PIP: Five types of Escherichia coli are responsible for as much as 25% of all diarrheal diseases in developing countries. They tend to be transmitted via contaminated foods, particularly weaning foods, and water. They include enterotoxigenic, enteropathogenic, enteroadherent, enteroinvasive, and enterohemorrhagic E. coli. Shigella species are responsible for 10-15% of acute diarrheas in children less than 5 years old and the most common etiologic agents of childhood dysentery. Shigellosis is common in the warm season. An outbreak of shigella dysentery in West Bengal, India, had a high attack rate in children less than 5 years old and was resistant to many drugs. Nontyphoid Salmonella species cause watery diarrhea with nausea, cramps, and fever. Worldwide, various Salmonella strains exhibit resistance to ampicillin, chloramphenicol, and co-trimoxazole. Campylobacter jejuni produces watery diarrhea which, in 33% of cases and 1-2 days after onset, contains blood and mucus. Many normal healthy children in developing countries are carriers of C. jejuni. Vibrio cholerae O1 is endemic in parts of Africa and Asia (e.g., 5-10% of hospitalized diarrhea patients). The ElTor cholera biotype is responsible for the 7th pandemic. Other bacterial enteropathogens are Aeromonas species, Bacteroides fragilis, and Providencia alcalifaciens. Rotavirus is a major cause of sporadic and epidemic diarrhea among 6-23 month olds. Its incidence peaks in cold or dry seasons. Other viral enteropathogens are Norwalk virus, adenoviruses, astroviruses, and coronaviruses. In India, the prevalence of Entamoeba histolytica varies from 3.6% to 47.4%. It occurs equally in high and low socioeconomic classes. Giardia lamblia usually infects 1-5 year old children. Its transmission routes are food, water, and the fecal-oral route. Cryptosporidia produce acute watery diarrhea, especially in children less than 2 years old. Cryptosporidia diarrhea is common among AIDS patients. Oral rehydration therapy and proper feeding during and after diarrhea reduces deaths from diarrhea.