The number of reported outbreaks of acute gastroenteritis due to norovirus in Marin County has increased significantly since October, 2015. While this is consistent with the seasonal nature of norovirus, the California Department of Public Health has announced higher than usual activity state-wide. In Marin, affected facilities have included adult congregate living facilities and childcare centers. The duration of most of the outbreaks is a few days to two weeks, reflecting both the natural history of the illness and the control measures taken by the facilities. Information about norovirus can be found here.