Dengue: Serotype 3 circulates again in Brazil
Dengue serotype 3 has seen a rise in positive cases across Brazil, particularly in the states of São Paulo, Minas Gerais, Amapá, and Paraná. This increase was most notable in the last four weeks of December. The situation has raised concerns among Brazilian health authorities, as the virus has not circulated predominantly in the country since 2008, leaving a large portion of the population vulnerable.
Data from the Ministry of Health show that, throughout 2024, dengue serotype 1 was the predominant strain in Brazil, identified in 73.4 percent of the samples that tested positive for the disease. "We are witnessing a significant shift towards serotype 3," said Ethel Maciel, the Secretary of Health Surveillance, during a press conference on Thursday (Jan. 9).
"This is a variable we are incorporating into our COE [Emergency Operations Center] to monitor the circulation of these viruses," she stated.
High incidence
A projection based on patterns observed in 2023 and 2024 in Brazil, presented by the Ministry, indicates that most dengue cases expected in 2025 will likely occur in the following states: São Paulo, Rio de Janeiro, Espírito Santo, Tocantins, Mato Grosso do Sul, and Paraná. In these areas, the incidence is anticipated to be higher than in the previous year.
"We are still experiencing the effects of El Niño, leading to high temperatures and extreme temperature fluctuations. Additionally, the drought problem causes people to store water, often in unsuitable containers, which contributes to the proliferation of mosquitoes," explained the Secretary of Health Surveillance.
