In June 2014, seven members of the Chitonawa tribe emerged from the Amazon rainforest. Naked except for loincloths, they began communicating across a river with people in the tiny village of Simpatia, part of a protected region in Brazil inhabited by a settled indigenous group called the Ashaninka.

In a video one of the locals took of the encounter, the Chitonawa initially appear cautious. One awkwardly brandishes a rifle he may have taken from a logging camp across the border in Peru. But a man from Simpatia wades into the water, offering the Chitonawa bananas, and the tribespeople eventually enter the village.

The Chitonawa complained of "quarrels among them," according to local media. Described as "very, very scared," the Chitonawa, who appeared to have traveled about 60 miles from their home in the Peruvian jungle, also said they had been "constantly persecuted and killed by whites" — likely drug traffickers and illegal loggers encroaching on their territory.

The Chitonawa emerge from the jungle near Simpatia.

"[The Chitonawa] say that so many people died that they couldn't bury them all, and their corpses were eaten by vultures," one of the Ashaninka said.

What the tribespeople didn't know was that simply being around outsiders, even the Ashaninka, could very well kill them. When one of the Chitonawa grabs what looks like a T-shirt off the railing of an Ashaninka hut, a villager yells, "No! No! No! No!" The villager wasn't concerned about losing the shirt — he was concerned that the shirt, loaded with microbes and pathogens relatively harmless to the outside world, could kill the Chitonawa tribesman.

According to figures provided to VICE News by anthropologist Rob Walker, an assistant professor at the University of Missouri who studies Amazonian cultures, 117 epidemics claimed the lives of more than 11,000 members of indigenous Amazon societies between 1875 and 2008. Of those, 75 percent died from measles, malaria, or the flu. The estimated 100 or so uncontacted and isolated tribes of today would have little or no immunity.

A team of medical experts was dispatched by Funai, the Brazilian government's official indigenous protection agency, in preparation for sickness among the Chitonawa. All seven of them came down with colds and the flu. Though they all survived, Funai's lead doctor worried that potentially fatal measles and pneumonia might soon take hold.

For reasons of cultural sensitivity, as well as the ever-present potential for biological catastrophe, the governments of Brazil and Peru support a "hands off" approach to uncontacted tribes. Protected reservations have been created, where access to outsiders is technically off-limits. But a fierce battle has erupted between academics and advocates over what to do next. The stakes are high; people's livelihoods, not to mention lives, hang in the balance.

Walker and his research partner, Kim Hill, argued in a recent editorial for the American Association for the Advancement of Science that the status quo has been an abject failure, and that uncontacted tribes don't stand a chance against modern threats encroaching on their territory. Wealthy corporate interests have powerful lobbies, and drug traffickers — like the ones who are suspected of attacking a Funai outpost in 2012 — don't pay much attention to government regulations. As a result, Walker and Hill insist "controlled contact" is the only ethical and humane way forward.

"We think the evidence is clear," Walker told VICE News. "People are going extinct while the world watches."

Not everyone feels that way. Survival International, a London-based nonprofit that advocates for indigenous peoples' rights, has called Walker and Hill's editorial "dangerous and misleading."

"I don't think Walker and Hill are expressing an opinion that is widely held by people who are knowledgeable about this issue," said Survival International director Stephen Corry. "What they are really saying is, 'Let's move in there and establish this supposed controlled contact,' which basically means, 'Take their land.'"

Corry told VICE News there exists a clear motive behind any push for contact. Industrialized society wants real estate. This, he said, "somehow justifies the fact that these people have to 'catch up with the modern world,' or however it's phrased. Our position is that there's really nothing particularly modern about industrialized society."

Watch VICE News' 'Fighting the Amazon's Illegal Loggers.'

Although the term uncontacted is common shorthand, many advocates agree that the tribes are actually refugees of a sort who purposefully broke away from the outside world. Corry argues there's nothing "backward" about the lives uncontacted people live. Instead, they've simply "gone down a different path."

"These people represent an alternative way of approaching the world, and it seems like the contemporary industrial and political elites just cannot cope with that," he said. "The industrialized nation-state of today is going to try and take their land and whatever else it wants — and of course it will, if everybody just rolls over and accepts it as inevitable."

Walker concedes that most people are in full agreement with Corry and Survival International's point of view.

"It just happens to be wrong," he said. "They are advocates, and we are scientists."

Those in the no-contact camp are interested in "cultural survival," Walker says, while those in the pro-contact camp are interested in "the survival of individuals." He believes this is particularly true if one has a feel for the reality of how hard life is pre-contact.

"Imagine your family was out there being persecuted by drug runners and loggers and miners," Walker said. "Would it suffice to try and keep some of [those groups] out? Would you deny your family modern health care advances?"

Nixiwaka Yawanawa is a member of the Amazonian Yawanawa tribe, which was first contacted two generations ago. The Yawanawa are extremely isolated; the nearest road is a full day away by motorboat. But they are also connected to the Internet, and supply annatto — a red pigment made from the seeds of the achiote tree — to Aveda for high-end cosmetics. Nixiwaka, who sometimes goes by "Joel," has lived in London for the past four years.

Nixiwaka Yawanawa sought to raise awareness of indigenous peoples' plights in London before the 2014 World Cup. (Photo by Helen Saunders/Survival)

"I don't think much good came from Western contact," he told VICE News. "We almost lost our spirituality, our culture, our identity, because of the Western influence. And we are still battling the effects of materialism, disease, and separation."

Nixiwaka, who opposes controlled contact, says he enjoys life in Europe, and can better help raise awareness of the things affecting the Yawanawa people from there.

"Many have told me that life in the forest is not something they would go back to, although older generations often reminisce about the good old days," Walker said.

Indigenous tribes can survive interaction with outsiders, Walker believes, if those making contact commit to providing food, translators, and around-the-clock medical treatment for as long as necessary. It's an expensive proposition, and one for which many South American governments don't have the money. Walker points to success stories, specifically that of the Puerto Barra Aché tribe in Paraguay. First contacted in the 1970s by an American missionary named Rolf Fostervold, the Aché were given ongoing support and medical care by Fostervold, his wife, Irene, and their two children. As a result, only one out of 28 Aché tribe members died as a result of first contact.

Bjarne Fostervold, Rolf's son, was on those first contact expeditions. Now 56, Bjarne remains in Paraguay, living among the Aché — who now number about 200 — with his wife, Rosalba, and their three kids. He calls the various no-contact nonprofits and NGOs "well-meaning," but tells VICE News that "hoping native peoples will never come into contact with outsiders is a little bit simplistic and tends to be a really romantic way of looking at things."

"The West doesn't always bring a whole lot of wonderful solutions to anyone's life, but at the same time, people living in the forest are struggling with their own issues," Fostervold said.

He thinks the methodology of a rigorously monitored controlled contact beats the almost-certain negative outcome of unplanned contact. Further, total isolation means a people could disappear and the rest of the world would never know it.

"We are dealing with a shrinking jungle, and uncontacted groups have nowhere left to turn," Fostervold said. "There's a group here in Paraguay that doesn't want to come out, but the bulldozers are moving in. At what point in time will there be a tragedy? Under the guise of protecting, are we actually disprotecting?"