BRASÍLIA, BRAZIL -- A Yanomami indigenous boy has died after contracting the coronavirus, authorities in Brazil said Friday, raising fears for the Amazon tribe, which is known for its vulnerability to imported diseases.

The 15-year-old boy, the first Yanomami to be diagnosed with the virus, was hospitalized a week ago at an intensive care unit in Boa Vista, the capital of the northern state of Roraima, officials said.

"He died Thursday night. The cause of death has not yet been confirmed," the Brazilian health ministry said in a statement.

Indigenous peoples in the Amazon rainforest are particularly vulnerable to diseases that are foreign to them, because they have been historically isolated from germs against which much of the world has developed immunity.

Brazil is home to an estimated 800,000 indigenous people from more than 300 ethnic groups.

The Yanomami, who are known for their face paint and intricate piercings, number around 27,000.

Largely isolated from the outside world until the mid-20th century, they were devastated by diseases such as measles and malaria in the 1970s.

Health Minister Luiz Henrique Mandetta had called the case of the Yanomami boy "very worrying."

"We have to be triply cautious with (indigenous) communities, especially the ones that have very little contact with the outside world," he said Wednesday.

The boy is the third indigenous person in Brazil to die after contracting the novel coronavirus, according to the newspaper Globo.

The others were from the Borari and Muru ethnic groups.

At least eight indigenous patients from five ethnicities in three states have tested positive for the virus so far, according to Globo.

Brazil is the country hit hardest by the coronavirus pandemic in Latin America, with 941 deaths so far.