Treponema DNA in bovine 'non-healing' versus common sole ulcers and white line disease.

Bovine digital dermatitis (BDD)-associated 'non-healing' white line disease (nhWLD) and 'non-healing' sole ulcers (nhSU) are increasingly encountered in cattle. Using established PCR protocols, 42 nhWLD/nhSU, 25 BDD and 15 common WLD DNA isolates were screened for the presence of Treponema DNA. Obtained amplicons were identified by gel electrophoresis and sequencing. Independent from their source, Treponema DNA was isolated from all lesions, but the lesion type varied with the detected Treponema phylotypes. Whilst Treponema pedis was omnipresent, T. medium was almost exclusively identified in BDD and associated nhWLD/nhSU lesions when compared to common WLD. This observation was confirmed by specific T. medium PCR scoring positive for all BDD and nhWLD/nhSU lesions, but for only 1/15 (6.7%) common WLD lesions. It is suggested that T. medium may have an active role in the pathogenesis of nhWLD/nhSU but further work is needed to verify this concept.