In the tortuous mythology of the AIDS epidemic, one legend never seems to die: Patient Zero, a.k.a. Gaétan Dugas, a globe-trotting, sexually insatiable French Canadian flight attendant who supposedly picked up H.I.V. in Haiti or Africa and spread it to dozens, even hundreds, of men before his death in 1984.

Mr. Dugas was once blamed for setting off the entire American AIDS epidemic, which traumatized the nation in the 1980s and has since killed more than 500,000 Americans. The New York Post even described him with the headline “The Man Who Gave Us AIDS.”

But after a new genetic analysis of stored blood samples, bolstered by some intriguing historical detective work, scientists on Wednesday declared him innocent.

The strain of H.I.V. responsible for almost all AIDS cases in the United States, which was carried from Zaire to Haiti around 1967, spread from there to New York City around 1971, researchers concluded in the journal Nature. From New York, it spread to San Francisco around 1976.</s>Image copyright SPL

One of the most demonised patients in history - Gaetan Dugas - has been convincingly cleared of claims he spread HIV to the US, say scientists.

Mr Dugas, a homosexual flight attendant, gained legendary status in the history of HIV/Aids when he became known as Patient Zero.

But a study, in the journal Nature, showed he was just one of thousands of infected people in the 1970s.

It also showed New York was a crucial hub for the spread of the virus.

Aids only started to be recognised in 1981 when unusual symptoms started appearing in gay men.

But researchers were able to look further back in time by analysing stored blood samples, some of them containing HIV, from hepatitis trials in the 1970s.

The team at the University of Arizona developed a new method to reconstruct the genetic code of the virus in those patients.

And after screening 2,000 samples from New York and San Francisco, the researchers were able to get eight complete HIV genetic codes.

That gave scientists the information they needed to build HIV's family tree and trace when it arrived in the US.

Dr Michael Worobey, one of the researchers, said: "The samples contain so much genetic diversity that they could not have originated in the late 1970s.

"We can place the most precise dates on the origins of the US epidemic at about 1970 or 1971."

The researchers also analysed the genetic code of human immunodeficiency virus taken from Mr Dugas's blood.

Like a failed paternity test, the results showed that the virus in his blood was not the "father" of the US epidemic.

Dr Richard McKay, a science historian at the University of Cambridge, said: "Gaetan Dugas is one of the most demonised patients in history and one of a long line of individuals and groups vilified in the belief that they somehow fuelled epidemics with malicious intent."

The Air Canada employee was labelled Patient O (the letter, not the number) by the US Centres for Disease Control because he was a case "Out-of-California".

Over time the O became a 0 and the term Patient Zero was born. It is still used to this day to describe the index case of an outbreak as with Ebola in west Africa.

Mr Dugas died in 1984, but was identified as Patient Zero in the book And the Band Played On.

Image copyright Getty Images

The study also uncovered New York's key role in the spread of the infection.

Aids: Origin of pandemic 'was 1920s Kinshasa'

Kinshasa in the Democratic Republic of Congo was seen as the city that started the global pandemic. From there it spread to the Caribbean and the US around 1970.

Dr Worobey said: "In New York City, the virus encountered a population that was like dry tinder, causing the epidemic to burn hotter and faster and infecting enough people that it grabs the world's attention for the first time.

"Just as Kinshasa was a key turning point for the pandemic virus as a whole, New York City looks like a turning point and acts as this hub from which the virus moves to the west coast and eventually to Western Europe, Australia, Japan, South America and all sorts of other places."

Prof Oliver Pybus, from the University of Oxford, commented: "This new data helps confirm the picture of HIV's origins in the US.

"It makes a very interesting point about Patient Zero, who has become a talking point in the origins of Aids, yet no matter how attractive a narrative it is, it doesn't have any scientific basis and it's really unfortunate that this person was identified."

Follow James on Twitter.</s>Patient Zero is no more. Gaëtan Dugas, the man accused of bringing HIV/AIDS to North America, has finally been exonerated.

The Canadian flight attendant’s name has been cleared by new research, which looked at the sequence of HIV in blood samples taken from early AIDS patients.

Researchers at the University of Arizona, writing in the journal Nature, concluded that — contrary to popular mythology — Dugas could not have been the primary source of the spread of the deadly virus, NPR reports.

The researchers looked at samples from eight other men infected with HIV during the 1970s. Based on their findings, they estimated that HIV first came to the U.S. from Haiti in 1970 or 1971, but went undetected for years, The disease spread around New York City for a few years, until, in 1976, one person took the virus across the country to San Francisco.

“The virus got to New York City pretty darn early,” says Michael Worobrey, the evolutionary biologist who led the study. “It was really under the radar for a decade or so.”

