In March 2012 staff at the Minnesota Department of Health (MDH) and Olmsted County Public Health Services (OCPHS) investigated an outbreak of norovirus at a bowling alley located in Rochester, Minnesota. Ill persons were identified from two different groups who attended events at the bowling alley on March 3. One event was a birthday party and the second event was a group of co-workers.

OCPHS staff obtained contact information for party attendees from each party host. A total 99 patrons were interviewed. Twenty four were excluded from further analyses due to incomplete symptom or exposure histories. Of the remaining 75 interviewed patrons, 31 primary cases were identified. In addition, 15 secondary cases were identified and excluded from further analyses. The median incubation period for cases was 36 hours (range, 13 to 47.5 hours). The median duration of illness was 47.5 hours (range, 20.5 to 104 hours). Four patron stool samples were submitted to the MDH Public Health Laboratory. Two tested positive for norovirus GI.6A with identical region D nucleic acid sequences. The positive stools were from individuals who attended two different March 3 events.

In a univariate analysis, consuming a "first frame starter" appetizer was significantly associated with illness. Individual appetizers, eating any food item and bowling activities were not significantly associated with illness.

All 11 bowling alley employees were interviewed. One employee reported gastrointestinal illness onset on March 6. This employee worked at the alley primarily as a bartender on March 2 through March 4. A stool sample from the employee tested positive for norovirus GI.6A with an identical region D nucleic acid sequence to patron sequences.

Investigators concluded this was an outbreak of norovirus associated with a bowling alley. Appetizers were identified as the outbreak vehicle. However, 45% of cases did not consume any food items at the alley, suggesting that contamination of the alley environment (e.g. bowling balls, surfaces, utensils) likely also played a role in transmission.