Acute viral gastroenteritis occurs throughout life, but the etiologic agents and disease severity vary with age. In infants, most cases are due to rotavirus. In adults, the most common cause is calicivirus. The clinical spectrum of acute viral gastroenteritis ranges from asymptomatic infection to severe dehydration and death. Mild fever is common.
Death results from dehydration and acidosis.
Factors associated with severe and prolonged disease are immunodeficiency and immune suppression, comorbid disease, and malnutrition. A similar spectrum of severity exists for adults, but severe illness is most common in elderly patients with comorbid disease. Viruses are the suspected cause of acute gastroenteritis when vomiting is prominent, when the incubation period is longer than 14 hours, and when the entire illness is over in less than 3 days. Vital signs are usually normal. Temperature may be slightly elevated.