Frequency of Brucella canis seropositivity in at-risk dogs referred for veterinary care in the UK

Background
Brucella canis is a canine pathogen of zoonotic concern. It is not considered endemic in the UK, with most infections diagnosed in travelled dogs or their offspring.

Methods
Between March 2021 and December 2022, all dogs with a history of travel outside of the UK or clinical signs compatible with brucellosis referred for veterinary care at a single UK centre underwent serological testing against B. canis. Their records were retrospectively reviewed, and signalment, reason for referral, travel history and B. canis serology results were collected.

Results
Of 375 dogs screened for B. canis using various assays, positive serological results were obtained in nine. Only one of five dogs with a positive lateral flow test (LFT) had a confirmatory positive result at a governmental laboratory. Meanwhile, two dogs with a negative LFT had positive results at a governmental laboratory. B. canis prevalence in travelled dogs tested at a governmental laboratory was 2.8% (5/179; 95% confidence interval 1.2%–6.4%).

Limitations
Too few positive cases hindered robust estimation of LFT sensitivity, although the results suggest suboptimal LFT performance within the tested population.

Conclusion
The apparent prevalence of B. canis in this population of ‘at risk’ dogs was low. Positive LFT results should be followed up with additional serological testing.