Rotavirus is the most common cause of diarrhea among infants and young children and is one of several viruses that cause the stomach flu. It is in the family Reoviridae and is a genus of double-stranded RNA. Most children have been infected by the age of five. Each infection builds on previous immunity and thus subsequent infections are less severe and adults are rarely affected. The fives species of the virus are referred to as A, B, C, D, and E. Type A, which is the most common, causes more than 90% of infections in humans.

The virus transmits by the fecal-oral route. It infects and damages cells that are line the small intestine and can cause gastroenteritis. It was discovered in 1973 but its importance is still mostly unknown within the public health community. It also infects animals and is a pathogen of livestock.

Generally the disease is easily managed; however, nearly 500,000 children under age five die from rotavirus infection each year. Samples were taken in 1943 which later proved to have an agent which was rotavirus. The virus was later found in mice and in 1973 Ruth Bishop described related viruses found in children with gastroenteritis. In 1974, Thomas Henry Flewett suggested the name rotavirus after observing a rotavirus particle that looked like a wheel. Vaccines were starting to be developed by the 1980’s. In 1998 a license for a rotavirus vaccine was given in the United States. It was found to be 80 to 100% effective at preventing severe diarrhea. It was withdrawn from the market in 1999 after the manufacturer discovered that the vaccine contributed to an increased risk for intussusceptions.

The virus is characterized by vomiting, water diarrhea, and low-grade fever. Once infected the incubation period takes about two days and then symptoms appear. Vomiting is usually the first sign with diarrhea following four to eight days later. Dehydration is more common in rotavirus infection than in most bacterial pathogens and is the most common cause of death related to rotavirus infection. Rotavirus A infections can occur throughout life and usually after the first infection subsequent infections are asymptomatic.
The viruses are stable in the environment. Diarrhea from the virus comes from Malabsorption and the protein NSP4. Treatment usually involves management of the symptoms and maintenance of hydration. Infections rarely cause other complications and if managed well the prognosis is excellent. Improved sanitation does not decrease the prevalence of rotaviral disease and thus hospitalization remains high. They replicate in the gut and small intestine.