Scientists warn: 2018 will be the ‘year of the tick’
This summer there will be a particularly large amount of ticks and thus a higher risk of getting meningitis or Lyme disease (borreliosis), because these diseases are transmitted by ticks. Scientists from DZIF (German Centre for Infection Research) in Munich predict a particularly strong ‘tick year’. They have developed a model that allows them to already in winter predict the density of ticks for the coming summer.
A summer stroll through the forest or through the garden can have unpleasant consequences. Because bushes, shrubs and grasses contain ticks, usually the common castor bean tick, Ixodes ricinus, which patiently waits for a vertebrate, for example a human, to come by and take it with him. If it finds a place of bare skin, then it bites and sucks blood until it almost bursts. However, with its saliva, it returns some of the blood, and in some cases along with unpleasant cargo. Thus, the castor bean tick is the main transmitter of the tick-borne encephalitis (TBE), a viral meningitis that can be fatal. Lyme disease is also transmitted by this species of ticks. While there is no cure and only preventative vaccination for TBE, there is no vaccine for Lyme disease, but only a treatment option with antibiotics. In any case, it is advisable to look out for ticks, especially in TBE risk areas. These are areas, where more ticks are infected with viruses than anywhere else. You can find the affected regions of Germany on the website of the Robert Koch Institute: TBE high-risk areas.
‘Overall, the risk is particularly high this year’, says associate professor Dr Gerhard Dobler. ‘We will see the highest number of ticks in the last decade.’ Since 2009, the DZIF scientist and his team at the Institute of Microbiology of the German Federal Armed Forces 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 at a source of infection in southern Germany. For this project, they meticulously collected monthly the nymphs (a developmental stage of the ticks before growing into adults) of castor bean ticks. Less than a millimetre, these nymphs are only recognisable as black dots and are often overlooked. This makes them particularly dangerous because even at this stage of development, they can transmit diseases. The scientists were able to show that the selected source of infection in southern Germany displays a model character. ‘If we find a large amount of ticks here, then we can find these high numbers elsewhere in southern Germany,’ explains Dobler.
Complex predictive model confirmed
‘Using the tick data from our model source and 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 summer,’ explains Dobler. The model of the research teams from Munich and Vienna are based on the number of beechnuts two years before the current summer as well as the average annual temperature and the winter temperature in the previous year. The more beechnuts there are two years before the summer in question, the more wild animals and rodents have food and serve as carriers of the ticks, which then also appear in larger numbers. Dobler and his colleagues have already been able to successfully use and confirm the connections in their complex model. For the summer of 2017, they had predicted 187 ticks per standardised area and actually found 180. Almost perfectly on point! For 2018, the highest number of ticks ever found was predicted with 443 ticks, and Dobler is now confident that this prediction will also be met exactly. ‘We have the highest number of ticks we have collected since the beginning of the study - good for the ticks, bad for us.’
Preventing 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. The only thing helps prevent it is to stay vigilant during forest walks and outdoor stays. The faster the tick is removed, the lower the risk of Lyme disease. Scientists warn that, in order to prevent the risk of meningitis, everyone can and should be vaccinated. 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 always finds things that go far back in history. At least one of these exciting discoveries from recent times should be mentioned here: They found a tick caught in a spider's web, smothered to death by spider silk. This dramatic event happened about 100 million years ago and was encapsulated and recorded for posterity in amber.
