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Experts are concerned: Several finds of tropical ticks in Germany
Experts are concerned: Researchers have discovered tropical tick species at various locations in Germany. One specimen carried a pathogen of the dangerous spot fever. The scientists fear that the insects may spread here in the future.
Growing danger from ticks
Only a few weeks ago, a growing danger from ticks had been warned. The small bloodsuckers can transmit infectious diseases such as Lyme disease and early summer meningoencephalitis (TBE). However, researchers in Germany have now discovered species of ticks that are not native to this country. One of these animals carried a pathogen of the dangerous spot fever. This disease can lead to death if left untreated.
A found specimen contained dangerous bacteria
Tick researchers at the University of Hohenheim in Stuttgart and their colleagues at the Bundeswehr Institute for Microbiology (IMB) in Munich have identified seven specimens of the Hyalomma species of tropical ticks this year.
Although the number sounds manageable, it causes the alarm bells to ring among the researchers. According to a statement, the experts fear that the bloodsuckers could establish themselves here.
And another worrying point: One specimen carried a dangerous bacterium, Rickettsia aeschlimannii, a well-known pathogen of the tick spot fever.
Illness can be fatal if left untreated
Spot fever occurs in higher, colder regions of Central and West Africa, South America and Asia, among others.
After an incubation period of ten to 14 days, symptoms such as headache, chills, high fever and body aches can occur.
After about five to six days, there is a red-stained rash, from which the name of the disease was derived.
According to health experts, the untreated death rate is up to 40 percent.
Tropical ticks discovered on horses and a sheep
The researchers from Stuttgart and Munich discovered three of the tropical ticks on a single horse, one on a sheep and three more on three individual horses.
"We were able to determine five of the seven ticks without a doubt, four are from the species Hyalomma marginatum and one from the species Hyalomma rufipes," explains Dr. Lidia Chitimia-Dobler, tick expert at the IMB.
"The horse owner had lost the other two when he collected them," says the scientist.
“We weren't expecting Hyalomma ticks here in Germany at this point in time. So far there have only been two individual finds between 2015 and 2017. "
No species found so far have been found in Central and Northern Europe
Hyalomma marginatum and Hyalomma rufipes are originally native to the dry and semi-arid regions of Africa, Asia and southern Europe. So far they have not been found in Central and Northern Europe.
In the Eurasian region, both species are considered to be important carriers of the virus that causes the Crimean-Congo hemorrhagic fever and the Alkhumra virus, the causative agent of the Arabic hemorrhagic fever.
The bacterium Rickettsia aeschlimannii, which triggers a form of tick spot fever, can also be transmitted by these ticks.
The adult ticks suck blood, especially on large animals. The 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 use the same animal to suckle blood and stay with their host for up to 28 days, so they can be brought to Germany with migratory birds.
Comparatively large animals
The comparatively large animals with the strikingly striped legs had appeared this year in the Hanover area, in Osnabrück and in the Wetterau, probably introduced via birds.
"These types of ticks could find their way into Germany," feared Prof. Dr. Ute Mackenstedt, parasitologist at the University of Hohenheim.
"We will be keeping an eye on her this year and are preparing to meet her more often in the next few months."
More heat-loving ticks due to global warming
However, this development is not surprising for the expert.
“Because of global warming, we can generally expect more and more heat-loving ticks. Ixodes inopinatus from the Mediterranean, for example, has now spread to Denmark. "
The big question now with the two Hyalomma species is whether they are still single introduced specimens or whether the species have established themselves here.
"In another species, the brown dog tick Rhipicephalus sanguineus, originally native to Africa, specimens have been found on dogs that had never left their farm," reports Prof. Mackenstedt.
"This meant that they could not be an unintentional holiday souvenir - an indication that the species could possibly already develop here."
Exotic species could establish themselves in Germany
This must be observed in the future for the Hyalomma species. "We know how long the time it takes the animals to develop," said Dr. Chitimia Dobler.
"This enables us to assess whether they can establish themselves in Germany if global warming continues with increasingly dry and hot periods."
The expert attributes the appearance of hyalomma ticks in Germany in 2018 to the hot, dry summer.
“These ticks prefer a lower humidity than the tick species that we find. This year the local weather is therefore very good for the living conditions of these ticks. "
The pathogens for Lyme disease and TBE have so far not been found in Hyalomma marginatum and Hyalomma rufipes.
But these bloodsuckers also harbor risks. Both types are particularly important carriers of the Crimean-Congo hemorrhagic fever, the Arabic hemorrhagic fever and a form of the tick-spot fever.
“In one of the specimens we found, we were able to detect the causative agent of a tropical form of tick-spotted fever. However, at least dangerous viruses as causative agents of hemorrhagic forms of fever have not yet been discovered, ”says PD Dr. Gerhard Dobler, medical doctor and microbiologist at the IMB. (ad)