The state Department of Health says no deaths have been attributed to the infections, but several people have been hospitalized.
Noroviruses cause gastroenteritis and inflammation of the stomach and intestines. Common symptoms include vomiting, diarrhea and stomach cramping. People who are infected may also get a fever or chills and muscle aches.
Most people recover in a day or two, but officials say dehydration can be a concern in the very young, the elderly or people with weakened immune systems.
State Epidemiologist Michael Landen says one of the best ways to protect against norovirus is for people to wash their hands.
Health officials say noroviruses are very contagious.