Encyclopedia of Canine Veterinary Medical Information


Brucellosis is a disease caused by a bacteria, Brucella canis. It is found throughout the world. It is spread through contact with aborted fetuses and discharges from the uterus of infected bitches, during mating, through maternal milk and possibly through airborne transmission in some cases. The bacteria enters the body through mucous membranes and spreads from there to lymph nodes and the spleen. It also spreads to the uterus, placenta and prostate gland as well as other internal organs at times.

In female dogs, infection leads to abortion or early death of infected puppies. Infected females may have no other clinical signs. In some cases there may be decreased fertility rather than abortion. This may be due to resorption of fetuses early in their development.

In male dogs, infection of the testicles can lead to infertility due to anti-sperm antibodies developed as the body attempts to fight off the bacterial infection. The testes may atrophy after the initial period of swelling. Scrotal enlargement or infection of the skin over the scrotum may be seen.

In both female and male dogs there may be infection of spinal discs (diskospondylitis) which can cause back pain and rear leg weakness or even paralysis. Eye inflammation may be seen in either sex.

It is not usually possible to culture Brucella canis bacteria from the blood or affected tissues so diagnosis is usually done by titer testing. There is a kit available to veterinarians for testing in their office. It is usually best to retest any dogs found positive on this test with other testing methods since there is a fairly high rate of false positives using the in-house test kit.

Brucellosis is very difficult to treat successfully. A combination of minocycline and streptomycin is thought to be most effective but is expensive. Tetracycline can be substituted for the minocylcine to reduce costs but also lowers the effectiveness of treatment. All infected animals should be neutered or spayed to prevent sexually related transmission. All infected animals should be considered to be lifelong carriers of the disease, even if treated.

It would probably be best not to breed dogs without testing both the male and female for this disease. Breeding should be a deliberate choice -- not a random event! For breeding kennels, routine isolation of new dogs would be a very good idea. After isolation and negative tests at entry into the kennel and one month later, it should be safe to let the new dog mix with the others in the kennel. If infection is suspected at any time, quaternary ammomium (like Roccal Rx) and iodophor (Betadine Rx) disinfectants can kill Brucella organisms in the kennel to limit spread of the disease.

One last thing. It is possible that brucellosis caused by Brucella canis may be a zoonotic disease -- meaning that people could potentially be infected by this organism. It is something to think about when handling infected dogs. Wear gloves around any body fluids and be careful about contaminating yourself in any way.