Caxias do Sul, Brazil is reporting meaningful progress in the fight against dengue fever, with cases dropping by 64% in 2025 compared to the previous year. This success, detailed in a new report, comes after local authorities declared a state of alert in April 2025 due to rising mosquito populations and implemented more aggressive preventative measures. The dramatic decrease in infections – from 269 cases and one fatality in 2024 to 97 cases and no deaths in 2025 – underscores the effectiveness of proactive public health strategies in combating the disease.
Caxias do Sul, Brazil – Dengue fever cases in Caxias do Sul decreased by 64% in 2025 compared to the previous year, falling from 269 infections and one fatality to 97 cases and no deaths. Public health officials attribute this significant reduction to intensified mosquito control efforts and preventative measures. This decline highlights the importance of proactive public health strategies in combating mosquito-borne illnesses.
In April 2025, the municipality declared a state of alert due to a rise in Aedes aegypti mosquito breeding sites across neighborhoods. Compared to all of 2024, identified breeding sites increased by 67%, rising from 899 to 1,501. However, Magda Beatris Teles, Director of Health Surveillance, explained that this increase was a direct result of more thorough and consistent inspections.
“We were able to carry out a greater number of visits, increased staffing, and decentralized the work of mosquito control agents to primary health care units,” Teles said. “As a result, we identified and eliminated more breeding sites.”
In total, 188,289 visits were conducted. This included 148,306 general visits to homes, 33,238 inspections during Rapid Index of Infestation (LIRAa) surveys, 4,114 inspections at strategically monitored locations every two weeks, and 2,631 inspections using ovitraps – containers with water and a wooden paddle where female mosquitoes lay their eggs.
Another key strategy was initiating preventative actions based on findings from the ovitraps, rather than waiting for confirmed cases. This proactive approach, combined with closer collaboration between agents and local communities, streamlined the inspection process.
“With the presence of ovitraps and agents working in primary care, they became more recognized within the communities, strengthening those relationships and improving surveillance at the local level,” Teles noted.
The application of insecticides in public buildings, particularly schools and healthcare facilities, also contributed to the decline in cases.
“We began this strategy in 2024 and continued it in 2025. We now apply the product to the walls of all health units, schools, and places with high foot traffic, helping to prevent future outbreaks,” Teles explained.
The same strategies will continue this year, but the Director of Surveillance celebrated the data recorded in 2025.
“Before, we were ‘putting out fires,’ treating areas only after a case was confirmed. Now, we are able to work with prevention as well,” she said.
Officials emphasize that community participation remains crucial to maintaining low infection rates and preventing mosquito proliferation, including dedicating 10 minutes per week to inspecting yards, allowing agents access for inspections, and reporting potential breeding sites through official municipal channels.
Case Profile for 2025
A total of 246 dengue notifications were recorded in Caxias do Sul in 2025. Of these, 97 cases were confirmed, with 65 being autochthonous – meaning the patients contracted the disease within the municipality.
The most affected age group was 30 to 39 years, followed by 40 to 49 years. The neighborhoods with the highest number of mosquito breeding sites were Fátima, with 122 occurrences, followed by São Caetano, with 81, and Santa Fé, with 76.
Neighborhoods with only one breeding site identified included Ana Rech, Bom Pastor, Campos da Serra, Glória, Linha 40, Loteamento Balardin, Planalto/Vila Mari, Santa Lúcia Do Piaí, and São Bernardo Franzoi.
Prevention Measures
- Eliminate standing water by turning over bottles, buckets, and flower pots; keep drains clean and screened.
- Ensure water tanks are tightly sealed, as loose lids are common mosquito breeding grounds.
- Remove saucers from plants to prevent water accumulation.
- Keep gutters clean and unobstructed, especially after rainfall.
- Dispose of trash properly in sealed containers to avoid creating breeding sites.
- Regularly empty and clean air conditioner drip trays and refrigerator pans.
- Treat swimming pools with chlorine and cover them when not in use.
