，主要为诺如病毒，发病具有季节性，呈现夏季的细菌感染高峰和冬季的病毒感染高峰。对腹泻病开展持续监测可掌握流行特征和病原学特征及流行趋势，进而采取针对性防控措施。.