U.S. doctors first noticed the disease that would come to be known as HIV/AIDS in the early 1980s.
The story starts with a group of doctors, who noticed an outbreak of a rare skin cancer called Kaposi sarcoma in young gay men in New York, San Francisco, and Los Angeles. We now know that Kaposi sarcoma is linked to HIV/AIDS, but at the time, those doctors didn't know what was causing the rare form cancer.
CDC researchers, suspecting that whatever was causing this disease was sexually transmitted, started asking patients to name their partners. And, through this work, the researchers started to build out a map of cases.
That's where a man named Gaetan Dugas comes in.
Dugas was a Canadian flight attendant, and he was named by several of the patients as one of their sexual partners. Soon enough, the scientists started talking to him. It turned out he was sick too.
Dugas' case started the phrase "patient zero," which you may have heard of. But the term — and its tie to Dugas — was more or less an accident.
Dugas did end up near the center of their map, which some people took to mean that he was the original source of this new and rare infection in the United States. But the scientists didn't mean to imply that.
Even the term, "patient zero" was an accident. Dugas was originally anonymized as Patient O, for "out(side)-of-California." It was only later, in a misunderstanding, that Dugas became "patient zero."
Dugas was originally anonymous, but once the media learned who he was, they turned him into the great HIV/AIDs villain.
Dugas' name first appeared in the book "And the Band Played On," by Randy Shilts. And the media, once they got wind of who he was, painted Dugas as some sort of purposefully malicious villain — the man who "brought" HIV/AIDS to the U.S.
"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 fueled epidemics with malicious intent," said Cambridge's Richard McKay in a statement.
But not everyone believed this was true, so scientists investigated. And they may have just cleared his name.
There have been previous suggestions that Dugas did not deserve the dubious moniker of "patient zero," but now a team, including McKay and led by Michael Worobey of the University of Arizona, may have definitive evidence that Dugas was not the original carrier of HIV.
To do this, the scientists got a hold of old blood samples containing the virus from Dugas and eight other patients. They then used sophisticated genetic techniques to sequence each HIV infection's genome, effectively building a kind of family tree of the virus.
If Dugas was really the first infectee (or what scientists more properly call the "index case"), his sample should have been at the root of the tree. But that wasn't the case. Instead, their research suggests that the disease actually entered the United States from the Caribbean sometime in the 1970s. It turned out he was simply another patient with a really tough disease.
This study will help us better understand how HIV/AIDS entered the United States. But it also shows why the idea of a patient zero can be so problematic.
We often want someone to blame when big things go wrong — a scapegoat makes things a lot easier. The idea of a patient zero provides an all-too-easy target.
"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. And Dugas, an unashamed gay foreigner in the 1980s, was, to many in America, one of the "others."
Though we have a much better grasp on HIV/AIDS today than we did in the 1980s, we continue to see this vilification with other diseases.
Take the stigma the family of Emile Ouamouno, the 2-year-old patient zero of the 2014 West African Ebola epidemic, has had to live through.
Scientifically, this vilification can be problematic as well. Identifying the origin of a disease is an important step in understanding how it spreads, but solely focusing on that can obscure other, larger contributing factors that contribute to how a disease spreads, such as unequal access to health care, said McKay in The Guardian.
In the end, the idea of a patient zero can also eclipse the human cost.
Rather, we can get so wrapped up in our obsession with blaming a patient zero, that we can lose sight of the very human cost of the disease itself, which often plays out right in front of us.
"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," said McKay.
The early days of the HIV/AIDS epidemic were a terrible, dark time for everyone who lived through them, and reducing that story to blaming just one man is a grave mistake. McKay said they hope this research will give people pause before using the phrase again.
Dugas died in 1984 of AIDS-related complications.