An "uncontacted" tribe of people living in the Amazonian rainforest have met with modern society for the first time, and promptly caught influenza.

Isolated from the rest of the human race, this small group of indigenous people has never before experienced the flu. This makes the disease highly dangerous - perhaps even fatal - for the little-known people.

A small group of natives traveled from their isolated home in Peru, traveling to the small village of Simpatia, home of the Ashaninka people. Three journeys were undertaken by travelers starting in mid-June 2014. Each visit lasted several hours, and people from each group were friendly with one another.

Now, five males and two young women from the previously uncontacted tribe have become sick with influenza. Those seven explorers to the modern world have now returned home to their remote outpost, according to Brazil's Indian Affairs department, FUNAI, which is responsible for monitoring such interactions.

Health officials treated each of the affected natives before they returned back home. A FUNAI monitoring station on the Envira River shut down by drug traffickers will be re-opened, the agency announced.

Survival International, a group dedicated to the survival of indigenous people described news of the influenza infections as "extremely worrying." They report that entire tribes have been wiped out in the past from diseases for which they possessed no immunity.

Brazilian authorities believe the natives came out of the rainforest due to encroachment and attacks from local poachers and drug traffickers. Lawmakers in Lima have allowed oil and gas exploration over 70 percent of the Amazonian rainforest in that nation. This includes land occupied by the newly-contacted people, as well as other remote tribes.

"This news could hardly be more worrying - not only have these people confirmed they suffered violent attacks from outsiders in Peru, but they have apparently already caught flu... Unless a proper and sustained medical program is immediately put in place, the result could be a humanitarian catastrophe," Stephen Corry, Survival International President, said.

The Nahua-Nanti reserve for uncontacted Indians is under development from the Camisea gas project. Other exploration for fossil fuels is taking place near the Matses tribe and uncontacted people, sponsored by oil developer Pacific Rubiales. Each of these projects could bring native people into contacts with hundreds of workers, as well as any diseases they may carry. Noise and human activity could also frighten away many game animals on which the native people depend.

Survival International has launched an international petition, calling on the governments of Brazil and Peru to protect uncontacted civilizations.