As soon as the temperatures rise, the tick season begins - sometimes quite early in the year. "We already had phases this year where ticks were already active in places," says Gerhard Dobler from the Bundeswehr Institute for Microbiology in Munich. In general, there is a shift in activity forward, explains the expert. "This is also reflected in the fact that TBE cases occur earlier."
Only at the beginning of the month did the Robert Koch Institute (RKI) identify three new German TBE risk areas in Bavaria and Saxony. Tick-borne encephalitis (TBE) is an inflammation of the brain. Ticks can transmit the virus. Most infections are asymptomatic. The risk of serious illness is significantly increased in people over 60 years of age. In the first phase, there are often flu-like symptoms, later inflammation of the brain, meninges or spinal cord can follow.
According to the RKI, there is a risk of infection above all in Bavaria and Baden-Württemberg, in southern Hesse, in south-eastern Thuringia, in Saxony and since last year also in south-eastern Brandenburg. There are also individual risk areas in other federal states. In the risk areas, the Standing Vaccination Committee (Stiko) recommends a TBE vaccination.
Ticks can also transmit the pathogens that cause Lyme disease, which often occurs hours after the act of sucking. According to the RKI, it is much more common and occurs throughout Germany. The first symptom is often increasing redness around the puncture site.
Not only in southern Germany, but also in the Czech Republic, Austria and Switzerland, despite vaccination, there has been an increase in TBE numbers since 2015, says Dobler. “We believe that climate change plays a role in this. We just don't know how yet."
Dobler and his team are currently collecting ticks in the risk areas to examine them for the virus. As early as February, he discovered ticks in a Munich park, says Dobler. In his opinion, the climate crisis could also be responsible for the increase in TBE cases at higher altitudes.
The expert Volker Fingerle from the Bavarian State Office for Health and Food Safety in Erlangen thinks it is likely that the most common tick species in this country, the common wood tick, could spread further in northern Europe. Individual studies have already provided indications that this occurs more frequently at higher altitudes. "But that requires long-term studies."
According to him, there are more than 20 different tick species in Germany. There are around 900 worldwide. With global warming, new species could also gain a foothold in this country, says Fingerle.
An example is the so-called Hyalomma giant tick, which is native to the arid and semi-arid areas of Africa, Asia and southern Europe. Migratory birds bring them to Germany. This tick usually dies in winter because it can't stand the cold, says Fingerle. "We will certainly be faced with the fact that the climate will be such that it will survive the winter or that it will adapt." Even if this is not yet established: the first hibernating Hyalomma ticks have already been detected in Germany, as the University of Hohenheim announced in 2019 - five in a horse farm in North Rhine-Westphalia, one on a horse in Lower Saxony.
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