As for Dugas’ involvement, several men who were among the first diagnosed with AIDS named him as a past sexual partner. But fingering him as “Patient Zero” happened largely because of a reporting error.

William Darrow, a scientist at the Centers for Disease Control and Prevention (CDC) who had investigated AIDS during the early days of the epidemic, began identifying patients by a code based on the city they lived in.

Darrow labeled Dugas “Patient O,” with the “o” representing “outside of California.”

Someone at the CDC referred to “Patient O” as “Patient Zero,” a moniker for Dugas that later took hold and continued to persist, even after his death in 1984.

Various media outlets began pointing to Dugas as the genesis of the disease, and the movie adaptation of Randy Shilts’ And the Band Played On further cemented Dugas as the person responsible for the virus’ spread.

But Worobrey says that the HIV sequence in Dugas’ blood looks similar to that of others infected with HIV around the same time. As such, he and his research team deduced that Dugas could not have been the originator of the epidemic.

“To me, there’s something nice about going back and correcting the record,” he says. “He has been blamed for things that no one should be blamed for.”</s>Genes taken from archived blood samples show the U.S. AIDS epidemic started in New York in the early 1970s, definitively debunking the long-held belief that the virus was spread in the early 1980s by a Canadian flight attendant who became vilified as “Patient Zero” for seeding the U.S. outbreak.

Scientists have long suspected that HIV had been circulating in the United States for a decade before the first few AIDS cases were identified in Los Angeles 1981. The new study, published in the journal Nature, offers some of the first genetic proof.

“What we’ve done here is tried to get at the origins of the first cases of AIDS that were ever noticed,” said Michael Worobey, the evolutionary biologist at the University of Arizona who led the study.

Using a painstaking new approach, Worobey and colleagues pieced together the entire genetic sequence of the HIV virus from eight archived blood samples taken in 1978 and 1979 from gay and bisexual men participating in a hepatitis B study.

The team traced genetic changes in the virus samples taken from male patients in New York and San Francisco. The researchers found that the HIV virus first jumped from the Caribbean to New York City around 1970, triggering the North American epidemic.

The team used the same approach to extract the full HIV genetic code from “Patient Zero,” an Air Canada flight attendant identified as Gaetan Dugas in the Randy Shilts 1987 bestseller “And the Band Played On.”

Shilts, who wrote his book after Dugas had died, identified him as playing a key role in spreading the virus; media accounts painted him as a villain. The new study, however, found no biological evidence suggesting Dugas was the primary cause of the HIV epidemic in North America.

Dugas was first associated with the epidemic through a study by the U.S. Centers for Disease Control and Prevention that connected AIDS to sexual transmission of the disease in a cluster of 40 homosexual men.

In the study, Dugas was identified as “Patient O” because he was from outside of California, where the outbreak was believed to have started. That letter “O” was later mistaken for the number “0” and Dugas eventually became known as “Patient Zero,” meaning the first patient infected in an epidemic.

“This individual was simply one of thousands infected before HIV was recognized,” study co-author Richard McKay, a medical historian at the University of Cambridge, told reporters in a telephone briefing.

Worobey said the technique developed to extract and restore HIV genes from old blood samples borrows from technology used to identify ancient DNA.

Once they had the genetic code, the team evaluated the mutations made by the virus as it copied itself. This allowed the team to build an HIV family tree. Worobey believes a chimp first infected a human in Africa in the early 20th century. The virus that caused the U.S. epidemic emerged from Africa in the mid to late-1960s, and caused an outbreak in Haiti and other Caribbean countries.

In 1970 or 1971, this strain hopped from Haiti to New York, making the city a hub of transmission, Worobey said. The virus spread to a large number of people “many years before AIDS was noticed,” he said.

The team believes the virus arrived in San Francisco in 1975. The first five cases of AIDS were identified in California 1981, and they were first attributed to HIV in 1984.

“Our analysis shows that the outbreaks in California that first caused people to ring the alarm bells and led to the discovery of AIDS were really just offshoots of the earlier outbreak in New York City,” Worobey said.</s>Researchers used newly available genetic evidence to show that Gaetan Dugas — who has been dubbed “Patient Zero” — could not have been the first person in the United States to have the virus that causes AIDS.

The Canadian flight attendant widely blamed for bringing HIV to the United States and triggering an epidemic that has killed nearly 700,000 people has been exonerated by science, more than 30 years after his death.

In a study published Wednesday in the journal Nature, researchers used newly available genetic evidence to show that Gaetan Dugas — who has been dubbed “Patient Zero” — could not have been the first person in the United States to have the virus that causes AIDS.

