Brings deadly virus

Giant tick also travels to Austria by car

This is what the giant Hyalomma tick looks like.

(Bild: Frank Günther)

Until now, it was assumed that the exotic giant tick Hyalomma arrived in Austria via migratory birds. Experts from the Agency for Health and Food Safety (AGES) have now described a new mode of travel for these animals for the first time: According to this, the bloodsuckers use the car as a ride.

This previously unknown way of introducing Hyalomma from their original habitat to the north has now been scientifically described for the first time in the journal "Ticks and Tick-borne Diseases". The increasing migration of the giant tick to the northern regions is no cause for celebration, as the publication states that this spread is a cause for concern for public health due to its ability to transmit the Crimean-Congo hemorrhagic fever virus (CCHFV) and several spotted fever variants that are dangerous to humans.

As part of an AGES Citizen Science project, in which ticks that resemble Hyalomma marginatum, i.e. ticks that are larger than the native tick species and have yellow striped legs, can be reported by laypersons, the previously unknown type of entry has now been registered.

By car from Croatia to Vienna
In May and June 2024, AGES was contacted by several people who had discovered these ticks in their car while traveling home from Croatia or after returning home. According to the information provided, Croatia is the closest region to Austria where Hyalomma ticks are endemic.

Size comparison: A giant tick (right) next to a common wood tick (left), the most common tick species in this country

(Bild: APA Pool/APA/dpa/Fabian Sommer)

One of the giant ticks made it as far as Vienna. It was discovered by a vacationer who had previously been staying in Zadar on the Dalmatian coast. On his arrival in Vienna, he found the tick in his car and sent it to the AGES laboratory, where it was identified as Hyalomma, according to the study.

The motorized journey is quite problematic, AGES wrote. This is because tick nymphs, the penultimate developmental stage of the blood-sucking parasite, usually reach Austria via migratory birds. The nymphs need a blood meal and time to develop into adult ticks.

The specimens found were fully grown
In contrast to the ticks that have now been examined, these were adult male and female specimens. This increases the probability of mating and favors the establishment of a population in Austria. The present study is therefore of essential importance for understanding the potential establishment of new ticks in areas where this species has not previously been found, wrote AGES.

The molecular biological examinations of the specimens revealed no evidence of Crimean-Congo fever virus (which can be potentially fatal, note), but the bacterium Rickettsia aeschlimannii was detected in one of them.

Rickettsiae are a genus of bacteria that cause a group of diseases, including Rocky Mountain spotted fever and typhus. However, diseases with a source of infection in Austria have not been documented in recent decades.

Species is an up-and-comer of its species
The tick species Hyalomma marginatum is an up-and-comer of its species in Austria. Favored by mild winters and climate change, it could become a permanent resident here.