The rate of spread of sheep scab within small groups of Merino and Dorper sheep : short communication

A single Merino sheep, artificially infested with the sheep scab mite, Psoroptes ovis, and a similarly infested Dorper sheep were placed with 9 uninfested Merino or 9 uninfested Dorper sheep respectively during winter and the rate of spread of infestation on the uninfested sheep observed. The same procedure was repeated in summer. It took 14 and 8 weeks respectively in winter before all sheep in the 2 groups displayed lesions of sheep scab, whereas in summer it took 10 and 12 weeks before all sheep had lesions.

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Host preference of the sheep scab mite, Psoroptes ovis : short communication

Journal of the South African Veterinary Association ◽

10.4102/jsava.v73i3.577 ◽

2002 ◽

Vol 73 (3) ◽

Cited By ~ 1

Author(s):

T. Meintjies ◽

L.J. Fourie ◽

I.G. Horak

Keyword(s):

Host Preference ◽

Short Communication ◽

Psoroptes Ovis ◽

Sheep Scab ◽

Merino Sheep ◽

Sheep Breeds ◽

Dorper Sheep ◽

Boer Goats

Sheep scab mites, Psoroptes ovis, collected from a Merino donor sheep, were used to infest Merino and Dorper sheep, and Angora and Boer goats. Mites were placed on the sheep on 1 or 2 occasions and on 5 occasions on the goats. All the animals were examined at regular intervals for the presence of scab lesions and living mites. Both sheep breeds developed lesions, but those on the Merino sheep were always larger than those on the Dorper sheep at the same intervals after infestation. None of the goats developed lesions or showed signs of irritation, or harboured any mites.

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Sheep scab spatial distribution: the roles of transmission pathways

Parasites & Vectors ◽

10.1186/s13071-021-04850-y ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Emily Joanne Nixon ◽

Ellen Brooks-Pollock ◽

Richard Wall

Keyword(s):

Disease Transmission ◽

Movement Control ◽

Cost Effective ◽

Infected Sheep ◽

Disease Spread ◽

Psoroptes Ovis ◽

Long Distance ◽

Sheep Scab ◽

The Uk ◽

The Impact

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

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