Rotaviruses, which belong to the family Reoviridae.
Transmission is primarily by the faecal–oral route, directly from person to person or indirectly via contaminated fomites. A respiratory mode of transmission has also been proposed.
Nature of the disease
Rotavirus causes an acute gastroenteritis in infants and young children and is associated with profuse watery diarrhoea, projectile vomiting and fever. Rapid dehydration can occur, especially in very young infants, requiring rehydration therapy. The virus replicates in the enterocytes of the small intestine, causing extensive damage to the microvilli that results in malabsorption and loss of fluids and electrolytes.
Rotaviruses are found worldwide. They are the leading cause of severe, dehydrating diarrhoea in children under 5 years globally: outpatient visits are estimated at more than 25 million and hospitalizations attributable to rotavirus infections at more than 2 million each year. Fatal outcomes, estimated in 2004 to be 527 000 (475 000–580 000) annually, occur predominantly in low-income countries. In temperate climates, the incidence of rotavirus gastroenteritis typically peaks during the winter season, whereas in tropical settings rotavirus occurs year round. Reinfection of older children and adults is common, although the infection is usually sub-clinical.
Risk for travellers
The potential risk for adult travellers is extremely limited since most individuals will have good immunity through repeated exposures early in life. Children under the age of 5 years are at risk.