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ObjectiveTo investigate the changes in the pathogen spectrum of viral diarrhea in local pediatric inpatients as well as any variations in genotypes of major pathogens during the COVID-19 control period.MethodsFecal samples were collected from the children

ObjectiveTo present the exploration and application of a prospective follow-up research method for acute infectious disease surveillance based on natural community populations， using COVID-19 infection as an example， and to provide a reference for improving the infectious disease surveillance and early warning system.MethodsA multi-stage probability proportional sampling method was employed to sample residents from all communities of 16 administrative districts in Shanghai， with households as the units. A cohort for acute infectious diseases based on natural community populations was established. The baseline survey was conducted for all cohort subjects， and COVID-19 antigen test kits were distributed. From December 21， 2022 to September 30， 2023， prospective follow-up monitoring of COVID-19 antigen and nucleic acid was carried out on the study subjects on a weekly basis. The baseline characteristics and follow-up information of the cohort subjects were described.ResultsThe cohort for acute infectious diseases included a total of 12 881 subjects， comprising 6 098 males （47.3%） and 6 783 females （52.7%）. The baseline survey revealed that 35.2% （4 540/12 881） of the subjects had a history of COVID-19 infection. During the follow-up period from December 21， 2022 to September 30， 2023， the average incidence density in the cohort was 0.61/person-year， with a higher incidence density in females （0.63/person-year） compared to males （0.59/person-year）. Individuals aged 60 and above （0.64/person-year） and those with underlying health conditions （0.67/person-year） had a higher incidence density. Healthcare workers showed a notably higher incidence density （0.84/person-year） than that in other occupational groups. As of September 30， 2023， a total of 340 subjects in the cohort experienced secondary infections， with a median interval of 170 days between the first and second infections.ConclusionThis study applies cohort study method to acute infectious disease surveillance， providing crucial data support for estimating infection rates and forecasting alerts for acute infectious diseases in the community. This method can be promoted and applied as a new approach for acute infectious disease surveillance.

ObjectiveTo investigate an outbreak of norovirus diarrhea in a welfare home for the elderly in Shanghai， and to analyze the epidemiology and virus genotype characteristics of the epidemic， thus providing a scientific basis for the prevention and control of norovirus epidemic.MethodsCase definition was clarified. After case definition， a standardized questionnaire was used to carry out case investigation to make comprehensive analysis in combination with field epidemiological investigation and laboratory tests results.ResultsThe epidemic lasted for 14 days， and 23 cases were reported with an incidence rate of 12.37% （23/186）， including 3 males and 20 females. There were more cases on the 1st， 4th and 6th floor of the main building in the welfare home， accounting for 52.17% （12/23） of total cases. 19 cases were reported in the main building， with an incidence rate of 11.59% （19/164）； 4 cases were reported in the auxiliary building， with an incidence rate of 18.18% （4/22）. There was no significant difference in the morbidity between the main building and the auxiliary building （χ2=0.779，P>0.05）. The main clinical manifestations were vomiting and diarrhea. There was a significant difference in the incidence of vomiting symptoms among the elderly， nursing staff and other staff in the welfare home （χ2=10.216， P0.05）. Fecal samples were collected from 23 cases， 1 case family member， 68 risk personnel and 14 environmental surface swab samples. Norovirus GⅡ was detected in stool samples of 19 cases， 1 family member and 36 risk personnel.ConclusionOutbreak of norovirus infection is reported in a welfare home in Shanghai. The close contact between the elderly and health workers might lead to the outbreak.

In order to meet the needs of prevention and control of intestinal infectious diseases， a comprehensive surveillance for diarrheal diseases has been innovated and explored in Shanghai since 2012. The surveillance has extensive distribution of sentinel hospitals， systematic sampling， multi-pathogen collection， and hospital information system （HIS） as the basis， which has achieved “One system for surveillance of multiple diseases and one sample for detection of multiple pathogens". Continual active surveillance for the whole population has been conducted， covering demography， clinical information， epidemiology， pathogen detection， and drug sensitivity test for diarrhea cases. The surveillance has obtained preliminary achievements as follows. First， diarrheal diseases and their periodic changes have been characterized， in which the most prevalent pathogen of diarrhea is determined to be norovirus in Shanghai. Second， some rare pathogens and serotypes have been identified that may provide clues to the sources of outbreaks. Third， it facilitates the information sharing between public health institutions and clinical institutions， and provides scientific evidence for clinical diagnosis and treatment. In the future， Shanghai diarrhea comprehensive surveillance will be improved for expanding range and depth of surveillance， artificial intelligence assisted diagnosis and treatment， early warning of outbreaks， prediction of epidemic trends， and application of new detection technologies.