Government Study Confirms Growing Tiger Mosquito Presence in Andorra's Urban Areas

A government study has confirmed the tiger mosquito's regular but growing presence in Andorra's southern parishes of Sant Julià de Lòria, Andorra la Vella, and Escaldes-Engordany, as well as the central valley, prompting coordinated action from authorities and communes.

Conducted by the Interministerial Commission 'One Health'—involving the Health and Environment, Agriculture and Livestock ministries—alongside Andorra Recerca + Innovació (AR+I), the research analysed mosquito diversity across the Principality during summer and autumn 2025. Experts from the Mosquito Service of Baix Llobregat County Council assisted with eight biweekly sampling campaigns from July to October. Traps targeting adults and eggs were placed at various sites nationwide.

Findings revealed steady increases in eggs, larvae, and adult specimens in the identified areas. The October campaign detected overwintering eggs, highlighting the species' winter survival capacity. This invasive insect poses public health concerns through frequent, painful bites and its potential to carry viruses. It thrives in small stagnant water sources like plant saucers, vases, buckets, or tyres, but not in flowing or large water bodies, making household prevention essential.

The results, shared with the seven communes' consuls last week, mark the third such study on local mosquito populations. Authorities are now rolling out measures in three key areas: a surveillance plan to monitor spread; public awareness campaigns urging residents to eliminate breeding sites; and targeted treatments at potential hotspots in public spaces.

Additionally, a scientific paper detailing the findings and implications is under peer review for publication in an impact journal. The government stresses citizen participation as critical to limiting proliferation.