Genetic evidence has exonerated the Canadian man widely blamed for introducing HIV to the United States and sparking the epidemic that has killed nearly 700,000 people so far, according to a study published in the journal Nature.
Researchers used newly available genetic evidence to show that HIV jumped to the United States from the Caribbean much earlier than previously thought.
In the process they also exculpated Gaetan Dugas, a handsome and sexually prolific Air Canada flight attendant dubbed “Patient Zero,” proving that he could not have been the first person in the U.S. to have the virus that causes AIDS.
Instead, the researchers concluded that Dugas was one of thousands of people who were infected with HIV by the late 1970s, years before it was officially recognized by the medical community in 1981.
To come to their conclusions researchers had to painstakingly study decades-old serum samples taken from gay men in New York City in 1978 and 1979, and in San Francisco in 1978.
The men were participating in a study of hepatitis B, which was prevalent in the gay community at the time. They weren’t tested for HIV because it was still unknown back then.
Researchers looked for traces of antibodies that their immune systems would have produced to fight the infection.
Once the presence of antibodies was found in certain samples, the next step was to search the samples for fragments of HIV RNA, a very uncertain proposition since RNA is very fragile and researchers weren’t sure it would have been preserved for more than four decades.
Researchers selected 53 samples and managed to sequence the full genomes of eight of them — three from San Francisco and five from New York.
Scientists were able to track the evolution of the HIV virus in the U.S. by tallying the number of mutations in its genome.
The research showed that the HIV strain that ravaged the U.S. – known as HIV-1 group M subtype B – first jumped from the Caribbean to New York City in 1970 or 1971, years before Dugas was infected. In fact, the research showed Dugas was infected with a different strain of HIV.
“In short, we found no evidence that Patient 0 was the first person infected by this lineage of HIV-1,” study authors wrote.
(For more on this study read this excellent article in the Los Angeles Times by Deborah Netburn)
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