Most origins of AIDS do not mention zoonosis. Instead, the story often begins in 1980 when doctors noticed gay men suffering from pneumonia their immune systems should have been able to cope with, along with a reduced count of T-cells, which are “crucial in regulating immune responses” (385). The doctor who wrote up these cases, Michael Gottlieb, worked at UCLA Medical Center. He published his findings in a CDC newsletter, about a month after a dermatologist published in the same publication about an uptick in cases of a rare cancer called Kaposi’s sarcoma in gay men who also had reduced T-cell counts. Another cluster of cases occurred among heterosexual Haitian immigrants, though this episode was left out of the narrative for a long time due to its seeming inexplicability.

A flight attendant named Gaëtan Dugas was incorrectly identified as “patient zero” for many years in part because he had traveled to Africa for his work. Dugas had numerous sexual partners and appears to have infected others deliberately toward the end of his life (387). By 1984, CDC experts had named AIDS and speculated that it was “blood-borne,” like hepatitis B. Their original paper focused on Dugas as the origin—Quammen goes on to explain how this assumption was incorrect.