Attachment sites of Ixodes ricinus, Ixodes hexagonus/Ixodes canisuga and Dermacentor reticulatus ticks and risk factors of infestation intensity and engorgement duration in dogs and cats.

Abstract

Background: Over the last decades, climatic and environmental changes have led to an expanding seasonal activity pattern and increasing distribution of ticks across Europe. In particular, Dermacentor reticulatus is now commonly found on dogs in central Europe. The present study compared attachment sites between Ixodes spp. and Dermacentor reticulatus ticks collected by veterinarians from dogs and cats, and investigated risk factors associated with tick infestation intensity and engorgement duration.

Results: The dataset comprised 6,335 dogs harbouring 10,287 ticks (8,095 Ixodes ricinus, 1,860 D. reticulatus, 218 Ixodes hexagonus/Ixodes canisuga, 114 of other tick species) respectively 4,248 cats harbouring 8,005 ticks (7,344 I. ricinus, 56 D. reticulatus, 505 I. hexagonus/I. canisuga, 100 of other tick species). Differing sites of tick attachment were not only found between the different host and tick species, but also between the tick developmental stages. Regarding the risk of infestation with multiple ticks, dogs and cats living in rural areas harboured significantly more often multiple than single specimens. Further, a long coat in cats was associated with a higher probability of multiple infestation, while this was not observed in dogs. However, there was a tendency towards a potential influence of the density of the undercoat (p = 0.051). In dogs, a tall to very tall body size as well as folded ears increased the risk of multiple infestation, while in cats, increasing age and increasing body size were negatively associated with multiple infestations. Ticks with an engorgement duration of > 48 h were found significantly more often on senior dogs and cats than on younger individuals, as well as on working/utility dog breeds, while engorgement duration was negatively correlated with infestation intensity in dogs. In cats, female gender and a rural residence were significantly associated with longer attachment duration.

Conclusions: Individual as well as breed specific characteristics can lead to a higher tick infestation intensity or longer engorgement duration. The knowledge of tick attachment sites and specific risk factors can help to raise awareness among owners concerning the importance of tick control with licensed acaricides, as recommended e.g. by the European Scientific Counsel Companion Animal Parasites (ESCCAP), and may aid in early tick removal to decrease the risk of pathogen transmission to dogs and cats whose owners nonetheless refuse acaricidal drugs.