Nonbacterial gastroenteritis.

Significant progress has been made toward determining the agents of acute, infectious, nonbacterial gastroenteritis. Two distinct types of viruses have been implicated. One of these, a particle about 27 nm in diameter, is involved in the acute epidemic form of the disease of short duration. The other, a 70-nm virus, is rarely involved in acute epidemic gastroenteritis, but it has been associated worldwide with infantile diarrhea and is responsible for a considerable proportion of all nonbacterial diarrheal illness in infants. Experiments with the 70-nm virus have induced disease in newborn piglets, calves, and rhesus monkeys. In addition, this human virus has been antigenically related to four other viruses, three of which cause gastroenteritis in their natural animal host.