The HIV virus entered the United States around 1971, a decade before AIDS was recognized as a disease, new research confirms. The new study dispels the "Patient Zero" myth that a handsome, sexually active flight attendant named Gaétan Dugas knowingly spread the virus to North America in the late 1970s. That could have implications for the nation’s controversial laws that criminalize knowingly exposing another person to HIV.

"In the context of the origins and evolutionary history of HIV-1, this is the last piece in the puzzle," says Beatrice Hahn, an expert on HIV evolution at the University of Pennsylvania who was not involved in the research.

"This is the last piece in the puzzle."

HIV is a virus that attacks the immune system. When the immune system becomes too weak to fight off infections that wouldn’t normally sicken a healthy person, the patient has progressed into AIDS, or acquired immunodeficiency syndrome. AIDS can be fatal if it’s not treated.





Researchers have long tried to map the spread of HIV in the US. In earlier studies, scientists concluded that after the virus jumped species from chimpanzees to humans in Africa, HIV traveled to the Caribbean around 1966. From there, it likely traveled to the US from Haiti around 1969. Those studies, however, used partial HIV genomes obtained from patients in the 1980s and their results were contentious. The partial genetic data didn’t allow scientists to exactly pinpoint when and how HIV spread in the US.

In today’s study, published in the journal Nature, researchers used complete HIV genomes to trace the virus’s evolution across North America, before transforming into the AIDS epidemic of the early 1980s. The full genomes were hard to obtain. Scientists led by Michael Worobey, a virologist at the University of Arizona and public health historian Richard McKay from the University of Cambridge, combed through thousands of 40-year-old serum samples. The samples had been collected in the late 1970s from men who have sex with men as part of hepatitis B studies in New York and San Francisco. When those samples were later screened, nearly 7 percent of the New York samples tested positive for HIV, and a little over 3 percent of the San Francisco samples did as well.

Gaetan Dugas





These HIV samples collected in the 1970s are the oldest ever collected outside of Africa. Because of how old they are, these samples were badly damaged. But by using a new genetic sequencing technique, the researchers were able to reassemble the full genomes of HIV obtained from eight individuals. (The HIV virus mutates rapidly and its genome can change over time within a single individual, and from person to person.) That allowed them to determine how the US virus was related to virus in the Caribbean and Africa and to pinpoint when and where the virus moved geographically: it first spread from Africa to the Caribbean around 1967, then from the Caribbean to New York in 1971, and to San Francisco in 1976.

"It changed our lives."

AIDS was recognized as a disease in 1981, when the Centers for Disease Control and Prevention published a bulletin describing five gay men in Los Angeles who were hospitalized with bizarre infections not normally seen in young, healthy people. (Two of the men died.) At the time, no one knew what AIDS was or what caused it. Within days, the CDC was getting more reports that young men were dying of strange infections.

"It was terrifying," says Chris Beyrer, an epidemiologist at Johns Hopkins University and author of the book War in the Blood: Sex Politics and AIDS in Southeast Asia. He was not involved in the study. Beyrer was a young, gay medical student living in New York City in the early 1980s and was touched by the AIDS epidemic when his partner tested positive for the virus. "It changed our lives," Beyrer says.

That’s when the myth of Patient Zero also emerged. The story of Gaétan Dugas, a flight attendant wantonly spreading HIV before dying of AIDS, was popularized by the 1987 book And the Band Played On by Randy Shilts. (Shilts himself died of AIDS in 1994 at the age of 42.) The book chronicled the early days of the AIDS epidemic, but Dugas’ story later turned to be false. When scientists sequenced the genome of the virus that had infected Dugas, they found that he had been infected with a strain already in circulation in the US. That means he couldn’t be the source of the North American epidemic. In fact, the Patient Zero moniker itself may be the result of a mistaken reading of the CDC’s identifier for Dugas: Patient "O" — where "O" stood for "Outside California," not zero.

At the time, however, Dugas’ story was used by politicians as rationale for laws in 33 states that criminalize knowingly exposing another person to HIV. Today, these laws are still in place and are criticized by many, including the United Nations Program on AIDS, for being a barrier to testing. That’s because these laws essentially criminalize knowing your status, according to policy experts and public health researchers. And testing for HIV is key for treatment and prevention.

In light of today’s study, these HIV laws should be repealed, Beyrer says. Today, HIV and AIDS are treatable although not curable, but even as new infections overall are down, young, gay, Latino, and black men are experiencing a spike in new HIV cases. Getting tested is the gateway to treatment and effective prevention, Beyrer says.

"It’s a public health problem," Beyrer says. "It’s painful to be back in a place like that, after all those decades."