SEATTLE  At least 2,000 students at Washington State University have reported symptoms of the H1N1 flu virus, university and local health officials said, in what appeared to be one of the largest outbreaks of the virus on a college campus.

“It’s real,” Sally Redman, a registered nurse who works in student health services at Washington State, said Saturday. “We’ve had a constant stream of people.”

So far, the cases at the university have been relatively mild, although at least two people in the area who are not students were hospitalized. The university, based in Pullman, in eastern Washington near the Idaho border, has about 19,000 students at its main campus.

Ms. Redman said the outbreak appeared about Aug. 21, during fraternity and sorority rush but before classes started. After that, she said, “it was rampant.”