People wait inside a provisional military field hospital treating people suffering from dengue, in the Ceilandia neighborhood of Brasilia, Brazil.

A dengue patient receives treatment at a provisional military field hospital, in the Ceilandia neighborhood of Brasilia, Brazil.

A dengue patient receives treatment at a provisional military field hospital, in the Ceilandia neighborhood of Brasilia, Brazil.

A person is received at a provisional military field hospital treating people suffering from dengue, in the Ceilandia neighborhood of Brasilia, Brazil.

A man is injected with a dose of the Qdenga vaccine, during a vaccination campaign against dengue in Rio de Janeiro, Brazil.

A woman is injected with a dose of the Qdenga vaccine, during a vaccination campaign against dengue in Rio de Janeiro, Brazil.

People wait outside a provisional military field hospital treating those suffering from dengue, in the Ceilandia neighborhood of Brasilia, Brazil.

Public health workers spray insecticide during a fumigation campaign against dengue-promoting mosquitoes, in the Ceilandia neighborhood of Brasilia, Brazil.

A public health worker sprays insecticide during a fumigation campaign against dengue-promoting mosquitoes, in the Ceilandia neighborhood of Brasilia, Brazil.