’Tis the season for giving, but health officials say too many Minnesotans are giving and receiving something nobody wants: the norovirus.

Noroviruses affect the stomach and intestines, leading to vomiting, diarrhea and stomach cramping. Other symptoms can include low-grade fever or chills, headaches and muscle aches. They’re highly contagious, and they’re the leading cause of foodborne illness outbreaks in Minnesota, infecting thousands of people each year.

Health officials believe it swept through a wedding in LeRoy earlier this month, causing many of the hundreds of guests to get sick. In Mankato in late November, officials think there was a norovirus outbreak at the Verizon Wireless Center.

The virus lurks in the stools or vomit of infected people, and makes its way to food, water or surfaces via the hands of infected people who haven’t washed them properly. Uncooked shellfish from contaminated waters can also harbor it.

Kirk Smith, foodborne disease supervisor at the Minnesota Department of Health, says the season of giving should also be the season of good hand-washing.

—The Associated Press contributed to this report.