A real tick year is underway
Researchers sound the alarm: There will be more ticks this summer than usual. There will also be more cases of infectious diseases such as meningitis or Lyme disease. The experts therefore warn that more should be done for preventive protection. Once infected, the diseases mentioned can sometimes cause serious damage.
This summer there will be a particularly large number of ticks and therefore a higher risk of developing meningitis or borreliosis - because these diseases are transmitted by ticks. DZIF scientists predict a “tick year” in Munich. They helped develop a model with which they can predict the tick density in winter for the coming summer.
A summer walk through the forest or through the garden can have unpleasant consequences. Because on bushes, shrubs and grasses there are ticks, usually the common woodbuck, Ixodes ricinus, which waits patiently for a vertebrate, for example a human, to come by and take it with them. Once it has found its place on the skin, it stabs and sucks blood until it almost bursts. However, together with its saliva, it returns part of the blood, and in some cases with unpleasant cargo.
The common woodbuck is the main carrier of early summer meningoencephalitis (TBE), a viral meningitis that can be fatal. Lyme disease is also transmitted by this type of tick. While there is no cure for the TBE, but there is a preventive vaccination, there is no vaccine for Lyme disease, but a treatment option with antibiotics. In any case, it is advisable to watch out for ticks, especially in TBE risk areas. There, more ticks are infected with viruses than anywhere else. In which regions of Germany this is the case, you can find out on the Robert Koch Institute's website: FSME card.
"Overall, the risk is particularly high this year," says Dr. Gerhard Dobler sure. "We will have the highest number of ticks in the past ten years." Since 2009, the DZIF scientist and his team at the Bundeswehr Institute for Microbiology have been researching the spread and activity of the TBE virus in Germany. Over a period of nine years, the researchers documented the number of ticks on an infection focus in southern Germany. To this end, they meticulously collected the common woodbuck nymphs every month - a stage in the development of ticks before they grew up. Smaller than a millimeter, these young animals are only recognizable as black dots and are often overlooked. This makes them particularly dangerous because they can transmit diseases at this stage of development. The scientists were able to show that the selected focus of infection in southern Germany has a model character. "If we have a lot of ticks here, then we also have these high numbers elsewhere in southern Germany," explains Dobler.
Complex prediction model confirmed
"With the help of the tick data from our model range and based on certain environmental parameters, the colleagues at the University of Veterinary Medicine in Vienna were able to develop a model that prepares us for the ticks in the summer," explains Dobler. The Munich and Vienna model includes the number of beech nuts two years before the current summer, as well as the annual average temperature and the winter temperature the year before. The more beech nuts there are two years before the summer in question, the more game and rodents have food and in turn serve as carriers of the ticks, which then also appear more frequently.
Dobler and colleagues have successfully used the relationships in their complex model and have already confirmed them. For summer 2017, they predicted 187 ticks per standardized area and found 180. Almost a spot landing. With 443 ticks, the highest number of ticks ever found was predicted for 2018 and Dobler now knows that this prediction will also be met exactly. "We have the highest number of ticks that we have collected since the start of the tests - good for the ticks, bad for us."
Prevent the risk of infection
More ticks always means an increased risk of getting sick. Lyme disease can be transmitted by ticks throughout Germany and can be found in about every fourth tick - regardless of the region. Only vigilance after forest walks and stays outdoors helps to prevent this. The faster the tick is removed, the lower the risk of developing Lyme disease. In order to prevent the risk of meningitis, one can and should be vaccinated, according to the scientists. Especially in southern Germany, where the density of virus-infected ticks is higher.
Tick dressed in silk
Collecting and mapping ticks is one thing. But the Munich team keeps coming across finds that go far back in history. One of these exciting recent discoveries should at least be mentioned here: the discovery of a tick that has got caught in a spider web and has been covered by the spider silk to death. This drama happened about 100 million years ago. And was trapped and held in amber for posterity. (pm, sb)