title: The role of the environment in transmission of Dichelobacter nodosus between ewes and their lambs.
abstract: Dichelobacter nodosus (D. nodosus) is the essential causative agent of footrot in sheep. The current study investigated when D. nodosus was detectable on newborn lambs and possible routes of transmission. Specific qPCR was used to detect and quantify the load of D. nodosus in foot swabs of lambs at birth and 5-13 h post-partum, and their mothers 5-13 h post-partum; and in samples of bedding, pasture, soil and faeces. D. nodosus was not detected on the feet of newborn lambs swabbed at birth, but was detected 5-13 h after birth, once they had stood on bedding containing naturally occurring D. nodosus. Multiple genotypes identified by cloning and sequencing a marker gene, pgrA, and by multi locus variable number tandem repeat analysis (MLVA) of community DNA from swabs on individual feet indicated a mixed population of D. nodosus was present on the feet of both ewes and lambs. There was high variation in pgrA tandem repeat number (between 3 and 21 repeats), and multiple MLVA types. The overall similarity index between the populations on ewes and lambs was 0.45, indicating moderate overlap. Mother offspring pairs shared some alleles but not all, suggesting lambs were infected from sources(s) other than just their mother's feet. We hypothesise that D. nodosus is transferred to the feet of lambs via bedding containing naturally occurring populations of D. nodosus, probably as a result of transfer from the feet of the group of housed ewes. The results support the hypothesis that the environment plays a key role in the transmission of D. nodosus between ewes and lambs.
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Mohd
authors.initials: M
authors.lastname: Muzafar
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Leo A
authors.initials: LA
authors.lastname: Calvo-Bado
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Green
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Edward M
authors.initials: EM
authors.lastname: Smith
authors.affiliation: Department of Clinical Veterinary Sciences, University of Bristol, Langford House, Langford BS40 5DU, UK.
authors.forename: Claire L
authors.initials: CL
authors.lastname: Russell
authors.affiliation: Department of Clinical Veterinary Sciences, University of Bristol, Langford House, Langford BS40 5DU, UK.
authors.forename: Rose
authors.initials: R
authors.lastname: Grogono-Thomas
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK. Electronic address: E.M.H.Wellington@warwick.ac.uk.
authors.forename: Elizabeth M H
authors.initials: EM
authors.lastname: Wellington
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D020376:Dichelobacter nodosus / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D005535:Foot Rot / Q000382:microbiology / Q000635:transmission*; D016905:Gram-Negative Bacterial Infections / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D018598:Minisatellite Repeats / Q000235:genetics; D008969:Molecular Sequence Data; D011247:Pregnancy; D017422:Sequence Analysis, DNA / Q000662:veterinary; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology / Q000635:transmission*; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial
keywords: D. nodosus; Disease reservoirs; Footrot; Pathogen transmission