The Minnesota Department of Health says the number of cases of H1N1 has more than doubled in the past week. There were 96 confirmed cases a week ago, and 221 today. Many more cases have not yet been tested.
Minnesota state epidemiologist Dr. Ruth Lynfield says some people who get the H1N1 virus are experiencing vomiting and diarrhea as well as sore throat, cough, and other symptoms.
"And some of the hospitalizations that we are seeing are because of dehydration, so we really want to urge that people have enough fluids," she said.
Lynfield says people with asthma or other underlying health problems are at special risk. The Health Department is urging anyone with symptoms to call their doctor and stay home from work.
The World Health Organization has declared the flu a pandemic, meaning it's widespread in many countries.