A sharp increase in norovirus cases is sweeping the United States, according to the latest data from the Centers for Disease Control and Prevention (CDC). Often called the "stomach flu," norovirus is a leading cause of gastroenteritis,

According to the latest CDC data, there were 91 outbreaks of norovirus reported during the week of Dec. 5. During the last week of November, there were 69 outbreaks, The Associated Press reported. In Minnesota, more than 40 outbreaks were reported in December, according to that state’s Department of Health.

The CDC reported more than double the cases of norovirus, commonly known as stomach flu, compared to previous years in early December.