MAT-SLF-Matprogr.:Prosj.fullfin.av SLF

In 2008 ovine footrot was detected for the first time in Norway since 1948. Ovine footrot begins as an interdigital dermatitis that may progress to necrotic separation of the horn from the underlying tissue. The disease causes pain and suffering, and is n otifiable in Norway. Dichelobacter nodosus is the main causative agent, but it acts in synergy with Fusobacterium necrophorum. These bacteria also affect cattle and together with Treponema spp, they are the main aetiological agents of bovine contagious cl aw diseases. The incidence of these diseases has increased in Norway over the last years. Synergism between Treponema spp and D. nodosus is important for the pathogenesis of digital dermatitis, and other contagious claw diseases may predispose for this co ndition. In Norway, sheep are often co-grazed with cattle, and interdigital dermatitis has been recorded in several such cattle herds. D. nodosus isolates belonging to the same serogroup have been detected in co-grazed sheep and cattle indicating possible transfer between the two species. The most central research tasks are to generate knowledge about clinical signs, characteristics of bacterial strains, and predisposing factors. This will support implementation of preventive measures and management of sh eep flocks and cattle herds. It will also improve diagnostic methods. Three PhD-students will collaborate closely. One of them will focus on claw lesions in cattle, the association between clinical findings and bacterial traits, their synergisms and cross -infection of D. nodosus between sheep and cattle. The second PhD student will focus on ovine footrot with emphasis on epidemiology including flock level diagnosis and risk factors in Norway. The third PhD student will work on isolation, genotyping and ch aracterization of the virulence traits of D. nodosus, and design a molecular epidemiological tool for the cross-infection studies.