The Rhinelander Superintendent shut down Pine Lake Elementary Wednesday morning after more than a third of students and staff had either called in sick or went home early.
All the victims had similar symptoms-stomach ache, vomiting and diarrhea.
Eighty-five students and 10 teachers were out by Wednesday, and enough teachers were still sick Thursday night for school to be called off Friday.
The Oneida County Health Department is investigating the illness. They have sent stool samples from the victims to the lab, and they hope to have some answers by Monday.
For now, healthy family members are encouraged to wash their hands after every activity.