Outbreaks of noroviral gastroenteritis in Florida, 2006-2007.

Noroviruses are an important cause of sporadic cases and outbreaks of acute gastroenteritis. During 2006-2007, widespread increases in acute gastroenteritis outbreaks consistent with norovirus were observed in the United States. We conducted a statewide survey to characterize norovirus outbreak activity in Florida during a 1-year period. From July 2006 to June 2007, 257 outbreaks of norovirus gastroenteritis were identified in 39 of Florida's 67 counties. About 44% of outbreaks were laboratory confirmed as norovirus and 93% of these were due to genogroup GII. About 63% of outbreaks occurred in long-term care facilities and 10% of outbreaks were classified as foodborne. The median number of ill persons per outbreak was 24, with an estimated total of 7880 ill persons. During the study period, norovirus outbreak activity in Florida was widespread, persistent, and consistent with increased activity observed in other parts of the country.