Dozens of tri-delts who became sick after a meal at their University of Michigan sorority house were stricken with norovirus.

The Detroit Free Press reports lab results released Wed. by the Washtenaw County Public Health Department confirmed norovirus. Spokeswoman Susan Cerniglia, said the outbreak was “most likely,” the result of food poisoning, but the virus also may have been transmitted through personal contact or shared surfaces at the Delta Delta Delta house near the university.