Isolated tribes in the Amazon basin stand exposed to diseases and loss of resources as they come in contact with the outside world. Reuters

After a gap of 20 years, an isolated Amazonian tribe has made contact with Brazilian scientists, according to an announcement from the country's Indian affairs department (FUNAI).

Emerging from the dense rainforests along the Upper Envira river, the group contacted the officials, who were in the area following complaints from local villagers about fearful strangers raiding their crops and tools.

The officials suspect the present tribe fled illegal loggers some 186 miles away in Peru. The loggers may have driven away the animals the tribe hunted, forcing them to migrate.

According to Science Now, there are at least 70 isolated tribes in the Brazilian Amazon and more outside.

Anthropologists are concerned for the group's welfare as such isolated tribes have been known to succumb to diseases like flu and whooping cough their body is not protected against. Between 1983 and 1985, almost half of another population was wiped out owing to illnesses contracted from loggers.

Stunning aerial shots of an isolated tribe in the same area had made news way back in 2008.

As oil drilling oil companies push ahead with drilling and laying pipelines inside such reserves, the tribes stand to lose out on their land and resources.

A controversial gas project recently approved by the Peruvian government has the potential to wipe out such uncontacted tribes who live in the area. According to Earth First Journal, Peru's Ministry of Culture, which is responsible for protecting the country's indigenous people, has approved a plan by three foreign oil and gas companies to perform oil exploration on land just 100km from Machu Picchu, where 15 uncontacted tribes live in isolated regions of the Amazon Rainforest.

The Camisea gas project, being carried out by three major companies from Argentina, the US and Spain, will involve detonating thousands of explosive charges, drilling exploratory wells and importing hundreds of workers into an area where these tribes now live in isolation.