College Doctor

You are a doctor at a small liberal arts college. During treatment of a student you discover that he is infected with HIV. You ask him if he has sex partners, and he replies that he does; however, he does not tell his partners that he has the HIV virus. He says that he practices “safe sex.” Should you warn someone at the college about the man? If so, who should you warn and how? Would your answer change if he did not say that he practices safe sex?