Instead, the researchers report that Dugas was one of thousands of people who were infected with the human immunodeficiency virus by the late 1970s, years before it was officially recognized by the medical community in 1981.

The genetic analysis also reveals the path taken by the most common strain of the virus after it traveled from the Caribbean to the United States. Upon arriving in New York City around 1970, it circulated and diversified for about five years before being dispersed across the country.

“There really is no question about the geographical direction of movement,” said study leader Michael Worobey, an evolutionary biologist at the University of Arizona in Tucson.

The new evidence comes from two caches of serum samples taken from gay men in New York City in 1978 and 1979, and in San Francisco in 1978. (Serum is blood with the red and white blood cells removed.)

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 wasn’t known to exist then. However, if any of them had it, there should be evidence in their blood in the form of antibodies, the proteins that our immune systems make to fight an infection.

To see if any of the men in the hepatitis B study had contracted HIV, a different group of researchers analyzed the New York City samples and found that, indeed, 6.6 percent of them contained HIV antibodies. Inspired by this work, Worobey and his team did a similar test for the West Coast samples and discovered HIV antibodies in 3.7 percent of them.

The presence of antibodies can show whether a person has contracted a certain virus, but they can’t provide much detailed information about the virus itself, Worobey said. So his group’s next step was to scour the serum samples for fragments of HIV RNA that may have been circulating in these men’s bloodstreams.

It was a bit of a longshot. The samples were decades old, and RNA is generally too fragile to survive for long periods.

But the researchers were persistent. They selected 53 samples for attempted genetic sequencing, and they were eventually able to cobble together the full HIV genomes of eight of them: three from San Francisco and five from New York.

“It took a mixture of patience and insanity, but these old sequences are as good as a time machine,” Worobey said.

Scientists track the evolution of a virus over time by tallying the number of substitutions, or mutations, in its genome.

Geneticists measure how many mutations occur in the genome in a given period. This is how they determined that HIV was first transmitted from a chimpanzee to a single human early in the 20th century in sub-Saharan Africa.

The HIV molecular clock also allows researchers to trace landmark moments in the evolution of the virus. After the initial transmission from chimp to human, the next one came when HIV began circulating in Kinshasa, the capital of the Democratic Republic of Congo. By 1960, viral samples from the city were tremendously diverse, suggesting HIV had been present in the area for a long time, Worobey said.

Around 1967, a branch of the virus known as HIV-1 group M subtype B took hold in the Caribbean and diversified in Haiti.

The new work makes clear that this strain first jumped from the Caribbean to New York City in 1970 or 1971.

By the late 1970s, when the eight serum samples were collected, the five viral genomes from New York already had a high degree of genetic diversity; the three from San Francisco did not. This indicates HIV probably was in New York much longer than it was in San Francisco.

“It appears that New York City was a key turning point,” Worobey said. “New York City acts as a hub from which the virus moved to the West Coast — and eventually to Western Europe, Australia, Japan, South America and other places.”

As part of this study, the authors assembled the complete HIV genome from a serum sample collected from Dugas in 1983, one year before his death at age 31.

The genome was typical of HIV strains in the United States at the time, the researchers reported, and there was nothing to indicate that it had set off the epidemic here.

“In short, we found no evidence that Patient Zero was the first person infected by this lineage of HIV-1,” they wrote.

So, how did this myth start?

It turns out Dugas was initially identified by the Centers for Disease Control and Prevention (CDC) as case No. 057, which means he was likely the 57th patient they heard about who had been sickened by the mysterious illness.

A few years later, he participated in a study by the CDC in California that connected 40 men in 10 U.S. cities who all had AIDS and were linked through sexual contact.

Dugas was placed near the center of this cluster, and identified as patient O for “Outside of California.” But when investigators numbered the cases according to the date when each patient’s symptoms started to appear, the letter O was mistaken for the number 0, and the Canadian flight attendant entered the literature with that dubious label.

In actuality, Dugas’ symptoms were not reported until 1979 and 1980, considerably later than other cases in the cluster.

The medical community never released Dugas’ name to the public, but journalist Randy Shilts identified him in his 1987 book “And the Band Played On,” about the first five years of the American AIDS epidemic.

Dugas told researchers that he averaged 250 sexual partners a year, and Shilts portrayed him as a vain and arrogant playboy who ignored doctors’ orders to stop having sex to keep his infection from spreading. Media reviewers took the idea of a villainous Patient Zero and ran with it.

“Despite attempts at clarification and protest then and since, many still believe the story today,” the study authors wrote.

While there are epidemiological benefits to knowing how an outbreak begins, the researchers say that doesn’t mean anyone is at fault.

