The tiger mosquito, known scientifically as Aedes albopictus, has increasingly taken up residence in Spain. Once a rarity, this species now thrives as higher fall and winter temperatures create conditions favorable for its survival and spread.
The typical activity window for this mosquito in Spain stretches from April to mid-November, yet recent years have seen its presence extend beyond that period. In particular, observers note that after mid-November the species remained more active than in previous seasons. This shift is documented by researchers and citizen scientists alike, including a team from Mosquito Alert, a program that collects observations from the public and builds a centralized database to track the species’ progression.
The unusual warmth of the autumn and winter seasons has provided an ideal breeding ground for the tiger mosquito. Mosquito Alert relies heavily on public reports to monitor trends and validate them through the database, highlighting how community participation supports a clearer picture of the species’ spread across the country.
Autumn-winter increase
Analyses show a notable rise in reports during November and December. Where those months previously accounted for about 1 to 2 percent of the annual tiger mosquito observations, in 2022 they represented nearly 5 percent. That figure is roughly three times higher than the year before, signaling a marked shift in activity patterns.
tiger mosquito 
Despite some drought years producing lower overall mosquito activity, higher temperatures in late autumn allowed these insects to stay active longer. A sighting in Catalonia on January 1 prompted experts to collect more data to determine whether this is an isolated incident or a genuine mid-winter uptick in activity.
The peak activity for the tiger mosquito remains concentrated along urban and peri-urban zones of the Mediterranean coast, including the islands, with evidence that it is gradually reaching inland areas and northern provinces. The species is now present in the Basque Country, Aragon, Madrid, and other autonomous communities, according to field observations from researchers. Vehicles and freight transport further accelerate the species’ spread by carrying eggs and larvae across longer distances, enabling colonization of municipalities that would be difficult to reach on their own.
Distribution of species in Spain and Europe
In addition to being a nuisance with its bite, the tiger mosquito poses a public health concern because it can transmit tropical diseases. It has demonstrated the capacity to carry a range of pathogens and has been associated with viruses such as dengue, chikungunya, Zika, and others in various settings. The species first appeared in Spain in 2004 and is known for daytime activity. It tends to breed in containers that hold standing water, including buckets, plant pots, saucers, and small puddles.
Àlex Richter-Boix stresses the value of citizen collaboration in reporting observations of this and other mosquito species. The Mosquito Alert app, which is straightforward to use, remains a key tool for gathering timely data across the country.
TIGER Mosquito Hazards
The tiger mosquito is recognized as a public health issue not only because of its painful bite but also due to its ability to spread a wide range of diseases. Laboratory studies have shown that it can transmit up to 22 different viruses. These include Rift Valley fever, Japanese encephalitis virus, and West Nile virus. In practice, locally transmitted diseases often observed include dengue fever, Zika, chikungunya, and, in some cases, yellow fever.
Across Europe, tiger mosquitoes have been linked to chikungunya outbreaks in Italy and France. Domestic cases of dengue transmitted by this mosquito have been reported in France, Croatia, and Spain. In 2019, Europe saw its first domestic Zika cases associated with the species in France. Besides humans, the tiger mosquito bites a wide range of mammals, which increases the potential for pathogen transmission between animals and people.
Another health consideration is heartworm, a disease caused by parasitic nematodes that primarily affects dogs and other canines. While humans can be affected, the risk is comparatively low.
……
No contact information is provided here. This article focuses on the biological and public health aspects of the tiger mosquito and emphasizes the importance of citizen science in monitoring its distribution.