How Long Has AIDS Been Around?

AIDS and HIV, the virus that causes the syndrome, have been tracked to chimpanzees in Africa as early as the 1950s. Scientists believe it was not spread to the greater global population, however, until the production of the hepatitis B vaccine in the 1970s.

The First Known Case

• Dr. Beatrice Hahn of the University of Alabama at Birmingham and her research team discovered that the first human known to be infected with HIV was a man from the Congo who had his blood stored in 1959, just prior to his death. The blood was tested again once AIDS was known to exist; it was positive. Hahn suspects that someone was either bitten by a chimp or cut while preparing one to eat, becoming infected with simian immunodeficiency virus, or SIV. It was then passed on to other people from there, bringing it to the Congo and elsewhere.

SIV to HIV

• It is known in the scientific community that there are three types of HIV-1, the viral strain responsible for most of the pandemic. By genetically analyzing chimp communities around Congo and Cameroon, Hahn discovered viral strains closely related to the most common of HIV-1 subtypes. As SIV spread in the human community in the 1950s, Hahn hypothesizes that the human version of HIV became deadlier to people than to primates.

Chimps and Hepatitis

• When the hepatitis B vaccine was produced, chimpanzees were used for testing. With viruses like SIV and HIV subtypes in their systems, scientists believe the vaccinations were contaminated prior to being distributed to gay men in New York City and Central African villagers in 1973.

Recognition of AIDS

• The first AIDS cases were reported primarily by gay men in New York in 1981. The majority had been given a hepatitis B vaccination prior to developing cancers and opportunistic infections that defied treatment. Dr. Luc Montagnier of the Pasteur Institute in Paris and Dr. Anthony Gallo of the National Cancer Institute in Washington both discovered the culprit, labeling it HIV, the virus that leads to AIDS.

Immune System Attacker

• Studies on HIV by Montagnier, Gallo and their teams determined that it was a lentivirus, or "slow virus," in a greater family of retroviruses known for attacking the immune system. Once this was known, it was easily linked to SIV, another immunodeficiency virus prevalent in west-central African chimpanzees.

Viral transfer

• In 1999, Dr. Hahn, along with Paul Sharp of Nottingham University and their team of researchers, discovered two distinct SIV strains infecting wild chimpanzees that came together and formed a third virus with the ability to infect humans. Known as "viral transfer," humans are susceptible to animal-made viruses in certain circumstances, HIV/AIDS being one.