“Nobody should be blamed for the spread of a virus that nobody even knew about,” Worobey said.</s>Scientists have managed to reconstruct the route by which HIV/Aids arrived in the US – exonerating once and for all the man long blamed for the ensuing pandemic in the West.

Using sophisticated genetic techniques, an international team of researchers have revealed that the virus emerged from a pre-existing epidemic in the Caribbean, arrived in New York by the early 1970s and then spread westwards across the US.

The research also confirms that Gaëtan Dugas, a Canadian flight attendant named in 1987 by author Randy Shilts, was not the first person in the US to be infected, despite being dubbed “Patient zero” by a study of homosexual men with Aids in 1984. 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. 



That, the authors say, ties in with a body of evidence that shows that Dugas was not the source of the pandemic in North America, highlighting that it was a typo that saw the original study’s reference to Dugas as “Patient O” (indicating that he lived outside of California), misleadingly written as “Patient 0” - a term now widely used to mean the first case of an outbreak. 



“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,” said Richard McKay, historian and co-author of the study from the University of Cambridge, adding that the authors of the original study pointed out he was unlikely to be the source. 



Nevertheless, the idea that Dugas - who died of Aids in 1984 - was to blame caught on and he was vilified in the press. 



“In many ways the historical evidence has been pointing to the fallacy of this particular notion of patient zero for decades,” said McKay. “This individual was simply one of thousands infected before HIV/Aids was recognised.”

Writing in the journal Nature, researchers from the US, UK and Belgium describe how they developed a new technique to unpick the history of HIV-1 group M subgroup B, the subtype of HIV that is most prevalent in the Western world.

Called “RNA jackhammering”, the technique tackles the problem that the genetic material of HIV, which exists in the form of a single-stranded molecule known as RNA, breaks down rapidly over time, making it difficult to extract and piece together. RNA jackhammering allows scientists to selectively copy tiny fragments of the virus’s RNA and stitch them together.

Using the new approach, a technique the team say took around four years to develop, the scientists turned to serum samples that had been collected in 1978 and 1979 from men who had sex with men in New York and San Francisco - samples collected before what became known as Aids was first reported in 1981.

That they were able to painstakingly assemble the complete HIV genome from eight of the oldest-known samples, allowed the team to place them on a sort of “family tree” of the virus. Even though the number of genomes is small, the team say the eight samples not only enabled them to explore the genetic diversity of the virus in North America in the late 1970s but also chart its history, revealing the importance of New York City in the chain of events.

The level of genetic diversity, they say, shows that the virus was circulating in the US for a decade before what eventually became known as Aids was recognised.

According to the team’s reconstruction, based on the new findings as well as previous data, after jumping from non-human primates to humans in Africa, HIV spread to Caribbean countries by around 1967, with the subtype arriving in New York by 1971 and reaching San Francisco by 1976. The conclusions, they add, are also supported by the prevalence of the HIV virus among the collection of serum samples and the spread and timing of later patient cases. 



“New York City looks geographically like the key turning point for the emergence of this subtype, and New York City acts as this hub from which the virus moves to the west coast somewhat later and eventually to western Europe and Australia and Japan and South America and all sorts of other places,” said Michael Worobey, co-author of the research from the University of Arizona.

The results back up previous work by the Worobey and others, who have spent years using a variety of approaches to trace the route of the HIV/Aids epidemic and emphasises that the virus travelled from the Caribbean to the US, not vice versa. But Worobey is quick to point out that the idea of culpability is misplaced.

“No-one should be blamed for the spread of a virus that no-one even knew about,” he said. “How the virus moved from the Caribbean to the US and New York City in the 1970s is an open question - it could have been a person of any nationality, it could have even been blood products.”

The mistaken emphasis placed on Dugas that saw him placed as a key link between the spread of HIV/Aids between the east and west coasts of the US in the 1984 study, he said, was likely down to Dugas’s efforts to help researchers.



“Probably what happened here was a case of a guy who was unusually helpful to investigators providing lots and lots of names of sexual contacts,” said Worobey. “He’s just one of many people who is highly sexual active and in this network of people who are popping up as early Aids cases but he ended up looking up as this central character almost certainly just because of how helpful he was.”

The case, adds McKay, also highlights the problems with trying to pinpoint the first person to be infected in an epidemic. “One of the dangers of focus on a single patient zero when discussing the early stages of an epidemic is that we risk obscuring important structural factors that might contribute to its development - poverty, legal and cultural inequalities, barriers to healthcare and education,” he said.

