Mato Grosso do Sul Braces for Potential Dengue Resurgence in 2026
After two years of decline, the Brazilian state of Mato Grosso do Sul faces a potential increase in dengue cases in 2026, according to projections from the InfoDengue–Mosqlimate challenge, a collaborative effort between researchers at Fiocruz (Oswaldo Cruz Foundation) and FGV (Getulio Vargas Foundation). The modeling suggests a rise in the incidence rate to 674.54 cases per 100,000 inhabitants – a level the World Health Organization (WHO) considers epidemic.
Understanding the Projections: It’s Not Inevitable
While the forecast raises concerns, experts emphasize it doesn’t guarantee a worsening situation. Julio Croda, an infectologist at Fiocruz and professor at UFMS (Federal University of Mato Grosso do Sul), explains the projections are based on mathematical models analyzing population immunity, Aedes aegypti mosquito circulation, and historical epidemiological data. Crucially, these models don’t fully account for recent preventative measures.
“The state has been experiencing a downward trend in dengue cases for the past two years, a contrast to much of Brazil,” says Croda. “This period of lower incidence means a larger proportion of the population is now susceptible, increasing the risk of renewed transmission.”
Innovative Prevention Strategies in Action
Mato Grosso do Sul isn’t passively awaiting the projected increase. Significant preventative strategies have been implemented in its largest cities. Campo Grande completed the release of Wolbachia-carrying mosquitoes in December 2023 – a groundbreaking technology that reduces the mosquito’s ability to transmit dengue. Preliminary data suggests a 63% reduction in cases in 2024 as a result.
Dourados implemented a mass vaccination campaign using the Qdenga vaccine, a partnership between Fiocruz, the municipality, and private initiatives. These interventions, concentrated in the state’s most populous areas, weren’t factored into the initial models, offering hope that the projections may not fully materialize.
Pro Tip: Even with advanced technologies like Wolbachia and vaccines, eliminating mosquito breeding grounds remains the most effective preventative measure. Focus on removing standing water around your home and community.
The Broader Arbovirus Picture: Chikungunya and Zika
Dengue isn’t the only concern. Mato Grosso do Sul also faces challenges with other arboviruses. In 2025, the state recorded 14,096 probable cases of chikungunya, the second-highest incidence in Brazil, trailing only Mato Grosso. This resulted in 17 confirmed deaths, representing approximately 14% of all chikungunya fatalities in Brazil during that period.
Zika virus also remains a threat, with 4,119 probable cases and one confirmed death reported in 2025.
Current Situation and Official Response (Early 2026)
The State Health Secretariat (SES) acknowledges the potential for increased dengue transmission in 2026 but emphasizes that a definitive forecast is premature. Initial data from the first epidemiological week of 2026 indicates low transmission levels, but these figures are preliminary and subject to change.
As of early 2026, Mato Grosso do Sul has reported 132 probable dengue cases (with two confirmed) and 131 probable chikungunya cases (also with two confirmed). No significant Zika cases have been detected.
The SES attributes the recent decline in dengue cases (2023-2025) to integrated prevention and control efforts. However, chikungunya cases remained stable between 2024 and 2025, with 2025 experiencing an epidemic peak. Early 2026 data suggests a decline in chikungunya cases, but officials caution that the situation remains fluid.
Risks Remain: Vigilance is Key
Despite the encouraging initial data, the SES stresses that risks persist. The Aedes aegypti mosquito remains widespread, and climatic conditions could facilitate renewed transmission. The current decrease in cases doesn’t eliminate the possibility of future outbreaks, including severe cases and fatalities, particularly among vulnerable populations.
The SES is reinforcing epidemiological and entomological surveillance, ongoing vector control, breeding site elimination, appropriate care for suspected cases, and timely notification through the SINAN (Notifiable Disease Information System). Public awareness and preventative measures – eliminating standing water, sealing water tanks, and proper waste disposal – are also crucial.
Did you know?
Aedes aegypti mosquitoes can breed in surprisingly small amounts of water – even a bottle cap!
Frequently Asked Questions (FAQ)
- What is Wolbachia? Wolbachia is a naturally occurring bacterium that reduces the ability of Aedes aegypti mosquitoes to transmit viruses like dengue.
- How effective is the Qdenga vaccine? The Qdenga vaccine has demonstrated significant efficacy in preventing dengue fever in clinical trials.
- What can I do to protect myself? Eliminate standing water around your home, use mosquito repellent, and wear long sleeves and pants when possible.
- Where can I find more information about dengue? Visit the World Health Organization’s dengue page or the Centers for Disease Control and Prevention’s dengue page.
Stay informed, take preventative measures, and contribute to a healthier Mato Grosso do Sul. Share this article with your community to raise awareness and encourage collective action against these mosquito-borne diseases.
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