CANTER: a pan-industry group that will promote sustainable control of equine parasites

Parasitic helminths (worms) are common pathogens of equids across the world. In some cases, heavy infections with these parasites can lead to severe disease. Resistance to the currently available anthelmintics (wormers) is a major issue, particularly in two key pathogens: the cyathostomins (small redworms) and Parascaris equorum (roundworm). Drug resistance in these worms has been demonstrated to all classes of anthelmintic currently available and, in some cases, multi-class resistance has been reported (Nielsen, 2022).

It would seem that no new equine anthelmintics are coming to market, leaving a situation where ever-increasing levels of multi-drug resistance will limit effective parasite control. It is therefore essential that steps be taken to reduce the further spread of anthelmintic resistance.

Central to mitigating the impact of resistance, is the effective dissemination and implementation of evidence-based approaches to parasite control. These focus on moving the equine sector away from interval treatment-based control programmes, where horses are treated regularly with wormers regardless of infection status and with no consideration of the resident worm population's drug sensitivity, to approaches which exploit knowledge of parasite epidemiology to break transmission cycles and employ diagnostics to identify worms present and levels of infection within, or excreted by, individuals.