AIDS stands for Acquired immune deficiency syndrome. AIDS is caused by a virus known as HIV, the human immunodeficiency virus. If HIV is contracted the body will begin to make anti-bodies in order to fight the infection, if these antibodies are found in the blood the person is known as HIV-positive. HIV causes the immune system to weaken which leads to opportunistic infections that can make the compromised host sick due to the weak immune system which is how HIV leads into AIDS. A person with HIV is known to develop AIDS when the immune system is too weak that it can no longer fight off infections or diseases that the body would have been normally able to deal with. (3) A person is diagnosed with having aids once there are more than one opportunistic infections present in the body and has less than 200 CD4+ T cells per cubic millimetre of blood.(4)
Scientists recognized a type of chimpanzee in West Africa as the source of HIV that infected humans. Scientists believe that simian immunodeficiency virus (SIV) was transmitted to humans when these chimpanzees where hunted by humans for their meat and the humans came in contact with the chimps infected blood. They also believe that SIV muted in humans to become HIV. Over the years the HIV virus has spread from Africa to around the world.(7)
HIV is spread through bodily fluids. The blood, semen, vaginal fluid and breast milk are all ways in which the virus is carried as in these fluids even in small amounts is enough to transmit the virus to another person. (1) HIV is spread mainly by not using a condom when having sex with a person who has contracted HIV, All sex without a condom with an infected person poses a threat, however unprotected anal sex is a higher risk then vaginal sex. Having multiple sex partners or sexually transmitted infections can increase the risk of contracting HIV during intercourse. Oral sex can also be a method of transmission if
References: (1) http://www.aids.org/topics/aids-factsheets/aids-background-information/what-is-aids/ (2) http://spider.iwr.uni-heidelberg.de/teaching/wes/2005/03_Structural_Biology_of_HIV_(Felix_Voigts-Hoffmann).pdf (3) http://www.hivaware.org.uk/be-aware/about-hiv/ (4) http://www.niaid.nih.gov/topics/HIVAIDS/Understanding/Biology/Pages/structure.aspx (5) http://www.who.int/features/qa/71/en/index.html (6) http://www.hivaware.org.uk/be-aware/timeline-of-hiv.php (7) http://www.cdc.gov/hiv/topics/basic/index.htm#origin