The brown dog tick opens up habitats in Germany

Temperatures around 25 degrees Celsius, dry and preferably a dog in the household. If the brown dog tick had to post a housing request, these would be its preferences.Originally native to North Africa and the Mediterranean, Rhipicephalus sanguineus, as it is scientifically called, also nests in living rooms and can become a nuisance there. As a vacation souvenir on their own dog or on imported dogs, the arachnid arrives more and more often in Germany. Occasionally, specimens of this species have also been found on dogs that have never been abroad. In Switzerland, the brown dog tick can be found in the wild. And also in the Netherlands individual representatives were sighted. The question arises whether the warming in our latitudes leads to the fact that the brown dog tick can go through its development cycle over egg, larva, nymph up to the adult animal in the future also in Germany, outside, or as "indoor tick" also in dwellings.

A Citizen Science project should help to clarify these and other questions. Ute Mackenstedt and Katrin Fachet from the University of Hohenheim are asking for the help of dog owners and people interested in ticks. If a suspicious specimen is sighted, an e-mail should first be sent to the University of Hohenheim with a photo, date and location of the tick."The prior examination by photo makes sense, because from carpet lint, skin crusts, bugs to mouse intestines, we have already received all kinds of curious sent," says Fachet. For the dispatch of collected specimens, a well-sealable container should be chosen. A simple envelope is not suitable. In Hohenheim, sometimes only bloodstains arrived or surviving arachnids escaped. The ticks should also not be fixed with scotch tape or glue, this makes it more difficult to determine their species.

In Hohenheim, the geographical origin of the parasites is documented and they are examined for pathogens. The brown dog tick can transmit unicellular parasites such as Babesia or Hepatozoon canis and bacterial pathogens such as Ehrlichia to dogs. TBE or Lyme disease pathogens have not yet been detected in this tick species."Although dogs are its preferred host, humans are also occasionally bitten. When it needs a blood meal, it is not choosy," Mackenstedt says. In this way, the brown dog tick could potentially also pass on the pathogens for Mediterranean spotted fever.

"In a study from Italy, the tick species was also found to pass to cats when no dog is available," Fachet reports: The nymphs also infest rabbits and smaller rodents. The brown dog tick is quite "gregarious": often several suck in one place, especially like in well-blooded body areas of the dog with thin skin.Preferred residence in homes is the dog's sleeping area. After a blood meal, the tick leaves its host and hides in cracks and crevices of walls or floorboards and under carpets. A female tick can lay between 1500 and 4000 eggs. The worst case Fachet has seen was hundreds of nymphs nesting in a natural stone wall in a living room. "But that represents an absolute exception; in most cases, dog owners discover a suspicious tick on their pet and contact us seeking help."Fachet takes up to two hours of driving to provide on-site assistance. Adult representatives of the brown dog tick can persevere for up to a year without a meal, nymphs for several months. So far, Katrin Fachet has analyzed 21 finds of the brown dog tick in more detail.

Amber chains, garlic and coconut oil are not effective

A study on variegated ticks proves how successful citizen science projects can be. From February 2019 to February 2020, a total of about 3900 dermacentor ticks were sent in by citizens. Of these, about four-fifths could be identified as an alluvial tick, Dermacentor reticulatus, and most others as a sheep tick, D. marginatus.The collected ticks had been sent in from all federal states except Hamburg. It was shown that the floodplain tick was able to significantly expand its range, especially in northern Germany. The results of the study also prove that adult Auwald ticks are active all year round and they can also transmit Babeiose. Dogs should therefore be protected from ticks all year round.For prevention, active substances from the pyrethroid group are suitable, which are mostly contained in collars and spot-ons. They keep ticks away and kill them. For dogs that swim regularly, tablets containing other active ingredients are more suitable. Veterinärzt:innen advise the most suitable preparations. Amber necklaces, garlic and coconut oil are not effective, as evidenced by cases of babesiosis in dogs this year. Undetected, babesiosis in dogs can be fatal.

Image by Jerzy Górecki