Some 600 Warao, a tribe from the delta of the Orinoco river, live in shelters in Manaus, the capital of Brazil's Amazonas state, where they started arriving in 2018 after escaping the economic crisis in Venezuela.

Municipal social workers who were moving families to new shelters to avoid crowding during the coronavirus epidemic found the baby had a cold and took her and the mother to a hospital 12 days ago. The baby tested positive for the virus on Monday.

Health experts and anthropologists have warned of the danger of the pandemic decimating Brazil's 850,000 indigenous people because they have no immunity to external diseases and live in communal homes where social distancing is not possible.

So far, the indigenous health service Sesai has reported three deaths from the coronavirus among indigenous people, including a Yanomami youth aged 15 in the northern state of Roraima, bordering Venezuela.

The Manaus mayor's office said in a statement it was not known where the baby contracted the virus. The father has been isolated and other Warao in the shelter are being monitored, it said.

At one of the shelters, seen from outside the fence by a Reuters photographer on Wednesday, Warao men played volleyball in the gymnasium and families gathered in an open area to chat while not wearing masks.

Manaus, a city of 2 million in the heart of the Amazon rainforest, has been particularly hard hit by the epidemic. Deaths in the state doubled in five days to 106 by Wednesday, Brazil's Health Ministry said.

Amazonas state's health system has been overwhelmed by the epidemic, with all intensive care beds and ventilators already taken as a result of the outbreak.