In December 2012, Olmsted County Public Health (OCPHS) staff investigated an outbreak of norovirus associated with a restaurant located in Rochester, Minnesota. Dining patrons from multiple parties reported illness. A total of 50 restaurant patrons were interviewed. Twenty-three met the case definition of illness. The median incubation period was 39 hours (range, 22 to 58 hours). The median duration of illness was 33.5 hours (range, 16.5 to 121 hours). One case sought medical attention at a doctor's office. No one was hospitalized and no one died. Five ill patrons submitted stool samples to the Minnesota Department of Health Public Health Laboratory for testing. Four tested positive for norovirus GII. Nucleic acid sequencing was performed on all four positive specimens. The nucleis acid sequences were identical.

In univariate analysis, only consumption of appetizers was significantly associated with illness (9 of 22 cases vs. 1 of 16 controls; odds ratio 11.1; 95% confidence interval 1.2 to 99.2; p=0.02). However, only 9 of 22 interviewed cases reported consuming an appetizer, suggesting that other ready-to-eat foods may have been contaminated as well.

Nineteen (90%) of 21 restaurant staff members were interviewed. No food workers reported being ill with either vomiting or diarrhea during the past month. Several concerns were noted by sanitarians during the environmental health assessment. It was noted that the hot water for the kitchen hand sink was not functioning, the paper towel dispenser was not feeding properly, and it did not appear that the soap dispenser was being used. Additionally, the water flow in the employee restroom sink was so restricted that thorough hand washing was not possible.