LONDON, UNITED KINGDOM – Sept, 2022 Farmers are reminded about the importance of testing incoming sheep for scab to avoid introducing a costly issue and administering unnecessary treatments.  

The Sheep Scab Blood ELISA test detects antibodies that sheep produce in response to infection as quickly as two weeks following exposure. 

Farmers bringing sheep onto the farm are advised to quarantine the flock for 3-4 weeks and test 12 animals from each group after two weeks using the blood test. The test costs about £84 for 12 animals.  

The test will indicate whether the group of sheep has been exposed to scab and whether treatment is necessary, explained Independent Sheep Consultant Lesley Stubbings. 

"You cannot tell simply by looking at sheep if they are carrying scab mites. Clinical sheep scab can take weeks, if not months, to present itself, by which time much of the flock can be infected.  

"The Sheep Scab ELISA test means scab can't hide from us anymore. It makes it much easier for farmers to use the right product at the right time, knocking sheep scab on the head," she added. 

Ms Stubbings says using medicines simply as insurance or 'just in case' leads to problems with resistance, but it is also expensive and often doesn't provide the required control.  

"By testing, farmers can be sure whether they need to treat or not," she said.  

Treatments to Control Scab 

Farmers can treat sheep scab in two ways:  

1. Using an injectable group 3-ML such as CYDECTIN 2% LA has been proven to treat scab infestations and prevent re-infestations for 60 days from a single injection.  
2. Plunge dipping using an organophosphate (OP) dip.  

Ms Stubbings says the treatment choice comes down to the most practical method for the farmer, ensuring every animal is treated correctly.  

"The main thing when treating for scab is that you do it properly, whether using an injectable or a dip. There's no reason why you shouldn't use an injectable, providing it is used properly, meaning the correct dose is administered and all the animals are treated. It is a practical option when there's only a small number of sheep to treat or if there aren't the facilities for dipping," she added.  

Impact of Scab  

Scab is such an important condition to control due to the welfare and economic impact it can have, explains Zoetis Vet Ally Ward.  

"Scab is so itchy for sheep, and in the later stages, they will spend all their time rubbing, scratching and biting their wool to alleviate the itching. This is a real welfare concern," she said.  

Figures estimate the cost of sheep scab to the UK sheep industry to be between £78-£202 million a year¹, with labour one of the most significant contributors to the cost. 9% of flocks are infected annually, with rates a lot higher in some hotspot areas².  

The Sustainable Control of Parasites in Sheep (SCOPS) group has worked with Zoetis, the makers of CYDECTIN 2% LA, to produce a Code of Practice for using injectables, which can be found on the SCOPS website   https://www.scops.org.uk/workspace/pdfs/best-practice-use-of-injectable-scab-treatments.pdf