Gkikas Magiorkinis, a clinical and evolutionary virologist at the University of Oxford, said that the research highlights the power of such genetic techniques in shedding light on how a virus spreads among a population. “They managed to get full sequences of viruses from old samples, and that has been very difficult up until now,” he said. That, he adds, could prove valuable for probing the history of many other viruses, including hepatitis C, and for designing better interventions. “If we want to know how we are going to stop an epidemic we need to know who infected who and how this happened, so it will have important applications with respect to controlling epidemics,” he said.</s>A new study has cleared Quebec flight attendant Gaetan Dugas as “Patient Zero” in North America’s AIDS pandemic.

The study conclude the AIDS virus was lingering in North America long before HIV-positive Dugas touched down in New York City in 1979 and unwittingly spread the disease to partners, who spread it to others.

In the study published Wednesday in the journal Nature, researchers used genomic sequencing of blood samples from that era to go back in time and reconstruct the “family tree” of the virus in unprecedented detail.

Charming and handsome Dugas, who bragged he’d bedded more than 2,500 sexual partners across North America, was named as “Patient Zero” in a study concluded in 1984. Even while vilified and hated for bringing the disease to Western shores, the assertion was always questioned.

It turns out Dugas’s strain of HIV was a typical one within the U.S. at the time, and certainly not the root of them all.

The virus actually crossed over from the Caribbean, the researchers found.

And it arrived in the U.S. around 1970 - more than a decade before it was officially recognized to be in the country.

“(Dugas) was evidently just one of many thousands infected prior to the recognition of HIV/AIDS,” the study concludes.

How the virus got to North America remains a question.

“It could have been a person of any nationality. It could have even been blood products. A lot of blood products used in the United States in the 1970s actually came from Haiti,” Michael Worobey from the University of Arizona, one of the study’s leaders, said.

Dugas was known as “the man who gave us AIDS.” He died in Quebec City in 1984 at age 31 of AIDS-related kidney failure.

“No one should be blamed for the spread of a virus no one even knew about,” Worobey said.

NOTE: The term ‘Patient Zero’ has been a misnomer from the start. Public health investigators at the time had dubbed Dugas “Patient ‘O’” — the letter O and not the number zero — because he came from ‘Out(side)-of-California’. The misinterpretation has become a common term for the first patient of an epidemic.

-- with files from The Washington Post</s>The story of how “Patient Zero” and AIDS arrived in New York in 1979 and triggered the epidemic in North America has been told so many times in so many different ways that for many people it’s become an accepted truth of our modern history.

It begins with a single man, a young flight attendant named Gaetan Dugas, who presumably became infected abroad and then unwittingly gave it to some of his sexual partners. His sexual partners in turn gave it to their sexual partners and so forth until the whole continent was full of clusters of people dying of the mysterious disease. In journalist Randy Shilt’s 1987 book, “And the Band Played On,” and in various media reports, he was described as sexually adventurous and said to have told Centers for Disease Control investigators he had approximately 250 sexual partners each year.

It’s a compelling narrative, but it’s not quite right.

In a study published Wednesday in the journal Nature, researchers used genomic sequencing of blood samples from that era to go back in time and reconstruct the “family tree” of the virus in unprecedented detail. The findings are stunning, debunking many popular beliefs about the virus’s origins and spread and filling in holes about how it made its way to the United States.

The work, led by Michael Worobey from the University of Arizona and Richard McKay from the University of Cambridge, confirms the controversial theory that the virus crossed over from the Caribbean (rather than going from the United States to the Caribbean, as some have argued). The researchers also found that it was New York City, not San Francisco, that was the location of the initial outbreak. And they pinpointed that the AIDS virus appeared to have been circulating in our borders for much longer than was previously known, and made the jump in or around 1970 - about a decade before it was officially recognized to be in the United States in 1981.

“Geographically there is an unmistakable signal that this lineage did diversify in the Caribbean before it moved into the U.S.,” Worobey said in a conference call with journalists on Tuesday. However, he added, how the virus got to the United States remains an open question.

“It could have been a person of any nationality. It could have even been blood products. A lot of blood products used in the United States in the 1970s actually came from Haiti,” he explained.

The analysis involved looking at archived serum samples, many nearly 40 years old, from studies that were discontinued long ago. One involved men who have sex with men in New York and San Francisco and two were of men at risk of contracting hepatitis B. A significant percentage of the samples — from 3.7 to 6.6 percent depending on the study - showed HIV antibodies, and the researchers randomly selected 20 to try to attempt to sequence. Unfortunately, many were degraded due to having been in long-term storage, so researchers spent years trying a number of new techniques to reconstruct and “amplify” the viral fragments. Finally, using a technique the researchers described as borrowing from the one scientists use to look at DNA from our Neanderthals ancestors and other ancient creatures that no longer roam the earth, they were able to complete the sequences for eight.

