Brucella canis: The Sneaky Pathogen Causing Infertility and Zoonotic Risks in Dogs"

Introduction

While the news of Rabies and Parvovirus dominates the front pages of veterinary journals, a stealthy and cunning foe, Brucella canis, silently attacks breeding stock and poses a danger to the general public. As a Gram-negative, facultative, intracellular coccobacillus, Brucella canis is the primary causative agent of Contagious Abortion and Reproductive Failure in Dogs. But most importantly, it's a Zoonotic disease, meaning that it can leap from your loyal canine companions to you.

Transmission

The transmission of Brucella canis from one dog to another, or from a mother to a puppy, or even from a puppy to a human, is a complex and not yet fully understood subject. However, Brucella canis is a highly contagious disease and can be transmitted as follows:

Oronasal contact

Oro-Nasal transmission of vaginal discharge, aborted fetuses, or urine.

Venereal Transmission

Venereal transmission, i.e., from a female in heat to a male through coitus.

Vertical transmission

Vertical transmission, i.e., from a pregnant female to a puppy or from a nursing female to a puppy.

Clinical Signs of Brucella canis Infection

While most infected dogs are asymptomatic, i.e., "healthy carriers" of Brucella canis, there are a few important signs that you need to look out for.

 In Females (Dams):

Late Term Abortions:

occurring between 45 to 60 days of gestation.

Early Embonic Death:

Often mistaken for a "failed breeding" or "blank" pregnancy.

Vaginal Discharge

often colored and occurring after abortion.

In Males (Sires):

Epididymitis and Orchitis, 

i.e., inflammation of the testicles.

Scrotal Dermatitis,

 i.e., irritation of the scrotum from constant licking of the area.

Sperm Abnormalities,

 i.e., increased head-to-tail agglutination and poor

The Zoonotic Risk:

Can Humans Get Sick?​Yes. Although less common than in livestock (B. melitensis), Brucella canis does pose a very real danger to veterinarians, lab techs, and breeders.

Symptoms in Humans

​What Are the Symptoms of Brucella Infection in Humans?​Known as "Undulant Fever," it results in recurring high fever, night sweats, fatigue, and joint pain.

Precautions

​What Precautions Should I Take?​Always wear gloves when handling birth fluids or cleaning kennels of suspected dogs.

​Diagnostic Protocols

​As medical professionals, how do we diagnose Brucella canis infections? Well, there are specific tests that need to be done for a positive diagnosis:

​RSAT (Rapid Slide Agglutination Test): 

This is a great test. It's quick, but sometimes yields "false positive" results.

​TAT (Tube Agglutination Test):

Used as a secondary test to confirm a positive RSAT result.

​Blood Culture:

The "Gold Standard" for diagnosis, although difficult to culture Brucella.

​PCR (Polymerase Chain Reaction):

A very sensitive test for detecting Brucella DNA in a blood or tissue sample.

​Management and Prevention

​Is there a "cure" for Brucella canis infections? Well, there isn't a "cure" for Brucella canis, as the bacteria reside within the cells of the host animal (intracellular), making it difficult for the antibiotics to penetrate the cell.

​What's the "Test and Segregate" Policy? 

In breeding kennels, infected dogs should be removed from the breeding program and spayed/neutered.

​What Antibiotics Are Used to Treat Brucella canis Infections?

A combination of Doxycycline and a secondary drug, such as Streptomycin, may be used, but the infection often relapses.

​What's the Screening Policy for Brucella canis Infections?

All dogs should be tested before breeding to keep the kennel Brucella-free.

​Conclusion

​Brucella canis Infections are a very big problem for us as a veterinary community, but if we keep up proper hygiene and testing of our breeding stock, not only will our animal's reproductive health be safe, but ours will be as well.