Good practice may be leaving a loophole.
A type of worm historically associated with intestinal damage, haemorrhage and sudden death could be re-emerging in UK horses.
Large redworm, once considered among the most dangerous equine parasites, was rendered uncommon in Britain thanks to routine worming.
However, it could be creeping back, warns Claire Shand from parasite control specialist Westgate Labs.
“As the industry quite rightly moves towards more targeted parasite control to help preserve wormer efficacy, there is growing discussion around the possibility of large strongyles* re-emerging unnoticed,” she says.
Many horse owners now rely on faecal worm egg counts to monitor their horses’ parasite burden. But these tests cannot differentiate between small and large strongyle eggs which look identical under the microscope in lab tests.
“While selective treatment is essential for slowing resistance in small redworm, we would seek to treat large strongyle infections as soon as they are detected,” adds Claire.
Video highlights the risks
Now Westgate Labs has launched a free film on YouTube explaining the risks.
SQP/RAMAs and animal health advisors are urged to share the ten-minute video with customers and contacts so they better understand the potential threat – and know what to do about it.
The film takes viewers from the stable yard to the laboratory to explain why worm egg counts alone cannot identify large redworm infection and how larval culture testing for large redworm can support targeted parasite control programmes.
Large strongyles, particularly Strongylus vulgaris, have historically been associated with peritonitis type symptoms, intestinal damage, haemorrhage and sudden death due to larval migration through the horse’s blood vessels, says Claire.
Annual screening is recommended for studs, competition and sales yards, horses travelling internationally, premises with frequent horse movement and horses receiving minimal or highly selective worming treatments.
Watch the film here:
*Large redworm is a collective common name for the different species of large strongyles - Strongylus vulgaris, Strongylus edentatus and Strongylus equinus - that infect horses.
