HIV stands for human immunodeficiency virus. HIV is the virus medical researchers believe causes AIDS. (Medical researchers believe that HIV is...

Hepatitis B is a serious disease caused by a virus that attacks the liver. The virus, which is called hepatitis B virus (HBV), can cause lifelong...

The term Chlamydia typically refers to Chlamydia trachomatis, the STD. But two other types of these bacteria also can lead to illness: Chlamydia...