In September 2011, Minnesota Department of Health epidemiologists investigated an outbreak of norovirus among members of opposing football teams. A game was played between High School Team A and High School Team B on September 1. Sixty players (48 from High School Team A and 12 from High School Team B) were interviewed. Twenty-nine players met the case definition, including 17 from High School A and 12 from High School Team B. Two stool samples from High School Team B players and one stool sample from a High School Team A player tested positive for norovirus GII. No one was hospitalized and no one died.

Having ice in an individual team water bottle was significantly associated with illness (18 of 19 cases vs. 4 of 12 controls; odds ratio, 36.0; 95% confidence interval, 2.8 to 1059; p <0.001). Ice was provided by High School A for both teams. The school's ice machine was broken, so ice was purchased in 20-pound bags from a nearby gas station and stored in the broken ice machine. It is unknown exactly how the individual water bottles were filled; however, it was confirmed that the individuals getting the ice out of the ice machine used their bare hands.