-ay isang lentivirus (na kasapi ng pamilyang retrovirus) na nagsasanhi ng acquired immunodeficiency syndrome (AIDS o nakukuhang kakulangan ng immunong sindroma), Ang AIDS ay isang kondisyon sa mga tao kung saan ang patuloy ng pagkabigo o paghina ng sistemang immuno ay pumapayag sa mga nakapanganganib sa buhay na mga oportunistikong mga impeksiyon na manaig.
HIV-1 from chimpanzees and gorillas to humans
Scientists generally accept that the known strains (or groups) of HIV-1 are most closely related to the simian immunodeficiency viruses (SIVs) endemic in wild ape populations of West Central African forests. Particularly, each of the known HIV-1 strains is either closely related to the SIV that infects the chimpanzee subspecies Pan troglodytes troglodytes (SIVcpz), or to the SIV that infects Western lowland gorillas (Gorilla gorilla gorilla), called SIVgor.
HIV-2 from sooty mangabeys to humans
Similar research has been undertaken with SIV strains collected from several wild sooty mangabey (Cercocebus atys atys) (SIVsmm) communities of the West African nations of Sierra Leone, Liberia, and Ivory Coast. The resulting phylogenetic analyses show that the viruses most closely related to the two strains of HIV-2 which spread considerably in humans (HIV-2 groups A and B) are the SIVsmm found in the sooty mangabeys of the Tai forest, in western Ivory Coast.
According to the natural transfer theory (also called 'Hunter Theory' or 'Bushmeat Theory'), the "simplest and most plausible explanation for the cross-species transmission" of SIV or HIV (post mutation), the virus was transmitted from an ape or monkey to a human when a hunter or bushmeat vendor/handler was bitten or cut while hunting or butchering the animal. The resulting exposure to blood or other bodily fluids of the animal can result in SIV infection. A recent serological survey showed that human infections by SIV are not rare in Central Africa: the percentage of people showing seroreactivity to antigens — evidence of current or past SIV infection — was 2.3% among the general population of Cameroon, 7.8% in villages where bushmeat is hunted or used, and 17.1% in the most exposed people of these villages. How the SIV virus would have transformed into HIV after infection of the hunter or bushmeat handler from the ape/monkey is still a matter of debate, although natural selection would favor any viruses capable of adjusting so that they could infect and reproduce in the T cells of a human host.
Connection between HIV to AIDS
The condition that is referred to as AIDS is caused by HIV damaging the immune system cells until the immune system can no longer fight off other infections that it would usually be able to prevent. If left untreated, it takes around ten years on average for someone with HIV to develop AIDS. However, this average is based on the person with HIV having a reasonable diet, and someone who is malnourished may well progress from HIV to AIDS more rapidly.
HIV is found in the blood and the sexual fluids of an infected person, and in the breast milk of an infected woman. HIV transmission occurs when a sufficient quantity of these fluids get into someone else's bloodstream. There are various ways a person can become infected with HIV: * Unprotected sexual intercourse with an infected person: Sexual intercourse without a condom carries the risk of HIV infection. * Contact with an infected person's blood: If sufficient blood from somebody who has HIV enters someone else's body, then HIV can be passed on in the blood. * Use of infected blood products: Many people in the past have been infected with HIV by the use of blood transfusions and blood products which were contaminated with the virus. In much of the world this is no longer a significant risk, as blood donations are routinely tested for HIV. * Injecting drugs: HIV can be passed on when...