Discussion

A large-scale survey was undertaken to assess the prevalence and distribution of Babesia and Borrelia pathogens in ticks infesting domestic dogs in the UK.  This involved the recruitment of 1094 veterinary practices over a period of 16 weeks. Participating practices randomly examined 5 dogs for ticks each week and sent a clinical history along with any ticks to the investigators.  A total 12,096 dogs were examined during this period. The ticks were identified to species. The overall prevalence of tick attachment was 30%. The relatively high prevalence may have been inflated by the method of participant recruitment.

For pathogen analysis DNA was extracted from 4,750 ticks collected over the first 13 weeks and were subjected to PCR and sequence analysis to identify Babesia and B. burgdorferi (s.l.) species.  From 4,737 ticks, B. burgdorferi (s.l.) was detected in 94 (2.0%). Four Borrelia genospecies were identified: Borrelia garinii (41.5%), Borrelia afzelli (31.9%), Borrelia burdorferi (s.s.) (25.5%) and Borrelia spielmanii (1.1%). One Rhipicephalus sanguineus, from a dog with a travel history outside the UK, was positive for B. garinii. Seventy ticks (1.5%) were positive for Babesia spp.: 84.3% were Babesia venatorum, 10.0% were Babesia vulpes sp. nov., 2.9% were Babesia divergens/capreoli and 1.4% were Babesia microti.  One isolate of Babesia canis was detected in a D. reticulatus tick from a dog that had recently travelled to France. The prevalence of Babesia spp.and B. burgdorferi (s.l.) did not differ significantly between different regions of the UK. The results map the widespread distribution of B. burgdorferi (s.l.) and Babesia spp. in ticks in the UK and highlight the potential for the introduction and establishment of exotic ticks and tick borne pathogens.