It didn’t start in Los Angeles or San Francisco.

The spread of the disease also probably began a decade or more before the medical community clearly identified it in the early 1980s.

And an airline employee was unfairly vilified as “Patient Zero” in the AIDS epidemic in the United States.

Those are some of the conclusions in two comprehensive reports released today by researchers at the University of Arizona and the University of Cambridge in England.

The findings, published in the journal Nature, shed new light on the beginning of the HIV crisis in North America more than three decades ago.

Researchers say their studies can also help other scientists better understand how other pathogens such as Ebola and the Zika virus move through populations.

They also hope their work will lead to better treatments for contagious diseases, in particular for HIV.

“Now we can look forward in time and really see a future in which — even if the virus is not completely eliminated — it could be driven down to no new transmission in large swaths of the world," Michael Worobey, Ph.D., a professor in the Department of Ecology and Evolutionary Biology at the University of Arizona, said in a press release. "Earlier detection and better alignment of the various options we have to make it harder for the virus to move from one person to the next are key to driving HIV out of business."

An official at the Centers for Disease Control and Prevention (CDC) who was a co-author of the paper, said the research shines a light on the importance of understanding diseases.

“This work uses both historical and biological perspectives to provide conclusive evidence regarding the strains that are responsible for the spread of HIV in North America. HIV silently transmitted for years before AIDS was identified,” added Walid Heneine, Ph.D., of the laboratory branch of the CDC’s Division of HIV/AIDS Prevention, in an email to Healthline. “These findings are a reminder that we must be vigilant regarding emerging infectious diseases and must invest in public health infrastructures and technologies to protect people from ever-changing infectious disease threats.”

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Early beginnings

The scientists used a molecular-level technique in their research.

They say the process allowed them to retrieve genetic material from 40-year-old serum samples and decipher the gene sequence of the HIV subtype that started the outbreak in North America in the early 1970s.

They analyzed 2,000 samples collected from U.S. men between 1978 and 1979.

The serum samples had deteriorated significantly over the years, so the scientists in Worobey’s laboratory used a technique called “RNA jackhammering” that broke down the human genome in the samples and allowed the researchers to extract the RNA of the virus.

"Standard methodology such as antibody-detecting serological blood tests will tell you whether a person had HIV, but you might not be able to get any of the HIV gene sequences out of it, because to do that, you need the RNA from the virus," Worobey said.

Worobey added the technique could have the potential for other applications, including screening blood samples for viruses or cancer markers.

From the research, the scientists concluded the AIDS virus traveled from its origins in Africa to islands in the Caribbean.

From there, it migrated to New York as early as 1970, where it spread rapidly.

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

The virus then traveled to San Francisco and other parts of California, where people with AIDS were first recognized in 1981.

The researchers concluded that by the late 1970s, the virus had diversified in almost the same genetic diversity we see today.

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The ‘patient zero’ myth

For decades, a French-Canadian airline employee named Gaetan Dugas, has been known as “Patient Zero” in the 1980s AIDS epidemic.

Dugas, a man who had sex with men (MSM), died in 1984. Since then he has been blamed by some as a primary source for the spread of HIV in North America.

Dugas was one of the primary villains in the 1987 book, “And the Band Played On,” by San Francisco journalist Randy Shilts.

However, the researchers now say Dugas was falsely accused and unfairly blamed.

"Gaetan Dugas is one of the most demonized patients in history, and one of a long line of individuals and groups vilified in the belief that they somehow fueled epidemics with malicious intent," said Richard McKay, D.Phil., a Wellcome Trust Research Fellow in Cambridge’s Department of History and Philosophy of Science, in a press release.

In fact, McKay says, Dugas actually provided scientists with valuable information before he died.

Dugas told researchers after he contracted HIV that he had 750 sexual partners the previous three years. That wasn’t necessarily an unusual number. Researchers said 65 percent of men in a Los Angeles cluster study at the time reported having more than 1,000 sexual partners in their lifetimes.

Much of that sexual connection was with anonymous partners, so many HIV patients couldn’t give medical officials any names.

However, McKay says, Dugas provided medical officials with 72 names. That helped scientists track down a wide range of people infected with HIV.

"Blaming 'others’ — whether the foreign, the poor, or the wicked — has often served to establish a notional safe distance between the majority and groups or individuals identified as threats," said McKay. "In many ways, the U.S. AIDS crisis was no different — as the vilification of Patient Zero shows. It is important to remember that, in the 1970s, as now, the epidemic was driven by individuals going about their lives unaware they were contracting, and sometimes transmitting, a deadly infection.”

In fact, McKay adds, the term Patient Zero was actually a mistake.

Patients in the Los Angeles cluster study were given case numbers with a letter and numbers based on where they were from and when they were identified as having HIV.

Dugas was listed as “Case O57.” The “O” stood for “outside of California.”

Along the way, the letter “O” was mistaken for the number “0” and the term “Patient Zero” was born.

"We hope this research will give researchers, journalists, and the public pause before using the term Patient Zero,” said McKay. “The phrase carries many meanings and a freighted history, and has seldom pointed to what its users have intended."

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