Berlin (dpa) - The Asian tiger mosquito, which can transmit tropical diseases in Europe, has probably spread little in Germany this year.

"We only know two new populations in Bavaria. One in Munich and one in Fürth, "said Doreen Werner, a mosquito researcher at the Leibniz Center for Agricultural Landscape Research in Müncheberg in Brandenburg (Zalf). In addition, evidence has been given only to previously known sites, for example in Frankfurt (Main), Heidelberg, Freiburg, the Oberrheingraben and Jena.

Tiger mosquitoes can transmit tropical pathogens such as Zika, Chikungunya and Dengue virus. For Germany, this is still considered unlikely, because the viruses - except for Chikungunya - can only multiply well in the mosquitoes at high temperatures. In southern France, however, the first Zika cases in Europe were reported this week, which were transmitted by local tiger mosquitoes. This virus is especially dangerous for pregnant women as it can lead to brain and skull malformations in the unborn child.

There is no representative overview of the tiger mosquito stocks in Germany. For evidence of populations, the scientist Doreen Werner relies on the help of the population for the research project "Mosquito Atlas". Anyone interested can send dead mosquitoes - of whatever kind - to the Zalf in Müncheberg. There, all bloodsuckers are determined in collaboration with the Friedrich-Löffler-Institute for Animal Health. So far, private mosquito hunters sent in around 24,400 animals. There are an estimated 50 different mosquito species in Germany, around 3500 worldwide.

Asian tiger mosquitoes were not native to Germany before. That has changed with climate change. Theoretically, tiger mosquitoes could even survive in northern Germany, explained Werner. This had shown controlled tests on the Baltic island of Riems. The bloodsuckers in the north have not yet been proven.

Tiger mosquitoes are striped white. They circle their victims in swarms, pursue them obtrusively and attack even when shooing after a few seconds again. If Doreen Werner receives a dead copy, she usually drives straight to the place of discovery. Sometimes it is a false alarm and tiger mosquitoes, for example, have entered in a car after returning home. But if there is a population, local authorities will be advised to combat it. Some stocks have been eliminated and disappeared from the map in the mosquito Atlas.

In the fight against mosquitoes, the help of the population is in demand, stressed Norbert Becker of the community action group for the control of Schnakenplage (Kabs) in Speyer. From the rain barrel over the watering can to the bird drinker - open water points in gardens are breeding grounds for mosquitoes and would have to be dried out or covered. The expert also recommends so-called BTI tablets for rain barrels. The biological agent destroys the intestine of mosquito larvae and kills them. Especially with the tiger mosquito attention is required. "It's important that everyone participates. One or two plots of land can contaminate entire areas. »

The researchers also want to stem the spread of the species with the help of sterilized males. Some 100,000 copies have been released between April and October. "It seems to work very well," says Becker.

In a representative survey on behalf of the health insurance KKH, exotic mosquitoes in Germany have the potential for anxiety: just under half (43 percent) of respondents are concerned about the transmission of dangerous diseases. In 2019, around 1000 people aged 18 to 70 years were interviewed.

mosquito Atlas

Map on the spread of the tiger mosquito in Germany