Eleven years ago, the first Asian tiger mosquito was discovered in Austria. At that time it was still a single specimen, but in the meantime the situation has changed: In the previous year, the tiger mosquito was found for the first time in all federal provinces as part of our Gelsenmonitoring. Even more: in parts of Vienna and Graz there are already established populations that can survive the winter with us.
Asian tiger mosquitoes(Aedes albopictus) are possible vectors of more than 20 different pathogens. Many of them, such as dengue, Zika or chikungunya, cannot be transmitted by native mosquito species. Although these pathogens have not yet been found in Austria, in the case of the Chikungunya virus, the European Centre for Disease Prevention and Control (ECDC) already assumes a high probability of introduction into Europe.
Surveillance is becoming increasingly important
In cooperation with the provinces, universities and associations, we carry out so-called ovitrap monitoring throughout Austria on behalf of the Ministry of Health from the beginning of May to the end of October. Ovitraps are traps that are inspected weekly for egg clutches of different species of catfish. These traps are mainly set up in urban areas and in places where alien species can be introduced into the country (e.g. freeway service areas). Cities tend to be much warmer than surrounding areas, which favors the survival of tiger mosquito populations over the winter. In Vienna, for example, the Asian tiger mosquito is introduced by long-distance traffic, especially in the area of Vienna's southeastern green belt or at individual inner-city long-distance bus stops. Since the first sighting in 2020, tiger mosquitoes have overwintered there and spread further into adjacent residential areas and garden settlements on a small scale.
Citizens can also provide valuable information about tiger mosquito occurrences. The free app "Mosquito Alert" provides a tool to easily report possible tiger mosquitoes. The submitted photos are reviewed by national and international experts and the findings are displayed on a publicly accessible map.
For representatives of municipalities, public health organizations and pest controllers, AGES will hold a training course on tiger mosquito control in Austria on May 22 and 23. The course will provide a general overview of mosquitoes and their control.
Everyone can help with containment
Tiger mosquitoes are so-called "container breeders" and prefer the smallest water spots to lay their eggs. In their natural environment, these are mainly tree hollows; in urban areas, they can be all kinds of containers in which water accumulates, such as rain barrels, birdbaths, watering cans, drains, clogged gutters, flower vases, plant coasters, tubs, cans, bottles or jars. Car tires stored outdoors with accumulated rainwater are also particularly attractive. A female lays about 40-90 eggs per oviposition cycle, which she distributes among various water sites. About 10-15 days after the larvae hatch, the adult tiger mosquitoes develop. Tiger mosquito eggs are very hardy and can survive months of drought and cooler temperatures (e.g., through winter) before hatching.
It is therefore especially important to eliminate potential breeding sites for the tiger mosquito. These simple measures can also prevent other pesky gnats:
- Empty small watering holes such as birdbaths or flower coasters at least once a week.
- Cover or fill with sand small water points such as umbrella stands, fence tubes, depressions in branch forks or decorative elements
- Store items such as watering cans, tires, empty flower boxes, ashtrays under roof or turn them over to prevent water from accumulating
- close rain barrels or cover with fine-mesh insect screen
- Avoid clogged gutters