These were of five patients from New York and three from San Francisco in 1978-79, which are among the oldest viral samples ever recovered in the world.

Researchers separately sequenced the virus found in Patient Zero and found that his HIV-1 genome appeared “typical” of U.S. strains of the time and that there was extensive genetic diversity around the time he appears to have been infected, indicating that the virus had likely been in the country and evolving several years earlier.

“He was evidently just one of many thousands infected prior to the recognition of HIV/AIDS,” they wrote in a supplementary discussion also published by Nature.

They explained that public health investigators at the time had dubbed him “Patient ‘O’” meaning the letter O and not the number zero because he came from ‘Out(side)-of-California’,” but that the letter became confused with the number in the medical literature and popular media and over time became part of the mythology of AIDS despite numerous attempts by some scientists to clarify his role in the epidemic.

Worobey, whose expertise is in virus evolution, and McKay, a science historian, wrote that their work shows there is “neither biological nor historical evidence for the widely held belief that he was the primary cause of the HIV epidemic in North America”

“This individual was simply one of thousands infected before HIV/AIDS was recognized,” McKay said.

The two spoke of the danger of the public’s instinct to want to assign blame in infectious disease outbreaks, and noted that, in the case of the United States, the instinct has often been to look to foreigners as the cause. This dates back to Irish-born Mary Mallon who was accused of spreading typhoid fever when she continued to work as a cook after she was identified as a healthy carrier.

In the early days of the AIDS epidemic it wasn’t just Canadian-born Dugas — written about in stories with headlines, such as ‘The man who gave us AIDS’ — who was vilified. In 1989, the CDC listed people from Haiti as being among the four “high-risk” groups for HIV, along with homosexuals, heroin users and hemophiliacs - a designation that sparked some horrible discrimination that involved denying people from the country or even their children and grandchildren employment, housing and schooling.

“One of the dangers of focusing on a single patient zero when discussing the early phases of an epidemic is that we risk obscuring important structural factors that might contribute to its development - poverty, legal and cultural inequalities, barriers to health care and education. These important determinants risk being overlooked if we focus too readily on a Patient Zero,” McKay said.

Worobey added that an important distinction to make is that their work tracing the origins of the AIDS is not the same as placing blame on any individual or group.

“The pandemic virus ultimately comes from nonhuman primates, probably circulating in sub-Saharan Africa for probably 100 years at this time point today,” Worobey said. “The lineage of the virus we’re talking about in this paper, so-called subtype B of HIV-1 group M, is just one of many branches on that evolutionary tree.”

“No one,” he emphasized, “should be blamed for the spread of a virus no one even knew about.”</s>(CNN) The man blamed for bringing HIV to the United States just had his name cleared.

New research has proved that Gaëtan Dugas, a French-Canadian flight attendant who was dubbed "patient zero," did not spread HIV, the virus that causes AIDS, to the United States.

A cutting-edge analysis of blood samples from the 1970s offers new insight into how the virus spread to North America via the Caribbean from Africa. More than 1.2 million people in the United States currently live with HIV.

The research, conducted by an international team of scientists, was published this week in the journal Nature

"No one should be blamed for the spread of a virus that no one even knew about, and how the virus moved from the Caribbean to the US in New York City in the 1970s is an open question," co-author of the research, Dr. Michael Worobey, a professor and head of the ecology and evolutionary biology department at the University of Arizona, said at a news conference Tuesday.

"It could have been a person of any nationality. It could have even been blood products. A lot of blood products used in the United States in the 1970s actually came from Haiti," he said. "What we've done here is try to get at the origins of the first cases of AIDS that were ever noticed. ... When you step back in time, you see a very interesting pattern."

'Patient zero' and the power of a name

The researchers began to study one cluster of homosexual men with HIV, and beginning in California, they eventually connected more than 40 men in 10 American cities to this network.

Dugas was placed near the center of this cluster, and the researchers identified him as patient O, an abbreviation to indicate that he resided outside California.

However, the letter O was misinterpreted as a zero in the scientific literature. Once the media and the public noticed the name, the damage was done.

Dugas and his family were condemned for years. In Randy Shilts' seminal book on the AIDS crisis, "And The Band Played On," Dugas is referenced extensively and referred to as a "sociopath" with multiple sexual partners.

"We were quite annoyed by that, because it was just simply wrong, but this doesn't stop people from saying it, because it's so appealing. You know, 'The man who brought us AIDS.' Well, if it were true, it would be annoying, but since it isn't true, it's even more annoying," said Dr. James Curran, dean of Emory University's Rollins School of Public Health and co-director of the university's Center for AIDS Research.

