HIV, or human immunodeficiency virus, is a virus that destroys CD4 cells, the white blood cells responsible for fighting infection. HIV is known as a lentivirus, which is a type of retrovirus. UNAIDS estimates that over 60 million people have become infected with the HIV virus since the pandemic first began. A person infected with HIV may go on to develop AIDS, or acquired immunodeficiency syndrome, which is a life-threatening illness. According to UNAIDS, AIDS is fourth leading cause of death worldwide. There are two known strains of the HIV virus.
HIV-1
According to AVERT, the international AIDS charity, HIV-1 is the predominant HIV virus worldwide. The HIV-1 virus can be subdivided into four groups. "M" stands for major, "O" stands for outlier, and N and P. The N strain of the HIV-1 virus was discovered in 1998 in Cameroon, and according to AVERT, is very rare. Most people with HIV-1 will be infected with the M group, which can be subdivided further into groups A, B, C, D, F, G, H, J and K. New subtypes may arise in the future; in fact AVERT states that it "is almost certain" that new subtypes will be discovered one day.
HIV-2
The HIV-2 strain is rare and is mainly found in West Africa. According to a 2008 article published in "AIDS Research and Therapy," the incidence of HIV-2 is so low in the United States that guidelines recommend testing for HIV-2 in patients known to have links with West Africa. According to AIDSmap, the origin of HIV-2 can attributed to the sooty mangabey monkeys, which are indigenous to Central and Western Africa. HIV-2 is less infectious than HIV-1 but the mode of transmission of both viruses is the same.
Super Strain
In 2005, doctors in New York discovered a man who was found to have a previously unseen form of the HIV virus. This strain of the HIV virus was termed the super strain as it was found to be resistant to four kinds of anti-viral drugs. However, some experts are skeptical as to whether there is such a thing as a super strain of the HIV virus and suggested it may be an anomaly since it was only found in one person.
