El Niño could increase cases of chikungunya and dengue in Brazil

The climate phenomenon El Niño may manifest itself in a moderate to strong form from the second half of this year, which favors the multiplication of the Aedes aegypti mosquito, points out the National Institute of Meteorology (Inmet).

Faced with this scenario, the Ministry of Health issued a technical note to alert states and municipalities about the increase in arboviruses, such as dengue and Chikungunya. According to projections from InfoDengue/Fiocruz, the country could register around 1.7 million cases of dengue in 2027.

Rising temperatures and increased rainfall in certain locations encourage the accumulation of water, which creates suitable environments for the vector to breed.

Recommendations

To mitigate this scenario, the Ministry of Health advocates for the intensification of surveillance and control actions by states and municipalities.

The body recommends blocking transmission as soon as the first cases are identified, restructuring the tasks carried out by agents to combat endemic diseases and applying vector control technologies recommended by the ministry.

It is also important for the population to be aware of possible mosquito breeding sites in their homes, in addition to paying attention to the signs and symptoms of viruses.

As they are epidemiological estimates, projections may undergo adjustments and updates according to new information implemented in the models.

Falling cases

Despite the attention scenario, the country showed a reduction in the number of cases of these diseases this year.

Until June 20, 2026, 392.8 thousand cases of dengue were registered, which represents a drop of 73% compared to the same period of the previous year. Chikungunya cases also showed a reduction of 46%.

Read Also: Brazilians suffered 258 blows per hour in 2025; Crime has increased fivefold since 2018

Related stories