Dengue-transmitting mosquito detected in 28 municipalities

Monday, 27 April 2026AI summary
Dengue-transmitting mosquito detected in 28 municipalities
Photo: ECO

The mosquito species capable of transmitting dengue and yellow fever has been identified in 28 municipalities across Portugal in 2025, according to the National Institute of Health (Instituto Nacional de Saúde or Insa). This represents an increase of 10 municipalities compared to 2024, with recent detections in Lisbon, Oeiras, Almada, and Sesimbra.

Context & Explainers

Excess mortality is the number of deaths above what would be expected based on historical averages (commonly a multi‑year baseline), and it captures deaths directly and indirectly caused by events like epidemics, heatwaves or healthcare disruptions. Portugal’s public health institute INSA (Instituto Nacional de Saúde Doutor Ricardo Jorge) monitors excess mortality to see the broader impact of seasonal illnesses and other stresses on the health system, so a drop in flu cases does not automatically mean overall mortality has returned to normal. Those following public‑health trends should note excess‑mortality figures because they show the pandemic and other factors’ continuing effect on population health.