More hiking, cycling or more frequent picnics: Corona is changing leisure behaviour, driving people out into nature. However, bloodsucking ticks are already waiting there. Are the rising TBE numbers just a trend? Or a development?
Climate change and the consequences of the Corona pandemic caused the number of tick-borne encephalitis (TBE) cases in Baden-Württemberg to skyrocket to a record high last year. In 2020, a total of 350 cases of TBE were reported to the State Health Office from 38 of 44 districts in Baden-Württemberg. This is more than twice as many as in the previous year with 171 cases and the highest value since 2001, the Ministry of Health announced.
Apart from the city district of Heilbronn, the entire federal state is designated as a TBE risk area by the Robert Koch Institute (RKI). Last year, most TBE cases were registered in the districts of Freudenstadt (28) and Ravensburg (23) as well as in the Ortenau district (27). In contrast, no cases were reported in Heilbronn, in the districts of Schwäbisch Hall, Neckar-Odenwald and Rhine-Neckar, and in Heidelberg. According to the University of Hohenheim in Stuttgart, the number of cases also reached an all-time high nationwide. According to the RKI, however, the annual number of TBE cases has also fluctuated greatly since 2001.
"As a cause for this dramatic trend, we can partly blame Corona," said Gerhard Dobler from the Institute of Microbiology of the German Armed Forces (Institut für Mikrobiologie der Bundeswehr, Munich). This is because the numbers of TBE cases reported to the RKI depend, among other things, on people's leisure behaviour. People now spend more time outdoors, so the risk increases.
However, as a result of climatic changes, certain tick species are now looking for hosts to bite earlier, said Dobler. This increases the risk for people to fall ill earlier in the year with pathogens transmitted by ticks, warned the head of the Department of Virology and Rickettsiology.
Most people infected with TBE remain symptom-free. But in severe cases, this viral disease can lead to brain inflammation and damage the spinal cord. Until a few years ago, it was mainly the common wood tick (Ixodes ricinus) that was considered the culprit. "But it is no longer only the common wood tick that can transmit TBE," the university announced. According to the RKI, the TBE virus has now also been detected in alluvial ticks. Researchers are monitoring both arachnids. Further figures on the diseases and new developments will be published by experts from Hohenheim and elsewhere on 10 March.
With the exception of a few districts, the disease is particularly widespread in southern Germany, as far as Hesse, Thuringia and Saxony. Vaccination is recommended for people who spend a lot of time in nature and are at risk of tick bites. It should be started early, before summer, because there must be enough time between the three vaccination dates. In risk areas such as Baden-Württemberg and Bavaria, the costs are covered by the health insurance companies. In contrast, there is no medication for the treatment of TBE.