HIV spread earlier than believed; ‘Patient 0’ a myth, study says

HIV likely landed in the United States a full decade before the first AIDS reports made headlines, according to a report released Wednesday that also strongly dismisses the long-held myth that a single man, a flight attendant notoriously known as “Patient Zero,” was responsible for the domestic epidemic.

The report, published Wednesday in the journal Nature, traces the lineage of HIV from Africa to Haiti to New York and, finally, San Francisco.

The virus seems to have arrived in New York around 1971, and in San Francisco five years later. By the time doctors were reporting the first AIDS cases in 1981, the virus would have been deeply embedded in cities all over the country.

The fact that HIV predated those first AIDS reports — and that the so-called Patient Zero could not have been responsible for the epidemic — has long been known by AIDS researchers. But the new paper, which relies on evidence drawn from some of the earliest known samples of HIV in human blood, provides perhaps the most detailed genetic history of the virus’ geographic movement.

For their research, scientists used blood samples taken from men in New York and San Francisco who participated in a hepatitis B vaccine study in the late 1970s. About 6 percent of the New York samples and 3 percent of the San Francisco ones were found to be positive for HIV at the time.

Because the blood had been in storage for decades, the samples were badly degraded. Scientists doing the new research used novel lab techniques and computer sequencing to essentially reconstruct the virus found in the samples, determine the genetic makeup and map the spread of the disease.

Genetic strains that are similar are closely related and share a recent, common ancestor; those that are less alike have a more distant ancestor. Applying mathematical models, the scientists were able to determine where the virus had come from and when it likely had landed in the community from which the samples were drawn.

“You can really come up with a rich model of how a virus moves through space and time,” said Satish Pillai, a UCSF scientist who studies HIV taken from samples in the same hepatitis B studies.

The new study, when coupled with previous work, gives a fairly clear picture of HIV’s global travel, said co-author Michael Worobey, an evolutionary biologist at the University of Arizona at Tucson. He said studies suggest the virus moved from chimpanzees to humans in the early 20th century, but languished in rural villages for decades before passing into Kinshasa, the capital of Congo.

From Kinshasa it may have spread throughout sub-Saharan Africa, and finally moved to the Caribbean, including Haiti, in the mid-1960s. There, HIV may have caused small outbreaks that would have escaped the attention of public health authorities.

How the virus traveled from Haiti to New York isn’t clear, Worobey said. It could have been spread by an individual or from a blood product like plasma. But New York was certainly a crossroads: HIV arrived during a sexual revolution among young gay men, a perfect environment for a sexually transmitted virus to flourish.

“Just as Kinshasa was a key turning point for the virus as a whole, New York City acts as this hub from which it moves to the West Coast, and eventually to Western Europe and Australia and Japan and South America and all sorts of other places,” Worobey said.

Noting these geographic patterns is not the same as assigning blame, Worobey and other scientists stressed. Just as New York can’t be blamed for spreading the virus to San Francisco, Haiti shouldn’t be blamed for what happened in New York.

Moreover, Patient Zero shouldn’t have been blamed at all. In the same paper, Worobey and his colleagues analyzed the blood of Gaëtan Dugas, the flight attendant named by former Chronicle journalist Randy Shilts as Patient Zero in his acclaimed 1987 book “And the Band Played On.”

Shilts, who died of AIDS in 1994, never blamed Dugas entirely for the epidemic, but in his book he placed Dugas as a central figure, going so far as to cast him as a villain, a man purposefully infecting others during wildly promiscuous years in the late 1970s and early 1980s.

The labeling of Dugas happened by mistake, historians of the epidemic now believe. Shilts latched on to the Patient Zero idea based on a misreading of a study in which Dugas, at the time an unidentified man, was labeled Patient O — as in the letter O. In that study, Dugas, a Canadian, was the lone patient from “outside” the country, thus the O designation.

In his reporting, Shilts figured out that Dugas was the patient, but he, along with some scientists at the time, got the numeral 0 and letter O mixed up.

“An ambiguous oval” cast an urban legend that persists to this day, said Richard McKay, a historian at the University of Cambridge in England who co-authored the new Nature paper.

Dugas died of AIDS in 1984. It’s not known when exactly he was infected. But in studying his blood, McKay and his colleagues determined that he contracted HIV long after it was first introduced to North America.

“He was the only person who’s ever mentioned to blame for the spread of this virus. And it was an invention,” said Volberding, who once treated Dugas during an emergency room visit at San Francisco General Hospital. “It’s a long time ago and all that, but it’s nice to clear somebody’s name.

“I knew Randy (Shilts) reasonably well,” added Volberding. “His book was fantastic. But it seems this was clearly a journalistic device.”

http://www.sfchronicle.com/health/article/New-study-traces-spread-of-HIV-affirms-myth-of-10416130.php