Discussion

Ticks are abundant, clinically-important, blood-feeding ectoparasites that damage their hosts both directly as they feed and indirectly through the transmission of an extensive range of bacterial, viral and protozoal pathogens. Recent changes in the distribution of tick vectors and the incidence of tick-borne disease, driven variously by factors such as climate change, habitat modification, increasing host abundance and the increased movement of people and animals, highlight the importance of active surveillance. As part of an on-going analysis of the tick-borne disease risk for dogs, large-scale national surveys were undertaken by asking veterinarians to collect ticks on dogs presented to veterinary practices in the UK. This participatory approach allows relatively cost- and time-effective extensive data collection. Participating practices were asked to select five dogs at random each week and undertake a thorough, standardized examination of each dog for ticks. The clinical history and any ticks found were then sent to the investigators. In two surveys, more than 15,000 dogs have been examined and 7,000 tick samples collected, identified and subjected to pathogen analysis by PCR and sequence analysis following DNA extraction. The results of these surveys provide a comprehensive spatial understanding of tick distribution, species abundance and tick-borne pathogen prevalence in the UK, contributing to our understanding of disease risk in dogs.