Brucellosis is an infectious disease that can affect many different species. The specific type of brucellosis that infects dogs is a serious infection that causes inflammation in the reproductive organs as well as other organs such as the spleen and lymph nodes. Knowing how to prevent a dog from contracting brucellosis is important for owners of a dog that hasn't been spayed or neutered to understand.
What is Brucellosis in Dogs?
The bacteria Brucella canis causes brucellossis in dogs. There are different types of Brucella bacteria that infect different species of animals but B. canis is the primary one that affects dogs. This bacterial infection is serious, and unlike many other bacterial infections, a dog is usually infected for life if it contracts it.
Signs of Brucellosis in Dogs
- Swollen testicle or scrotum
- Rash on the scrotum
- Shrunken testicles
- Difficulty getting pregnant
- Miscarriage 45-55 days into pregnancy
- Vaginal discharge
- Giving birth to a stillborn puppy
- Giving birth to a weak puppy that dies a few days after birth
- Enlarged lymph nodes
Most of the signs of brucellosis are very different in males and females since they have different reproductive organs but swollen or enlarged lymph nodes may be noted in both male and female dogs that have brucellosis.
Male dogs that have not been neutered have a scrotum with two testicles in it. When infected with brucellosis, one of these testicles can swell to be larger than the other one due to an infection of a part of the testicle called the epididymis. A rash or inflammation of the scrotum may also be present. In chronic, untreated cases of brucellosis the testicles may even atrophy or shrink. Finally, a male dog may be infertile due to a Brucella infection.
For a female dog that has not been spayed it may have difficulty getting pregnant or be infertile. Of those female dogs infected with Brucella that do manage to get pregnant, many will miscarry only a couple of weeks before they should be going into labor, give birth to a stillborn puppy, or give birth do a puppy that is so weak that it dies within a few days after being born. Vaginal discharge is usually also seen in a female dog with brucellosis. In rare cases, other organs such as the eye and spine can be affected.
Causes of Brucellosis in Dogs
The most common form of transmission of brucellosis in dogs is by the oral route but many consider it to be a sexually transmitted disease. Some bacteria is spread in the saliva and urine but the majority of Brucella is spread through vaginal and penile discharge. Dogs tend to lick themselves as well as other dogs and items, so the bacteria is easily spread.
- Licking of infected urine
- Licking of infected vaginal or penile discharge
- Licking infected fetuses or placental material
- Mating with an infected dog
- Inhalation of infected urine
- Inhalation of infected vaginal or penile discharge
- Contact of mucous membranes with infected material
Diagnosing Brucellosis in Dogs
A veterinarian will perform a full physical examination and obtain a history of an intact dog. If there is concern for Brucella canis having been contracted recently, a blood sample will be collected and a rapid slide agglutination test (RSAT) will be performed. Another type of test called an agar gel immunodiffusion test (AGID) may also be performed if infection was thought to be over twelve weeks prior even if an RSAT was performed. It can take up to four weeks after infection before any testing can confirm Brucellosis.
Treatment of Brucellosis in Dogs
Since brucellosis is a bacterial infection, antibiotics will be used to treat a dog that has tested positive for this disease. Treatment usually combines two or more antibiotics and are needed for at least four weeks. Probiotics may be recommended to be used alongside antibiotics to prevent stomach upset. It is important for dog owners to remember though that brucellosis cannot be completely cured and the bacteria can shed intermittently. Neutering or spaying an intact dog with brucellosis will also help to decrease how much bacteria is shed.
How to Prevent Brucellosis in Dogs
Since brucellosis is transmitted via breeding, the best way to prevent a dog from getting it is to have it tested for the infection prior to breeding. Dogs in a breeding kennel situation should be kept away from new dogs until a quarantine period of two to three months has been completed along with a negative test for brucellosis.
Is Brucellosis in Dogs Contagious?
Brucellosis is considered to be a zoonotic disease so both dogs and people are at risk for contracting this type of bacteria. While uncommon in a healthy adult, brucellosis can occur in an immune-compromised person after coming into contact with an infected dog. But despite the low risk, gloves should always be worn by any person that is in contact with bodily discharge, fetuses, and the placenta of an infected dog, and proper hand washing techniques should be followed.
Santos, Renato L, Souza, Tayse D., et al. Canine Brucellosis: An Update. Frontiers in Veterinary Science, vol 8, 121, 2021. doi:10.3389/fvets.2021.594291
Brucellosis in Dogs. VCA Animal Hospitals.
Best Practices for Brucella canis Prevention and Control in Dog Breeding Facilities. Animal and Plant Health Inspection Service, United States Department of Agriculture.
Hensel, Martha E et al. Brucellosis in Dogs and Public Health Risk. Emerging infectious diseases vol. 24,8 (2018): 1401-1406. doi:10.3201/eid2408.171171