Curran, who was not involved in the new research, coordinated the AIDS task force at the CDC in 1981 and then led the HIV/AIDS division until 1995.

"The CDC never said that he was patient zero and that he was the first person," Curran said of Dugas.

"In addition to the potential damage to his reputation, it was also a damage to scientific plausibility. That there would be a single-point source to start the epidemic in the United States is not very likely. It's more likely that several people were infected," Curran said. "I think that the concept of patient zero has always been wrong and flawed, and scientists never said it."

Dugas died in 1984 of AIDS-related complications. Now, more than 30 years later, scientists have used samples of his blood to clear his name.

Going back in time with blood

For the new research, Worobey and his colleagues gathered archival blood samples in New York and San Francisco that were originally collected for a hepatitis B study in 1978 and 1979. The samples came from men who had sex with men.

The researchers screened the samples and noticed that "the prevalence of HIV positivity in these early samples from hepatitis B patients is really quite high," Worobey said Tuesday.

From the samples, the researchers recovered eight genome sequences of HIV, representing the oldest genomes of the virus in North America. They also recovered the HIV genome from Dugas' blood sample.

As many of the samples had degraded over time, Worobey's lab developed a technique called "RNA jackhammering" to recover the genetic material.

"The major contribution which interested me the most was their capacity to restore full sequence genomes from very old serum samples using the jackhammer technique," Curran said of the new research.

After analyzing the genomes, the researchers found no biological evidence that Dugas was the primary case that brought HIV to the United States, and the genome from Dugas appeared typical of the other strains already in the United States at the time.

The researchers discovered strong evidence that the virus emerged in the United States from a pre-existing Caribbean epidemic in or around 1970.

How HIV arrived in the United States

Sequencing genomes allows scientists to take a peek back in time to determine how a virus emerged and where it traveled by examining how many mutations appear in the genome.

Scientists estimate that HIV was transmitting in humans after a chimpanzee infected a single person sometime in the early 20th century in sub-Saharan Africa. The general consensus among scientists is that HIV then crossed the Atlantic and quickly spread through the Caribbean before it arrived in the United States, probably from Haiti, Curran said.

The research team behind the new genetic analysis now hopes that its findings may lead to a better understanding of how HIV moved through populations -- and how blaming a single patient for the pathogen's rise remains troublesome.

"In many ways, the historical evidence has been pointing toward the fallacy of this particular notion of patient zero for decades," Richard McKay, a historian of medicine at the University of Cambridge and a co-author of the new research, said at Tuesday's news conference.

"The study shines light from different angles to better understand the complexity of an important period in the past," he said. "In view of this complexity, one of the dangers of focusing on a single patient zero when discussing the early phases of an epidemic is that we risk obscuring important, structural factors that might contribute to its development: poverty, legal and cultural inequalities, barriers to health care and education. These important determinants risk being overlooked."</s>In a study published Wednesday in the journal Nature, researchers used newly available genetic evidence to show that Gaetan Dugas — who has been dubbed “Patient Zero” — could not have been the first person in the United States to have the virus that causes AIDS.

Instead, the researchers report that Dugas was one of thousands of people who were infected with the human immunodeficiency virus by the late 1970s, years before it was officially recognized by the medical community in 1981.

The genetic analysis also reveals the path taken by the most common strain of the virus after it traveled from the Caribbean to the United States. Upon arriving in New York City around 1970, it circulated and diversified for about five years before being dispersed across the country.

“There really is no question about the geographical direction of movement,” said study leader Michael Worobey, an evolutionary biologist at the University of Arizona in Tucson.

The new evidence comes from two caches of serum samples taken from gay men in New York City in 1978 and 1979, and in San Francisco in 1978. (Serum is blood with the red and white blood cells removed.)

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 wasn’t known to exist back then. However, if any of them had it, there should be evidence in their blood in the form of antibodies, the proteins that our immune systems make to fight an infection.

To see if any of the men in the hepatitis B study had contracted HIV, a different group of researchers analyzed the New York City samples and found that, indeed, 6.6 percent of them contained HIV antibodies. Inspired by this work, Worobey and his team did a similar test for the West Coast samples and discovered HIV antibodies in 3.7 percent of them.

The presence of antibodies can show whether a person has contracted a certain virus, but they can’t provide much detailed information about the virus itself, Worobey said. So his group’s next step was to scour the serum samples for fragments of HIV RNA that may have been circulating in these men’s bloodstreams.

It was a bit of a long shot. The samples were decades old, and RNA is generally too fragile to survive for long periods.

