In Rio de Janeiro, on the eve of Carnival, a state of emergency is declared due to an outbreak of dengue fever.

RIO DE JANEIRO (AP) — Rio de Janeiro has declared a public health emergency due to an outbreak of dengue fever, the municipality said in an official bulletin Monday, days before the start of Carnival.

However, the outbreak is not expected to disrupt the celebrations, which officially begin Friday and run until Feb. 14.

The municipality announced the opening of 10 health centers, the establishment of an operations center and the allocation of hospital beds specifically for dengue patients. Authorities will also use “sanitary carts” in areas with the highest infection rates, from where insecticides will be released into the air.

The municipality has recorded more than 10,000 dengue cases since the start of 2024, just under half of the total – 23,000 – recorded in all of 2023.

The announcement came as tourists and revelers began arriving to take part in street parties and lavish parades of samba schools.

Dengue is a viral infection transmitted through mosquito bites and is common in tropical climates. Frequent rain and warm weather, which encourage mosquito breeding and larval development, make Rio a city prone to dengue fever outbreaks.

But the problem is nationwide: four states – Acre, Minas Gerais and Goiás, as well as the Federal District – have declared a public health emergency due to dengue fever.

On Monday, the Brazilian Air Force built a 60-bed field hospital in Seilandia in the Federal District to care for dengue patients.

“Our goal is to provide assistance to medical units in the region, given that today 20% of dengue fever cases in the country occur in the Federal District,” Air Force Commander Lt. Marcelo Canitz Damasquin said in a statement.

Most people who contract dengue do not develop symptoms, but when they do, they usually include fever, headache, body aches, nausea and skin irritation, according to the World Health Organization. While most patients get better after about a week, there are some who contract a more severe form of dengue and have to be hospitalized. In such cases, dengue fever can be fatal.

Climate change, leading to higher temperatures and heavier rainfall, is associated with an increased risk of dengue fever, WHO said in December.