Definition
Three or more liquid or watery stools in a 24-hour period are considered as diarrhea. Diarrhea may also be bloody, called dysentery. An episode of diarrhea lasting for less than 14 days is defined as acute diarrhea. Persistent diarrhea is defined as an episode of diarrhea that begins acutely and lasts for at least 14 days.
Etiology
Intestinal infection is the most common cause of acute diarrhea worldwide. The etiologic pathogen may be virus, bacteria, protozoa, or helminth (Table 1). In spite of the numerous diarrhea-causing organisms, recent studies have shown that the majority of cases in virtually all setting are caused by five organisms: rotavirus, E. coli,Shigella, C. jejuni, and C. parvum. Salmonella and V. cholerae are also important causes of acute diarrhea in some developing countries.