Brucellosis in Dogs

Overview of Canine Brucellosis

Brucellosis is a contagious disease of dogs caused by Brucella canis, a small bacterial organism. Brucellosis affects primarily the reproductive system. The disease causes late abortions and infertility in bitches, and infertility, testicular and scrotal inflammation in males. Brucellosis may also cause puppies to be stillborn or very weak at birth. Certain nonreproductive signs may also develop.

Brucellosis occurs mainly in dogs and has not been reported in cats. There is no evidence that some dog breeds are more susceptible that others, but there is a high prevalence in beagles. Brucellosis is more common in sexually mature dogs, but can affect dogs of any age. Both males and females are affected, but it is more common in females. Dogs from breeding kennels, pack hounds and stray dogs are most commonly affected, because of their increased risk of exposure.

Brucellosis is transmitted by contact with infected fluids (vaginal, preputial), especially during breeding or birth. Brucellosis may be transmitted from dogs to people.

What to Watch For

Overview of brucellosis in dogs may include:

• Lethargy or sluggishness
• Loss of sex drive
• Swollen lymph nodes
• Back pain and difficulty walking with infections around the spine
• Weak or dying puppies
• Abortion
• Vaginal discharge
• Swollen testicles
• Dermatitis (inflammation of the skin) on the scrotum
• Weakness
• Cloudy eyes from inflammation inside the eye
• Some infected dogs show no signs of illness

Diagnosis of Brucellosis in Dogs

Brucellosis can be difficult to diagnosis. Confirmation of the disease may require several tests be performed, including the following:

• A complete blood count (CBC), biochemical profile and urinalysis are recommended in all animals suspected of having brucellosis, but they may be normal or show only vague changes.
• Serologic blood tests that measure antibodies to the bacteria are the most frequent tests used to diagnose brucellosis. There are screening tests for Brucellosis that may be performed in your veterinarian’s office or local laboratory. If the screening tests are positive, then further specialized testing is required to confirm the diagnosis.
• Radiographs (x-rays) of the spine may show changes in the vertebrae (spine) consistent with brucellosis.
• The organism may occasionally be cultured and isolated from blood cultures, vaginal fluid cultures, semen cultures or urine cultures. Negative cultures do not rule out the disease, however.
• Examination for semen quality may be helpful. Male dogs with brucellosis often have abnormal semen.
• Lymph node biopsy may confirm diagnosis, but it often requires special staining techniques to identify the organism.

Treatment of Brucellosis in Dogs

Because brucellosis can be transmitted from dogs to people, there is concern about whether all infected dogs should be treated. In some cases it may be preferable to euthanize the animal. Treatment is not recommended for breeding animals, as it is unlikely that they will ever be fully cured and will continue to pass on the disease or will remain sterile.

When treatment is attempted, the goal of treatment is to eradicate B. canis from the patient, but this can be difficult to accomplish. Any intact dogs are spayed or castrated. Medical treatment is often begun as an outpatient, although some of the antibiotics used for the disease must be given as injections.

• A combination of two antibiotics are often administered. Choices include tetracycline, minocycline and doxycycline given with one of the aminoglycoside antibiotics, such as gentamicin.
• The antibiotics are usually administered for about four weeks and may need to be repeated at various time intervals for several months.

Home Care and Prevention

Administer all medication as directed by your veterinarian and return for follow up examinations as directed. Sequential serologic tests are recommended at three to six month intervals to monitor the outcome of treatment. If any change is noted in your dog’s condition, notify your veterinarian.

Overall prognosis is guarded, as animals, especially males, may become chronic carriers of the disease. The pet owner should not breed, sell, or give away infected dogs.

All dogs should be tested for brucellosis prior to their use as breeding dogs. Test all brood bitches and breeding males that are kept in kennels at frequent intervals. Dogs confirmed to be positive for the disease should not be used in breeding. Quarantine and test all new dogs before allowing them to enter a breeding kennel.