Patient Zero

The term “patient zero” as the original victim of an epidemic originated from a misunderstanding.

In March 1984, the US Centers for Disease Control and Prevention (CDC) published a study which had tracked the sexual liaisons of gay and bisexual men in the nation, especially in California and New York. The study’s aim was to understand the early propagation of HIV: the 2 human immunodeficiency viruses which cause AIDS (acquired immunodeficiency syndrome).

A CDC researcher based in Los Angeles, Dr. William Darrow, had code-named Canadian flight attendant Gaëtan Dugas as “Patient O”: the letter ‘O’ designating “outside California.” Many readers of the study report misconstrued the letter ‘O’ to be the number zero. The idea of “patient zero” was born.

Gaëtan Dugas (1953–1984) was a homosexual who acquired the HIV virus in the mid-1970s. That did not slow his sex life. Dugas himself estimated that he had hundreds of sex partners per year, and claimed to have had over 2,500 partners across North America from when he began broadly brandishing his pecker in 1972 until AIDS retired him. Dugas was posthumously branded a sociopath for his proclivity in spreading HIV.

A 2016 genetic epidemiological study led by American evolutionary biologist Dr. Michael Worobey determined that Dugas was not “patient zero” or its primal propagator. Instead, Worobey concluded: “On the family tree of the virus, Dugas fell in the middle, not at the beginning.”

“Patient Zero” has become a popular disease term: featured in horror novels, movies, songs, video games, and is even labeled a beer brewed by Black Plague Brewing.


Research was rather extensive for this blog entry. The single best article (which, alas for me, was read after the blog entry was written) is:

Jacqueline Howard, “The truth about ‘patient zero’ and HIV’s origins,” CNN (29 October 2016).