Abstract: Objective To analyze the characteristics of diarrhea cases and pathogen detection in children under 5 years old in Mianyang, and provide a scientific basis for preventing the occurrence of diarrhea in children. Methods Cases of children with diarrhea under 5 years old who were admitted to the outpatient clinic of a hospital in Mianyang City from January 1, 2018 to December 31, 2020 were used as the research objects to collect the basic information, and the feces of children were collected for pathogen detection. The results were analyzed by descriptive epidemiological analysis method. Results A total of 565 cases of diarrhea in children under 5 years old were collected in this study, including 187, 176 and 202 cases in 2018, 2019 and 2020, accounting for 33.1%, 31.2% and 35.8% respectively. The sex ratio of boys to girls was 1∶1.05. The age of the cases was mainly from 12 to <60 months, accounting for 54.7%, and the season of occurrence was mainly summer and autumn, accounting for 63.5%. A total of 157 cases of pathogens were detected, all of them were single infections, and the pathogen detection rate was 27.8%. The detection rate of pathogens in children with diarrhea in different years, ages, and seasons was significantly different （P<0.05 or P<0.01）. Among them, 152 strains were virus and 5 strains were bacteria. Rotavirus was the main virus strain, accounting for 38.8%, and adenovirus and norovirus respectively accounted for 22.4%. Conclusion From 2018 to 2020, the pathogen detection rate of diarrhea in children under 5 years old in a hospital in Mianyang is decreasing year by year. The pathogens are mainly viruses, especially rotavirus, adenovirus and norovirus, and the proportion of bacterial infection is relatively low. Targeted prevention and control measures should be taken according to the case characteristics in this area to prevent the risk of diarrhea in children.

Key words: Diarrhea, Etiology, Detection status, Epidemiological characteristic, Rotavirus