Analysis of exotic pathogens found in a large group of imported dogs following an animal welfare investigation

Abstract

Background: Increased dog relocation can cause dissemination of pathogen and vector populations, and this is being recognised in countries across Northern Europe, including the UK. Data regarding the prevalence of exotic infections in dogs entering the UK would be beneficial to veterinarians to help assess pets entering the UK from abroad and to help calculate the risk of establishment of novel pathogens. This study reports the findings from a group of imported dogs that was seized as part of a Royal Society for the Prevention of Cruelty to Animals (RSPCA)-led animal welfare investigation and subsequently blood tested for exotic pathogens.

Methods: As part of the RSPCA investigation, 151 dogs were removed from the site. Blood tests were performed for Babesia canis, Ehrlichia canis, Hepatozoon canis and Leishmania infantum by PCR, Brucella canis by antibody serology and Dirofilaria immitis by blood antigen. In addition to pathogen screening, a serology titre for rabies was measured for each dog. A clinical examination was performed by a veterinary surgeon, and clinical signs were recorded.

Results: Overall, 24% (32/133) of the dogs tested positive for an infection with one or more exotic pathogens. Two dogs were positive for Br. canis antibodies and had no clinical signs indicative of infection. Leishmania was identified in 10.5% (14/133) of dogs, and all but two of these were implanted with microchips of Romanian origin. H. canis was identified in 9.6% (10/104) of dogs, all of whom had a Romanian microchip. D. immitis was identified in 4.1% (5/121) of dogs, B. canis in 2.3% (3/129) of dogs and E. canis in only 1.5% (2/131) of dogs tested. Only four dogs were found to have co-infections. No significant association was found between the pathogens detected and presenting clinical signs.

Limitations: This was a group of rescued dogs that were tested for a range of pathogens. They were not randomly selected and as such do not represent the true prevalence of these pathogens in dogs imported into the UK.

Conclusions: This study demonstrates a range of exotic pathogens entering the UK, including Br. canis, and demonstrates the importance of screening imported dogs. The emphasis on early recognition of exotic pathogens in imported dogs has relied on screening based on relevant clinical signs and the country of origin. While these factors are useful, this study demonstrated no significant association between presenting clinical signs and the pathogens carried.

Keywords: blood testing; dogs; parasitology; relocation; vectors; welfare.