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Glossary of Terms

Human Immunodeficiency Virus Type 1 – definition from AIDSinfo – http://aidsinfo.nih.gov
1. The retrovirus isolated and recognized as the etiologic (i.e., causing or contributing to the cause of a disease) agent of AIDS. HIV-1 is classified as a lentivirus in a subgroup of retroviruses.
2. The genetic material of a retrovirus such as HIV is the RNA itself. HIV inserts its own RNA into the host cell's DNA, preventing the host cell from carrying out its natural functions and turning it into an HIV factory.

Human Immunodeficiency Virus Type 2 – definition from AIDSinfo – http://aidsinfo.nih.gov
A virus closely related to HIV-1 that has also been found to cause AIDS. It was first isolated in West Africa. Although HIV-1 and HIV-2 are similar in their viral structure, modes of transmission, and resulting opportunistic infections, they have differed in their geographic patterns of infection.

HIV Disease - definition from AIDSinfo – http://aidsinfo.nih.gov
During the initial infection with HIV, when the virus comes in contact with the mucosal surface and finds susceptible T cells, the first site at which there is truly massive production of the virus is lymphoid tissue. This leads to a burst of massive viremia, with wide dissemination of the virus to lymphoid organs. The resulting immune response to suppress the virus is only partially successful and some virus escape. Eventually, this results in high viral turnover that leads to destruction of the immune system. HIV disease is, therefore, characterized by a gradual deterioration of immune functions. During the course of infection, crucial immune cells, called CD4+ T cells, are disabled and killed, and their numbers progressively decline. See Acquired Immunodeficiency Syndrome; Human Immunodeficiency Virus Type 1.

Acquired Immunodeficiency Syndrome – definition from AIDSinfo – http://aidsinfo.nih.gov
The most severe manifestation of infection with the Human Immunodeficiency Virus (HIV). The Centers for Disease Control and Prevention (CDC) lists numerous opportunistic infections and cancers that, in the presence of HIV infection, constitute an AIDS diagnosis. In 1993, CDC expanded the criteria for an AIDS diagnosis in adults and adolescents to include CD4+ T- cell count at or below 200 cells per microliter in the presence of HIV infection. In persons (age 5 and older) with normally functioning immune systems, CD4+ T- cell counts usually range from 500 - 1,500 cells per microliter. Persons living with AIDS often have infections of the lungs, brain, eyes, and other organs, and frequently suffer debilitating weight loss, diarrhea, and a type of cancer called Kaposi's Sarcoma.