Objective   To understand the types and epidemiological characteristics of diarrhea outbreaks in Zhejiang province, and provide evidence for diarrhea outbreak control.

  Methods   The incidence data of diarrhea outbreaks reported in Zhejiang from 2013 to 2019 were collected. The outbreak time, space distribution, attack rate, duration, clinical symptoms of the cases, and laboratory results were described and compared.

  Results   In 851 reported public health emergencies, 317 diarrhea outbreaks were identified, which were caused by 16 diseases or conditions, i.e. acute gastroenteritis caused by norovirus, cholera, influenza, dengue fever, Salmonella gastroenteritis, adenovirus infection, diarrheagenic Escherichia coli infection, acute gastroenteritis caused by sapovirus, severe fever with thrombocytopenia syndrome, Campylobacter jejuni infection, food poisoning due to Vibrio parahaemolyticus, Staphylococcus aureus infection, suspected abnormal reaction after vaccination, mushroom poisoning, hand foot mouth disease and chickenpox. The annual incidence had two peaks, one was during March-May and another one was during October-December. The outbreaks were reported in all the 11 prefectures (municipality) in Zhejiang. In the outbreaks, 264 (83.28%) occurred in schools. The outbreaks with attack rate more than 10% were caused by acute gastroenteritis caused by norovirus, cholera, influenza, adenovirus infection, Salmonella gastroenteritis, and diarrheagenic E. coli infection. The outbreaks with average duration of more than one week were caused by influenza, dengue fever, adenovirus infection, C. jejuni infection, and severe fever with thrombocytopenia syndrome. The proportions of the outbreaks in which cases had symptoms of vomiting, abdominal pain and fever were 87.38% (277), 71.61% (227) and 65.93% (209), respectively.

  Conclusion   The diarrhea outbreaks were mainly caused by gastrointestinal pathogens, but other kinds of pathogens were also found. For disease surveillance and outbreak response, the epidemiological characteristics of the diseases should be considered beside clinical symptoms.