Ticks

Due to their way of life, ticks frequently transmit pathogens between hosts, but without themselves becoming ill. More types of pathogens are involved than in any other parasitic animal group. Threat to humans exists through transmission of the pathogens for:

• Lyme disease
• early summer meningoencephalitis (FSME)
• Rickettsial diseases
• Tularemia (Dermacentor species)
• Babesiosis (Ixodes species; malaria-like disease)
• Human granulocytic anaplasmosis (human granulocytic ehrlichiosis)
• Neoehrlichiosis (very rare, 10 cases known in Europe)

A tick bite is a process that should be taken into account. The most important carriers in Central Europe are the species of the genus Ixodes with the most common native species, the so-called "common wood tick"(Ixodes ricinus), also the genera Rhipicephalus, Dermacentor, Haemaphysalis, Amblyomma and from the family of leather ticks the genera Argas and Ornithodorus.

Ticks (Ixodidae) are a superfamily within the mites (Acari) with leathery skin that belong to the class of arachnids. Ticks are among the largest mite species. Most species are ectoparasites (they do not penetrate inside the host). Birds, reptiles and mammals serve as hosts. There are about 650 tick species worldwide (see also pigeon tick).

Ixodidae lay eggs in various protected places such as the undersides of blades of grass. Six-legged larvae hatch from these eggs. After a few days, they look for an intermediate host (rodent), attach themselves to it and ingest blood within two to three days. After sucking, they drop off and moult after a few months at the end of their development to form the first eight-legged nymph, which is around 1.5 to 2 millimeters in size. This in turn looks for another intermediate host (cat). They then enter a dormant stage until the following spring. Only after this break do they look for another host. They then moult again to become a second nymph (leather tick) or an adult (shield tick). The adult tick then infests the final host (humans, cattle). This is followed by mating with the female. This lays up to 3,000 eggs shortly afterwards. The male ticks die after mating, the females only after laying their eggs.

The tick scores the skin with its paired mouthparts (so-called chelicerae) and pushes the hypostome (biting apparatus) into the wound. This is symmetrically covered with barbs. However, they only pierce the skin superficially and then "lick up" the emerging blood. The process is colloquially referred to as a "tick bite", but the correct term is "tick bite". The technical term for this type of bloodsucking is telmophagy (pool sucking).

The infection of ticks with Borrelia burgdorferi rarely occurs transovarially. Instead, the larvae become infected via a blood meal from infected mice. The mice themselves form the largest natural reservoir.

For the transmission of TBE, north-eastern and eastern Europe are considered to be the regions with the highest transmission risks of TBE. The risk zones include Bavaria, Baden-Württemberg, parts of Hesse, Rhineland-Palatinate, Thuringia, regions in Austria, Switzerland, Northeast and Eastern Europe, and Asia. The highest TBE risk in Europe, with several hundred cases per year, is found in the Baltic States, Slovenia, and the Czech Republic. Travelers in endemic areas are recommended to be vaccinated (information from the Center for Travel Medicine CRM).

1. An attached tick should be removed as soon as possible after discovery.
2. The tick is best grasped with fine tweezers or tick forceps as close to the skin as possible (not on the body, as this can cause pathogens to be squeezed into the wound) and slowly pulled out of the skin. Thorough removal of tick remains (usually the so-called hypostome of the tick). Thoroughly disinfect the puncture site afterwards. The use of oil or nail varnish for removal is not recommended because it is not certain that these procedures do not accelerate the penetration of germs. On the contrary, it can be assumed that aggressive agents cause the tick to release secretions and thus possible pathogens more quickly.
3. Smaller ticks: Often small ticks cannot be safely grasped with tick tweezers. In this case, professional removal with a scalpel is recommended. The blunt side of the blade rests on the patient's skin and the tick is levered out.

4. If a remnant of the biting apparatus (often misinterpreted as a "head") remains in the skin, this can be removed with a sterile needle or curette. As far as the transmission of Borrelia is concerned, leaving the "biting apparatus" in the skin is harmless.

5. In principle, ticks can also be removed by means of a punch biopsy under local anesthesia. This procedure is recommended if the infected person has already manipulated the tick in some other way. There is no risk of the tick being crushed or tick remains remaining in the skin.
6. Carefully search the body and, in the case of children, especially the head for other ticks.
7. Lyme borreliosis can be completely cured in the early stages with antibiotic therapy in line with the guidelines. This prevents late manifestations.
8. It is not advisable to test the tick for borrelia, as if the result is positive, it is not certain whether the borrelia have been transmitted into the skin at all and whether they will lead to a disease if they are transmitted. A negative result does not rule out transmission.
9. Only a small proportion of people infected with Borrelia get sick! For this reason, preventive oral antibiotic therapy is not advisable.

• Wear sturdy shoes.
• Wear light-coloured clothing to better detect ticks.
• Walking on paths instead of in the field.
• Putting socks over your trouser legs.
• Examination especially of children after walks or hikes in the wild.
• Rubbing the lower legs, wrists and neck with insect repellent e.g. Zanzarin Bio-Lotion or Nexa Lotte Skin Protection Milk (the effect lasts up to 6 hours).
• Garlic: In studies, taking garlic capsules has been shown to reduce the tick bite rate in endemic areas by about 30%. Alternative: use of garlic spray.

Leather ticks often live close to their hosts and prefer rather dry dark shelters. Particularly well suited conditions are provided by forest edges and clearings with tall grasses, wet meadows and brook margins with similar vegetation, and also deciduous or mixed forest with grassy or herbaceous undergrowth. They normally carry out their activities from March to October. Their life span is between two and five years. Ticks can survive a full wash of clothing, so a tick bite can occur long after a walk in the forest.

In the next few years, tropical tick species of the genus Hyalomma could also spread to Central Europe. These tick species can carry the bacterium Rickettsia aschlimanni, the causative agent of spotted tick fever. Individual specimens have been found in Germany.

Ixodes inopinatus from the Mediterranean region has now spread as far as Denmark.

Rhipicephalus sanguineus, the "brown dog tick", originally native to Africa, has also been discovered on Hunades in Central Europe.

1. Carroll J (2007) Tough: Ticks survive the full wash cycle. Close to the skin 6: 318 (see also http://www.ars.usda.gov/is/pr/2007/071005.htm)
2. Laursen K et al (2003) Tick-borne encephalitis: a retrospective study of clinical cases in Bornholm, Denmark. Scand J Infect Dis 35: 354-357
3. Lesnicar G et al (2003) Pediatric tick-borne encephalitis in 371 cases from an endemic region in Slovenia, 1959 to 2000 Pediatric Infect Dis J 22: 612-617
4. Oehme R et al (2002) Foci of tick-borne diseases in southwest Germany. Int J Med Microbiol 291(Suppl 33): 22-29
5. Perkins SE et al (2003) Empirical evidence for key hosts in persistence of a tick-borne disease. Int J Parasitol 33: 909-917
6. Spitalska E et al (2003) Tick-borne microorganisms in southwestern Slovakia. Ann NY Acad Sci 990: 196-200
7. Stjernberg L et al (2000) Garlic as insect repellant. J Am Med Assoc 284: 831
8. Thuile T et al (2015) Cutaneous and systemic Lyme disease. Act Dermatol 41: 234-241