Children's Vaccines Health Center

What is rotavirus, and what causes it?

Rotavirus is a virus that infects the intestinal tract of almost all young children by age 5. Children can get rotavirus more than once, but the first infection is usually the worst. Most children get sick from rotavirus by age 2. This infection causes stomach upset and diarrhea.

Babies and very young children with rotavirus infections need to be watched closely, because they can become dehydrated very quickly. Dehydration occurs when the body loses water more quickly than it is replaced. When your child becomes dehydrated, severe health problems can arise.

Rotavirus infections spread easily. Outbreaks usually occur in the winter and early spring. Rotavirus infections often spread in settings where many children are together, such as day care centers.

The virus spreads through contact with the stools from an infected child. The virus can spread easily even when people try very hard to keep places clean. For example, when a caregiver changes the messy diaper of a child who has rotavirus infection, germs can get on the changing table, the caregiver's hands, or the hands of the already infected child. The rotavirus germs can then spread to other children from the caregiver's or child's unwashed hands. It may be only a few steps to the sink, but the germs may get on surfaces that the caregiver or child touches along the way. For example, the germs may get on toys, doorknobs, or sink surfaces. The germs can live for days on objects and surfaces if they are not disinfected right away.

Other children who get the rotavirus germs on their hands can get the infection when they put their hands in their mouths. They can also get infected with rotavirus by chewing on a toy that has the germs on it.

What are the symptoms?

It takes about 1 to 2 days for a child who is exposed to the rotavirus germs to start having symptoms.

Vomiting is often the first symptom. Usually, a fever and diarrhea follow. Most children with rotavirus have very watery diarrhea that seems like a large amount for a baby or small child. The most severe diarrhea lasts 4 to 8 days. But episodes of diarrhea can last long after your child starts feeling better. In some children, diarrhea can last for a few weeks.

Diarrhea, especially when it occurs along with vomiting, can quickly lead to dehydration in babies and young children who have rotavirus. For this reason, it is important to keep feeding your baby breast milk or formula.

Watch your child closely for signs of dehydration, such as having only 1 wet diaper in a 12-hour period. Call your doctor right away if you think your child may be dehydrated.

How is rotavirus diagnosed?