In 1990, the U.S. Centers for Disease Control and Prevention (CDC) reported viral causes of gastroenteritis, helping identify ways to prevent and manage outbreaks of diarrhea. Each year, infectious gastroenteritis causes greater than 210,000 children in the United States to be hospitalized and 4-10 million children to die worldwide.

Rotavirus, the most common cause of diarrhea among children, infects virtually every child in the United States by the age of 4 years and causes potentially lethal dehydration in 0.75% of children less than 2 years of age. Other recently identified pathogens include the enteric adenoviruses, calicivirus, astrovirus, and the Norwalk family of agents. Conclusive diagnosis of these viruses requires electron microscopic examination of stool specimens, a laboratory technique that is available only at a few large centers, including CDC.

As a result of rapid progress, etiologic identification may soon be possible in most cases of diarrhea, and within a few years a rotavirus vaccine may be licensed.