Analysis of Acute Gastroenteritis Incidence and Rotavirus Infection Characteristics Among Infants and Young Children Aged 0-2 Years Based on Active and Passive Community-Based Surveillance in Zhejiang Province

Objective To systematically analyze the epidemiological characteristics and disease burden of acute gastroenteritis (AGE) and rotavirus gastroenteritis (RVGE) among children aged 0-2 years in Zhejiang Province, based on community active-passive surveillance.Methods A birth cohort of 1000 full-term healthy newborns was established in Jiangshan, Longyou, and Yuhuan counties of Zhejiang Province between January 2019 and April 2019. Prospective active-passive surveillance was conducted for two years (March 2019 to March 2021). AGE episodes were recorded through caregiver reports and active follow-up, collecting information on clinical symptoms, stool samples, and treatment.Results A total of 347 children reported 439 AGE episodes. The cumulative incidence rate of AGE was 34.7%, with an incidence density of 21.9 episodes per 100 person-years. Twenty-seven cases were confirmed as RVGE, with a cumulative incidence rate of 2.7%; the predominant genotypes were G9 and P[8]. The proportion of moderate-to-severe cases was significantly higher in the RVGE group (44.4%) than in the non-rotavirus AGE group (10.3%) (P<0.001). Fever (74.1% vs 31.3%), vomiting (81.5% vs 25.3%), dehydration (25.9% vs 8.8%), and hospitalization rates (18.5% vs 4.7%) were also significantly higher in the RVGE group (P<0.05). The age of onset for non-rotavirus AGE was concentrated in infants <12 months old (70.3%). In contrast, RVGE onset exhibited a bimodal distribution, peaking at 7-12 months and 19-24 months (both 48.1%), a significant difference (P<0.001). RVGE incidence was also significantly higher during autumn and winter (December-January).Conclusion The disease burden of AGE is significant among children aged 0-2 years in Zhejiang Province, with approximately one-third experiencing at least one episode by age two. Although RVGE accounted for a low proportion (2.7%), it demonstrated higher pathogenicity and was the core pathogen for severe diarrhea. RVGE exhibited a distinct bimodal age distribution and a pronounced autumn/winter seasonal peak. These findings provide community-based evidence to optimize prevention and control strategies for infantile diarrhea.