Sheep Scab Biobank
To understand the spread of macrocyclic lactone resistance across the UK, Moredun is requesting the submission of positive skin scrape submissions for inclusion in a new biobank.
Sheep scab is endemic in the UK and is estimated to infest 10-20% flocks nationally each year. It has severe impacts on both production and animal welfare. Infested sheep suffer from pruritus (itching), which can lead to dehydration, emaciation, secondary bacterial infections, and in severe cases can result in seizures and mortality. The disease is highly infectious and spread through direct contact or through fomites.
There are currently only two treatment options for sheep scab, an organophosphate (OP) plunge dip (diazinon) and injectable macrocyclic lactones (MLs). However, increasing reports of resistance have been reported to the MLs since 2017, with ML-resistance confirmed in 2018 along with evidence of its spread across the UK. This raises a serious challenge for the treatment of sheep scab where dipping is not advised (e.g. during late pregnancy) and threatens our future ability to control the disease if resistance to the OP dip is established.
What will the samples be used for?
The samples will help to confirm the status of ML resistance, assist with mapping the spread of ML resistant mites across the UK and help define the potential origin of ML resistance.
Any samples not used may be stored and used for future research studies to benefit sheep scab control efforts.
How to submit samples
Positive skin scrape samples should be collected and submitted by a veterinary surgeon. Wool plucks are NOT suitable for submission. We are in the process of creating a guide on how to take a good skin scrape, along with information on packaging the sample to comply with UN3373 biological substance requirements.
Each submission must also be sent with a submission form.
How to take a skin scrape
The mites will normally be located around the moist edge of the lesion with the greatest numbers found at the leading edge which is usually the lowest point down the flanks (furthest from the head). Remove excess fleece with curved scissors to expose the edge of the lesion and take the skin scraping using a scalpel blade held at around 45’. Examine the sample microscopically under low magnification (x100). Samples can also be sent to a diagnostic laboratory.
How to package samples for submission
1. Place the sample plus any microscope slides containing mites into a rigid container e.g. screw cap universal or pot.
2. This primary container should then be placed inside a leak proof secondary container such as a Ziploc bag. Blue roll or another suitable absorbent should also be placed inside the bag.
3. This bag should then be placed inside a box or padded mailing bag for shipment and affixed with the correct address label (which can be printed with the submission form). Packages must have a return address. Please complete this on the postage label.
