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New Research Sheds Light on Origin of HIV in U.S., Dispelling Patient Zero Myth


A new genetic analysis shows that HIV likely spread from the Caribbean to New York City around 1971 and from there to San Francisco around 1976, laying to rest the misconception that a Canadian flight attendant, Gaetan Dugas, was responsible for sparking the epidemic in the United States.

The persistent myth about a so-called "Patient Zero" was popularized by gay journalist Randy Shilts in his 1987 book about the early epidemic, And the Band Played On.

Richard McKay, a historian from the University of Cambridge and co-author of the paper published in the October 26 edition of Nature, found that Dugas was designated as case "O" -- meaning outside California -- in an early Centers for Disease Control and Prevention (CDC) analysis of HIV sexual transmission networks. During publication of the study in 1984, the letter "O" was misinterpreted as the number zero.

"It's great that modern science can be brought to bear on this and resolve questions of those early moments of HIV," said Paul Volberding, director of the UCSF AIDS research Institute, who once cared for Dugas at San Francisco General Hospital. "None of this is about blame. New York doesn't blame Haiti, nor does San Francisco blame New York. And now we can add that we can't blame Patient O."

Evolution of HIV

Michael Worobey, an evolutionary biologist from the University of Arizona in Tucson, led a genetic analysis of stored blood samples from gay men participating in hepatitis B research in the late 1970s.

Looking at a repository of nearly 9000 stored samples from New York and nearly 7000 from San Francisco, Worobey's team found that 6.6% of the New York samples and 3.7% of those from San Francisco contained HIV in 1978-1979.

The researchers then attempted genetic sequencing of a subset of the stored viruses. Although the blood samples have been available for decades, the team had to develop a new laboratory technique -- dubbed "jackhammering" -- to analyze the old and degraded viral RNA. They were able to obtain complete HIV genetic information from 5 New York samples and 3 from San Francisco.

Worobey's team then constructed an evolutionary tree for HIV-1 group M subtype B, which accounts for most cases in North and South America, Europe, and Australia. Because HIV accumulates genetic mutations at a steady rate over time, virus with more genetic diversity is known to be older.

The researchers determined that subtype B, thought to have originated in Kinshasa in the Democratic Republic of Congo (formerly the Belgian Congo and later Zaire), made its way to Haiti around 1967. From there it spread to New York around 1971 -- well before Dugas began travelling as a flight attendant for Air Canada.

HIV arrived in San Francisco by 1976, and the 3 sequenced San Francisco viruses all appeared to descend from a single New York strain. The first reports of the disease later known as AIDS were published in medical journals in 1981, and the virus that caused it was finally identified in 1983.

Worobey and his colleagues also obtained and sequenced HIV from a sample donated by Dugas not long before he died of AIDS in 1984, showing that his virus fell in the middle of the evolutionary tree, not near its base.

"[We] found neither biological nor historical evidence that he was the primary case in the U.S. or for subtype B as a whole," the researchers wrote, noting that his virus "appeared typical of U.S. strains of the time."

Dugas did, however, play an important role in understanding HIV transmission because he kept a diary of his sexual partners and provided this information to CDC investigators.

While the new genetic analysis offers clues about the time frame of HIV's introduction into the U.S., it does not provide definitive answers about who introduced it or how it happened -- it may have come from contaminated blood products produced in Haiti -- but it does let one historical suspect off the hook.

Myth Contributes to Stigma

Advocates said misconceptions about "Patient Zero" had done much to promote stigma and blame of people with HIV and of gay and bisexual men in general.

"The 'Patient Zero' story created a folk figure that responded perfectly to the fears and prejudices of American society," said community historian Gerard Koskovich. "It reflected and reinforced longstanding homophobic stereotypes of gay men as irresponsible, sex-obsessed, narcissistic, amoral, and self-destructive. Given that combination of elements, the 'Patient Zero' myth is one of the most persistent and harmful tales to have come out of the darkest years of the AIDS epidemic."

Scientists have said all along that Dugas was not the first person with HIV in the U.S. and that the origins of HIV likely cannot be traced to any single individual. But the myth has persisted in popular culture, and advocates hope Worobey's study will finally help dispel it.

"It's hard to overestimate the damage that the 'Patient Zero' myth has done to expand the hatred and discrimination against gay men for allegedly starting AIDS," said former ACT UP/New York member and Treatment Action Group cofounder Mark Harrington. "This paper represents science at its best, and, one hopes, the truth will set many free from destructive self-blame or social stigma."



M Worobey, TD Watts, RA McKay, et al. 1970s and 'Patient 0' HIV-1 genomes illuminate early HIV/AIDS history in North America. Nature. October 26, 2016 (online ahead of print).