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Epidemics. Disease transmission on fragmented contact networks: Livestock-associated Methicillin-resistant Staphylococcus aureus in the Danish pig-industry
[Source: Epidemics, full page: (LINK). Abstract, edited.]
Epidemics, Available online 15 September 2012
Disease transmission on fragmented contact networks: Livestock-associated Methicillin-resistant Staphylococcus aureus in the Danish pig-industry
M. Ciccolini<SUP>a</SUP>, J. Dahl<SUP>b</SUP>, M.E. Chase-Topping<SUP>a</SUP>, M.E.J. Woolhouse<SUP>a</SUP>
<SUP></SUP>
<SUP>a</SUP> Centre for Immunity, Infection and Evolution, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh EH9 3JT, UK; <SUP>b</SUP> Danish Agriculture & Food Council, Axelborg, Axeltorv 3, DK-1609 Copenhagen, Denmark
Received 9 December 2011 / Revised 17 August 2012 / Accepted 7 September 2012 / Available online 15 September 2012 / http://dx.doi.org/10.1016/j.epidem.2012.09.001
Abstract
Animal trade in industrialised livestock-production systems creates a complex, heterogeneous, contact network that shapes between-herd transmission of infectious diseases. We report the results of a simple mathematical model that explores patterns of spread and persistence of livestock-associated Methicillin-resistant Staphylococcus aureus (LA-MRSA) in the Danish pig-industry associated with this trade network. Simulations show that LA-MRSA can become endemic sustained by animal movements alone. Despite the extremely low predicted endemic prevalence, eradication may be difficult, and decreasing within-farm prevalence, or the time it takes a LA-MRSA positive farm to recover a negative status, fails to break long-term persistence. Our results suggest that a low level of non-movement induced transmission strongly affects MRSA dynamics, increasing endemic prevalence and probability of persistence. We also compare the model-predicted risk of 291 individual farms becoming MRSA positive, with results from a recent Europe-wide survey of LA-MRSA in holdings with breeding pigs, and find a significant correlation between contact-network connectivity properties and the model-estimated risk measure.
Highlights
- We model the between-farm transmission of LA-MRSA in the Danish pig-industry. - Movement-induced transmission alone can yield a high probability of persistence at very low prevalence. - There are currently no practical, low-cost, farm-based control strategies that will effectively tackle endemicity in the pig-industry. - A low level of non-movement induced transmission strongly affects colonisation dynamics.
Keywords
LA-MRSA; MRSA ST398; Livestock movement network; Mathematical model
Copyright ? 2012 Published by Elsevier B.V.
Note to users: Accepted manuscripts are Articles in Press that have been peer reviewed and accepted for publication by the Editorial Board of this journal. They have not yet been copy edited and/or formatted in the journal house style, and may not yet have the full ScienceDirect functionality, e.g., supplementary files may still need to be added, links to references may not resolve yet etc. The text could still change before final publication. Although accepted manuscripts do not have all bibliographic details available yet, they can already be cited using the year of online publication and the DOI, as follows: author(s), article title, journal (year), DOI. Please consult the journal's reference style for the exact appearance of these elements, abbreviation of journal names and use of punctuation. When the final article is assigned to an issue of the journal, the Article in Press version will be removed and the final version will appear in the associated published issue of the journal. The date the article was first made available online will be carried over.
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Epidemics, Available online 15 September 2012
Disease transmission on fragmented contact networks: Livestock-associated Methicillin-resistant Staphylococcus aureus in the Danish pig-industry
M. Ciccolini<SUP>a</SUP>, J. Dahl<SUP>b</SUP>, M.E. Chase-Topping<SUP>a</SUP>, M.E.J. Woolhouse<SUP>a</SUP>
<SUP></SUP>
<SUP>a</SUP> Centre for Immunity, Infection and Evolution, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh EH9 3JT, UK; <SUP>b</SUP> Danish Agriculture & Food Council, Axelborg, Axeltorv 3, DK-1609 Copenhagen, Denmark
Received 9 December 2011 / Revised 17 August 2012 / Accepted 7 September 2012 / Available online 15 September 2012 / http://dx.doi.org/10.1016/j.epidem.2012.09.001
Abstract
Animal trade in industrialised livestock-production systems creates a complex, heterogeneous, contact network that shapes between-herd transmission of infectious diseases. We report the results of a simple mathematical model that explores patterns of spread and persistence of livestock-associated Methicillin-resistant Staphylococcus aureus (LA-MRSA) in the Danish pig-industry associated with this trade network. Simulations show that LA-MRSA can become endemic sustained by animal movements alone. Despite the extremely low predicted endemic prevalence, eradication may be difficult, and decreasing within-farm prevalence, or the time it takes a LA-MRSA positive farm to recover a negative status, fails to break long-term persistence. Our results suggest that a low level of non-movement induced transmission strongly affects MRSA dynamics, increasing endemic prevalence and probability of persistence. We also compare the model-predicted risk of 291 individual farms becoming MRSA positive, with results from a recent Europe-wide survey of LA-MRSA in holdings with breeding pigs, and find a significant correlation between contact-network connectivity properties and the model-estimated risk measure.
Highlights
- We model the between-farm transmission of LA-MRSA in the Danish pig-industry. - Movement-induced transmission alone can yield a high probability of persistence at very low prevalence. - There are currently no practical, low-cost, farm-based control strategies that will effectively tackle endemicity in the pig-industry. - A low level of non-movement induced transmission strongly affects colonisation dynamics.
Keywords
LA-MRSA; MRSA ST398; Livestock movement network; Mathematical model
Copyright ? 2012 Published by Elsevier B.V.
Note to users: Accepted manuscripts are Articles in Press that have been peer reviewed and accepted for publication by the Editorial Board of this journal. They have not yet been copy edited and/or formatted in the journal house style, and may not yet have the full ScienceDirect functionality, e.g., supplementary files may still need to be added, links to references may not resolve yet etc. The text could still change before final publication. Although accepted manuscripts do not have all bibliographic details available yet, they can already be cited using the year of online publication and the DOI, as follows: author(s), article title, journal (year), DOI. Please consult the journal's reference style for the exact appearance of these elements, abbreviation of journal names and use of punctuation. When the final article is assigned to an issue of the journal, the Article in Press version will be removed and the final version will appear in the associated published issue of the journal. The date the article was first made available online will be carried over.
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