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Managing sheep scab in UK flocks: there may be trouble ahead



A male Psoroptes ovis, the parasitic mite that causes sheep scab.

Press release issued: 1 October 2018

Parasites, including sheep mites, remain one of the most important limitations to animal health, welfare and productivity. A University of Bristol research paper about managing scab mites in UK sheep flocks has been presented with an Impact Award by the Vet Record, the official journal of the British Veterinary Association (BVA).

The 2018 'Vet Record Impact Award' has been given to the paper 'First evidence of resistance to macrocyclic lactones in Psoroptes ovis sheep scab mites in the UK'.  The research was carried out by MSc student, Emma Doherty, while working with Professor Richard Wall in Bristol's School of Biological Sciences, in collaboration with co-authors Dr Stewart Burgess at the Moredun Research Instituteand Dr Sian Mitchell at the Animal and Plant Health Agency. The work was supported by Zoetis Animal Health.

Sheep scab is a clinical condition caused by the infection of sheep by parasitic Psoroptes mites. It is a growing problem of considerable economic and animal welfare concern in the UK. This paper presents the first quantitative evidence showing that scab mites have now developed resistance to one of the macrocyclic lactones – one of the main classes of compound widely used to treat and prevent scab. The research highlights the major difficulties that will be encountered by farmers and vets in managing scab as macrocyclic lactone resistance becomes more widely established in the UK.

Richard Wall, Professor of Zoology, said: "I am delighted to accept this award on behalf of my co-authors. Sheep scab is an ongoing problem and urgent, evidence-driven action is required to manage its increasing prevalence. 

"Unfortunately, dependence on one or a small number of endectocides to control any group of parasites will inevitably result in selection for resistance and, if Psoroptes mite resistance to macrocyclic lactones becomes widespread, this will make the fight against scab all the harder."

The prize was awarded at the BVA Members’ Day held on Thursday 20 September at the National STEM Learning Centre at the University of York.

Further information


'First evidence of resistance to macrocyclic lactones in Psoroptes ovissheep scab mites in the UK' by Emma DohertyStewart BurgessSian Mitchell and Richard Wall in Vet Record

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