Prevalence and geographic variation of enteric pathogens among asymptomatic individuals in China: a nationwide, cross-sectional, multiplex molecular survey

The increasing use of multiplex molecular assays has improved the detection of enteric pathogens, but baseline carriage in asymptomatic populations remains poorly characterized, complicating the interpretation of positive test results. We aimed to investigate the prevalence and geographic distribution of enteric pathogens among individuals without diarrhoeal symptoms in China. In this nationwide cross-sectional study, stool specimens were collected from asymptomatic individuals between June and August 2025. A total of 1,407 specimens from 28 provincial-level administrative regions were tested using a multiplex nucleic acid panel targeting 25 bacterial, viral, and parasitic enteric pathogens. Pathogen positivity and spatial heterogeneity were analyzed across geographic, climatic, and socioeconomic classifications. More than 80% (80.10%) of individuals carried at least one detectable enteric pathogen, whereas 19.90% tested negative for all pathogens. The most frequently detected pathogens were enteroaggregative Escherichia coli (EAEC; 52.52%), Clostridium perfringens (39.45%), and enteropathogenic E. coli (EPEC; 26.08%). Vibrio cholerae , rotavirus, sapovirus, Cryptosporidium spp., and Entamoeba histolytica were not detected. Overall pathogen positivity varied substantially across provinces, ranging from 15.22% to 97.83%. Diarrhoeagenic E. coli pathotypes and several frequently detected foodborne bacteria exhibited marked geographic heterogeneity associated with climatic zones, regional development level, and geographic location. Enteric pathogen carriage is common among asymptomatic individuals in China and shows substantial spatial variation. Several organisms traditionally regarded as diarrhoeal pathogens were frequently detected in individuals without symptoms, indicating that molecular detection alone does not necessarily imply disease causation. These findings provide important baseline data for interpreting multiplex gastrointestinal pathogen testing and for understanding the epidemiology of enteric pathogen carriage.