BURLINGTON, Vt. — The Vermont Health Department is investigating an outbreak of norovirus at a South Burlington restaurant and pub, following more than 50 reports of illness.

Health officials said Friday that the Windjammer Restaurant and its Upper Deck Pub have voluntarily closed for 48 hours to do a thorough cleaning and to discard prepared foods. The department said it has confirmed nine cases of norovirus infection.

Norovirus can cause what’s sometimes referred to “the stomach flu” but is not related to influenza. It’s highly contagious and can be spread through contaminated surfaces and ingestion of contaminated food or water.

Symptoms typically include nausea, vomiting, diarrhea and some stomach cramping and usually resolve within 24 to 48 hours. Anyone having those symptoms is advised to contact a health care provider.