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Miscarriage Due to Bacterial Infection (Brucellosis) in Dogs

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Brucellosis in Dogs


Brucellosis is a contagious bacterial disease that affects several animal species. In dogs, this condition is caused by a bacterium known as Brucella canis. The bacteria are typically spread through breeding and through contact with tissue remains from miscarried pregnancies, but may also be spread through an infected mother’s milk. An infected bitch may spontaneously abort the pregnancy, or may have a marked decrease in her fertility levels. If she does carry the puppies to term, they often still die as a result of infection, since puppies have undeveloped immune systems that are not capable of fighting these aggressive bacteria.


Brucellosis is highly contagious amongst dogs. It frequently affects kenneled dogs, but dogs that have never been kenneled may also become infected. This disease is responsible for a decrease in 75 percent of pups that are weaned in breeding kennels.


The Brucella bacterium has zoonotic properties, meaning that it can affect humans, and possibly other animals as well. Though chances for human infection are found to be quite low, it is still best to take preventative precautions while treating an infected dog. An extra sanitary environment, along with personal protection (e.g., disposable gloves) should be standard until the infection has been eradicated entirely.


While brucellosis can affect any breed of dog, it is commonly seen in beagles. The causative organism has a tendency to replicate successfully in the reproductive organs of both male and female dogs. It causes abortion and infertility in female dogs, and testicular atrophy and infertility in male dogs.


Symptoms and Types



  • Typically appears healthy
  • Vaginal discharge
  • Decrease in fertility
  • Loss of sex desire
  • Abortion (usually 6-8 weeks after conception, though may abort at any stage of pregnancy)
  • Birth of weak pups



  • Swollen scrotal sacs in males due to infection of testicles
  • Shrinkage of testicles
  • Infertility


Both genders:

  • Inflammation of the eyes/cloudy eyes
  • Back pain due to infection of spinal disks
  • Leg pain or weakness
  • Weakness
  • Lethargy
  • Swollen lymph nodes
  • Fever
  • Loss of control over movements in chronic cases




You will need to provide a thorough history of your dog's health leading up to the onset of symptoms. Once your veterinarian has thoroughly examined your dog, standard fluid samples will be taken for laboratory testing. However, often it is the case with Brucella canis that it is not diagnosed with standard blood tests; laboratory test results are usually normal.


A combination of various serological tests may be necessary in order to confirm the diagnosis, but usually, a titer test will verify that your dog is infected with the Brucella bacterium. This test measures your dog's antibody levels and will show whether there are specific antibodies to the Brucella organism in your dog's blood. To confirm the presence of Brucella, your veterinarian will take blood samples to grow the organism on culture media in the laboratory. Similarly, cultures of vaginal fluids or semen can also be used for isolation of the causative organism. As the lymph nodes are also affected by this infection, a lymph node biopsy can also be used in some cases for diagnostic purposes.




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