A common source outbreak of Brucella melitensis infection in male dogs: Serological and molecular investigation

The present study aims to describe an outbreak of canine brucellosis in a dog shelter on serological and molecular bases. The infected dogs exhibited testicular enlargement, epididymitis, prostatitis, and orchitis. All dogs were serotested for brucellosis using Rose Bengal plate test (RBPT), and buffered acidified antigen plate test (BAAPT). Serum samples and whole blood of serologically positive dogs were subjected to conventional, species-specific real-time, and multiplex PCRs to identify the circulating Brucellae on genus, species, and biovar levels, respectively. Positive results from serological tests confirm the presence of smooth brucellae. The overall seroprevalence of Brucella antibodies was 56.7 % as detected by RBPT and BAAPT. Molecular identification using primer sequences targeting the Immunodominant antigen, gene bp26 confirmed Brucella on the genus level. Results of species-specific real-time PCRs confirm the presence of B. melitensis DNA in blood sera of dogs. Multiplex PCR has amplified three fragments of 587 bp, 1071 bp, and 1682 bp characteristic for B. melitensis biovar 3. Trace investigation revealed that the dog's raw meat diet was the most likely source of infection.