The Yellow fever outbreak in Brazil has killed 200 people, nearly double the toll recorded on the 22nd of March, the country’s healthy ministry said.

As of April 6, a total of 604 people were diagnosed with the disease, while another 552 were being tested, latest government data showed.

The outbreak has so far been confined to rural areas. No city-dwellers have been reported to have contracted the illness.

A total of 148 people have died in the southeast state Minas Gerais, and 438 others were infected.

Yellow fever is a deadly infectious viral disease. It spreads through mosquito bites in Latin America and Africa.

Vaccination can prevent infections. Brazil used to require people to get the vaccines every decade, but the World Health Organization (WHO) said getting the shot once would be good for a person’s lifetime. 

The health ministry decided to follow the WHO suggestion on Wednesday.