FORT COLLINS, Colo. -- The number of confirmed or probable cases of H1N1 swine flu at CSU jumped from 60 to more than 400 this week.

University officials said Hartshorn Health Center verified that 45 students had flu-like symptoms who were probable H1N1 cases on Wednesday alone, contributing to an estimated total of 215 active cases on campus, according to the Collegian, the student newspaper.

"We're likely on the front end of this without knowing exactly where it will takes us," Anne Hudgens, dean of students, told the paper.

Activity at Hartshorn Health Center has "increased dramatically," Hudgens said.

She said 500 students showed up at the Hartshorn Health Center on campus just on Monday with swine flu and other medical questions. CSU student Amy Harr said her Music 100 class was canceled Thursday because her professor was sick with swine flu.

The university is telling students with symptoms not to attend class. The school launched a new online system last week to make it easier for students to self-report their illnesses and to avoid spreading germs. If the program confirms they have the flu symptoms, they'll be excused from class for up to 10 days.

Students should go to the health center if they experiencing a serious illness and need to see a doctor.

Despite all its precautions, CSU still anticipates a rough fall season. "The CDC has said we could expect as many as 30 percent of the [campus] population could get H1N1," Hudgens said.