Brucella canis
Also known as: Canine brucellosis, Brucella canis infection
In short
Canine brucellosis is a highly contagious bacterial infection caused by Brucella canis that primarily targets the reproductive systems of dogs, causing infertility, pregnancy loss, and joint or eye inflammation, with significant public health implications due to its zoonotic potential.
TL;DR. Canine brucellosis is a highly contagious bacterial infection that causes reproductive failure, joint pain, and eye inflammation in dogs, carries a guarded prognosis for a complete cure, and can spread to humans.
Lethargy and subtle discomfort can be early, non-specific signs of systemic Brucella canis infection.
Canine brucellosis is a contagious, infectious venereal disease of dogs caused by the bacterium Brucella canis. This bacterium has a unique and highly effective survival strategy: it is an intracellular pathogen, meaning it lives and multiplies inside the host dog's cells, particularly within white blood cells called macrophages. This intracellular lifestyle shields the bacteria from the dog's immune system and makes it incredibly difficult for standard antibiotics to reach and eliminate the infection.
While the disease primarily targets the reproductive organs, it is also a systemic infection. Once the bacteria enter a dog's body, they quickly spread to the lymph nodes and travel through the bloodstream to various organs. This can lead to widespread inflammatory complications, such as diskospondylitis (a painful infection of the spinal discs) and uveitis (severe inflammation inside the eye).
For pet owners, breeders, and veterinary professionals, canine brucellosis is a disease of profound concern. It is highly contagious among dogs, difficult to diagnose, and notoriously resistant to complete cure. Furthermore, Brucella canis is zoonotic, meaning it can be transmitted from dogs to humans, making it a significant public health concern alongside its devastating veterinary impacts.
Canine brucellosis is caused by the bacterium Brucella canis. The primary route of transmission is venereal, occurring during mating between an infected and a non-infected dog. However, sexual contact is far from the only way this disease spreads. The bacteria are shed in massive quantities in reproductive fluids, including vaginal discharge following an abortion or pregnancy loss, aborted fetuses, placenta, and semen.
Non-sexual transmission occurs when dogs sniff, lick, or ingest these contaminated materials. Additionally, other bodily fluids serve as significant sources of environmental contamination. According to a leading veterinary internal medicine reference:
"Urine can serve as a contaminated vehicle because of the proximity of the urinary and genital tracts in the dog, with shedding present for months to years; this is more prevalent in males. Organisms can also be shed in milk." [2]
Because the bacteria can persist in urine for years, especially in male dogs, any environment where multiple dogs mingle—such as breeding kennels, shelters, or dog parks—presents a risk if an infected dog is present.
There are no specific breed predispositions for canine brucellosis; any dog, regardless of breed, can contract the infection if exposed. However, intact breeding dogs, dogs imported from regions with high infection rates, and dogs kept in crowded, unscreened kennel environments are at the highest risk of contracting and spreading the disease.
Canine brucellosis can be a silent and deceptive disease. Many infected dogs appear completely healthy, showing no obvious signs of illness while actively shedding the bacteria into their environment. When clinical signs do emerge, they most commonly relate to reproductive failure, though systemic signs can also occur.
Uveitis, or inflammation inside the eye, is an occasional but serious systemic manifestation of canine brucellosis.
Diagnosing canine brucellosis is a complex process. Because the bacteria live inside cells and are not always consistently present in the bloodstream, a single test is rarely sufficient. Your vet will typically use a combination of screening tests, confirmatory tests, and direct detection methods.
Treating canine brucellosis is exceptionally challenging. Because Brucella canis resides inside host cells, standard antibiotic courses are ineffective. There is no treatment protocol that is guaranteed to completely cure the infection, and lifelong carrier status is common.
Your vet will prescribe long-term, multi-drug antibiotic protocols to suppress the infection. Single-antibiotic treatments are highly prone to failure. The primary classes of antibiotics used include:
Because antibiotics rarely clear the infection completely, medical treatment must be combined with strict management practices:
As noted in a leading veterinary internal medicine reference:
"Infected dogs and bitches should be removed from breeding programs and quarantined. Eradication of the disease in kennel situations has not been successful without removal (culling) of all infected (current or historically) dogs." [3]
The prognosis for dogs diagnosed with canine brucellosis is guarded for a complete cure. While adult mortality from the disease is very low—meaning the infection itself is rarely directly fatal to adult dogs—the likelihood of completely clearing the bacteria from the body is minimal. Relapses are common, even after months of aggressive antibiotic therapy.
For breeding kennels, the prognosis for the facility's operations is severe, often requiring complete depopulation or rigorous, expensive testing and quarantine protocols to eradicate the disease. For individual household pets, a diagnosed dog can live a relatively normal lifespan, but they must be managed as a lifelong carrier. This means they must be spayed or neutered, kept isolated from other dogs, and monitored closely for signs of relapse, such as returning joint pain or eye inflammation.
Furthermore, because of the zoonotic risk, owners of infected dogs must take strict hygiene precautions, particularly when handling urine or cleaning up after their pet. Immunocompromised individuals, young children, and pregnant women should not live in the same household as a Brucella canis-positive dog.
Prevention is the single most effective tool against canine brucellosis. Because the disease is so difficult to treat, keeping it out of your home or kennel is paramount.
Every dog intended for breeding should be screened for Brucella canis prior to every mating. This applies to both the male and female dog. As a leading veterinary textbook emphasizes:
"Screening for B. canis infection is an important part of the prebreeding evaluation of any dog and should be included in the initial diagnostics in any case of canine abortion, orchitis, epididymitis, and apparent infertility in bitches or dogs." [1]
If you own an intact breeding dog or have recently adopted a dog with an unknown medical history, you should contact your vet if you notice any reproductive abnormalities.
Contact your vet immediately if you observe any of the following emergency red flags:
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
Canine brucellosis is a highly contagious bacterial infection caused by Brucella canis that primarily targets the reproductive systems of dogs, causing infertility, pregnancy loss, and joint or eye inflammation, with significant public health implications due to its zoonotic potential.
Abortion、Pregnancy loss、Epididymitis、Infertility、Orchitis、Stillbirth、Vaginal discharge、Diskospondylitis
2-mercaptoethanol modified RSAT (ME-RSAT)、Agar gel immunodiffusion (AGID) assay、Blood, urine, or tissue culture、Histopathology、Polymerase chain reaction (PCR) assay、Rapid slide agglutination test (RSAT)
Treatment must be prescribed by a licensed veterinarian based on your pet. Specific drug doses are intentionally not shown here.
This article is for general education and is not a substitute for professional veterinary advice. If your pet is unwell, please consult a veterinarian.
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