In June 2017, staff from the Minnesota Department of Health (MDH) and Washington County Public Health and Environment (WCPHE) investigated an outbreak of norovirus associated with an outdoor event held at a restaurant in Hugo, Minnesota. The implicated meal date was June 24. Sixty-one patrons were interviewed; 11 (18%) met the case definition for an outbreak case. No one was hospitalized and no one died. Three stool specimens were positive for norovirus GI.2 with identical Region C nucleic acid sequences.

In a univariate analysis, using the portable toilet (6 of 11 cases vs. 4 of 48 controls; odds ratio [OR], 13.2; 95% CI 2.8 to 63.3; p<0.001) and consuming lime garnish from a tent bar (4 of 11 cases vs. 6 of 48 controls; OR, 6.3; 95% CI, 1.3 to 31.0; p=0.024) were significantly associated with illness. The case-control study included a relatively small sample size, as the event was estimated by restaurant management at 4,000 attendees over a two-day period.

Sixty-five of 68 (96%) employees were interviewed. Nineteen (29%) reported recent gastrointestinal illness. Servers and cooks reported illness. Given the large numbers of employees reporting illness, investigators concluded that transmission was likely both foodborne and environmental.