# Dengue outbreaks in Northeastern Brazil

> Live situation record from CLSTR: https://clstr.news/situations/dengue-outbreaks-in-northeastern-brazil
> Updated: 2026-08-23T22:02:00.000Z. Sources: 6. Developments: 2.

In the municipality of Caicó, health authorities placed the area under a state of alert to prepare for potential dengue transmission. While no active outbreak or cases of hemorrhagic dengue were confirmed at that time, officials intensified vigilance and mosquito control efforts, such as fogging, due to increased rainfall and the proliferation of the Aedes aegypti mosquito.

By late August, the situation escalated across the northeastern region of Brazil. In Ceará, confirmed cases rose by 172.7% compared to the previous year, with 34 municipalities placed on alert. Health officials expressed concern over the circulation of the DENV-3 serotype alongside the dominant DENV-2 strain. Ceará has reported 18 deaths related to the disease. Similarly, Piauí has recorded over 10,000 confirmed cases and 15 deaths, with the capital, Teresina, being the most heavily impacted area.

## Claims

- Dengue confirmed cases in Ceará increased by 172.7% compared to the same period in 2025. (corroborated by 2 sources)
- Ceará has recorded over 11,000 confirmed dengue cases and 36,393 notifications as of early August 2026. (corroborated by 2 sources)
- 34 municipalities in Ceará are under alert due to high or very high incidence of probable dengue cases. (corroborated by 2 sources)
- The DENV-2 serotype is the predominant strain in Ceará, accounting for 85.7% of analyzed samples. (corroborated by 2 sources)
- The DENV-3 serotype has been detected in Brejo Santo, Iguatu, Russas, Fortaleza, Aracati, Caucaia, and Camocim. (single source)
- Piauí has recorded 15 confirmed deaths from dengue in 2026. (single source)
- Teresina accounts for approximately 43% of all probable dengue cases in Piauí. (single source)
- The DENV-3 serotype has been detected in Brejo Santo and Iguatu. (single source)
- Ceará has recorded 18 confirmed deaths from dengue in 2026. (single source)

## Timeline

### 2026-08-23: Dengue cases surge in Ceará and Piauí as Brazil faces rising infection rates

Dengue cases are surging in Brazil's Ceará and Piauí states. Ceará reports a 172.7% increase in confirmed cases and the emergence of the DENV-3 serotype, while Piauí has recorded 15 deaths in 2026.

3 sources. https://clstr.news/cluster/dengue-cases-surge-in-cear-and-piau-as-health-alerts-are-issued

### 2026-08-20: Caicó enters state of alert over dengue risk

Caicó, Brazil, is under a health alert for dengue. Officials are intensifying surveillance and mosquito control measures to prevent an outbreak following increased rainfall.

3 sources. https://clstr.news/cluster/caic-enters-state-of-alert-over-dengue-risk

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Cite as: Dengue outbreaks in Northeastern Brazil. CLSTR, https://clstr.news/situations/dengue-outbreaks-in-northeastern-brazil