RESUMEN
464 stool specimens from children under 5 with acute diarrheal disease and other 149 specimens from the control group were studied from July, 1993, to May, 1995. The specimens were collected at the Pediatric Emergency Department of the Autonomous Institute of the Teaching Hospital of Los Andes, MÚrida, Venezuela. The presence of the internationally recommended bacterial, parasitary and viral agents was investigated. The commonest bacteria isolated as unique pathogens were: Shigella (42.85), Shigella sonnei, the most found, (66.67), and the thermotolerant Campylobacter, Aeromonas sp. and enteropathogenous Escherichia coli, with 15; 15 and 13.5, respectively. 6.5 of parasites and 24.12 of Rotavirus were also found. It was concluded that in the period of time under study the infectious and mainly, the bacterial origin is an important cause of acute diarrheal disease in Mérida.