Subtypes of HIV
The subtypes of HIV include two main subtypes, known as HIV type 1 (HIV-1) and HIV type 2 (HIV-2). These subtypes have distinct genetic differences and are associated with different epidemiological patterns and clinical characteristics.
| Human immunodeficiency viruses | |
|---|---|
| Phylogenetic tree of the SIV and HIV viruses | |
| Scientific classification | |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Pararnavirae |
| Phylum: | Artverviricota |
| Class: | Revtraviricetes |
| Order: | Ortervirales |
| Family: | Retroviridae |
| Subfamily: | Orthoretrovirinae |
| Genus: | Lentivirus |
| Groups included | |
| Cladistically included but traditionally excluded taxa | |
| |
HIV-1 exhibits a genetic relation to viruses indigenous to chimpanzees and gorillas that inhabit West Africa, while HIV-2 viruses are affiliated with viruses present in the sooty mangabey, a vulnerable West African primate.
HIV-1 viruses can be further stratified into groups M, N, O, and P. Among these, HIV-1 group M viruses are the most prevalent, infecting nearly 90% of people living with HIV and are responsible for the global AIDS pandemic. Group M can be further subdivided into subtypes based on genetic sequence data. Certain subtypes are known for their increased virulence or drug resistance to different medications used to treat HIV.
HIV-2 viruses are generally considered to be less virulent and less transmissible than HIV-1 M group viruses, although HIV-2 is also known to still cause AIDS.
One of the prevailing challenges in the pursuit of effective management of HIV is the virus's pronounced genetic variability and rapid viral evolution.