Abstract
Abstract
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
Funder
Biotechnology and Biological Sciences Research Council
national institute for health research health protection research unit
medical research council
Publisher
Springer Science and Business Media LLC
Subject
Infectious Diseases,Parasitology
Reference44 articles.
1. Burgess STG, Downing A, Watkins CA, Marr EJ, Nisbet AJ, Kenyon F, et al. Development of a DNA microarray for the measurement of gene expression in the sheep scab mite Psoroptes ovis. Parasites Vectors. 2012;5:30.
2. Agricultural Development Advisory Service. Sheep scab controls in Scotland—a review of the evidence base. The Scottish Government. 2008. https://www.webarchive.org.uk/wayback/archive/20170701074158/www.gov.scot/Publications/2008/07/17113358. Accessed 29 Aug 2019.
3. Kirkwood AC. Some observations on the biology and control of the sheep scab mite Psoroptes ovis (Hering) in Britain. Vet Parasitol. 1985;18:269–79.
4. Loxam JG. Sheep scab epidemic January 1973. State Vet J. 1974;29(85):1–10.
5. French NP, Berriatua E, Wall R, Smith K, Morgan KL. Sheep scab outbreaks in Great Britain between 1973 and 1992: spatial and temporal patterns. Vet Parasitol. 1999;83:187–200.
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