you can't tell if someone has HIV AIDS by simply looking at them. HIV, the virus that causes AIDS, travels invisibly through four bodily fluids. Blood, semen, vaginal fluids and breast milk. Way can't stay safe, though. Avoid risky behaviors and drugs and alcohol can impair your judgment. Having unprotected can also increase your chances of transmitting HIV and other sexual diseases. Remember, HIV is preventable. Your choice, your action, your life,