With a scary name reminding of a mythological creature, the Asian Tiger Mosquito has made itself at home in the temperate areas of Europe. The consequences of its bite can be more concerning than a simple, but surely annoying, cutaneous rush.
Let’s see what the Asian Mosquito Tiger is, where it comes from, why it is dangerous, and how to prevent its bites.
What is the Asian Tiger Mosquito?
The Asian Tiger Mosquito (Aedes albopictus) is an invasive species from the tropical forests of Southeast Asia; it arrived in Europe and the Americas about 30 years ago through the accidental transport of eggs laid on imported tyres and plants. Accidental human-mediated transport is the major cause of its spreading since this insect has a restricted flight range (about 200 metres).
It has black legs and body with white/silver horizontal stripes and a single white band on the abdomen.
Where can we find the Asian Tiger Mosquito in Europe?
This mosquito has shown great adaptability to a wide range of climate conditions, being resistant to both drought and cold. It has been reported on all inhabited continents and is considered among the 100 most invasive species in the world.
It was first detected in Europe in 1979, but the massive spreading started in the 90s when eggs were accidentally carried to Italy through imported goods. The Asian Mosquito Tiger is now established in Albania, Italy, France, Germany, Belgium, Greece, Spain, Slovenia, Bulgaria, Romania, Russia, and Turkey, and its presence has been sporadically reported in Switzerland and the Netherlands.
How did the Asian Tiger Mosquito spread globally?
In a few words, the global spread of the Asian Tiger Mosquito has been promoted by:
– GLOBALISATION: intercontinental travel and commerce, migration;
– URBANISATION: reduction of biodiversity and competition between species;
– CLIMATE CHANGE: higher temperatures induce the proliferation of this mosquito species.
Why is the Asian Tiger Mosquito dangerous?
Female Asian Tiger mosquitos feed on the blood of several animal species (amphibians, reptiles, birds, and mammalians including humans), therefore they can transmit viruses both within the human population and from animals to humans (zoonosis). These mosquitos are particularly aggressive and annoying and bite mostly during daylight both outdoors and indoors with artificial light. They take advantage of closed environments with plant vases, cans and other water containers.
The Asian Tiger Mosquito transmits Dengue (DENV) and Chikungunya (CHIKV) viruses, as well as the parasite Dirofilaria immitis (the “heartdog warm”) that can infest human lungs.
Several studies suggest that the Asian Tiger Mosquito can transmit 22 other viral diseases including:
- Yellow Fever
- Rift Valley Fever
- Japanese Encephalitis
- West Nile Disease
- Usutu Virus
- Zika Virus
- Eastern Equine Encephalitis
- Western Equine Encephalitis
- Venezuelan Equine Encephalitis
In particular, Dengue and Chikungunya viruses have been introduced in Europe by returning travellers who became infected in areas where these viruses are endemic. The viruses were then transmitted by the Asian Tiger mosquitos already present in Europe to other people, causing the first autochthonous outbreaks.
Another indirect negative effect of the presence of this insect is the increase in infant obesity rate: it is so aggressive that it causes a reduction in children’s outdoor activities.
When is the Asian Tiger Mosquito active?
The Asian Tiger Mosquito can stay active during the winter season in temperate regions. The eggs are laid on the surface of stagnant water (even in small containers in urban areas) and the adult mosquito will develop in 3-8 weeks depending on the temperature (development speeds up at higher temperatures, this is why in Italy and Southern Europe the Asian Tiger Mosquito population peaks between May and September). Its favourite habitats are urban and peri-urban areas.
How to prevent Asian Tiger Mosquito bites?
Asian Tiger Mosquito invasion and the warming of temperate regions due to climate change enhance the spreading of tropical viral diseases in Europe. For this reason, it is crucial to constantly monitor the presence of this insect on the territory.
The proliferation of the Asian Tiger Mosquito can be counteracted with insecticides and larvicides, and by avoiding stagnant water reservoirs. The controlled use of the bacteria Bacillus thuringiensis israeliensis ser. H14, able to infect this insect, has proven helpful in reducing the mosquito population. Other methods like the release in the environment of male mosquitos either sterile or carrying a lethal mutation to be transmitted to the progeny, and the introduction of predators are under consideration.
Traditional precautions like repellents, mosquito nets and long-sleeve clothes are also useful.
Image: “Asian tiger mosquito” from openverse.com (Public domain)
Bibliography
European Centre for Disease Prevention and Control (ECDC) – Aedes albopictus – Factsheet for experts: https://www.ecdc.europa.eu/en/disease-vectors/facts/mosquito-factsheets/aedes-albopictus
European Centre for Disease Prevention and Control (ECDC) – Aedes albopictus – Current known distribution: February 2023 https://www.ecdc.europa.eu/en/publications-data/aedes-albopictus-current-known-distribution-february-2023
Istituto Superiore di Sanità (ISS) – Zanzara tigre https://www.epicentro.iss.it/zanzara/ (Italian only)
Invasive mosquito vectors in Europe: From bioecology to surveillance and management, Giunti G. et al., Acta Tropica 2023, https://doi.org/10.1016/j.actatropica.2023.106832
Dengue and chikungunya: future threats for Northern Europe? Laverdeur J. et al., Frontiers in Epidemiology 2024, https://doi.org/10.3389/fepid.2024.1342723
Virus&Co. 