Both types of HIV, type 1 and 2, are believed to have been transmitted to humans from primates in the West-central Africa region early in the 20th century. It seems that HIV-1 originated from southern Cameroon through the emergence of a simian immunodeficiency virus, or SIV, that infects wild chimpanzees. On the other hand, the closest relative of HIV-2 is a different viral strain of SIV that infects the sooty mangabey, an Old World monkey native to forests in West Africa coastal regions. HIV type 2 is mostly restricted to West Africa due to its low capacity for transmission.
It is believed that HIV type 1, the most pathogenic as well as common strain of the virus, jumped the species barrier at least three isolated times. This gave rise to the three subgroups of the virus, identified by differences in the envelope region, M, N, and O, with group M, which stands for major, being the most common of all and thought to be cause of the AIDS pandemic.
Studies of the genetic code of the virus indicated that the most recent common ancestor of group M of HIV-1 dates back to the early 1900s and this lead some to link the epidemic with the rise of colonialism and growth of cities in Africa. The …show more content…
Although the majority of infections, not including those of sub-Saharan Africa, can be linked to a single person who became infected in Haiti and later brought the virus along to the US some time near 1969, it is thought that the virus may have been here since the 1950’s due to a sixteen year-old male from Missouri who first showed symptoms in 1966 and then died in 1969. The outbreak spread fast among groups at highest risk such as homosexual men and drug users who used needles and by 1978, HIV type 1 infections were estimated to be approximately 5 percent of gay male communities of New York and California. This statistic suggests that thousands of people were already infected in the country by
It is believed that HIV type 1, the most pathogenic as well as common strain of the virus, jumped the species barrier at least three isolated times. This gave rise to the three subgroups of the virus, identified by differences in the envelope region, M, N, and O, with group M, which stands for major, being the most common of all and thought to be cause of the AIDS pandemic.
Studies of the genetic code of the virus indicated that the most recent common ancestor of group M of HIV-1 dates back to the early 1900s and this lead some to link the epidemic with the rise of colonialism and growth of cities in Africa. The …show more content…
Although the majority of infections, not including those of sub-Saharan Africa, can be linked to a single person who became infected in Haiti and later brought the virus along to the US some time near 1969, it is thought that the virus may have been here since the 1950’s due to a sixteen year-old male from Missouri who first showed symptoms in 1966 and then died in 1969. The outbreak spread fast among groups at highest risk such as homosexual men and drug users who used needles and by 1978, HIV type 1 infections were estimated to be approximately 5 percent of gay male communities of New York and California. This statistic suggests that thousands of people were already infected in the country by