Along with the transportation of dairy products infected with Brucella melitensis and Brucella abortus, the international dog trade and the lower veterinary control have led to the occurrence of Brucella canis infected dogs in Europe.
Brucella canis (B. canis) infections are spread across many regions in the world (South America, Mexico, South Africa), predominantly in countries with a large population of stray dogs. This ensures high levels of distribution and retention of the pathogen in the dog generations. B. canis can cause abortions in females. However, many cases showed chronically infected puppies were born, survived and became a dangerous source for spread of the disease. Breeding colonies are also exposed on a higher risk for canine brucellosis infection. Most studies report canine brucellosis is indicated in young dogs diagnosed with discospondylitis. B. canis can be transmitted from infected dogs to humans who have close contact like pet owners, vets, laboratory workers. An increase of cases with humans infected with B. canis has been reported, predominantly in patients and children with lower immunity. Symptoms described in B. canis-positive people are weakness, fever, fatigue, spleen enlargement. The epidemiological potential of B. canis is low in comparison with B. melitensis, B. suis and B. abortus, which are usually the pathogens that cause human brucellosis.
PCR is reported to be the more sensitive and reliable method for diagnosis of B. canis infection even in its early stage. It shows the occurrence of Brucella spp. DNA in clinical samples. The PCR method is also used for rapid detection of Brucella infection in dogs with discospondylitis. Serological analyses for detection of antibodies against B. canis often can give false-positive results. Due to this, specialists advise to use a combination of serological tests to obtain accurate results. Most vet clinics use rapid tests for extremely fast qualitative detection (in 20 minutes) of the presence of antibodies against Brucella spp.
Veterinarians recommend combined therapy with tetracyclines and aminoglycosides against Brucella canis. Brucella suis-positive dogs may be successfully cured with a complexed use of doxycycline and rifampicin. Additional treatment with hydroxychloroquine at early stage has reduced the risk of chronical brucellosis disease in human patients. Despite all schemes for antibiotic treatment, no therapy can eliminate completely Brucella canis from infected kennels and the disease can relapse. The spread of B. canis infections can be stopped by strict veterinary control on breeding and dog trafficking in the European countries.