The Human Immunodeficiency Virus (HIV) is a virus that targets immune system cells, particularly T cells, which play a critical role in the body's fight against infections. This virus progressively weakens the immune system, making individuals vulnerable to various infections and diseases. If left untreated, the most advanced stage of HIV infection, Acquired Immunodeficiency Syndrome (AIDS), can develop. AIDS is characterized by severe damage to the immune system, rendering it unable to combat opportunistic infections and certain types of cancers that would not typically affect a healthy person. HIV is a chronic, lifelong infection; however, with current antiretroviral therapy (ART) methods, the virus can be kept under control, disease progression can be prevented, and quality of life can be significantly improved. Early symptoms may resemble the flu (fever, headache, sore throat, muscle aches, swollen lymph nodes, night sweats). In advanced stages, symptoms such as oral thrush, diarrhea, and various opportunistic infections may occur. Definitive diagnosis requires testing.