Gastroenteritis is diarrhea associated with nausea and vomiting. Dysentery is diarrhea that contains blood, pus, or mucus. Diarrhea generally lasts from 3-7 days. Rotavirus is a common cause of diarrhea in infants. Norwalk virus is the most common cause of epidemics of diarrhea among adults and schoolage children.
Adenovirus infections are common in all age groups.
Bacterial infections cause the more serious cases of diarrhea. Bacterial infections also cause severe symptoms with vomiting, fever, and severe abdominal cramps or abdominal pain. Diarrhea is very frequent and may be watery. In more serious cases, the stool may contain mucus, pus, or bright red blood. Most of these infections are associated with local outbreaks of disease.