But the researchers were persistent. They selected 53 samples for attempted genetic sequencing, and they were eventually able to cobble together the full HIV genomes of eight of them — three from San Francisco and five from New York.

“It took a mixture of patience and insanity, but these old sequences are as good as a time machine,” Worobey said.

Scientists track the evolution of a virus over time by tallying the number of substitutions, or mutations, in its genome.

To explain how this works, Worobey likes to conjure a cactus. (He lives in Arizona, after all.)

Imagine you are staring at a saguaro with a tall central column and a couple of branches curving up like arms. If you have just a single time point — now — it’s difficult to gauge the cactus’s age.

However, if you could get a picture of the cactus from 10 years ago, you could calculate the growth rate for each of its branches over that time. Then you can make an educated guess about how much the cactus grows each year.

“That’s what we do with HIV molecular clocks,” Worobey said.

Geneticists measure how many mutations occur in the genome in a given time period. This is how they determined that HIV was first transmitted from a chimpanzee to a single human early in the 20th century in sub-Saharan Africa.

The HIV molecular clock also allows researchers to trace landmark moments in the evolution of the virus. After the initial transmission from chimp to human, the next one came when HIV began circulating in Kinshasa, the capital of the Democratic Republic of Congo. By 1960, viral samples from the city were tremendously diverse, suggesting HIV had been present in the area for a long time, Worobey said.

Around 1967, a branch of the virus known as HIV-1 group M subtype B took hold in the Caribbean and diversified in Haiti.

The new work makes clear that this strain first jumped from the Caribbean to New York City in 1970 or 1971.

By the late 1970s, when the eight serum samples were collected, the five viral genomes from New York already had a high degree of genetic diversity; the three from San Francisco did not. This indicates HIV probably was in New York much longer than it was in San Francisco.

“It appears that New York City was a key turning point,” Worobey said. “New York City acts as a hub from which the virus moved to the West Coast — and eventually to Western Europe, Australia, Japan, South America and other places.”

Dr. Beatrice Hahn, a professor of medicine at the University of Pennsylvania who studies the origin and evolution of immunodeficiency diseases, said she was impressed by the lengths the authors went to in order to find actual virus samples from so long ago.

Hahn, who was not involved in the research, noted that while many of the findings had been put forward before, the new study provides more convincing evidence because it was the first to isolate the complete, full-length virus genome from such early samples.

“It always helps to nail it,” she said.

She added that the work does provide some new insights, including that the virus came to New York much earlier than previously recognized and that thousands of people were already infected by the time HIV was first recognized in the medical literature.

As part of this study, the authors assembled the complete HIV genome from a serum sample collected from Dugas in 1983, just one year before his death at the age of 31.

The genome was typical of HIV strains in the United States at the time, the researchers reported, and there was nothing to indicate that it had set off the epidemic here.

“In short, we found no evidence that Patient Zero was the first person infected by this lineage of HIV-1,” they wrote.

So, how did this myth start?

It turns out Dugas was initially identified by the Centers for Disease Control and Prevention as case No. 057, which means he was likely the 57th patient they heard about who had been sickened by the mysterious illness.

A few years later, he participated in a study by the CDC in California that connected 40 men in 10 American cities who all had AIDS and were linked through sexual contact.

Dugas was placed near the center of this cluster, and identified as patient O for “Outside of California.” But when investigators numbered the cases according to the date when each patient’s symptoms started to appear, the letter O was mistaken for the number 0, and the Canadian flight attendant entered the literature with that dubious label.

In actuality, Dugas’ symptoms were not reported until 1979 and 1980, considerably later than other cases in the cluster.

The medical community never released Dugas’ name to the public, but journalist Randy Shilts identified him in his 1987 book “And the Band Played On” about the first five years of the American AIDS epidemic.

Dugas told researchers that he averaged 250 sexual partners a year, and Shilts portrayed him as a vain and arrogant playboy who ignored doctors’ orders to stop having sex to keep his infection from spreading. Media reviewers took the idea of a villainous Patient Zero and ran with it.

“Despite attempts at clarification and protest then and since, many still believe the story today,” the study authors wrote.

While there are epidemiological benefits to knowing how an outbreak begins, the researchers say that doesn’t mean anyone is at fault.

“Nobody should be blamed for the spread of a virus that nobody even knew about,” Worobey said.
A research team led by an evolutionary biologist at the University of Arizona publishes a paper in Nature on the genetic history of HIV proving that Gaëtan Dugas, the Canadian flight attendant who had been identified for years as "Patient Zero" of the AIDS epidemic in the U.S., did not spread the virus to the country. The study indicates that HIV first spread to the U.S. from the Caribbean around 1970.