Lyme-borreliosis in dogs: Risk of infection, interpretation of laboratory diagnosis and vaccination

Lyme-borreliosis is the most frequent tick-borne disease in humans and anim als in Germany. The risk of infection is high and leads to seroconversion i n 25 per cent of all dogs. This limits the value of serodiagnosis. Thus cli nical diagnosis of the diseased dog is most important. The multisystemic in fection causes manifestations of the disease in several organ systems, incl uding the skin. However this opens possibilities to take skin biopsies from any part of the body for cultural isolation of borrelia. This direct demon stration of the active infection needs 3-4 days and was successful in 98 pe r cent of infected cases. In 1999 a vaccine for dogs, based on an European strain of B. burgdorferi sensu stricto was introduced to the German market by Merial company which promises an active protection. With experimental in fection of vaccinated dogs no dissemination of borrelia into the organs app eared. Through natural infection acquired antibodies and antibodies produce d by vaccination cannot be differentiated and may confuse the serological d iagnosis in case of disease. Already existing active infections and disease s suspicious for Lyme-borreliosis occurring after the end of the protective vaccination immunity of vaccination need to be diagnosed by isolation and demonstration of the borrelia.