The Genesee County Health Department is issuing a warning that the county is experiencing an increase in gastroenteritis cases.

The viruses that cause gastroenteritis, such as norovirus, can be easily spread by food, person-to-person contact, or contaminated surfaces or objects.

Possibly in connection to the norovirus outbreak, two elementary schools in Grand Blanc are closed because many students are sick with the flu. McGrath Elementary and Anderson Elementary are both closed Friday. It's unclear when classes will resume.

Genesee County last had an outbreak of norovirus in February of this year.

Officials said norovirus causes an illness which typically includes nausea, vomiting, diarrhea and stomach cramping. Symptoms may also include low-grade fever, headache, fatigue and muscle aches. Symptoms last between 12 and 60 hours. In most cases, ill persons recover on their own.

The very young and the elderly are at higher risk for dehydration. Those with severe diarrhea should drink plenty of fluids.

Health officials said norovirus is very contagious and can be easily spread from person-to-person, especially in group settings. Individuals can reduce their risk of becoming infected by frequent hand washing using soap and warm water for a minimum of 20 seconds (alcohol based hand sanitizers do not  prevent the spread of norovirus).

Preventing contamination of food, drinks and surfaces is critical to preventing the spread of norovirus. Anyone with norovirus should not prepare or serve food for others for three days after symptoms have stopped.

Spread of norovirus can be prevented by disinfecting contaminated surfaces with household chlorine bleach-based cleaners and prompt washing of contaminated articles of clothing. Since the virus is passed in vomit and stool, children should not go to daycare or school while they have diarrhea or vomiting. Persons who work in nursing homes, take care of patients or handle food should stay out of work for two to three days after symptoms end.

Norovirus is known incorrectly as the "stomach flu." Norovirus is not related to the flu (influenza) which is a respiratory illness caused by a different virus. Additional information about can be found at www.gchd.us.

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