Detection of spirochetes by polymerase chain reaction and its relation to the course of digital dermatitis after local antibiotic treatment in dairy cattle

The aim of the study was to monitor the course of digital dermatitis after local antibiotic treatment in an experimental group (treated on diagnosis) and a control group (treated 5 days later). The present study was carried o ut on 2 farms involving 18 animals. Monitoring was performed by means of cl inical findings and detection of spirochetes on the surface of the lesions, using a polymerase chain reaction. Superficial wound smears were taken bef ore and alter treatment. Twelve animals on both farms followed the classica l healing process, bur sis animals responded poorly to treatment. We observ ed that without treatment, there was no sell-cure in the control group with in 5 daps. There was a significant improvement in the clinical condition of ail animals after treatment on both farms, during the follow-up period. Th e time until reappearance of new digital dermatitis lesions was not signifi cantly different between the experimental and control group, but it was dif ferent between the two farms which could be due to the influence of farm fa ctors. Using primers specific for Treponema denticola and Treponema vincent ii, all the disease stages had at least one positive polymerase chain react ion result indicating the presence of spirochetes in samples of all the dis ease stages during the healing process. This implies that the spirochetes a re not completely eradicated from the surface of the lesions after treatmen t. it was also observed that the classical ulcerative disease stage (M2) ha d relatively more positive polymerase chain reaction results compared to an y other disease stage, showing a possible link between the presence of spir ochetes and clinical disease.