Ticks are important vectors; cats acquire tick-borne pathogens when bitten by ticks. Ticks derived from cats have rarely been evaluated for the presence of pathogens; small studies have been described in Spain, Italy and Poland, but no studies have yet been performed in ticks found on cats in the UK.

The aim of this study was to determine the prevalence of selected tick-borne pathogens in ticks collected from cats in the UK; pathogens evaluated were Anaplasma phagocytophilum, Bartonella spp. including Bartonella henselae, Hepatozoon spp., Babesia spp., Borrelia spp. including Borrelia burgdorferi sensu lato, and haemoplasma species including Mycoplasma haemofelis (Mhf), 'Candidatus Mycoplasma haemominutum' (CMhm) and 'Candidatus Mycoplasma turicensis' (CMt).

Ticks were collected from cats presenting to veterinarians in UK practices. Tick species were identified morphologically and underwent DNA extraction using commercially available kits followed by PCR assays (either conventional or quantitative real-time [qPCR]) for the tick-borne pathogens specified above. All assays had been previously validated for detection of the target species. Feline 28S rDNA served as an endogenous internal PCR control (assessed within the haemoplasma qPCRs). Additionally, the samples were spiked with an internal amplification control (IAC) to monitor for inhibition. Positive samples from the generic PCRs (Bartonella spp., Hepatozoon spp., Borrelia spp.) were submitted for DNA sequencing for species identification.

A total of 541 ticks were collected. Of these 309 (57.1%) were Ixodes ricinus, 224 (41.4%) were Ixodes hexagonus and 8 (1.5%) were Ixodes trianguliceps. 28S rDNA was amplified from 476 (88.0%) of the ticks (undetected results likely being due to some ticks being unfed). The IAC PCR results revealed no evidence of inhibition. Of 541 ticks, 33 (6.1%) contained pathogens, and 1 tick contained two. Agents detected were: 6 (1.1%) Babesia spp. (Babesia microti-like and Babesia venatorum), 10 (1.8%), Borrelia spp. (Borrelia afzelii and Borrelia garinii), 5 (0.9%) A. phagocytophilum, 7 (1.3%) Bartonella spp. (including B. henselae and Bartonella clarridgeiae), 6 (1.1%) haemoplasma species [4 (0.7%) CMhm, 1 (0.2%) Mhf and 1 (0.2%) CMt]. Additionally, Hepatozoon silvestris was detected.

The resulting data provide valuable information on the prevalence of tick-borne pathogens in ticks found on cats in the UK. The prevalences found were similar to those reported in ticks collected from dogs in the UK but lower than those reported in ticks from cats in other European countries. This is the first report of the detection of H. silvestris in ticks collected from domestic cats in the world.

Disclosures

Disclosures to report
This study was supported financially by MSD Animal Health. FD and SD have no competing interests. SF is supported by a Langford Trust-funded PhD scholarship. SA is supported by a Zutshi Smith PhD scholarship. SK, FD and ST have received grants from Langford Vets Clinical Research Fund for another research project. HN is an employee of MSD Animal Health. CH, ST and RW have previously had research funded by a wide range of funding organisations (e.g., BSAVA Petsavers, Langford Trust, Petplan Charitable Trust, Morris Animal Foundation, Dogs Trust, South West Biosciences DTP, Elizabeth Blackwell Institute of the University of Bristol, ECVIM Clinical Studies Fund, the University of Bristol Campaigns and Alumni Fund, the RCVS Trust Fund Blue Skies, The Wellcome Trust and Langford Vets Clinical Research Fund), pharmaceutical companies (e.g., Zoetis Animal Health, Bayer Animal Health, MSD Animal Health), and animal health charities. ST and CH work for the Molecular Diagnostic Unit, Langford Vets, University of Bristol, which carried out the PCRs described in the study. RW is a director of AgriEnt Ltd. ST has been paid for providing continuing professional development for not-for-profit organisations, and occasionally for commercial companies, around the world. ST is a member of the World Forum for Companion Animal Vector Borne Diseases, supported by Bayer Animal Health. ST is a member of the European Advisory Board on Cat Diseases, which is supported by Merial.