RT Journal Article SR Electronic T1 Identifying maintenance hosts and risk factors for infection with Dichelobacter nodosus in free-ranging wild ruminants in Switzerland: a prevalence study JF bioRxiv FD Cold Spring Harbor Laboratory SP 691600 DO 10.1101/691600 A1 Gaia Moore-Jones A1 Flurin Ardüser A1 Salome Dürr A1 Stefanie Gobeli Brawand A1 Adrian Steiner A1 Patrik Zanolari A1 Marie-Pierre Ryser-Degiorgis YR 2019 UL http://biorxiv.org/content/early/2019/07/03/691600.abstract AB Footrot is a worldwide economically important, painful, contagious bacterial hoof disease of domestic and wild ungulates caused by Dichelobacter nodosus (D. nodosus). Benign and virulent strains have been identified in sheep presenting mild and severe lesions, respectively. However, in Alpine ibex (Capra ibex) both strains have been associated with severe, fatal lesions. In Switzerland a nationwide footrot control program for sheep focusing on the virulent strain shall soon be implemented. The aim of this cross-sectional study was to estimate the nationwide prevalence of both strains of D. nodosus in four wild indigenous ruminant species and to identify potential susceptible maintenance hosts that could be a reinfection source for sheep. During two years (2017-2018), interdigital swabs of 1,821 wild indigenous ruminants species (Alpine ibex; Alpine chamois, Rupicapra rupicapra; roe deer, Capreolus capreolus; red deer, Cervus elaphus) were analysed by Real-Time PCR. Furthermore, observed interspecies interactions were documented for each sample. Overall, we report a low prevalence of D. nodosus in all four indigenous wild ruminants, for both the benign (1.97%, N = 36, of which 31 red deer) and virulent (0.05%, N = 1) strain of D. nodosus. Footrot lesions were documented in one ibex with the virulent strain, and in one ibex with the benign strain. Interactions with domestic livestock occurred mainly with cattle and sheep. In conclusion, the data suggest that domestic ungulates represent a significant source of infection for wild ungulates, while wild ruminants are likely irrelevant for the maintenance and spread of D. nodosus. Furthermore, we add evidence that both D. nodosus strains can be associated with severe disease in Alpine ibex. These data are crucial for the upcoming nationwide control program and reveal that wild ruminants should not be considered as a threat to footrot control in sheep in this context.