No 'patient zero' in HIV epidemic, new research finds

At the height of the AIDS epidemic sweeping across North America, a 1987 New York Post headline screamed: "The Man Who Gave Us AIDS."

That man was Gaétan Dugas, a gay flight attendant from Quebec who had died of the disease three years earlier. He would be demonized as "patient zero," the man whose promiscuous ways led to a public health crisis. 

New research helps put an end to that idea, once and for all.

• HIV's 'patient zero' myth shattered by new research, CBC Radio's Quirks & Quarks

Researchers based at the University of Arizona looked at the human immunodeficiency virus (HIV) in blood samples collected in the late 1970s, giving them a snapshot of the virus at the time, and allowing them to reconstruct its spread through North America in unprecedented detail.

"The samples contain a large amount of genetic diversity. So much genetic diversity that they could not have arisen from the late 1970s," says Michael Worobey, one of the study's authors.

The researchers believe the virus first jumped from Africa to the Caribbean, before entering the U.S. around 1971, where it took hold in New York City before spreading rapidly throughout the continent.

Oldest look at virus

Researchers tested more than 2,000 blood samples collected from men who had sex with men in New York City and San Francisco in 1978 and 1979.

Since the genetic material of the virus had broken down considerably over nearly four decades in the lab, they had to develop a new technique they describe as "jackhammering" that allowed them to detect what was left of the virus and analyze its genetic material. 

In the end, the researchers were able to recover nearly complete genetic material in eight of the samples, offering them the earliest look at the virus in North America.

The recovered samples showed that the virus had enough genetic diversity to indicate it had been spreading throughout the United States earlier than previously thought, and earlier than AIDS was first recognized in 1981.

"It does push back the date of the expansion of the epidemic in North America further than we thought and gives us a better picture of how the epidemic expanded," says Richard Harrigan, an HIV researcher at the British Columbia Centre for Excellence in HIV/AIDS.

He estimates there were probably 20,000 cases of HIV in North America when reports of patients with a strange new disease — soon to be called AIDS — first surfaced.

If this was the case, then it means early efforts to trace the spread of the disease by connecting the first AIDS patients were years too late.

Blaming 'patient zero'

Which brings us back to Gaétan Dugas.

He was just one of the men included in an early study investigating the sexual links between people with AIDS in Southern California.

At the time, he was only known as Case 057, and his name came up several times as researchers conducted their interviews.

When the researchers began to code the study's patients, he was identified as Patient O, the letter O standing for "Out(side)-of-California." But O was soon mistaken as the number 0, and the name stuck.

Journalist Randy Shilts seized upon the idea of a "patient zero" in his 1987 bestselling history of the AIDS crisis, And the Band Played On, in which Dugas was named for the first time. While the idea of a "patient zero" has long been discredited by scientists who study the HIV epidemic, it was an idea eagerly seized upon by the public. 

In the new study, the Arizona team of scientists decided to analyze the HIV in a blood sample from Dugas that was collected in 1983. When compared with the other eight samples, they found there was nothing to suggest Dugas had a unique role in the spread of the virus.

Richard McKay, a historian from Cambridge University who collaborated on the research, says that blaming others has long been a way for societies to create a difference between the majority and groups or individuals identified as threats.

He hopes the mistake will call into question the very idea of a patient zero, with its focus on an individual, rather than the larger causes that lead to an epidemic.

"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," he says.

The research was published in today's advance online publication of Nature.