During 2009–2010, a total of 2,259 person-to-person AGE outbreaks were reported in NORS from 42 states and the District of Columbia (USA)
These outbreaks resulted in 81,491 reported illnesses, 1,339 hospitalizations, and 136 deaths. No etiology was reported in approximately 40% (n = 840) of outbreaks.
82% of outbreaks caused by Norovirus
Of the remaining 1,419 outbreaks with a reported etiology, 1,270 (89%) were either suspected or confirmed to be caused solely by norovirus. Other reported etiologies included Shigella (n = 86), Salmonella (n = 16), Shiga toxin-producing Escherichia coli (STEC) (n = 11), and rotavirus (n = 10). Most (82%) of the 1,723 outbreaks caused by norovirus or an unknown etiology occurred during the winter months, and outbreaks caused by Shigella or another suspected or confirmed etiology most often occurred during the spring or summer months (62%, N = 53 and 60%, N = 38, respectively).
Nursing homes and long-term-care facilities account for 80%
A setting was reported for 1,187 (53%) of total outbreaks. Among these reported settings, nursing homes and other long-term–care facilities were most common (80%), followed by childcare centers (6%), hospitals (5%), and schools (5%).