PIP: In a community-based longitudinal study of 126 urban Gambian children from birth to 2 years, bacterial and/or viral pathogens were identified significantly more often in diarrheal episodes studied (27.5%) than during control periods (19.0%), (p0.001). Rotavirus and ST-toxigenic Escherichia coli emerged as the most frequently-occurring pathogens in symptomatic children. Campylobacter species, accounting for nearly 1/3 of all pathogens, isolated, occurred more frequently during control periods, as did Salmonella species. Shigellosis may have been underdiagnosed. Even so, the cause of diarrhea during the 1st 1/2 of infancy was largely unresolved, with approximately 90% of cases studied being unexplained, a similar figure emerging for all attacks studied during the spring-time 1/4 of the year. We remain notably ignorant of the cause of most unselected cases of childhood diarrhea in the community in West Africa. author's modified