Cases of norovirus have spiked in Minnesota this month, with more than 40 reported so far in December, according to the Minnesota Department of Health.

That's more than twice the usual number of reports of the virus, also referred to as "stomach flu," the Health Department expects during the month. Symptoms can include vomiting, diarrhea, stomach cramps and potentially low-grade fever or chills, headaches and muscle aches.

Norovirus is also very contagious.

In response, the Health Department is urging the public to take the following steps to prevent the illness from spreading further to family and friends during the holidays.

Wash your hands with soap and water for 20 seconds before preparing or eating foods and after using the bathroom or changing diapers. Most hand sanitizers do not kill norovirus.

Do not prepare food for others if you have been vomiting or had diarrhea in the last three days.

Clean and disinfect surfaces with a household bleach solution immediately after it comes in contact with vomit or diarrhea.

Always cook shellfish before eating them.

The illness usually goes away in one or two days. Those who become sick with norovirus should drink plenty of fluids. Facilities including restaurants, schools, child care centers, long-term care and similar facilities should follow outbreak prevention guidelines and employee or attendee vomiting and diarrhea illness exclusions.