The Human Immunodeficiency Virus (HIV) is a retrovirus that specifically infects several kinds of cells in the human body, the most important of which is a type of white blood cell called the CD4 T-Lymphocyte (generally referred to in the field of HIV as “T-cells”). The CD4 cell is a major component of the human immune system which helps keep people free from many infections and some cancers. HIV can effectively disable the body’s immune system and destroy its ability to fight diseases by specifically invading CD4 cells and destroying them.
HIV is spread through human exposure to HIV contaminated blood, semen, pre-cum, and vaginal fluids (including menstrual blood). Exposure to these fluids occurs during unprotected sex (e.g. sex without condoms) or unsafe and risky sexual practices that expose an individual to one of these fluids. HIV can also be transmitted from mother to child through birth or by breast feeding. Exposure also occurs through the sharing of needles while injecting drugs or other substances.
There are two major types of HIV that have been identified:
HIV-1 is the most common of the two major retroviruses, and it is the one that infects most people around the world.
HIV-2 has been found mostly in West Africa, and it is not as common as HIV-1.
Acquired Immunodeficiency Syndrome (AIDS) is a diagnosis given by a physician to an HIV infected individual whose immune system has been compromised by the retrovirus. When an individual’s immune system has been compromised by HIV, it means that the individuals CD4 T-Lymphocyte cell count has fallen below 200, and/or the individual has developed some specific and opportune infections (AKA: Opportunistic Infections- OIs) that are usually present with weakened immune systems. Some of these infections include, but are not limited to, Candidiasis, Toxoplasmosis, Kaposi Sarcoma, Pneumocystis Carinii Pneumonia, Cytomegalovirus, and many others.
AIDS Info Net:
Centers for Disease Control and Prevention – HIV/AIDS: