[Epidemiological and etiological surveillance on infectious diarrhea in Pudong New Area, Shanghai, 2013-2017]

Objective: To understand the epidemiological characteristics of infectious diarrhea pathogens in Pudong New Areas of Shanghai from 2013 to 2017 to provide evidence for control and prevention of the disease. Methods: From Jan 2013 to Dec 2017, active surveillance program on diarrhea was conducted in 14 sentinel hospitals (three tertiary-level and nine secondary-level, and two primary-level hospitals) in Pudong New Areas of Shanghai, based on location, catchment areas and number of patients. All recruited outpatients were interviewed in hospitals, using a standard questionnaire. Stool specimens were collected and tested for five viral and eight bacterial pathogens. Results: A total of 9 301 cases with infectious diarrhea were included, and the overall positive rate was 55.7% (5 179). Positive rates of single virus, single bacteria and mixed infections were 26.7% (2 481), 17.0% (1 579) and 12.0% (1 119), respectively. For single infection, the most commonly detected viruses appeared as norovirus (15.4%, 1 428/9 301) and rotavirus (7.2%, 667/9 301). The most commonly detected bacteria were diarrheagenic Escherichia coli (6.7%, 619/9 301) and non-typhoid Salmonella (3.3%, 305/9 301). The most common mixed infections were caused by virus-bacteria (4.9%, 459/9 301). Norovirus (17.0%, 838/4 938) showed the highest positive rates, followed by Escherichia coli (7.2%, 354/4 938), both seen in the age group of 20-59 years old group. Rotavirus (9.4%, 178/1 896) and non-typhoid Salmonella (4.9%, 93/1 896) were the most common pathogens found in the age group of 0-4 years old. The prevalence of norovirus peaked both in spring and autumn. The other peaks were seen as: Rotavirus in winter, diarrheagenic Escherichia coli in summer and non-typhoid Salmonella in summer. Conclusions: Our data showed that the positive rates of infectious diarrhea pathogens were high in Pudong New Areas of Shanghai from 2013 to 2017. The dominant pathogens would include norovirus, rotavirus and diarrheagenic Escherichia coli but with differenct distributions in age groups. Obvious seasonal patterns were also observed.