Iowa authorities say reports of norovirus outbreaks have been increasing in recent weeks.
The quick-spreading bug includes diarrhea, vomiting, nausea and stomach cramps among its symptoms.
The Iowa Department of Public Health medical director, Dr. Patricia Quinlisk, says "we need everybody to stay home when they are ill with diarrhea and vomiting."
She says the illness can spread in food, in the air, by shaking hands and by touching things such as door knobs and counters that a
sick person has touched.
Health authorities say people can help stop the spread of norovirus by washing hands frequently, especially after using the toilet or changing diapers, and always before preparing or eating food.