Cross-infection of virulent Dichelobacter nodosus between sheep and co-grazing cattle.
Dichelobacter nodosus is the main aetiological agent of ovine footrot and the bacterium has also been associated with interdigital dermatitis is cattle. The aim of this study was to investigate possible cross-infection of virulent D. nodosus between sheep and co-grazing cattle. Five farms, where sheep previously diagnosed with virulent D. nodosus were co-grazing with cattle for different periods of time, were included. The study sample consisted of 200 cows and 50 sheep. All cows were examined for the presence of interdigital dermatitis, and ten ewes, preferably with symptoms of footrot, had the footrot scores recorded. On each farm, the same ten ewes and ten cows were chosen for bacterial analyses. Swabs were analysed for D. nodosus by PCR and culturing. D. nodosus isolates were virulence-tested and assigned to serogroups by fimA variant determination. Biopsies were evaluated histopathologically and analysed by fluorescent in situ hybridization for D. nodosus, Treponema spp. and Fusobacterium necrophorum. D. nodosus defined as virulent by the gelatin gel test were isolated from 16 sheep from four farms and from five cows from two of the same farms. All five cows had interdigital dermatitis. Two of the cows stayed infected for at least eight months. By pulsed-field gel electrophoresis (PFGE), the isolates from the five cows were found to be genetically indistinguishable or closely related to isolates from sheep from the same farm. This indicates that cross-infection between sheep and cows have occurred.
Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep, N-0033 Oslo, Norway. Electronic address: maren.knappe-poindecker@nmbu.no.
Maren
M
Knappe-Poindecker
Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106 Oslo, Norway.
Marianne
M
Gilhuus
National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, DK-1870 Copenhagen, Denmark.
Tim K
TK
Jensen
Animalia-Norwegian Meat and Poultry Research Centre, P.O. Box 396 Økern, N-0513 Oslo, Norway.
Synnøve
S
Vatn
Norwegian Veterinary Institute, P.O. Box 750 Sentrum, N-0106 Oslo, Norway.
Hannah J
HJ
Jørgensen
Department of Production Animal Clinical Sciences, Norwegian University of Life Sciences, P.O. Box 8146 Dep, N-0033 Oslo, Norway.
Terje
T
Fjeldaas
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology / Q000473:pathology / Q000635:transmission*; D020376:Dichelobacter nodosus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D016521:Electrophoresis, Gel, Pulsed-Field; D005535:Foot Rot / Q000382:microbiology / Q000473:pathology / Q000635:transmission*; D005674:Fusobacterium Infections / Q000662:veterinary; D005675:Fusobacterium necrophorum; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D016133:Polymerase Chain Reaction; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology / Q000473:pathology / Q000635:transmission*; D014208:Treponema; D014211:Treponemal Infections / Q000662:veterinary
Cattle; Cross-infection; Dichelobacter nodosus; Sheep