The many species of mosquitoes in Germany are difficult to distinguish from one another for the average person. Does the annoying “tzz” come from a domestic mosquito, or from the Asian tiger mosquito? The difference can be significant – if the mosquito bites. Because the tiger mosquito can transmit a number of dangerous pathogens such as dengue and chikungunya viruses.
The Asian tiger mosquito originates in the tropics, but has spread significantly in southern Europe and parts of central Europe since the 1990s as a result of climate change, such as Friedrich Loeffler Institute he is called. Local breeding was first discovered in Germany in 2014. There are now well-established populations, says mosquito expert Doreen Werner of the Leibniz Research Center for Agricultural Landscapes (ZALF). Mainly in Bavaria and Baden-Württemberg, but also in Hesse, Thuringia and Berlin.
Just a matter of time
So far, no cases have been known in Germany of the disease being transmitted through the bite of the tiger mosquito that lives here – but experts believe it is only a matter of time due to climate change. In the south of France, for example, Zika infection from tiger mosquitoes native to the area has been reported several times. Dengue fever has been confirmed in Madeira, Croatia and France, for example. Chikungunya also spread in the Mediterranean region.
The European Union’s health authority ECDC recently warned of an increased risk of mosquito-borne diseases. The Asian tiger mosquito is widespread in northern and western Europe. The number of affected regions in the European Economic Area (EEA) has nearly tripled in ten years. Unlike native mosquitoes, white-striped animals often use small water tanks, for example in flower pot dishes, and are particularly common in urban areas – even in large cities such as Berlin.
Local temperatures are sufficient for the dengue virus
If a tiger mosquito bites an infected person, the absorbed viruses can multiply in the insect and pass on to other people if the mosquito bites again. However, the decisive factor here is not just the presence of mosquitoes: according to experts, Zika viruses, for example, need a lot of heat to be able to multiply well in mosquitoes, with temperatures rarely reached in Germany. far. On the other hand, dengue virus can reproduce well in mosquitoes even in moderate temperatures. The pathogen causes long-term problems in the joints, for example in the hand, which is often misjudged as a rheumatic disease.
In addition, exotic mosquitoes are not the only potential carriers of dangerous diseases in Germany: in 2019, the Robert Koch Institute (RKI) recorded infections with West Nile virus, which originally came from Africa, in patients in Germany for the first time. , indicating transmission by indigenous mosquitoes. Since the pathogen can hibernate in mosquitoes in Germany, experts expect an increasing number of cases amounting to larger seasonal waves of the disease. Such outbreaks have been occurring in southern and southeastern European countries for years.
17 injuries in West Nile last year
According to the RKI, 17 West Nile infections were detected in people in Germany last year, compared to 4 in the previous year. West Nile virus infection is asymptomatic in 80 percent of cases, and thus is never recognized. According to the RKI, approximately 20 percent experience mild, nonspecific symptoms such as a fever or rash. These often go unnoticed. The most severe and fatal courses usually affect the elderly with pre-existing illnesses. Only about one percent of infections lead to such severe invasive neurological disease. Since tests and therefore reliable evidence are usually only provided in such cases, if they are provided at all, an alarmingly high number of annual infections can be assumed for Germany.
Tropical medicine gives it all
So in the future, should we be afraid of every mosquito bite, maybe sleep under mosquito nets soon? “Having concerns about every mosquito bite is definitely overrated at the moment,” says tropical medicine specialist Thomas Jelinek. “It’s a serious disease, but you don’t have to expect a widespread occurrence in Germany.” However, it is very likely that there will also be smaller West Nile outbreaks in this country in the future.
It is unclear when the first dengue infection, transmitted by the tiger mosquito that lives here, will be noticed. Werner stresses that destroying existing insect populations is important. She has been in charge of the so-called Mosquito Atlas since 2012 and is investigating He finds mosquitoes from all over Germany. Citizens who find a mosquito can capture it, freeze it, and mail it to Werner and her team.
Tiger mosquitoes “laugh” at our winter
The northernmost place in Germany where the tiger mosquito has been found is Berlin. In the fall of 2019, a first sample arrived at the institute by mail from an allotment park in the Treptow-Köpenick district. In the years that followed, animals were also found there. “The mosquito has now adapted so well that it’s laughing at our winter,” Werner says.
This year, the world didn’t have a tiger mosquito in the mail. However, this is not surprising: the season does not begin until the end of June or the beginning of July and continues until September or October, depending on the temperature. Do we have to get used to the occurrence of invasive mosquito species? “You’ll gain weight, it’s only a matter of time,” says Werner. Education and prevention are needed.