Brucellosis in Dogs

Introduction      

    

Brucella canis is a cause of abortion in kenneled dogs. Dogs are the definitive host of this organism, and natural infections in other animals are rare. Infection has caused a reduction of 75% in the number of pups weaned in some breeding kennels. The disease disseminates rapidly among closely confined dogs, especially at time of breeding or when abortions occur. Transmission occurs via ingestion of contaminated materials or venereal routes. Both sexes appear to be equally susceptible. Transmission of brucellosis from dogs to humans occurs but appears to be very rare.

Although dogs occasionally become infected with Brucella abortus , B. suis , or B. melitensis , these sporadic occurrences are usually closely associated with infected domestic livestock.

Pathogenesis of canine brucellosis

Signs

Primary signs are abortion during the last trimester of pregnancy without premonitory signs, stillbirths, and conception failures. Prolonged vaginal discharge usually follows abortion. Abortions may occur during subsequent pregnancies. Infected dogs may develop generalized lymphadenitis and frequently epididymitis, periorchitis, and prostatitis. Spondylitis and uveitis are occasional complications. Fever is not characteristic.

Diagnosis

Diagnosis is based on isolation and identification of the causative agent or by serology. The organisms can usually be readily isolated from vaginal exudate, aborted pups, blood, milk, or semen of infected dogs. The most widely used serologic test is an agglutination test by a tube or slide method. Nonspecific agglutination reactions occur in some dogs from which Brucella has not been isolated. To eliminate nonspecific antibodies, the serum is treated with 2-mercaptoethanol and retested. An agar gel immunodiffusion test performed in some laboratories is quite specific.

Control

Attempts at immunization have not been successful. Control is based on elimination or isolation of infected dogs identified by positive cultural or serologic tests. Incidence of infection is much lower in kennels where dogs are caged individually. Neutering of infected dogs is sometimes an alternative to euthanasia.

Treatment

Longterm therapy, eg, with a combination of streptomycin or gentamicin and tetracycline, has been successful in many cases.