Epidemiology of viral gastroenteritis in children

TGastroenteritis is one of the most common causes of morbidity and mortality in children worldwide accounting for 2 to 3 million deaths per year and viruses are their leading cause. Currently rotaviruses remain the most important pathogens causing diarrheal disease overall, killing 600.000 children annually, while noroviruses are the most common gastrointestinal viruses in developed country where rotavirus immunizations have been adopted. In United States, more than 90% of the outbreaks of gastroenteritis is now attributed to noroviruses. Both rotaviruses and noroviruses are more frequently detected and cause more severe clinical manifestations in young children especially under 5 years of age; in particular rotaviruses are responsible for over 2 million hospitalizations per year in children under 5 accounting for 40% of hospitalization for acute diarrhea. Other viral pathogens that have been proven to cause diarrhea in children are sapoviruses, astroviruses and enteric adenoviruses. Virtually all children are infected with sapoviruses by the time they are 5 years of age although the illness most likely is sporadic with a high rate of asymptomatic infection. Astroviruses have been detected in as many as 10% of sporadic nonbacterial gastroenteritis and like sapoviruses have a seasonal peak in winter. Enteric adenoviral disease occurs year-round and as astrovirus and sapovirus infections it affects primarily children less than 4 years of age with high rate of asymptomatic disease.