Human Immunodeficiency Virus, an AIDS (AIDS, Acquired Immunodeficiency Syndrome) virus, is a virus that causes defects in the human immune system. In 1981, the human immunodeficiency virus was first discovered in the United States. It is a lentivirus that infects cells of the human immune system and is a type of retrovirus.
On October 27, 2017, the World Health Organization's International Agency for Research on Cancer published a preliminary list of carcinogens, human immunodeficiency virus type I (infection) in a list of carcinogens, human immunodeficiency virus type 2 (infection) List of Class 2B carcinogens.
On March 4, 2015, scientists from many countries found that the four known strains of HIV, from chimpanzees and gorillas in Cameroon, were the first to fully identify all sources of HIV strains.
There are four known HIV strains, M, N, O, and P, each with different origins. The most widely spread M and N have long been confirmed to be from chimpanzees, but the rarer O and P are. It was later confirmed that both O and P were gorillas from southwestern Cameroon.
There are only two P-type cases in the world, and there are only 100,000 O-types, mainly concentrated in Central and West Africa.