Andalucía is expanding its surveillance program to include the tiger mosquito as part of its ongoing efforts to monitor and control the West Nile virus, with officials likewise expressing concern over the potential introduction and spread of dengue, chikungunya, and Zika viruses. The announcement, made Monday in Huelva by regional Health, Presidency and Emergencies Minister Antonio Sanz, marks a significant broadening of the region’s vector control strategy.
Last year, Andalusia recorded 17 cases of dengue fever and 14 cases of chikungunya, all classified as imported – meaning contracted by individuals who had recently traveled to Central and South America. Seven additional suspected cases of Zika virus were reported, though not confirmed. “All were imported cases, people who had traveled to countries in Central and South America. But these cases introduce the virus into our land, so we must be on alert to prevent the virus from spreading,” Sanz stated, according to a press release from the Junta de Andalucía.
Officials emphasize that conditions in certain areas of Andalusia are conducive to the establishment of locally transmitted cases. The presence of the Aedes albopictus mosquito – commonly known as the tiger mosquito – combined with favorable environmental factors and the influx of imported cases, creates a risk environment. “In Andalusia, all the necessary elements coexist in certain areas for an autochthonous case to appear,” Sanz explained.
The integrated Vector Surveillance and Control Program, established in 2025, will continue with an annual cycle. Authorities have already communicated risk levels to municipalities across the region, and public health agents are working with local officials to develop and implement pest control plans. This year, 117 municipalities are classified as high risk, 302 as medium risk, and 366 as low risk – an increase of 13 municipalities in the high-risk category compared to the previous year.
The expanded surveillance program comes after a particularly severe outbreak of West Nile virus in 2024, which resulted in eleven fatalities. Last year, however, the program was credited with preventing any deaths related to the virus.
To further coordinate efforts, Seville will host the Southwest Vector Days from March 10-12, bringing together over 150 professionals from Madrid, Castilla-La Mancha, Extremadura, the Canary Islands, Ceuta, and Andalusia, as well as representatives from the Ministry of Health. Andalusia will present its vector monitoring and control program as a potential model for other autonomous communities.
The Junta de Andalucía is also focusing on monitoring municipalities bordering areas designated as high alert, recognizing that mosquitoes can travel up to 10 kilometers. As of February 28, no virus has been detected in the 40 traps maintained throughout the region during the winter months. Monitoring will continue in March and April with 38 sentinel traps in municipalities previously designated as alert areas, transitioning to weekly checks and 120 traps distributed across the region starting May 1, supplemented by three mobile traps.
In 2025, 31 municipalities were designated as alert areas, with four confirmed human cases of West Nile virus. Virus circulation was detected in over 60 mosquito traps, and seven cases were identified in equines and three in birds.
