The data are contained in the REVIVE Report – Vector Surveillance Network, produced by the National Institute of Health Dr Ricardo Jorge (INSA), through the Centre for Vector and Infectious Disease Studies.
In 2025, the five mainland health regions and the Madeira Regional Health Directorate participated in the REVIVE surveillance programme, with mosquito collections carried out in 243 municipalities.
In total, 44,123 mosquitoes of 22 species and 48,503 eggs of invasive species were identified.
The ‘Aedes albopictus’ mosquito, a vector for viruses and parasites that cause diseases such as chikungunya, dengue, yellow fever and Zika, was first identified in Portugal in 2017 in the North region, and was subsequently detected in the Algarve in 2018, in the Alentejo in 2022, in the Lisbon region in 2023 and in the Central region in 2024.
In 2025, the species was recorded in 28 municipalities, confirming the expansion of its geographical distribution across the country.
In that year, it extended its presence in the Central region to the municipalities of Condeixa-a-Nova and Covilhã, as well as to Lisbon, Oeiras, Almada and Sesimbra.
According to the report, testing for flaviviruses and human-pathogenic alphaviruses was negative in the majority of the samples analysed. However, dengue virus serotype 2 (DENV2) was detected in samples of ‘Aedes aegypti’ from the Autonomous Region of Madeira.
The invasive ‘Aedes aegypti’ mosquito has been present in Madeira since 2005.
The report also presents surveillance results for other disease vectors.
Among Ixodidae (ticks), 6,612 specimens were identified in 2025, with 2.3% testing positive for Borrelia and 19.7% for Rickettsia. Exotic specimens of the Argasidae family were also detected.
During surveillance of sand flies – small mosquito-like insects and vectors of diseases such as leishmaniasis – 1,448 specimens were collected, with five species identified in Portugal.
The Toscana phlebovirus, which can cause encephalitis and meningitis, was also detected in the municipalities of Pedrógão Grande and Resende.














Madeira is already infested, if you are sensitive to its bites like me you better not visit the island at all. It itches like hell for weeks, particularly on your feet.
By Diogo F. from Madeira on 28 Apr 2026, 17:32
This Spring seems much worse than last - even with window screens and nets over the bed.
By Mark from Lisbon on 29 Apr 2026, 21:14
Is the Portuguese government doing anything to combat these ticks? It is a true health hazzard.
By Debbie Sainer MD from USA on 29 Apr 2026, 21:59
To my knowledge a vaccine against Dengue Fever exists, but it is not part of the Portuguese vaccination plan. Like many other very useful vaccinations, which are standard in other European countries.
By Tom from Lisbon on 30 Apr 2026, 07:53