Summary. The aim of this study was to recognize an etiological factor of diseases with symptoms of lameness and subcutaneous tissues oedema, which occurred in 4 dogs after invasions of the ticks. The serological examinations [ELISA and Western blot] were done. In the samples of all 4 sera a presence of specific anti-Borrelia afzelii antibodies (IgG) were detected. The results of serological examinations, and the reaction of sick animals on tetracycline therapy showed, that in all four cases an etiological factor of the diseases were spirochetes Borrelia afzelii. In the light of the research, veterinary practitioners should keep in mind the presence of Lyme disease in dogs in Poland and include it in differential diagnosis for lameness.

Key words: Borrelia burgdorferi, ELISA, Western blott, tetracycline.