Canine brucellosis

Canine brucellose is caused by the brucella canis bacteria. It is considered to be very contagious to other dogs. The bacteria is principally transmitted orally via bodily fluids (sperm, urine, vulva discharge during oestrus, birthing or even while aborting).

There is a very mild risk of transmission from dog to human (there has been about 40 reported cases since 1960). Canine brucellose is listed as a disease that has a mandatory declaration in the U.S.A.


The classical clinical symptom of the infection in females is aborting between the 45th and 55th days of gestation. The less typical symptoms are prolonged pus-like vulva discharge and weakened or dead puppies at birth. In males, it is mostly epidymitis (inflammation of the epidyme) that is the common sign. The other symptoms are skin infections of the scrotum and palpable pain in the area of infection if the infection is recent, testicular atrophy and low quality sperm if the infection is chronic. Infected females and males may become infertile.


Since the bacteria penetrates the cells, diagnosing brucellose is difficult. The most accurate test is the immunodiffusion on agar gel (AGID). If we have a strong suspicion of brucellose, we must proceed with testing once every month over three months. If the three test results are negative, then the animal can be considered as non-infected.

The two goals of treatment are to minimize the propagation of the disease throughout the population as well as stopping its progression in the infected dog. The disease is considered to be incurable. Therefore, an animal with brucellose is considered to be positive for life, even if it’s received an antibiotic treatment or has been sterilized.

1) Sterilization: (castration or ovariohysterectomy) reduces the excretion of the bacteria though the dog remains a carrier.
2) Antibiotic therapy: there isn’t a 100% effective antibiotic. A dog should never be considered cured after one or many treatments.
3) Infected animals should never be kept by humans susceptible to contracting the infection (immunosuppressed).
4) As for contaminated breeders: all animals must be tested. Those that are positive for brucellose must be put up for adoption or euthanized. Every month, over 3 months, tests must be done and those that are positive must be removed from the colony. Then, to a void new contamination, all newly adopted animals deemed for reproduction must be quarantined for 8 to 12 months and tested at the end of this period.

To prevent the contamination of the colony, the reproductive males and females should be screen-tested every 3 to 6 months with a quick agglutination test (RSAT).