Rotavirus is a very common virus that causes severe diarrhea, most often seen in young children and infants. It is one cause of stomach flu, unrelated to influenza, and can most often be treated at home with extra fluids and rest. Symptoms can also include fever and vomiting.
Severe cases of dehydration may require hospitalization, but there is no treatment for the viral infection itself. There are two oral vaccines used to prevent rotavirus infection, Rotateq and Rotarix; both are for infants younger than 6 to 8 months.