A NOVEL SPIROCHAETE ISOLATED AND CHARACTERISED FROM SEVERE VIRULENT OVINE FOOT ROT Demirkan

Using immunomagnetic separation with beads coated with polyclonal anti-treponemal antisera and prolonged anaerobic broth culture a novel spirochaete was isolated from a case of severe virulent ovine foot rot (SVOFR). The as yet un-named treponeme differs considerably on morphology, enzymic profile, and 16SrDNA sequence from the only other spirochaete isolated from ovine foot rot. On the basis of 16SrDNA it was most closely related to another un-named spirochaete isolated from cases of bovine digital dermatitis in the USA raising the possibility of cross-species transmission. Further information is required to establish this novel ovine spirochaete as the cause of SVOFR. Introduction Severe virulent ovine foot rot (SVOFR) is a recently identified and important disease of sheep, and an increasing cause of lameness in UK sheep. SVOFR is a chronic, necrotizing disease of the epidermis of the interdigital skin, in some cases involving the entire hoof matrix. Immunomagnetic separation was successfully used to isolate a spirochaete from affected cattle. We have employed a similar approach in a case of SVOFR and describe the morphological, biochemical and genotypic characteristics of the novel treponeme isolated. Material and Methods A flock of sheep from Northern Ireland with epidemic lameness due to SVOFR was selected for study. A biopsy (c.1 gm) of a lesion was taken and immediately placed in Oral Treponema Enrichment Broth, (OTEB: Anaerobe Systems, Morgan Hill, Ca USA), supplemented with rifampicin (5 mg/L) and nalidixic acid (500 mg/L). The biopsy in OTEB was shipped to Liverpool by surface mail (48 hour journey time). The material was placed in fresh antibioticcontaining OTEB supplemented with fetal calf serum (FCS: 10% v/v) and incubated in an anaerobic cabinet, (Don Whitley Scientific, Shipley, West Yorkshire, UK), at 37o C for 24 hours. Immunomagnetic separation: The method used was as described previously for the isolation of a spirochaete from a case of bovine digital dermatitis. Enzyme Profile: The API-ZYM strip system (bioMerieux, Basingstoke, UK) which contains 19 different substrates was used and reactions interpreted according to manufacturer’s instructions. 1 Contact at: Department of Veterinary Surgery, School of Veterinary Medicine, Kafkas University, 36100-Kars, TURKEY Close window to return to IVIS