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Family of Rotaviruses
Epidemiology
Rotaviruses are divided into seven serogroups (A through G) of which group A is the most important cause of outbreaks of disease in humans. Transmission of rotaviruses is via the fecal oral route. There is a marked seasonal incidence associated with rotavirus infections, with the peak months in the United States being January through March. Because infectious particles are relatively stable, they can survive for extended periods on various surfaces. Rotavirus infections account for about fifty percent of cases of severe diarrhea in infants and young children (up to two years of age)
Clinical significance
Following ingestion, rotaviruses infect the epithelial cells of the small intestine, primarily the jejunum. [Note: Rotaviruses are able to reach the small intestine because they are resistant to the acid pH of the stomach.] The incubation period is usually 48 hours or less. Infection can be subclinical or may result in symptoms ranging from mild diarrhea and vomiting to severe, nonbloody, watery diarrhea with dehydration and loss of electrolytes. Although rotavirus infections are probably equally widespread around the world, the outcomes of infection vary significantly in different regions of the world. Despite the fact that more than ninety percent of children in the United States may have antibodies to rotaviruses by the age of three or four, mortality is low because patients who are severely ill are generally hospitalized, with fluid and electrolyte losses rapidly corrected.