The Sustainable Control of Parasites in Sheep (SCOPS) group is launching a campaign reminding sheep farmers, contractors and prescribers that Organophosphate (OP) can only be used as a plunge dip.
Lesley Stubbings of SCOPS says:
As we go into autumn and winter the number of cases of sheep scab will increase. We must make sure that when OP is used it is fully effective, and the only way to achieve that is with a plunge dip.
In 2018, cases of resistance in sheep scab mites to the injectable products were confirmed. Since then there has been an increase in the number of flocks using OP, which once used correctly will remove resistant mites from a flock.
"However, it is clear that despite warnings to the contrary, there are still instances where farmers being sold OP and are then using showers, jetters or sprayers to apply the product to sheep,” said Lesley.
This results is the survival of some mites, leaving sheep infested and able to spread scab when apparently they have been treated.
"Even more worrying is the risk that this sub-lethal exposure to a treatment will result in the development of mites that are resistant to OP, which is our last line of defence," she added.
SCOPS fact check:
- Showers and jetters do not treat sheep scab effectively. This is because the OP must get down to the skin to kill the mites and these methods cannot achieve the penetration of the fleece that is necessary;
- OP dip is only authorised for use as a plunge dip. This means that OP dip should not be prescribed for use via any other application method (e.g. via a shower, jetter or sprayer). The VMD's Enforcement Team will take action in response to any reported cases of the sale or promotion of OP dip for use via an unauthorised application method. This may include referral of such cases for disciplinary consideration by the RCVS or SQP registration body, as appropriate;
- Resistance to OP - there is a real risk that mites may develop resistance to OP if they are subjected to a sublethal dose via a shower or jetter.