What Is Brucellosis in Dogs?
Brucellosis — formally known as Brucella Canis or B. Canis — is a highly contagious bacterial infection in dogs that cannot be cured. There is no effective antibiotic treatment and no vaccine. Once a dog is infected, they carry the bacteria for life.
This isn’t a minor pathogen. Brucella Canis is the only bloodborne pathogen recognized by OSHA in veterinary medicine. That classification alone should signal how seriously this disease is taken at the occupational health level.
Symptoms of Brucella Canis in Dogs
Brucellosis doesn’t always announce itself. Some infected dogs show zero clinical signs while actively spreading the bacteria to other animals. That’s what makes it so dangerous.
When symptoms do appear, they vary by sex and can mimic other conditions.
In Male Dogs
Infection often targets the reproductive system, leading to testicular atrophy and infertility. Males may appear otherwise healthy while their breeding capability is permanently compromised.
In Female Dogs
Females typically abort in late gestation and may present with vaginal discharge. Litters born to infected females can include a mix of dead puppies, infected puppies, and puppies that appear healthy but may still carry the bacteria.
General Signs in All Dogs
Beyond reproductive issues, brucellosis can cause spinal infections (discospondylitis), eye inflammation (uveitis), lethargy, decreased appetite, and enlarged lymph nodes. These non-specific signs are easy to miss or attribute to something else — which is exactly why routine testing matters.
How Does Brucellosis Spread?
This is where it gets alarming. Brucella Canis is present in saliva, urine, feces, and reproductive fluids. The bacteria can survive for months under the right conditions, including high humidity, low temperatures, absence of sunlight, and dry surfaces. It even survives the semen freezing process.
That means dust, dirt, water, clothing, equipment, and any surface an infected dog contacts becomes a potential transmission vector. Venereal transmission is the most direct route, but casual contact with contaminated urine or genital discharge — at dog shows, boarding facilities, or breeding operations — is enough.
There is no safe exposure. If a dog has been in contact with an infected animal or contaminated environment, they are at risk.
Is Brucellosis Contagious to Humans? (Zoonotic Risk)
Yes. Brucella Canis is zoonotic, meaning it transmits from animals to people.
Once the bacterium enters a human host, it colonizes the bone marrow and may never be fully eliminated. Symptoms include recurring fever, body aches, and flu-like illness that can persist for years. It’s especially dangerous for three groups: young children, elderly individuals, and anyone who is immunocompromised.
Pregnant women face an additional threat — Brucella infection can cause pregnancy loss. This is a critical concern because the majority of caretakers in shelters, humane societies, rescue organizations, and breeding kennels are women of childbearing age.
Why There Is No Cure for Canine Brucellosis
Brucella Canis is resistant to standard antibiotic protocols. While treatment can sometimes reduce bacterial shedding temporarily, it does not eliminate the infection. Dogs remain positive and infectious for life. There is also no commercially available vaccine for B. Canis in dogs.
Because of this, brucellosis is a reportable disease. Once diagnosed, your county or state animal health officials are notified and will direct next steps. In many jurisdictions, that means the entire kennel — including all exposed dogs — may be ordered euthanized.
Testing Recommendations from the Society for Theriogenology
The Society for Theriogenology — the leading professional organization for animal reproduction — has clear guidance on this.
All breeding dogs, both male and female, should be tested for Brucella Canis prior to each breeding, based on risk factors and breeding frequency. Males should also be tested and confirmed negative before any semen collection for freezing.
The Society further recommends that all dogs and dog semen imported into the United States be confirmed negative for B. Canis before entry.
The Growing Outbreak Problem in the U.S.
Brucellosis outbreaks are increasing across the United States, particularly within commercial breeding operations. As infected dogs move out of these facilities — either sold as breeding stock or placed through rescue organizations — the bacteria travels with them.
These dogs then co-mingle with other dogs in new breeding programs, foster homes, and private residences. The result is a widening web of exposure that extends far beyond the original source. Dogs can also pick up the infection through non-venereal routes at dog events, shows, and kennels where urine and genital discharge create environmental contamination.
The veterinary and breeding communities can no longer afford complacency around B. Canis testing. The cost of a missed diagnosis is catastrophic — for the dogs, for the kennel, and for the humans involved.
Our Policy: Annual Brucellosis Testing Required for Stud Dogs
For all of these reasons, we now require annual brucellosis testing for any stud being frozen with us. This policy is in line with the Society for Theriogenology’s recommendations and reflects the current reality of B. Canis prevalence in the U.S.
This isn’t optional caution — it’s responsible practice.
Frequently Asked Questions About Brucellosis in Dogs
Can brucellosis in dogs be treated with antibiotics?
No. While antibiotics may temporarily suppress symptoms, Brucella Canis is resistant to treatment and cannot be eliminated from an infected dog. Dogs remain carriers for life.
How is brucellosis transmitted between dogs?
Through direct contact with reproductive fluids, urine, saliva, and feces. The bacteria also persists on contaminated surfaces, clothing, and equipment for months.
Can I catch brucellosis from my dog?
Yes. Brucella Canis is zoonotic. Humans can contract the infection through contact with an infected dog’s bodily fluids. The bacteria settles in bone marrow and can cause chronic, recurring illness.
How often should breeding dogs be tested for brucellosis?
The Society for Theriogenology recommends testing prior to every breeding and before any semen freezing. At minimum, breeding dogs should be tested annually.
What happens if my dog tests positive for brucellosis?
Brucellosis is a reportable disease. Your local animal health authorities will be notified and will determine the required course of action, which may include euthanasia of the infected dog and any exposed animals.
Is there a vaccine for brucellosis in dogs?
No. There is currently no vaccine available for Brucella Canis in dogs.
