Brucella canis: Emerging zoonotic disease? Implications for commercial breeding kennels and public health

Introduction Canine brucellosis, a contagious disease affecting all breeds of dogs, is caused by the bacteria Brucella canis, which is transmitted between dogs via venereal and oral routes. Transmission occurs mainly through vaginal secretions during estrus and whelping (in both the fetus and placenta) and via semen. Bacteria can also be found in urine, and is more commonly found there in male dogs. Additional sources of infection include milk, saliva, nasal and ocular secretions, feces, and contaminated cages and equipment. Humans become infected through contact with tissue and secretions from infected dogs. The disease represents a potential source of economic loss to breeding kennels. Outbreaks can result in the loss of hundreds of breeding animals. The cost associated with quarantine, including changes in the facility in order to isolate infected dogs, the costs of repeated testing, and not being able to breed, sell, buy or move dogs for any reason, can be prolonged (several months) and may result in kennels going out of business (Hollett, 2006). Therefore, it is important for kennel managers and owners of dog breeding facilities to understand the disease and its implications for dog care and welfare. B. canis infection in dogs Clinical signs of brucellosis infection in dogs can range from weight loss and lethargy, to late-term abortions in females, epididymitis and prostatitis in males, and infertility, lymphadentitis (inflammation of the lymph nodes) and diskospondylitis (a destructive, inflammatory process of the intervertebral disks) in both sexes. Puppies can become infected in utero, during birth by contact with placenta and blood, and as neonates through milk or contact with infected surfaces. Many infected dogs remain asymptomatic. Several diagnostic blood tests exist, but diagnosis can be difficult and often requires testing more than once, using two different diagnostic tests. One test commonly used for screening —the rapid slide agglutination test (RSAT) — is useful because false negatives are rare, it can be used for early detection, and it is easy to use, sensitive, and commercially available. Antibiotic treatment has proven successful in some cases of B. canis infections, but no treatment has been found to be 100% effective. Consequently, many veterinarians recommend euthanasia for breeding dogs that test Judith Stella and Candace Croney, Purdue College of Veterinary Medicine