title: Survival of the ovine footrot pathogen Dichelobacter nodosus in different soils.
abstract: Dichelobacter nodosus (D. nodosus) is the causative agent of footrot in sheep; one of the most important health and welfare issues of sheep worldwide. For control programmes to be effective, it is essential that the transmission cycle of D. nodosus is understood and bacterial reservoirs in the environment are better defined. This study evaluated the survival of D. nodosus in different soils using soil microcosms. Cultivation independent and dependent methods were used to detect D. nodosus over 40 days from seeding in soil. A D. nodosus specific probe was used for quantification by qPCR and viability was assessed by cell permeability to an intercalating dye, PMA, and by culture. Survival varied dramatically depending on soil type, matric potential (MP) and temperature. Our findings indicate that D. nodosus survival was higher at 5 °C compared with 25 °C in all soils and significantly longer at both temperatures in clay soil (>44% clay) compared with other soil types. Survival under all conditions was longer than 30 days for both culture independent and dependent methods, this is substantially longer than previous studies and, if this is an infectious dose, longer than the current recommendation of resting a field for 14 days to prevent onward infection.
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
authors.forename: Mohd
authors.initials: M
authors.lastname: Muzafar
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
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, United Kingdom.
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, United Kingdom.
authors.forename: Esther
authors.initials: E
authors.lastname: Tichauer
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
authors.forename: Hayley
authors.initials: H
authors.lastname: King
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom.
authors.forename: Philip
authors.initials: P
authors.lastname: James
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, United Kingdom. Electronic address: E.M.H.Wellington@warwick.ac.uk.
authors.forename: Elizabeth M H
authors.initials: EMH
authors.lastname: Wellington
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology; D001386:Azides / Q000494:pharmacology; D004269:DNA, Bacterial; D020376:Dichelobacter nodosus / Q000145:classification / Q000302:isolation & purification / Q000502:physiology*; D005535:Foot Rot / Q000382:microbiology*; D050296:Microbial Viability; D011419:Propidium / Q000031:analogs & derivatives / Q000494:pharmacology; D012756:Sheep; D012757:Sheep Diseases / Q000382:microbiology*; D012988:Soil Microbiology
chemical_list: D000890:Anti-Infective Agents; D001386:Azides; D004269:DNA, Bacterial; C533957:propidium monoazide; D011419:Propidium
keywords: Dichelobacter nodosus; Disease reservoirs; Footrot; Ovine foot disease; Pathogen survival