Screen Shot 2017-06-13 at 6.44.19 PMHeath officials have determined the source of a norovirus that sickened dozens of people attending a festival at the Northern Wisconsin State Fairgrounds last month.

Wisconsin Department of Health Services spokeswoman Jennifer Miller told the Leader-Telegram the gastroenteritis outbreak at the Special Kids Day event was caused by contaminated food.

Miller says multiple stool samples collected from those who became sick indicated that the illness was caused by food and wasn’t passed through physical contact. She says the specific contaminated food source remains under investigation.

Symptoms of the sickness include vomiting, diarrhea, low-grade fever and fatigue. There isn’t a cure for norovirus but people have generally recovered within a few days.