South Dakota is seeing a spike in norovirus, an illness that can begin suddenly with cramping, vomiting or diarrhea.
State health officials are reminding residents to practice good personal hygiene to prevent the illness, sometimes called the stomach flu.
It is highly contagious and spreads quickly in day cares, nursing homes and other close environments.
People are infected by eating food and drinking liquids that are contaminated with norovirus. Caring for or sharing food, drinks or eating utensils with an infected person also cause infections.
Most people recover within one to two days with no long-term health effects. However, norovirus infection can be more severe for young children, the elderly, and people with other health conditions.