HIV stands for human immunodeficiency virus and is the virus that can lead to acquired immunodeficiency syndrome, or AIDS. HIV is unlike other viruses in the sense that the human body cannot get rid of HIV, in other words, once you have HIV you have it for life. There are two types of the HIV virus, HIV-1 and HIV-2. AIDS was first recognized in 1981, but the causative virus was not identified until 1983 when a reverse transcriptase containing virus was recovered from the lymph node of a man with persistent lymphadenopathy syndrome at the Pasteur Institute (Levy, 1993). This was the first indication that AIDS could be caused by a retrovirus. According to the AIDS.gov webpage, it is believed that HIV came from a particular kind of chimpanzee in Western Africa. Scientists predict that the chimpanzee had a version of the immunodeficiency virus that was transmitted to humans and mutated into HIV. Humans acquired this disease from hunting these chimpanzees for meat and ingested their infected blood (What is HIV/AIDS?).
HIV is a retrovirus that is spherical in shape, with an approximate diameter of 100nm. Retroviridae is a family of enveloped viruses that replicate in a host cell through the process of reverse transcription. A retrovirus is a single stranded RNA virus that stores its nucleic acid in the form of mRNA and targets the host cells as an obligate parasite. HIV consists of an envelope of glycoproteins, core proteins and an inner core of viral RNA and reverse transcriptase (Harmening, 2005). HIV infections cause a slowly progressing immune disorder, which is why it was termed an immunodeficiency virus.
HIV-1 and HIV-2 are similar in structure and vary primarily in the envelope proteins. HIV-1 consists of glycoprotein120, glycoprotein41 and protein24; whereas, HIV-2 consists of glycoprotein125, glycoprotein36, and protein26 (Harmening, 2005). Almost all cases documented in the United States result from an infection with the HIV-1 virus. HIV-2 is more prevalent in West Africa but is very rarely diagnosed in the United State and usually is linked to an association with West Africa.
HIV can be spread mainly by having unprotected anal or vaginal sex with an infected person or by sharing drug-use equipment with an infected person. Researchers believe that the HIV virus attaches to dendritic cells when HIV enters the body through sexual contact, transfusions with infected blood or by injection with a needle contaminated with infected blood (What is HIV/AIDS?). Dendritic cells are found primarily in mucosal membranes and these cells are believed to transport the virus from the site of infection to the lymphatic system, where HIV can infect other immune system cells. The most at risk group of people for HIV are gay, bisexual and other men who have sex with men and African American males rank the highest in this group for infected people (HIV/AIDS). Other at risk groups include injection drug users, people who are in poverty...