Some new findings on the endophilic vector tick Ixodes hexagonus in Germany

The authors of the present study received a number of hard ticks (Acari: Ixodidae) from different regions of Germany in 2018-2021. In most cases, the ticks were removed from pet dogs or cats. In one case, engorged and detached ticks were found in a house, and it was unclear how they had gained entrance. Morphological examination revealed that all the specimens (n = 18, larvae, nymphs, and adults) were hedgehog ticks, Ixodes hexagonus. Morphological identification for two larvae was confirmed by 16S rRNA gene amplification. These two larvae were also examined for tick-borne encephalitis virus RNA, but were found to be negative. In a previous, unreported study by one of the authors, which commenced in the late 1980s, it was observed that unfed larvae of I. hexagonus were extremely long-lived. They were still alive 5 years after the engorged female had detached from the host when maintained at a moderate temperature under controlled not too warm laboratory conditions (constant 15 °C, 91% relative humidity, and darkness).