Abstract
Background: Ticks feeding on pets represent a serious health risk because of the direct effects produced on hosts and as vectors of zoonotic pathogens. Human actions on the landscape, the presence/absence of wildlife, and the trend toward a less predictable and warmer climate are transforming the distribution of ticks on dogs. We investigated the faunal composition and the distribution of ticks in pet dogs across the biogeographical Spanish territory, including the Canary Islands.
Methods: Overall, 24 veterinary practices collaborated to randomly collect ticks from cats and dogs monthly (June 2021 to July 2022). Veterinary practices were selected according to the biogeographical regions of Spain, aiming not only for a spatial pattern, but for ecological preferences of the ticks. Ticks were morphologically identified, and the pathogens within individual ticks were identified by standard molecular methods. The owner’s postal code defined the area of residence.
Results: In total, 299 ticks belonging to 13 species, plus a few immature Hyalomma spp., were identified. Eleven specimens were damaged, preventing morphological identification. The dominant species were Rhipicephalus sanguineus s.l., Dermacentor reticulatus and Ixodes hexagonus. While R. sanguineus s.l. is prevalent throughout Spain, the other species appeared only in the northern (colder and wetter) regions of Spain. Ehrlichia sp., Babesia sp. and two strains of Rickettsia massiliae were found in the ticks, plus the anecdotal presence of Anaplasma ovis. There was a lack of correlation between some animal traits, including age and sex, with parasitism. Dogs spending most of their time in a garden or in fields had a propensity to be more parasitized. The most abundant tick species were consistently linked to biogeographical areas (with corresponding climatic conditions) in the target territory.
Conclusions: This survey of randomly sampled pet dogs showed a year-round tick infestation risk. The survey supports the widespread distribution of R. sanguineus s.l. and its winter activity in most of the Spanish territory. Other common species of ticks in Europe (like Ixodes ricinus) are less common in Spain. Mixed species infestations were never observed. These results underpin the need for year-round tick control on dogs even during the winter months.