The Candoshi tribe in Peru's Amazon region has said their existence is threatened by a hepatitis B outbreak that began almost two decades ago.
A health emergency has now been declared in the area to tackle the epidemic.
Venancio Ucama Simon, the head of the tribe, said his people began contracting the disease around 1990 and members are dying because they have not received treatment.
"My people are suffering, we're in real danger of extinction," Ucama said on Wednesday.
Gianina Lucana, a Candoshi nurse working for the World Wildlife Fund (WWF), said that "so far, 80 people have died from hepatitis B since 2000" in her region.
She said the disease broke out when Occidental Petroleum Corporation was granted exploration rights in the remote northern Datem del Maranon Province.
Lack of reliable data has made it difficult to determine how many people have been infected with hepatitis B, Lucana said. The latest statistics, in 2000, suggested there were 169 cases.
"From that time to now, however, things have deteriorated badly. There have been lots of deaths apparently from hepatitis B, but it's been impossible to determine exactly how many because of lack of medical attention," she said.
The Candoshi population is currently estimated to number 2,400 people.
A health emergency was declared in the area after Ucama and members of his tribe travelled to the capital, Lima, to draw attention to their case.
"We will guarantee permanent human and economic resources to launch a massive inoculation drive against that disease," Oscar Ugarte, Peru's health minister, said.
The tribe leader said the epidemic is also threatening to wipe out other indigenous groups, including the Shapra, Awajun, Achuar and Huambisa, all living in Peru's north.
Ucama said that federal and local health authorities were trading blame for the plight of the Candoshi and citing the high cost of hepatitis B treatment as a reason for the inattention.
The Candoshi tribe has its homeland in a wetland ecosystem and lives off of sustainable fishing
The tribe is known for its conservationist culture, which the WWF said has helped restore Amazon wildlife around lake Rimachi.