Brazil: 49% of municipalities at risk for Aedes aegypti

The Brazilian Ministry of Health has released results from the second cycle of the Rapid Survey of Aedes aegypti Indices (LIRAa), conducted between May and August. The data reveals that 49.2% of the 3,732 municipalities that submitted information are in a state of alert or risk for the presence of the mosquito responsible for transmitting dengue, chikungunya, and zika.

Despite the high infestation risk, infection rates have seen a significant decline compared to the previous year. Probable dengue cases in Brazil fell by approximately 70% in 2026 compared to the same period in 2025, dropping from 1.5 million to 470,500. Chikungunya cases decreased by 43%, and zika cases saw a 35% reduction.

The survey identified common household items as primary breeding sites: 42.3% in small containers like plant saucers and bottles, 26.1% in water reservoirs such as tanks and cisterns, and 23% in tires and solid waste. Breeding patterns vary by region, with tires and trash being more prevalent in the North, while water storage is more common in the Northeast, and household containers dominate the Southeast, South, and Central-West regions.