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Disease vector: Tropical Hyalomma tick hibernates in Germany for the first time
In the past few days, several specimens of the tropical Hyalomma tick have been sighted in Germany. Researchers are convinced that the newly immigrated species hibernated for the first time in the local area. The animals can transmit life-threatening diseases.
Carrier of dangerous infectious diseases
In recent months, health experts have increasingly warned of an increasing risk from ticks. The small bloodsuckers can transmit infectious diseases such as Lyme disease and early summer meningoencephalitis (TBE). In the meantime, non-native species have also been sighted here. In the past few days, six specimens of the tropical Hyalomma tick have appeared in Germany. Researchers are convinced that the animals have hibernated in the local areas for the first time.
Twice to three times the size of European species
As the University of Hohenheim reports in a recent release, five hyalomma ticks and one on a horse in Lower Saxony were found in a horse farm in North Rhine-Westphalia.
"We have the first evidence of Hyalomma ticks in Germany this year," said Prof. Dr. Ute Mackenstedt from the University of Hohenheim. "And this time we have to assume that these animals could spend the winter here in Germany."
According to the information, the striking animals with the curled legs are twice to three times the size of their European relatives.
Population called for help
Last year, tick researchers detected animals of the genus Hyalomma in large quantities for the first time.
Prof. Mackenstedt then had together with PD Dr. Gerhard Dobler and Dr. Lidia Chitimia-Dobler from the Bundeswehr Institute for Microbiology in Munich asked the population in February to send in possible finds of Hyalomma ticks.
Now they found what they were looking for.
"Both finds were made in the last few days, practically at the same time," says PD Dr. Dobler. "We therefore assume that the three hot days were responsible for the fact that the heat-loving Hyalomma ticks were now active in different locations at almost the same time."
Tropical ticks can overwinter in this country
But while the specimens were most likely introduced with migratory birds last year, this should not be the case this time.
"The juvenile stages of the ticks, the larvae and nymphs, can often be found on migratory birds," explained Prof. Mackenstedt. "Then you just drop off."
However, the animals found now appeared relatively early in the year. "If you look back at the development cycle, they should have been brought in at a time when the migratory birds weren't there yet."
According to the scientists, two Hyalomma species were detected last year, H. Marginatum and H. Rufipes.
In this year's ticks, the exact species identification is still pending, "but we suspect that all are H. Marginatum," says Dr. Lidia Chitimia-Dobler.
"The species mainly comes from Turkey and Eastern Europe, which is why it is more adapted to our climate than H. Rufipes from Africa."
There is the possibility of creating an independent population
Wintering does not necessarily mean that Hyalomma has already become at home in Germany.
"In order for a population to develop, males and females would have to be found," said Prof. Mackenstedt.
“This is difficult with a small population size. In addition, larvae and nymphs would have to develop that birds or rabbits need as hosts. We do not yet know whether and how this works. We have to keep an eye on that. "
However, the discovery of five Hyalomma ticks in a single horse farm suggests that several individuals were present there at the same time and that there was therefore the possibility of mating and the emergence of an independent population.
The researcher is therefore also targeting other tropical ticks. For example the brown dog tick Rhipicephalus sanguineus:
“It is originally from Africa. But we assume that this tick will be transported to Germany with dogs. Specimens have already been found on dogs that have never left their farm, ”said the expert.
"This meant that they could not be an unintentional holiday souvenir - an indication that the species could possibly already develop here."
Background information on the tick genus Hyalomma
As explained in the University of Hohenheim communication, Hyalomma marginatum and Hyalomma rufipes are originally native to the dry and semi-arid regions of Africa, Asia and Southern Europe.
The animals have so far not been found in Central and Northern Europe. With their striped legs, they are a striking appearance, significantly larger than the normal wooden trestle.
In the Eurasian region, both species are considered to be important carriers of the virus of the Crimean-Congo hemorrhagic fever and the Arabic hemorrhagic fever (alkhumra virus).
Crimean-Congo fever also appears on a list of diseases and pathogens that, according to the World Health Organization (WHO), "pose a public health risk and for which there are no or inadequate countermeasures," as the organization writes on its website .
Accelerated research is urgently needed for these diseases "given their potential to cause a public health emergency and the lack of effective medicines and / or vaccines".
According to the University of Hohenheim, the Rickettsia aeschlimannii bacterium, which triggers a form of tick-spot fever, can also be transmitted by these ticks.
The adult ticks, which suck blood mainly from large animals, can actively move towards their host and cover a distance of up to 100 meters.
Humans are also potential hosts of animals. Larvae and nymphs, on the other hand, are mainly found in birds and small mammals. They stay on their host for up to 28 days and can thus be brought to Germany with migratory birds. (ad)