Big increase in DENV-3 Dengue serotype reported in Santa Catarina, Brazil
Santa Catarina state is facing a significant increase in cases of the DENV-3 dengue serotype this year. DENV-3 can cause symptoms similar to those of other serotypes, but it has the potential to lead to severe dengue if exposed to a different serotype later. Infections with DENV-3 are also associated with immune enhancement phenomena that can worsen symptoms if exposed to other serotypes in the future.
Data released this Monday by the State Department of Health and Lacen-SC (Central Public Health Laboratory) indicate that between January 1 and October 24 of this year, confirmed cases increased by 7,166% compared to the same period in 2024, rising from 3 to 218 confirmations.
The growth is attributed to the reintroduction of DENV-3 in areas with high circulation of other serotypes, which increases the risk of epidemics.
To date, Santa Catarina has recorded 25,371 probable cases of dengue in 2025, of which 17,859 were confirmed.
In September, notifications of probable cases increased by 230% compared to the previous month, indicating the beginning of the seasonal proliferation period of the Aedes aegypti mosquito, the vector of the disease, which occurs from October to May.
The state has already recorded 20 dengue deaths this year. The most affected regions include the Northeast, Itapocu Valley, Greater Florianópolis, Middle Itajaí Valley, West, Upper Uruguai Catarinense, and Foz do Rio Itajaí, where the mosquito’s proliferation is most intense.
To contain the spread, the government of Santa Catarina intensified preventive actions in partnership with the Department of Education and FECAM (Santa Catarina Federation of Municipalities).
Between today and November 8, a mobilization will be carried out in municipal, state and private schools involving students, teachers and families in the elimination of mosquito breeding grounds, such as containers with stagnant water.
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In addition, the state’s Contingency Plan was updated, and 280 municipal technicians from 13 health regions underwent training.
The SES recommends that the population adopt simple prevention measures, including removing objects that accumulate water, using repellents and screens on windows, and keeping yards clean.
Authorities warn that the combination of rain and high temperatures is expected to lead to a further increase in cases in the coming weeks. Epidemiological monitoring continues in all regions.