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For Equine Vets Everywhere

Anthelmintic Stewardship and Sustainability – A Call to Arms

News Medicines BEVA News
17 Dec 2021 BEVA

As environmental issues come to the fore in the veterinary sector, President Elect Dave Rendle talks us through the challenges our profession faces and how BEVA aims to address them.

Wind the clock back a few years and environmental issues never made the veterinary press. Now they are regularly front-page news and in the wake of COP26 the spotlight is firmly on sustainability in veterinary practice. The recent BVA policy statement on responsible use of parasiticides in cats and dogs is therefore very timely. BEVA were pleased to have been consulted by the BVA’s policy group prior to the preparation of this statement and to provide a large animal perspective as background to their policy making in small animals.

BEVA’s own sustainability working group chaired by Tim Mair have been working in collaboration with other groups to raise awareness of sustainability in veterinary practices. As part of his postponed Congress, Tim also programmed discussion of the environmental effects of anthelmintics following a presentation by Bryony Sands from the University of Bristol.

Bryony presented the results of her research on dung beetle biodiversity in South West England. The study of 24 farms showed a reduction in dung beetle number and species where parasiticides were used. Rainwater run-off from manure contaminated with ivermectin was highly toxic for the entire 4 months it was stored in the study. Insect emergence and pasture productivity were significantly lower when spread with ivermectin-contaminated manure (Sands 2021).

The BVA position statement and recent correspondence in The Veterinary Record demonstrate the potential environmental damage that parasiticides can cause when applied  to companion animals as well as horses. The solution to this must be found through collaboration across the profession. A more considered approach to the use of anthelmintics is required with all vets now being urged to take a risk-based approach to prescribing them, irrespective of the species they treat.

In the autumn it has become the norm for anthelmintics to be administered to horses de facto to reduce the risk of disease associated with encysted cyathostomins. This approach becomes ever harder to justify and the risk of disease to the individual has to be balanced carefully against the risk not only to the environment but also to the wider equine population as a consequence of anthelmintic resistance.

In order to change human behaviour, simple and consistent messaging is required. This is challenging where parasite control is concerned as there are infinite variables and there is a lack of evidence upon which to hang recommendations. The BVA’s advice highlights the need for greater research to provide evidence-based answers. Where equines are concerned, BEVA and EVJ recently presented the results of their clinical guidelines process and will shortly be publishing evidence-based guidelines

for practitioners. Large knowledge gaps remain but the need to reduce anthelmintic use is clear and vets need to be bolder in questioning the requirement for anthelmintics and avoid hiding behind ambiguity in the veterinary literature.

The need for a more pro-active approach to reducing anthelmintic use was highlighted in work performed by BEVA’s anthelmintic working group that was published in The Veterinary Record earlier this year. By obtaining sales data for faecal worm egg counts and anthelmintics, the group proved that whilst the use of worm egg counts had increased, the quantity of anthelmintics purchased has remained consistent in recent years (Rendle and others 2021b).

Tamzin Furtado and I followed-up by exploring the reasons for failure of owners to engage with anthelmintic stewardship. We reviewed the motivators for human behaviour and challenged whether meaningful reductions in anthelmintic use will ever be achieved whilst anthelmintics remain freely and easily available -  for as long as it is easier to administer anthelmintics than it is to perform diagnostics.

The BVA are again calling for the reclassification of parasiticides to be considered, as well as for restrictions on advertising of pharmaceuticals to be extended to companion animal products. BEVA have discussed the threat of anthelmintic resistance to equine health and welfare with the VMD who have indicated that they have no plans to reclassify anthelmintics. The VMD have however organised a meeting for equine stakeholders to discuss concerns around anthelmintic resistance to which BEVA will contribute.

Some suggest that vets show little interest in the need for anthelmintic stewardship, citing shortcomings in the provision of advice by veterinary surgeons. To combat this, every practice needs to be offering appropriate risk based and diagnostic-led worming programmes that aim to minimise the use of anthelmintics through appropriate management and integration of diagnostics.

BEVA will continue to highlight the dangers of anthelmintic resistance to equine health and welfare and the increasing evidence of ecotoxocity associated with anthelmintic administration. Following publication of EVJ’s clinical guidelines, BEVA

will also look to follow-up with tools that make it easier to engage with anthelmintic stewardship.

The sustainability of parasiticides is a genuine one-health issue that will have to be resolved through collaboration with other groups.

The more veterinary practices can lead by example in publicly advocating a risk based and diagnostic-led approach that minimises the need for anthelmintics, the easier and more productive our engagement with other organisations will be.