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Sheep scab spatial distribution: the roles of transmission pathways

BACKGROUND: Ovine psoroptic mange (sheep scab) is a highly pathogenic contagious infection caused by the mite Psoroptes ovis. Following 21 years in which scab was eradicated in the UK, it was inadvertently reintroduced in 1972 and, despite the implementation of a range of control methods, its preval...

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Autores principales: Nixon, Emily Joanne, Brooks-Pollock, Ellen, Wall, Richard
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8243883/
https://www.ncbi.nlm.nih.gov/pubmed/34187531
http://dx.doi.org/10.1186/s13071-021-04850-y
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author Nixon, Emily Joanne
Brooks-Pollock, Ellen
Wall, Richard
author_facet Nixon, Emily Joanne
Brooks-Pollock, Ellen
Wall, Richard
author_sort Nixon, Emily Joanne
collection PubMed
description BACKGROUND: Ovine psoroptic mange (sheep scab) is a highly pathogenic contagious infection caused by the mite Psoroptes ovis. Following 21 years in which scab was eradicated in the UK, it was inadvertently reintroduced in 1972 and, despite the implementation of a range of control methods, its prevalence increased steadily thereafter. Recent reports of resistance to macrocyclic lactone treatments may further exacerbate control problems. A better understanding of the factors that facilitate its transmission are required to allow improved management of this disease. Transmission of infection occurs within and between contiguous sheep farms via infected sheep-to-sheep or sheep–environment contact and through long-distance movements of infected sheep, such as through markets. METHODS: A stochastic metapopulation model was used to investigate the impact of different transmission routes on the spatial pattern of outbreaks. A range of model scenarios were considered following the initial infection of a cluster of highly connected contiguous farms. RESULTS: Scab spreads between clusters of neighbouring contiguous farms after introduction but when long-distance movements are excluded, infection then self-limits spatially at boundaries where farm connectivity is low. Inclusion of long-distance movements is required to generate the national patterns of disease spread observed. CONCLUSIONS: Preventing the movement of scab infested sheep through sales and markets is essential for any national management programme. If effective movement control can be implemented, regional control in geographic areas where farm densities are high would allow more focussed cost-effective scab management. GRAPHICAL ABSTRACT: [Image: see text]
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spelling pubmed-82438832021-06-30 Sheep scab spatial distribution: the roles of transmission pathways Nixon, Emily Joanne Brooks-Pollock, Ellen Wall, Richard Parasit Vectors Research BACKGROUND: Ovine psoroptic mange (sheep scab) is a highly pathogenic contagious infection caused by the mite Psoroptes ovis. Following 21 years in which scab was eradicated in the UK, it was inadvertently reintroduced in 1972 and, despite the implementation of a range of control methods, its prevalence increased steadily thereafter. Recent reports of resistance to macrocyclic lactone treatments may further exacerbate control problems. A better understanding of the factors that facilitate its transmission are required to allow improved management of this disease. Transmission of infection occurs within and between contiguous sheep farms via infected sheep-to-sheep or sheep–environment contact and through long-distance movements of infected sheep, such as through markets. METHODS: A stochastic metapopulation model was used to investigate the impact of different transmission routes on the spatial pattern of outbreaks. A range of model scenarios were considered following the initial infection of a cluster of highly connected contiguous farms. RESULTS: Scab spreads between clusters of neighbouring contiguous farms after introduction but when long-distance movements are excluded, infection then self-limits spatially at boundaries where farm connectivity is low. Inclusion of long-distance movements is required to generate the national patterns of disease spread observed. CONCLUSIONS: Preventing the movement of scab infested sheep through sales and markets is essential for any national management programme. If effective movement control can be implemented, regional control in geographic areas where farm densities are high would allow more focussed cost-effective scab management. GRAPHICAL ABSTRACT: [Image: see text] BioMed Central 2021-06-29 /pmc/articles/PMC8243883/ /pubmed/34187531 http://dx.doi.org/10.1186/s13071-021-04850-y Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Research
Nixon, Emily Joanne
Brooks-Pollock, Ellen
Wall, Richard
Sheep scab spatial distribution: the roles of transmission pathways
title Sheep scab spatial distribution: the roles of transmission pathways
title_full Sheep scab spatial distribution: the roles of transmission pathways
title_fullStr Sheep scab spatial distribution: the roles of transmission pathways
title_full_unstemmed Sheep scab spatial distribution: the roles of transmission pathways
title_short Sheep scab spatial distribution: the roles of transmission pathways
title_sort sheep scab spatial distribution: the roles of transmission pathways
topic Research
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8243883/
https://www.ncbi.nlm.nih.gov/pubmed/34187531
http://dx.doi.org/10.1186/s13071-021-04850-y
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