Known for transmitting diseases such as dengue, chikungunya, and Zika, the Aedes albopictus mosquito continues to expand across the country. The Directorate-General of Health (DGS) confirmed that, in 2025, the insect was identified in four new municipalities: Condeixa-a-Nova, Covilhã, Lagos, and Portimão.

According to the Jornal de Notícias, the spread of the species is being closely monitored by health authorities. Between January 1st and October 9th, 37 cases of dengue were registered in Portugal, of which 35 were imported and two were autochthonous, both in the Autonomous Region of Madeira.

According to the DGS (Directorate-General of Health), all cases “are outside the infectious period,” and do not represent a risk of new transmission chains. The two autochthonous cases identified in Madeira at the beginning of the year are associated with the Aedes aegypti mosquito, distinct from the one observed on the mainland.

Despite the expansion of the species, the Secretariat emphasizes that the Aedes albopictus mosquitoes detected so far “do not carry the pathogen responsible for the disease.”

The growing presence of the insect is explained by environmental and climatic factors. The increase in average temperatures, longer summers, less severe winters, and irregular rainfall patterns create ideal conditions for its multiplication.

These changes have allowed the mosquito to find an increasingly favourable environment for its survival in the country.

Carla Sousa, a researcher at the Institute of Hygiene and Tropical Medicine of the Nova University of Lisbon, confirms that the area of ​​dispersion of the species “is increasing.” The expert explains that mosquitoes use "human-mediated dispersal methods," since the eggs can be easily transported in containers with small amounts of water.

According to the same source, the phenomenon is closely linked to globalisation and the increase in the traffic of goods and human mobility.

Climate change, she adds, emerges as a consolidating factor, allowing the establishment and adaptation of invasive species to new regions.

The researcher also emphasises that areas that previously did not present suitable conditions may, in the near future, become conducive to the presence of the mosquito. "Globalization is a determining factor, and climate change ends up consolidating the presence of these species in territories where they previously could not survive," concludes Carla Sousa in the report by Jornal de Notícias.