Rapid response Task Force: addressing the detection of Aedes albopictus in Lisbon, Portugal

Abstract Issue The invasive Aedes albopictus mosquitoes are spreading in southern Europe and pose a heightened risk of mosquito-borne diseases, like Dengue and Chikungunya. On September 2023, A. albopictus was first identified in Lisbon through community-based surveillance and a multidisciplinary national Task Force (TF) was convened. Description of the problem The TF included experts in epidemiology, entomology, environmental health, laboratory diagnosis, prevention and control and communication. The objectives were to i) confirm A.albopictus presence in Lisbon and adjust the risk assessment, ii) raise awareness and prevent mosquitoes’ spread, iii) revise national guidelines on arboviruses surveillance and control. During September-December 2023, the National Network for Vectors Surveillance (REVIVE) and the Hygiene and Tropical Medicine Institute sampled mosquito-prone habitats within 2km-radius of the detection point using QGIS software. They used snowball sampling to identify any new foci. They placed ovitraps for ongoing surveillance and conducted morphological analysis and xenomonitoring for pathogen DNA and RNA detection at the national reference laboratory. Results By November 2023, A.albopictus was detected in two new foci. No mosquitoes tested positive for arboviruses, and no autochthonous cases of mosquito-borne diseases were identified. The TF developed national guidelines for vector prevention and control and awareness for arboviruses and trained municipality workers. To raise awareness, we communicated with experts and the public through existing channels and media. As of April 2024, no new foci have been detected. Lessons Community-based surveillance and REVIVE approach were crucial for invasive A.albopictus detection and monitoring in Lisbon. Rapid multidisciplinary TF coordination may have been key for timely vector control.