Date: Wed 14 Aug 2019
Source: Universitat Hohenheim [in German, trans. Britta Lassmann, edited]
The University of Hohenheim and the Bundeswehr Institute of Microbiology [IMB] have detected spotted fever in a hyalomma tick, the 1st time such a tick is suspected to have caused disease in a human in Germany.
This tick feeds on humans and can transmit a form of spotted fever in Germany. What were still unanswered questions about the tropical giant tick hyalomma is now certainty. At the beginning of August , it was suspected that for the 1st time, a human in Germany had contracted a disease with the typical symptoms of rickettsiosis from the bite of a hyalomma tick. Experts from the University of Hohenheim in Stuttgart and the IMB in Munich were able to detect the pathogen _Rickettsia aeschlimannii_ in the tick. The number of hyalomma ticks in Germany increased significantly in 2019 compared to the previous year . In nearly half of the hyalomma ticks, _R. aeschlimannii_ can be detected. The tick researchers continue to ask the population to send them suspicious ticks.
It was probably no coincidence that this 1st case was in a horse owner. Tropical ticks of the genus _Hyalomma_ feed on large mammals. For several years, these ticks have been on the rise in Germany. Now tick researchers report the 1st suspected case of spotted fever transmitted in Germany. "Not only do we now know for sure that the hyalomma tick is also targeting humans," says Prof Dr Med Ute Mackenstedt, a parasitologist at the University of Hohenheim, "but also that there is the urgent suspicion that the transmission of spotted fever by these ticks is actually possible here in Germany."
The case: At the end of July , the horse owner from near Siegen was bitten by a hyalomma tick. He sent the tick to the tick researcher in Hohenheim. He then presented to the hospital only a few days later with severe symptoms. Spotted fever caused by the bacterium _R. aeschlimannii_ was suspected. The tick was sent by courier service to the IMB in Munich, where the pathogen was detected in the tick. Thereafter, the patient received targeted antibiotic therapy, and his symptoms rapidly improved.
"We are talking about a suspected case, because direct detection of the pathogen from the patient was not possible," explains PD Dr Med Gerhard Dobler, medical doctor at the IMB. "The treatment of the patient came 1st. But the preceding tick bite, the typical symptoms
and, above all, the proof of the pathogen in the tick suggest that the case was spotted fever. The fact that the patient responded to targeted antibiotic therapy further supports this."
_R. aeschlimannii_ causes a feverish infection with headache and muscle pain, extreme joint pain, and a burning sensation. Typical for the disease, however, is the rash that gave the disease its name. This classic sign shows mainly on the extremities. The incubation period is about one week.
"If spotted fever is suspected after a hyalomma bite, a swab should be taken from the bite site and sent for examination," advises PD Dobler. "If there are questions, you are welcome to contact us. Ideally, we would also like to examine the tick."
About half of the hyalomma ticks, the researchers say, are infected with rickettsia. Transmission takes place exclusively via tick bite. "The number of hyalomma ticks in Germany is significantly higher this year  than in the previous year ," reports Prof Dr Med Mackenstedt, referencing the publication in which the situation was presented in 2018. The Hohenheim parasitologist not only cooperates closely with the IMB in Munich, but also with the working group of Prof Dr Med Christina Strube at the Veterinary University (TiHo) Hannover. "Together they already have found 50 such ticks in Germany in 2019. Last year  there were a total of 35." Last year, these ticks had survived the winter in Germany for the 1st time.
"Rickettsia are the only pathogens that we have been able to detect so far," explains PD Dr. Dobler. "We have not found the virus that causes the dangerous Crimean Congo hemorrhagic fever, nor the pathogens _Theileria equi_ and _Babesia caballi_, both of which can be transmitted from ticks to horses."
The research team continues to ask the population for support to further explore the spread and potential dangers. In case of a tick bite, it's best to remove the tick with a tick remover, TickCard, or tweezers. Then send the animal in a small, tightly closed container to:
University of Hohenheim
Prof. Dr. Ute Mackenstedt
Department of Parasitology
Background: Tick genus _Hyalomma_
_Hyalomma marginatum_ and _Hyalomma rufipes_ are native to the dry and semi-arid areas of Africa, Asia, and southern Europe. Until recently, they did not occur in central and northern Europe. Their striped legs are striking, and they are much larger than the native ixodes ticks.
The adult ticks feed on large animals. They are active hunters and move quickly towards their host. They cover a distance of up to 100 m [328 ft]. Humans can serve as hosts. In contrast, tick larvae and nymphs mainly infest birds and small mammals and can stay up to 28 days with their hosts. Migratory birds can introduce larvae and nymphs to Germany.
In Eurasia, both _Hyalomma_ species are considered transmitters of the Crimean Congo hemorrhagic fever virus and the Arabic hemorrhagic fever virus (Alkhumra virus). They also transmit the bacterium _Rickettsia aeschlimannii_, which causes a form of spotted fever.
Chitimia-Dobler L, et al. Imported _Hyalomma_ ticks in Germany in 2018. Parasites & Vectors. 2019; 12 (134).
Picture and video material [in German]
Press release: Tropical ticks in Germany: University of Hohenheim asks to send conspicuous tick finds [in German]
Press release: Tropical ticks: New immigrant species winters in Germany for the 1st time [in German]
Superior Health Council
[Given that the ticks were found last year (2018) and that they overwintered and were found again this year (2019), it is likely that this genus of tick is becoming established in Germany. Although the species of _Hyalomma_ that infected the man with _Rickettsia aeschlimannii_ was not determined, there is a clear association of this rickettsia with the 2 species of _Hyalomma_ that were tested. The published report cited above states, "35 ticks with an unusual appearance or behaviour were reported to us during summer-autumn 2018. For 17 of them, the description or photos implied that they belong to the hard tick genus _Hyalomma_. The remaining 18 ticks were sent to us and were identified as adult _Hyalomma marginatum_ (10 specimens) or adult _Hyalomma rufipes_ (8 specimens). All ticks tested negative for CCHF virus, _Coxiella burnetii_, _Coxiella_-like organisms, _Babesia_ spp. and _Theileria_ spp. The screening for rickettsiae gave positive results in 9 specimens. The _Rickettsia_ species in all cases was identified as _R. aeschlimannii_." Given that these ticks can be transported by birds migrating from Africa, continued surveillance in Germany for the rickettsia and the other pathogens that were not found currently is prudent. - ProMED Mod.TY]
The first human case of _R. aeschlimannii_ infection was identified in a patient who had fever, rash, and an eschar similar to _R. conori_ infection (Mediaterrian spotted fever) after travel in Morocco (1). _R. aeschlimannii_ infections in humans have been previously confirmed in South Africa, in Algeria, and in Tunisia (2). To our knowledge, the first human case of _R. aeschlimannii_ infection reported in Europe occurred in Greece and was reported in 2013 (3).
1. Raoult D, Fournier PE, Abboud P, Caron F. First documented human Rickettsia aeschlimannii infection. Emerg Infect Dis. 2002; 8: 748-9. doi: 10.3201/eid0807.010480
2. Demoncheaux JP, Socolovschi C, Davoust B, Haddad S, Raoult D, Parola P. First detection of _Rickettsia aeschlimanii_ in _Hyalomma dromedarii_ ticks in Tunisia. Ticks Tick Borne Dis. 2012; 3: 398-402.
3. Germanakis A, Chochlakis D, Angelakis E, Tselentis Y, Psaroulaki A. _Rickettsia aeschlimannii_ infection in a man, Greece. Emerg Infect Dis. 2013; 19: 1176-7. - ProMED Mod. LL]
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