How to protect yourself from ticks

As in all of Europe, more than 90 percent of all ticks belong to one species: the common wooden goat (ixodes ricinus). The best-known shield tick is responsible for the transmission of Lyme Borrelia and TBE viruses-the causers of Lyme Borreliosis and early summer meningoencephalitis (TBE).

« The common wooden buck loves a damp, shady microclimate, » says expert Dania Richter. « He likes to lurk on grass and shrubs. » On the other hand, sunny, dry locations avoids the species that measures two to four millimeters in the adult stage.

With his hosts, the tick is less picky. « The wooden stone sucks pretty much on everything except for fish and amphibians, » says Richter. In rodents in particular, these mites, which are three to five years old, can infect themselves with many pathogens, which also affect humans, especially different Lyme Borrelia. Several types of these bacteria can make people sick – if they manage to infect them.

Infection only many hours after a stab

Because that takes, as judge explains. Usually the bacteria remain inactive in the middle intestine of the ticks, attached to the intestinal wall through their surface protein OSPA.

Only when you come into contact with the tank and blood of the host after the tank stitch do you multiply, rave out in the body and also reach the salivary glands. With the saliva that the tick releases into the wound – for example to prevent blood clotting and inflammatory reactions – you get to the host.

« About 16 to 20 hours after a stitch, the likelihood of a Borrelia infection increases, » says Richter. « This offers us the advantage of prevention. » If you look twice a day during the tick season, the risk of lyme disease is minimized.

The transmission of TBE is different: « The viruses are transferred shortly after the sting, » says RKI epidemiologist Antonia Pilic. Because these pathogens are already in the salivary glands.

Number of annual cases fluctuates strongly

Is the number of diseases in Europe transmitted by ticks? This question can hardly be answered, because from year to year the number of Borreliosis and TBE cases fluctuates considerably. This depends, for example, on the climate, also on the frequency of the hosts, especially rodents in which the ticks infect themselves, and last but not least, people's leisure behavior also plays a role.

« The number of infections is extremely environmentally dependent, » says Volker Fingerle, head of the National Reference Center for Borrelia in Oberschleißheim near Munich. A simple example: « If people go out little because it rains a lot, there are fewer cases. »

Diagnosis of Lyme disease is often difficult

In addition, the diagnosis of Lyme disease is often difficult: Because the symptoms are diverse and rarely clear depending on the affected body region-skin, joints, nervous system, heart.

In principle, antibody tests only show that someone was in contact with Borrelia: According to Fingerle, this applies to about ten percent of the population. And not every infection leads to an illness.

« The diagnosis is typically a puzzle, » says Fingerle, referring to history, symptoms and laboratory diagnostics. Other diseases often have to be excluded.

Lyme disease can be clearly seen on the wings (erythema migrans)-an at least five centimeters in size, which is expanding in a circular redness around the puncture site. According to Fingerle, antibiotics kill the pathogens very efficiently – however, some symptoms could sometimes last.

Lyme Borrelia are widespread across Europe-but this is very variable locally. Depending on the area, five to 50 percent of the ticks are infected, says Richter. On average, around every third to fourth common wooden stone contains Lyme Borrelia. According to a message from the Luxembourg government of 2023, the proportion of infected ticks in Germany fluctuates from year to year and from region to region between zero and 30 percent.

TBE risk areas expand

Unlike in other countries, such as Germany, TBE is not subject to reporting in Luxembourg. 686 TBE diseases were reported in the neighboring country of Germany last year-after the record of 718 cases, this was the second highest value since data recording in 2001. However, the numbers fluctuate from year to year, according to RKI.

The disease, which often begins with flu -like symptoms, is rare, but can take a difficult course and ends in about one percent of cases fatal. The average TBE incidence increases significantly from the age of 40; Men are more affected than women.

However, the affected areas, formerly more limited to the south of Germany, extend to the north and east. It was only in February that the RKI showed three new risk areas: in the city district of Augsburg and in the districts of Celle and Elbe-Elster in the south of Brandenburg. There is also a risk area right behind the Luxembourg border: the Saar-Palatinate district has been classified as such in neighboring Saarland for years.

According to RKI, risk areas are circles, in which there were more than one TBE case to 100,000 residents within five years.

Vaccination that the constant vaccination commission (STIKO) recommends for exposed people in risk areas also protects against this disease for professional groups such as forest workers. According to RKI, the three vaccine cans offer protection for at least three years. In Luxembourg, vaccination is recommended for all adults and children aged six and over, which are in forests and areas during the tick season in which the virus can be found frequently- especially in northern and central Europe.

Borreliosis vaccination is currently being tested

There is still no vaccination against Lyme disease – but two admission studies for possible vaccines are currently underway in Europe and North America. The manufacturers Pfizer and Valneva could apply for admission to the VLA15 vaccine in the coming year.

The vaccination, which would probably have to be renewed annually, aims at the surface protein OSPA, with which Lyme Borrelia survive in the tick. The vaccine covers the OSPA types 1 to 6 and is intended to prevent transmission of Lyme Borrelia. According to Fingerle, it is directed against the most important local species, but not against everyone.

The results of the phase-1 and phase-2 studies presented in the journal « The Lancet InfectIoS Diseases » indicate that this new vaccination is safe. The most common side effects were headaches, fatigue and muscle pain. There are no figures on the protective effect.