A rotavirus infection usually starts within two days of exposure to the virus. Initial symptoms are a fever and vomiting, followed by three to eight days of watery diarrhea. The infection can cause abdominal pain as well.

In adults who are otherwise healthy, a rotavirus infection may cause only mild signs and symptoms or none at all.

Rotavirus is present in an infected person's stool several days before symptoms appear and for up to 10 days after symptoms subside. The virus spreads easily through hand-to-mouth contact throughout this time — even if the infected person doesn't have symptoms.

If you have rotavirus and you don't wash your hands after using the toilet — or your child has rotavirus and you don't wash your hands after changing your child's diaper or helping your child use the toilet — the virus can spread to anything you touch, including food, toys and utensils. If another person touches your unwashed hands or a contaminated object and then touches his or her mouth, an infection may follow. The virus can remain infectious on surfaces for weeks or longer if the area isn't disinfected.

Because there are many types of rotavirus, it's possible to be infected more than once, even if you've been vaccinated. However, repeat infections are typically less severe.

Rotavirus infections are common in children ages 3 to 35 months — particularly those who spend time in child care settings. Older adults and adults caring for young children have an increased risk of infection as well.

In the United States, the risk of rotavirus is highest in winter and spring.

Severe diarrhea can lead to dehydration, particularly in young children. Left untreated, dehydration can become a life-threatening condition regardless of its cause.