Brucella Multiplex Testing for Dogs
Brucellosis is a zoonotic disease caused by Brucella species, a genus of gram-negative, facultative intracellular, small rod-shaped bacteria. There are several strains of Brucella that infect both humans and animals. Brucella canis is the most common species of Brucella that infects dogs, although dogs can also be infected with B. suis, B. abortus, and B. melitensis (1).
B. canis was first described in 1968 as the causative agent of a series of abortion storms in beagle kennels (2–4). Clinical manifestations of B. canis infection in dogs include discospondylitis, uveitis, and orchitis/epididymitis (5–7). In breeding operations, conception failure may occur, but frequently the only indication of canine infection with B. canis is spontaneous abortion between gestation days 30 and 57 (2).
Infected dogs shed B. canis in vaginal secretions, particularly during estrus and parturition, and in aborted tissue; B. canis can also be shed in semen, urine, and to a lesser extent in saliva, blood and feces (8). Horizontal transmission of B. canis can occur in settings where dogs are in close proximity, including shelters or kennels. Frequently, transmission occurs during breeding, and vertical transmission from dam to offspring can also occur (1). Therefore, it is prudent to test dogs for evidence of B. canis infection prior to introduction to group-housing settings, and in particular, prior to breeding.
How does the Canine Brucella Multiplex Assay work?
The Canine Brucella Multiplex Assay was developed at the Animal Health Diagnostic Center at Cornell University. It detects antibodies to two different B. canis antigens in canine serum (Figure 1). The test is based on antigen-coated fluorescent beads and simultaneously measures antibodies against both antigens in a single sample. Measuring antibodies against both antigens provides enhanced sensitivity for the detection of Brucella-specific antibodies in canine serum. Seroconversion following infection with B. canis typically requires at least 3-4 weeks, but may take as long as 8-12 weeks (1).
How are results interpreted?
A negative test result for both antigens provides a strong indication that antibodies against Brucella were not present in the sample. All samples containing antibodies against PO1 and/or BP26 antigens are tested for confirmation by Canine Brucella Slide Agglutination/AGID II tests at the AHDC.
Advantages of the Canine Brucella Multiplex Assay
- High sensitivity. Based on parallel testing of over 1500 diagnostic samples submitted for the Canine Brucella Slide Agglutination/AGID II combination testing, the sensitivity of the Canine Brucella Multiplex Assay is estimated to exceed 95%, greater than the sensitivity of a commonly used in-clinic RSAT screening test (9).
- Rapid turn-around time. Negative test results will typically be available within 1 business day.
- Quantitative measurement of antibodies against individual antigens. Unlike the agglutination and immunoprecipitation assays, the Canine Brucella Multiplex Assay provides a quantitative test result proportional to the amount of Brucella-specific antibody present in serum.
For detection of antibodies to B. canis, submit 2mL of canine serum. Serum should be collected in a red top blood tube. The entire red blood tube or isolated serum should be shipped by overnight shipment on an ice pack to the Animal Health Diagnostic Center at Cornell University. For more information, please see the submission page.
Samples are tested every day (Mon-Fri), and results are available one to three business days after the sample arrives in the laboratory. Consultation on B. canis diagnostic testing is available by contacting one of our Diagnostic Intelligence Officers on our Veterinary Support Services team or the Bacteriology Laboratory at the Animal Health Diagnostic Center at Cornell University.
- Greene CE, Carmichael LE. 2012. Canine brucellosis, p. 398–411. In Infectious diseases of the dog and cat, 4th ed.
- Carmichael LE, Kenney RM. 1968. Canine abortion caused by Brucella canis. Journal of the American Veterinary Medical Association 152:605–616.
- Spink WW, Morisset R. 1970. Epidemic canine brucellosis due to a new species: Brucella canis. Trans Am Clin Climatol Assoc 81:43–50.
- Vinayak A, Greene CE, Moore PA, Powell-Johnson G. 2004. Clinical resolution of Brucella canis-induced ocular inflammation in a dog. J Am Vet Med Assoc 224:1804–7, 1788–9.
- Anderson GI, Binnington AG. 1983. Discospondylitis and Orchitis Associated with High Brucella Titre in a Dog. Can Vet J 24:249–252.
- Egloff S, Schneeberger M, Gobeli S, Krudewig C, Schmitt S, Reichler IM, Peterhans S. 2018. Brucella canis infection in a young dog with epididymitis and orchitis. Schweiz Arch Tierheilkd 160:743–748.
- Kerwin SC, Lewis DD, Hribernik TN, Partington B, Hosgood G, Eilts BE. 1992. Diskospondylitis associated with Brucella canis infection in dogs: 14 cases (1980-1991). J Am Vet Med Assoc 201:1253–1257.
- Wanke MM. 2004. Canine brucellosis. Animal Reproduction Science 82–83:195–207.
- Keid LB, Soares RM, Vasconcellos SA, Megid J, Salgado VR, Richtzenhain LJ. 2009. Comparison of agar gel immunodiffusion test, rapid slide agglutination test, microbiological culture and PCR for the diagnosis of canine brucellosis. Research in Veterinary Science 86:22–26.