Health Committee Description & Mission
Submitted by Gail Hendry
More recently focus has been drawn to an infectious disease that has affected more dogs than ever suspected. Lifetime breeding programs have been wiped out and many kennels never recover from loses incurred as a result of sterility, abortions, and weak puppies that fail to thrive as a result of this infection. In this article I hope to bring awareness of the dangers of canine brucellosis and how it can be prevented from infecting your kennel and breeding program.
What is Canine Brucellosis?
Canine brucellosis is a disease of the reproductive tract which may cause abortion in females, infection of the sexual organs in males, and infertility in both sexes. The disease can also cause non-reproductive problems, like infections of the backbone (diskospondylitis – inflammation of the vertebrae and disks), recurrent uveitis (inflammation of the iris in the eye), glomerulonephritis (inflammation of the kidneys), meningoencephalitis (infection of the brain and spinal cord), and swollen lymph nodes.
Brucellosis is caused by Brucella canis bacteria (B. canis) a gram-negative, intracellular bacterium. Dogs are also susceptible to infection from Brucella abortus (cattle) and Brucella suis (pigs), but the B. canis is the most common Brucella species found in dogs. Most experts’ estimate 1% to 6% of the canine population are infected, with the main source of the disease being stray dogs. There is no vaccine for this disease in dogs, and treatment, which usually consists of prolonged administration of Tetracycline and Streptomycin, may not be effective.
Why is knowledge about Canine Brucellosis so important to dog owners?
B. canis is a disease that can be transmitted to humans as well as other dogs and is a significant cause of reproductive failure, in breeding programs. Perhaps the most dangerous aspect of the disease is it’s insidiousness, symptoms are not always seen. In many cases an infected dog may show no outward signs at all. Infected bitches will have normal heat cycles and breed normally, in fact in many cases a bitch infected with Brucellosis may abort a litter and then conceive and whelp a live litter in the future. The danger in this is that such a bitch can infect any males she is bred to, and her puppies will most likely all be carriers of the disease and go on to infect other dogs.
How do dogs get infected with Canine Brucellosis?
Canine brucellosis is mainly transmitted during breeding, through contact with the semen or vaginal discharge of an infected dog or bitch. The disease may also be contracted by ingestion of contaminated placental materials or aborted fetuses from infected dogs, cattle or pigs.
B. canis may be shed for several weeks or intermittently for months following an abortion. Both sexes also excrete the bacteria in their urine, but the male urine has a much higher concentration of the germ. Chronically infected males may shed organisms in the urine for several years, even after castration. Low concentrations of the B. canis bacteria are often found in saliva, feces, eye fluids and nasal discharges. The disease can also be transmitted by direct contact with an infected dog’s hardware like bowls, leashes, collars, kennels and the hands of handlers have also produced positive cultures for B. canis. It is also thought to be spread by the airborne route in an indoor kennel situation. Documented cases have been traced to entry of the germ through the genital tract, the mouth, nose, and the eye. All dogs that assemble in large numbers (dog shows, dog parks, obedience/agility trials, etc.) are at risk of coming into contact with the B. canis bacteria.
How can I prevent Canine Brucellosis in my dog?
Brucellosis is easy to prevent in dogs. Before breeding your dog, both the male and the female should be examined by your veterinarian and tested for the disease. The test involves a simple blood test. There are several screening tests used for diagnosis of
B. canis. The Indirect Fluorescent Antibody Test (IFA), the Rapid Slide Agglutination Test (RSAT), and the Agar Gel Immunodiffusion Test (AGID). Each of these screening tests may have false positive results. In fact, with the RSAT, a negative slide test is strong evidence that the dog is not infected but about 60% of dogs who test positive are actually negative for the bacteria. An AGID test currently being used by Cornell University makes use of protein antigen to the cell cytoplasm of Brucella and is considered to be highly specific for B. canis. The Cornell AGID test thereby diminishes the problem with false positive testing. Blood cultures are recommended to confirm a positive diagnosis, regardless of the screening test used. This is due to the dire consequences a positive infection will have on the animal being tested. Culturing aborted puppies, vaginal discharges, urine and semen is also done. Avoiding “accidental” mating is naturally also important.
Artificial Insemination (AI) can lessen the risk of Brucella transfer at breeding. Transmission of B. canis to a bitch can occur during AI, especially if infected semen is used. However, AI will protect an infected female from transferring it to a non-infected male. All positive males and females should be removed from a breeding program.
How can I control or eliminate brucellosis if my Kennel is affected?
There is no reliable treatment for Brucellosis. B. canis lives inside of the dog’s cells so it is difficult to reach the bacteria the with antibiotics. Although various antibiotics have been partially effective at causing temporary reduction in the bacterial organisms, a complete cure is unlikely. Contaminated wet areas should be dried and disinfected with a 1% bleach solution. Isolation, testing, and euthanasia of confirmed infected dogs are the primary methods necessary to eliminate and prevent the spread of disease in a breeding facility. Infected animals that are neutered or spayed are still carriers of the B. canis bacteria. In some states the Health Department requires any dog that tests positive for the disease be destroyed because of the threat to humans. The disease is most often transmitted to a human by handling aborted pups from a bitch with brucellosis. For this reason, if you should have a bitch that aborts or has stillborn pups, the dead pups, membranes, placentas, etc. should be handled with gloved hands and the area disinfected thoroughly.
Naturally prevention is the most important part of protecting your dogs and kennel. Always require a brucellosis test before doing any breeding. Even when breeding within your own kennel it is recommended to have your dogs tested. Statistically one out of ten dogs may be carriers and those are disturbing odds. As a general rule every male and female should be tested before each breeding. If you have aborted or stillborn puppies they can also be tested for the B. canis bacteria. Canine Brucellosis is a very serious disease, not because dogs are very likely to contract the disease, but because of the consequences if a dog does become infected. The disease itself will not kill your dog, but your dog will be genetically dead because he or she will be unbreedable, even if the disease does not render the dog sterile. In the case of Brucellosis, it is definitely a matter of “Better safe than sorry”.
Antech Diagnostic News
Textbook of Veterinary Internal Medicine
AKC CHF and Zoetis Reproduction Series Podcast: Brucellosis