It arose from a virus called SIV, found in the immune system of chimpanzees and the African green monkey. Despite not making these animals sick, SIV is a highly mutated virus, which would have given rise to HIV, the AIDS virus.
The SIV present in the green monkey would have created HIV2, a less aggressive version, which takes longer to cause AIDS. Chimpanzees, on the other hand, gave rise to HIV1, the deadliest form of the virus. “It is likely that transmission to humans, both of HIV1 and HIV2, occurred in tribes in central Africa that hunted or domesticated chimpanzees and green monkeys”, says infectologist Jacyr Pasternak, from Hospital Beneficência Portuguesa, in São Paulo.
There is no consensus on the date of the first transmissions. The most likely, however, is that they happened around 1930. In the following decades, the disease would have remained restricted to small groups and tribes in central Africa, in the region south of the Sahara desert.
In the 1960s and 1970s, during the wars of independence, the entry of mercenaries into the continent began to spread AIDS around the world. Haitians taken to work in the former Belgian Congo (now the Democratic Republic of Congo) also helped spread the disease to other countries. “Between 1960 and 1980, there were several cases of illnesses that no one could explain, with patients usually presenting Kaposi’s sarcoma, a type of cancer, and pneumonia”, says epidemiologist Cássia Buchalla, from the University of São Paulo (USP). AIDS was only finally identified in 1981.
decades of mystery
The disease, which may have appeared in the 1930s, was only identified in 1981
1930
One of the main studies on AIDS points out that in that year the first transmission from monkeys to humans took place. But there is no consensus among scientists. Some even believe that man’s first contact with the virus happened centuries before.
1957
A few years ago, a popular theory said that HIV transmission to humans would only have occurred in 1957. A polio vaccine would be contaminated with organic remains of monkeys carrying the virus. Recent tests, however, have debunked this theory.
1959
The first proven case of death caused by AIDS is a man who lived in Kinshasa, in the former Belgian Congo (today Congo). This, however, was only discovered decades later, with a test carried out on his blood, which was kept frozen.
1981
AIDS is recognized as a disease. There are several reports of symptoms in homosexuals in the United States. Also in 1981, the so-called “zero patient” died in that country: a flight attendant who spread the disease on his travels.
1983
Researchers isolate the AIDS virus for the first time. Two years later, the test that identifies the presence of antibodies in the blood appears. The name HIV, however, only appeared in 1986. The first drug to help treat the disease, AZT, was only created in 1987