Dozens of students at an elementary school in the western suburbs stayed home with the flu Thursday, forcing administrators to close the school for the day.
Officials at Robinson school in Lyons say about 80 students called in sick.
Many of the kids visited the school nurse's office Wednesday complaining of flu-like symptoms.
Administrators closed the school so crews could clean and disinfect classrooms.
Robinson school will reopen Friday, but health officials say students shouldn't return until they are free of symptoms for 24 hours.
No other schools in the area reported unusually high cases of flu.