Ticks: First typhus transmission in Germany

Half of the hyalomma ticks in Germany carry the typhus pathogen

The tropical hyalomma tick can spread typhus pathogens to humans - a first case is now also available in Germany. © University of Hohenheim / Marco Drehmann
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Worrying precedent: For the first time a man in Germany has been infected with typhus by a tick bite. The carrier was a tick-borne hyalomma tick - originally a tick species only found in warmer countries. Meanwhile, however, their number is increasing in this country and about half of these animals carries the typhus pathogens, as researchers report.

Thanks to global warming, more and more species of mosquitoes and ticks are spreading to us, originally only native to tropical regions. In addition to the tiger mosquito and the bush mosquito, they also include the brown dog tick and the hyalomma tick. The latter even winters in Germany. The problem: many of these newcomers can transmit pathogens from tropical diseases. As early as 2018, a hyalomma tick with typhus pathogens had been detected in Germany for the first time.

A horse owner was the first to hit it

Now there is the first case of transmission of typhus pathogens from the hyalomma tick to humans. "Not only do we now know for sure that the hyalomma tick also affects humans, " says Ute Mackenstedt, a parasitologist at the University of Hohenheim. "Unfortunately, there is also the urgent suspicion that transmission of tick-borne fever by the animals is actually possible here in Germany."

In the present case, a horse owner was bitten by a hyalomma tick in July 2019. He then sent the exotic belt terin to the parasitologists in Hohenheim. A few days later, however, he got a fever, pain and rashes - suspected tick typhus fever. After the Rickettsia aeschlimannii pathogen was detected in the tick, the doctors treated the patient with special antibiotics and the symptoms returned.

First case of a transfer

"The immediately preceding tick bite, the typical symptoms and above all the detection of the pathogen in the tick suggest that the case was tick typhus, " says Gerhard Dobler from the Institute of Microbiology of the German Armed Forces (IMB) in Munich. Also, the fact that antibiotic therapy struck immediately underlines this. There is now another type of tick in Germany that can transmit diseases to humans. display

"The fact that we are talking about a suspected case is because direct detection of the pathogen on the patient was not possible, " says Dobler. "The treatment of the patient was simply in the first place." That it first hit a horse owner, was probably no accident: Tropical ticks of the genus Hyalomma suck especially on large mammals.

Half of the ticks carry typhus pathogens

The rate of infection of the hyalomma ticks is relatively high in this country: About half of the hyalomma ticks are infected with rickettsia, the researchers report. "If typhus fever is suspected after a hyalomma sting, a swab should be taken at the sting site and sent back for examination, " says Dobler. "If you are unsure, you are welcome to contact us. Ideal, of course, is if we can examine the tick. "

The typhus causes a feverish infection with headache and muscle pain, extreme joint pain and a feeling of being burned. Also typical of the disease is the eponymous rash, which is especially evident in the extremities. The incubation period is about one week.

Hyalomma ticks are becoming more common in Germany

After all, the tropical ticks so far seem to carry no other pathogens in themselves: "Rickettsia are the only pathogens that we have been able to detect, " emphasizes Dobler. Although hyalomma ticks can transmit the causative agent of the hemorrhagic Crimean Congo fever, so far no ticks have been found in Germany with this virus. The pathogens that are dangerous for horses, Theileria equi and Babesia caballi, were also not detected, as Dobler reports.

In the meantime, the hyalomma tick has not only survived the local winters, it is also becoming more common: After the Hohenheim researchers identified a total of 35 of these tropical ticks last year, by 2019 there are already 50 individuals. Most were reported or sent to scientists from the population. They continue to ask for reports of unusual ticks.

Hyalomma is actively hunting

With their striped legs, the hyalomma ticks are a striking feature, they are also much larger than the domestic wood buck (Ixodes ricinus). The adult hyalomma ticks suck blood especially on large animals such as horses or deer, but also man is a potential host. In contrast to the more passive for a host waiting wooden goat, the hyalomma tick is an active J ger. She walks quickly towards her host and can cover distances of up to 100 meters.

The research team continues to ask the population for support to further explore the spread and potential dangers. If you find a tucked tick, it's best to remove it like a local tick with tick tweezers, tick card or tweezers. Then place the animal in a small, tightly closed container and send it to the tick researchers. You will find the address and further information on packaging on this website.

Source: University of Hohenheim

- Nadja Podbregar