Veterinarian-written / veterinarian-approved articles for your dog.

Brucellosis in Dogs

Brucellosis is a serious infection in dogs.

Brucellosis is an infection in dogs caused by the bacteria, Brucella canis. It targets the reproductive and immune systems and sometimes the spinal cord and lining of the brain.

Brucellosis is spread through bodily fluids. It may be sexually transmitted or spread through ingestion of infected urine, semen, or vaginal secretions. It can also take hold through breaks in the skin.

Brucellosis is more common in parts of the southern US than in other areas. It's incredibly contagious between dogs, especially in kennel or breeding situations.

Signs of Brucellosis in Dogs

Brucellosis commonly causes spontaneous pregnancy loss and infertility in female dogs and epididymitis (infection of a part of the testicle) and testicular atrophy (shrunken testicles) in males. In the early stages of the infection, a male dog may experience swollen testicles.

Enlarged lymph nodes are often noted during the early part of the infectious process. Dogs may also be lethargic.

Less common signs of brucellosis include cloudy eyes, pain in the spine, wobbliness, and signs of meningitis (neurologic deficits, head tilt, etc.)

Diagnosis of Canine Brucellosis

If a veterinarian suspects a case of brucellosis, he or she will also be considering several other conditions that can cause similar signs, including herpesvirus, leptospirosis, and toxoplasmosis. In male dogs, other causes of swollen testicles such as blastomycosis and Rocky Mountain spotted fever will need to be considered.

If the dog is experiencing back pain or neurological signs, other causes for those, such as IVDD, and other bacterial causes of meningitis will be considered.

Usually, brucellosis is diagnosed with an RAST test, which stands for rapid agglutination slide test. It is relatively reliable for negative tests, but it does have a lot of false positive results. A positive test needs to be confirmed with an AGID test (agar gel immunodiffusion).

Blood cultures can sometimes grow Brucella bacteria for identification. Cultures of vaginal fluid, semen, or urine may be able to grow the bacteria as well, but urine and semen, especially, may have too many other contaminants to be reliable.

X-rays and other blood tests can help rule out other causes of the dog's clinical signs.

Dogs with enlarged lymph nodes may be diagnosed through a fine needle aspirate sample of the lymph node.

Treatment of Brucellosis in Dogs

Antibiotics can be used to treat an infected dog, but treatment is often not 100% effective in eliminating the bacteria. Dogs infected with Brucella canis should be considered to be infected for life.

Brucellosis is Zoonotic: Humans Can Contract It from Dogs

Brucellosis is a reportable disease in the United States. Sheep, cows, pigs, goats, and other animals can carry and spread the infection. Humans can contract it through ingesting unpasteurized milk, hunting, or working in slaughterhouses. Veterinarians are also at increased risk because of their exposure to the bodily fluids of pets or other animals.

While it is uncommon for people to contract brucellosis from their dogs, it is possible. It is more common when a person is immunocompromised or dealing directly and frequently with their dog's bodily fluids.

You May Also Like These Articles:

Canine Distemper Virus: What You Need to Know

Leptospirosis in Dogs

Canine Influenza

Tips for Giving Oral Medication to Your Dog

How to Help Your Dog Deal with Grief

Disclaimer: This website is not intended to replace professional consultation, diagnosis, or treatment by a licensed veterinarian. If you require any veterinary related advice, contact your veterinarian promptly. Information at is exclusively of a general reference nature. Do not disregard veterinary advice or delay treatment as a result of accessing information at this site. Just Answer is an external service not affiliated with

Notice: Ask-a-Vet is an affiliated service for those who wish to speak with a veterinary professional about their pet's specific condition. Initially, a bot will ask questions to determine the general nature of your concern. Then, you will be transferred to a human. There is a charge for the service if you choose to connect to a veterinarian. Ask-a-Vet is not manned by the staff or owners of, and the advice given should not delay or replace a visit to your veterinarian.