AIDS is caused by which virus?

AIDS, or Acquired Immunodeficiency Syndrome, is caused by the Human Immunodeficiency Virus (HIV). This virus attacks and weakens the immune system, specifically targeting CD4 cells (T cells), which play a crucial role in helping the body to fight off infections. If left untreated, HIV can progress to AIDS, which is characterized by a significant decline in the immune system's ability to function, making the individual more susceptible to opportunistic infections and certain cancers.

In terms of the other options, HBV (Hepatitis B Virus), HCV (Hepatitis C Virus), and HSV (Herpes Simplex Virus) are related to different diseases that affect the liver and skin, respectively, and are distinct from HIV. While they are important in their own rights and represent significant health concerns, they do not cause AIDS. Understanding HIV’s role in the progression to AIDS is crucial for effective treatment and prevention strategies within public health.