Any dog can be infected with Canine Brucellosis

By Martin Coffman, D.V.M.

In the 1970s, as a young veterinarian and a Beagle field trailer, I was intimately involved in the epidemic of Canine Brucellosis that wreaked havoc on that breed. While I never had a case in my own dogs, I saw the effects of this disease in many kennels. Lifetime breeding programs were wiped out and many kennels never recovered from the losses incurred as a result of sterility, abortions, and weak newborn puppies that were caused by this infection. Great young stud dogs with their producing career in front of them were lost to the Beagle breed, as well as the crucially important brood bitches in major breeding kennels. As a result of this epidemic in the Beagle breed, increased awareness led to preventive steps that eventually curtailed the problem, but breeders of other hunting dogs, e.g. bird dogs, assumed the problem was just in the Beagle breed and for decades have minimized the danger this disease carries. The reality is that any dog can be infected with the brucellosis bacteria and it lurks as a threat to all breeders of all breeds. Since the disease can be transmitted by direct contact with infected dogs and hardware like bowls, leashes, truck boxes, and training collars, all dogs that assemble in large numbers, e.g. at a field trial, are especially susceptible.

Since Dr. Leland Carmichael first isolated the Brucella canis organism in 1966, veterinarians have had difficulty convincing breeders that their valuable dog?s reproductive career is finished once the diagnosis is made. The economic losses that have resulted from this disease cannot be over estimated. It can be devastating to a kennel. The disease is more common in the southern United States but has been reported in most states and many foreign countries.

The highly contagious disease is spread primarily through mating and via oral ingestion of the bacteria. Typical signs are late-term abortions in females and testicular and prostate inflammation in males with infertility and sterility a common final result. The disease can also cause non-reproductive problems, like infections of the backbone and swollen lymph nodes. Some dogs carry the disease without symptoms and appear quite normal despite positive blood tests. This makes it difficult for the owner to understand that the dog?s breeding career has ended. Some cases respond to aggressive antibiotic treatment, but relapses are common. Despite the appearance of a ?cure,? it is ethically unacceptable to continue to breed a dog that has a positive blood test for Canine Brucellosis and extremely risky from a kennel health standpoint.

The disease is transmitted primarily through secretions from the bitch?s vagina, both during estrus and while whelping. Males excrete the bacteria through their semen. Both sexes also excrete the bacteria in their urine, but male urine has a much higher concentration of the germ. Bacterial concentration in the bitch?s milk is also very high, but most researchers think this is a minor problem since the pups are infected while in the uterus prior to whelping. Low concentrations of the Canine Brucellosis bacteria are often found in saliva, feces, eye fluids and nasal discharges. Kennel bowls, cages and the hands of handlers have also produced positive cultures for three. canis. Documented cases have been traced to entry of the germ through the genital tract, the mouth and nose, and the eye. Typical cases show positive blood tests within one to four weeks after infection, which persists for at least six months and up to 64 months in some dogs.

General symptoms of Canine Brucellosis are not very evident. These dogs rarely have fevers and general signs of ill health are often absent. The classic symptom of Canine Brucellosis is late abortion, between 30 and 57 days into pregnancy, with the highest number between 45 and 55 days of gestation. Aborted puppies usually have a swollen appearance due to fluid under the skin and signs of disease on the liver, spleen and kidneys. Affected bitches tend to have a discharge for a longer than normal period. Sometimes, puppies are born that appear normal but eventually develop illness. These puppies should not be kept in the kennel.

The most frequent signs in males are swollen, painful testicles. Males will often lick their scrotum, increasing the swelling. The inflamed testicle leads to decreased fertility and often true sterility. Damaged testicles may take up to five weeks to be obvious but damaged sperm can take up to 16 weeks to appear on microscopic examination.

The only method for a positive diagnosis of Canine Brucellosis is isolation of the bacteria but this is not always possible. Five blood tests that vary in sensitivity and accuracy are available to practicing veterinarians for the disease. Normally the veterinarian will use the reproductive history of the dog, clinical symptoms and blood tests to arrive at the diagnosis. The simplest test is called the Rapid Slide Agglutination Test. It is available in a ?kit? form (D-Tec CB; Synbiotics Corp) and is useful in screening tests and early stages of the infection. Since false negatives are rare on this test, it is especially useful in filtering dogs scheduled for breeding. A positive on the RSAT test requires further testing for confirmation of the diagnosis.

For a truly positive diagnosis, culturing tissue for the germ is ideal. Unfortunately, a negative culture does not rule out the disease because the germ might have been absent in the cultured tissue at the time of sampling. Cultures of blood are commonly used because of the ease in obtaining the sample, but culturing aborted puppies, vaginal discharges, urine and semen is also done.

Dogs with Canine Brucellosis can be treated, but the organism is sensitive to relatively few antibiotics. Many different drugs have been tried alone or in combination, and none have proven 100 percent effective. Even after aggressive treatment, positive blood tests are found at times weeks after completion of the treatment. Usually, even if males are treated successfully, they remain sterile due to permanent damage to the testicles.

Control of the infection in a specific kennel is crucially important. These steps must be implemented quickly once a diagnosis is made:

• Isolation and quarantine of the entire facility.
• Blood test and culture all dogs in the kennel.
• All infected dogs must be removed from the kennel. Simple separation of infected dogs in an isolation area is not enough.
• All infected dogs must be neutered or spayed and, again, removed from the kennel.
• Treat all dogs that tested negative with appropriate antibiotics for at least 30 days. Continue to re-test these dogs every 30 days and remove new positives. New positives can be expected for at least five months.
• Institute an immaculate cleaning and disinfection program in the kennel. The germ does not live outside the dog for very long, so disinfection will kill it. However, the bacteria do live longer in the presence of organic material (feces, hair, etc.), so rigorous cleaning is equally important.
• Continue testing all dogs in the kennel every 90 days for one year. Even if bitches whelp normal-appearing puppies, these offspring are often infected and serve as a source of continuing infections.

Prevention is, obviously, the most important part of protecting your kennel. To approach Canine Brucellosis casually can lead to the tragic and extremely expensive testing, treating and culling of valuable animals. All females should be tested routinely prior to mating. All dogs, including males, should be tested at least annually, and busy stud dogs should be tested every six months. All new dogs brought into the kennel should be placed in an isolated area for at least eight weeks. Obviously, no dogs that test positive or have a history suggestive of Canine Brucellosis should enter the kennel. The incidence of Canine Brucellosis in handlers, breeders and trainers is not clear. Although B. canis can infect man, few human cases have been reported and the disease, usually contracted by handling aborted puppies, is usually mild in people. Canine Brucellosis is the type of disease that bird-dog people have heard about but assume it will happen to someone else. Simple preventive measures, like blood testing all dogs scheduled for breeding, can help control this tragic disease and protect a lifetime of accomplishments in breeding. Do not take it lightly.