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Brucellosis in Dogs

General Information

Brucellosis is caused by bacteria known as Brucella canis. The disease spreads from one dog to another during breeding or oral contact with vaginal discharges, aborted fetuses and placentas, semen or urine. It occurs most frequently in breeding kennels, though family pets may become infected also.

Pregnant females with brucellosis abort their puppies, while nonpregnant bitches may fail to conceive when bred. Males develop swelling of the testicles and usually become sterile. Some dogs appear to be in excellent health yet are infected and capable of spreading the disease.

Diagnosis is by blood culture and/or blood testing. More than one blood sample is usually required.

Public Health Significance

Brucellosis can affect people, though the chance of infection appears to be remote. Have your physician contact your veterinarian.

Important Points in Treatment

There is no effective treatment for dogs with brucellosis, and no vaccine for prevention is available. Since the disease may spread to other dogs and may also be a threat to human health, the pet may have to be euthanized (put to sleep). Treament can be attempted and testing done to confirm success. Infected animals should be neutered if they have not been prior to diagnosis

Disease Control

The only practical method for controlling brucellosis is identification of infected animals by blood test. Any dog used for breeding purposes should be tested prior to each breeding period. The mate to be used for breeding should be tested PRIOR to exposure for breeding purposes.


Understanding your pet's diagnosis


Brucellosis is a disease caused by Brucella canis which is a bacteria that was first isolated from dead puppy fetuses in the middle 1960’s. It is the most common bacteria that can infect bitches and their fetuses. It seems that over the years much has been written on brucellosis in breeding dogs but despite it all, infection rates may run as high as 8-10%. That’s right, it is suspected that one in ten dogs in this country may carry Brucella canis.

Brucella canis also poses a significant public health hazard since it is transmissible to humans especially those handling aborted fetuses. Humans may develop a serious liver impairment or arthritis.

Medical advancements in controlling this disease have been few and far between. Contrary to some opinions, it is a very difficult disorder to treat and in most cases, treatment is unsuccessful. A prevalent attitude among many people is that "if my dogs get it, then I will treat it." This is a serious mistake because you probably will not cure it and if you do, the individual will probably be sterile or be a poor breeding specimen.

Transmission of Brucella canis
B. canis is sexually transmitted by the mating of infected males and females. Brucella canis in the female dog will live in the vaginal and uterine tissue and secretions for years and except in rare cases, for life. The infected female usually appears healthy with no signs of disease or indication that she is a "carrier" or harborer of the organisms. She can spread the bacteria to other animals through her urine, aborted fetuses, or most commonly through the act of breeding. Once pregnant, the bacteria will also infect the developing fetuses causing illness.

In males, the Brucella bacteria live in the testicles and seminal fluids. An infected male is just as dangerous as the female as he can spread the Brucella bacteria via his urine or semen. Often times there are no signs except in advanced cases when the testicles may be uneven in size.

Litters are commonly aborted, usually in the last two weeks of gestation, or the puppies may die shortly after birth. If a pregnant dog aborts after 45 days of gestation, you should be highly suspicious of brucellosis. Usually the fetuses are partially decayed and accompanied by a gray to green vaginal discharge. This discharge can have very high numbers of Brucella canis. If embryos die early, they may be resorbed and the female may never appear to be pregnant at all.

What are the risks?
The risks are great. Since the Brucella canis organisms are transmissible to humans, it is best to avoid all contact with the dead fetuses and their associated vaginal discharge. The infected mother will likely be unable to sustain a pregnancy in the future. Furthermore she would likely transmit the disease to any male which breeds her causing fertility problems in him as well.

Testing for Brucellosis usually requires a blood test by your veterinarian and all positives should be retested for a confirmation. Since Brucella canis is mainly spread by the act of breeding, it is paramount to test all canines, male and female, prior to breeding. Test between every breeding of different animals. In other words, if a male (or female) was tested one year ago but has bred since, it must be tested again. In the case of a male, if he serviced a female since his last test, then he must be tested again even if his last test was as recent as four weeks ago. Testing is the only sure way to detect carriers.

In cases of abortion, the bacteria may be isolated from the aborted fetuses. Blood tests can also be performed on the mother's blood to help confirm a positive diagnosis of Brucellosis.

When possible, all incoming breeding dogs should be isolated for two weeks upon arrival at the kennel. At the end of two weeks, have the individual (male or female) tested by your veterinarian for brucellosis. Do this even if the dog was tested before shipment. This may seem excessive but you will spend a lot more money if Brucellosis creeps into your kennel, not to mention the disruption in your breeding program and loss of genetic potential.

Artificial Insemination (AI) can lessen the risk of Brucella transfer at breeding. While rare, transmission of Brucella canis to a bitch can occur during AI, especially if infected semen is used. However, AI will protect an infected female from transferring it to a noninfected male.

All positive males and females should not be bred. Surgical spaying or neutering of these individuals is recommended. Various blood tests are available to screen breeding dogs (male and female) and identify those who are infected (carriers). All individuals used for breeding should be routinely tested prior to breeding.

There is no reliable treatment for Brucellosis. Brucella canis lives inside of the dog's cells so it it difficult to reach the bacteria with antibiotics. Any attempt at treatment would require the use of multiple types of antibiotics. Various antibiotics such as doxycycline, minocycline and dihydrostreptomycin have been partially effective at causing a temporary reduction in the bacterial organisms after several weeks of treatment. A complete cure is unlikely. It is recommended that infected animals be castrated or spayed.

As a rule, do not breed with an individual that is said to be treated and cured. (Unless of course it is the last of its breed and even that would be questionable.) "Cured" patients often begin shedding the bacteria months to years after treatments...Don't knowingly take a chance.

Human health hazards
People can become infected with Brucella canis. People should avoid contact with dead fetuses or the discharge from aborting dogs. Transmission has also occurred from contact with secretions from male dogs.

In conclusion, test and isolate. Do not rely on an uncertain cure. If you do not heed these suggestions, then you are playing with fire in your kennel and perhaps with your own health. Remember, statistically one out of ten dogs may be carriers and those are very disturbing odds.

The information on this page was obtained from the site www.peteducation.com