Researchers believe that sometime in the

1930s

• Researchers believe that sometime in the 1930s a form of simian immunodeficiency virus jumped to humans in central Africa. The mutated virus becomes HIV-1.^[1]

1959

X-ray showing infection with Pneumocystis carinii pneumonia.

• The first known case of HIV in a human occurs in a person who died in the Congo, later confirmed as having HIV infection from his preserved blood samples. ^{[2] [3]} The authors of the study did not sequence a full virus from his samples, writing that "attempts to amplify HIV-1 fragments of >300 base pairs (bp) were unsuccessful, . . . However, after numerous attempts, four shorter sequences were obtained" that represented small portions of two of the six genes of the complete AIDS virus.^[3]
• In New York City, "Ardouin A.", a 49-year-old American shipping clerk dies of Pneumocystis carinii pneumonia, a disease closely associated with AIDS. Dr. Gordon Hennigar, who performed the postmortem examination of the man's body, found "the first reported instance of unassociated Pneumocystis carinii disease in an adult" to be so unusual that he pickled Ardouin's lungs for later study. The case was written up in two medical journals at the time, and Hennigar has been quoted in numerous publications saying that he believes Ardouin probably had AIDS.^[4][5]

1960s

• HIV-2, a viral variant found in West Africa, is thought to have transferred to people from sooty mangabey monkeys in Guinea-Bissau during this period.^[1]

1964

• Jerome Horwitz of Barbara Ann Karmanos Cancer Institute and Wayne State University School of Medicine synthesized AZT, under a US National Institutes of Health (NIH) grant. AZT was originally intended as an anticancer drug.

1966

• Genetic studies of the virus indicate that, in or about 1966, HIV first arrived in the Americas, infecting a single person in Haiti. At this time, many Haitians were working in Congo, providing the opportunity for infection.^[6]

1968

• A 2003 analysis of HIV types found in the United States, compared to known mutation rates, suggests that the virus may have first arrived in the United States in this year.^[1] The disease spread from the 1966 American strand, but remained unrecognized for another 12 years.^[6]

1969

• A St. Louis teenager, identified only as Robert R., dies of an illness that baffles his doctors. Eighteen years later, molecular biologists at Tulane University in New Orleans test samples of his remains and find evidence of HIV present.^[7]

1975

• The first reports of wasting and other symptoms, later determined to be AIDS, are reported in residents of Africa.^[8]

1976

• Norwegian sailor Arvid Noe dies; it is later determined that he contracted HIV/AIDS in Africa during the early 1960s.

1977

• Danish physician Grethe Rask dies of AIDS contracted in Africa.
• A San Francisco prostitute gives birth to the first of three children who would later be diagnosed with AIDS, and whose blood, when tested after their deaths, would reveal HIV infection. The mother would herself die of AIDS in May 1987. She was clearly infected by 1977 and perhaps earlier.^[9]

1978

• A Portuguese man known as Senhor Jose dies; he will later be confirmed as the first known infection of HIV-2. He was believed to have been exposed to the disease in Guinea-Bissau in 1966.