Dynamics of tick infestations in foxes in Thuringia, Germany

This study aimed to provide up-to-date information on the dynamics of tick infestations on foxes in Thuringia, as the most recent information available was published in 1997. Fox carcasses that had been sent to the Thuringian State Authority for Food Safety and Consumer Protection (Thüringer Landesamt für Lebensmittelsicherheit und Verbraucherschutz – TLLV), between January 1st and December 31st, 2009, were examined for the presence of ticks. All ticks collected were stored at −20 °C before being identified and classified according to their developmental stage and sex. Out of a total of 1286 foxes examined, 989 (76.9%) were infested with ticks. A total of 13,227 ticks were collected from the foxes. The stage most frequently found was the larva (48.1%), followed by the adult (34.1%), and the nymphal stage (17.8%). Regarding the adult stage, Ixodes ricinus was the most frequent tick species detected (82.2%), followed by I. canisuga (10.8%) and I. hexagonus (6.7%). Dermacentor reticulatus ticks were very rare (0.3%). With regard to nymphs, I. canisuga and I. hexagonus were the most frequent tick species found, and this was also assumed for the larval stage. The results indicate the occurrence of tick infestations in foxes throughout the year, mainly by I. ricinus, I. canisuga, and I. hexagonus, with seasonal variations. Foxes were infested by I. ricinus ticks significantly more frequently from April to September. This applied to all tick developmental stages, but especially to adults. In contrast to I. ricinus, the infestation of foxes with I. canisuga and I. hexagonus was significantly higher from January to March and from October to December, especially with the immature developmental stages.