People from three different dining groups became ill following a meal at a restaurant located in Burnsville, Minnesota. Implicated meal dates were December 14 or 15. Fourteen persons met the case definition eating dinner (n=9) on December 14 or lunch (n=5) on December 15. Four cases called a health care provider. One visited the emergency room. No one was hospitalized and no one died.

Sixty-one food workers were interviewed. Four reported a recent history of acute gastrointestinal illness, with onsets of December 13, 14, 17 or 18. Three food workers reported working while ill. Among the ill restaurant employees, one employee who worked on salad and pizza prep experienced vomiting and diarrhea while at work on December 14, reported it to the manager, and continued to work because a replacement could not be found. Although restaurant management was aware of illness among employees, they did not it to the Minnesota Department of Health (MDH). Additionally, although the restaurant received complaints of illness from patrons, they did not report the complaints. to MDH.

MDH tested stool specimens from four ill patrons, including at least one from each complaint group, and two restaurant employees. All six samples tested positive for norovirus; five were GII.1 of the same sequence and one from a patron was GII.7. One sample from a patron also tested positive for adenovirus.

Investigators concluded the outbreak was likely caused by an ill restaurant employee who worked while ill.