title: Experimental infection of cattle with ovine Dichelobacter nodosus isolates.
abstract: BACKGROUND
  Dichelobacter nodosus is the main causative agent of ovine footrot, and there are strong indications that the bacterium can be transferred to cattle grazing on the same pasture as sheep. The aim of this study was to investigate if benign and virulent D. nodosus strains isolated from sheep can be transferred to the interdigital skin of cattle under experimental conditions. Further, we wanted to observe the impact of such infection on bovine foot health, and test the effect of topical chlortetracycline (Cyclo spray(®): Eurovet) on the infection.
  
  
  RESULTS
  Six heifers were included in the study. After an initial 18-day maceration period, three heifers were inoculated on one single foot with a benign strain and three with a virulent strain by adding bacterial suspension in a bandage. The bandages were left on for 17 days, and when removed, D. nodosus was isolated from all six heifers. All six heifers developed interdigital dermatitis. In five of the heifers D. nodosus organisms were demonstrated within the epidermis. Twenty-four days after treatment with chlortetracycline all heifers were negative by cultivation, but tested positive for D. nodosus by polymerase chain reaction (PCR). Two of the six heifers still tested positive for D. nodosus by PCR 49 days after treatment. After 70 days, all heifers tested negative for D. nodosus.
  
  
  CONCLUSIONS
  This study shows that both virulent and benign D. nodosus strains originating from sheep can be transferred to naïve heifers under experimental conditions. Further, the study supports the hypothesis that infections with virulent D. nodosus in cattle are associated with interdigital dermatitis. No conclusion regarding the treatment of D. nodosus infection with chlortetracycline was possible.
authors.affiliation: Norwegian University of Life Sciences, PO Box 8146, 0033, Oslo, Norway. knappemaren@gmail.com.
authors.forename: Maren
authors.initials: M
authors.lastname: Knappe-Poindecker
authors.affiliation: Norwegian Veterinary Institute, PO Box 750, 0106, Oslo, Norway. hannah.joan.jorgensen@gmail.com.
authors.forename: Hannah Joan
authors.initials: HJ
authors.lastname: Jørgensen
authors.affiliation: National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1870, Frederiksberg C, Denmark. tije@vet.dtu.dk.
authors.forename: Tim Kåre
authors.initials: TK
authors.lastname: Jensen
authors.affiliation: Norwegian Veterinary Institute, PO Box 750, 0106, Oslo, Norway. bereket.tesfamichael@vetinst.no.
authors.forename: Bereket
authors.initials: B
authors.lastname: Tesfamichael
authors.affiliation: Norwegian University of Life Sciences, Campus Sandnes, Kyrkjevegen 332/334, 4325, Sandnes, Norway. martha.ulvund@nmbu.no.
authors.forename: Martha Jakobsen
authors.initials: MJ
authors.lastname: Ulvund
authors.affiliation: Norwegian Sheep Health Service, Animalia, PO Box 396, Økern, 0513, Oslo, Norway. lisbeth.hektoen@animalia.no.
authors.forename: Lisbeth
authors.initials: L
authors.lastname: Hektoen
authors.affiliation: Norwegian University of Life Sciences, PO Box 8146, 0033, Oslo, Norway. terje.fjeldaas@nmbu.no.
authors.forename: Terje
authors.initials: T
authors.lastname: Fjeldaas
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000382:microbiology* / Q000635:transmission; D002751:Chlortetracycline / Q000627:therapeutic use*; D020376:Dichelobacter nodosus / Q000502:physiology*; D058066:Digital Dermatitis / Q000188:drug therapy / Q000382:microbiology* / Q000635:transmission; D005260:Female; D005535:Foot Rot / Q000382:microbiology / Q000635:transmission; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology / Q000635:transmission; D034561:Sheep, Domestic
chemical_list: D000900:Anti-Bacterial Agents; D012336:RNA, Ribosomal, 16S; D002751:Chlortetracycline