A new study offers insight into the route by which HIV/AIDS arrived in North America and also claims it debunks a theory about the first person in the United States to be infected.

In 1987, author Randy Shilts reported that Gaëtan Dugas, a Canadian flight attendant, was the first person infected in the US and dubbed him “Patient zero.” The new study offers further evidence that Dugas was not actually the source of the pandemic in North America, and "ties in with a body of evidence" that corroborates this view, The Guardian reported.

“The current study provides further evidence that patient 57, the individual identified both by the letter O and the number 0 was not patient zero of the North American epidemic,” Richard McKay, historian and co-author of the study from the University of Cambridge, told The Guardian. Dugas was identified as the letter O in a typo, and that was then misconstrued to mean "zero."

"Analysis of his HIV genome shows that it was typical of strains of the virus within the US at the time and was not the root from which the virus diversified in North America," according to The Guardian. The researchers say the virus originally emerged from an outbreak in the Caribbean, came to New York by the 1970s, and then moved west.

There are many theories about how humans first became infected with HIV. Back in 1999, a group of scientists reported that they had discovered the origins of HIV-1, the predominant strain of HIV, in the developed world. So, what was the original source of the virus? A subspecies of chimpanzees native to west equatorial Africa, according to The AIDS Institute. The researchers believe that HIV-1 was introduced into the human population when hunters became exposed to infected blood.

The earliest known case of HIV in a human was detected in a blood sample collected in 1959. The infected man was in Kinshasa, Democratic Republic of the Congo, and it’s still unknown how he contracted the lentivirus.

According to the World Health Organization, more than 70 million people have been infected with HIV worldwide, and about 35 million have died of the virus.

Source: Worobey M, Watts TD, McKay RA, Suchard MA, Granade T, Teuwen DE. 1970s and ‘Patient 0’ HIV-1 genomes illuminate early HIV/AIDS history in North America. Nature. 2016.

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