The real and present dangers of resistance
Over-reliance on antibiotics is a serious concern that needs to be urgently addressed by vets and owners alike
STARK warnings have been issued over resistance to wormers and antibiotics used in equines — with the latter having serious implications for human health.
In a session at the British Equine Veterinary Association annual congress this month, experts discussed the major implications of resistance.
David Rendle, a specialist in equine internal medicine from Rainbow Equine Hospital, said that as early as 1945, Alexander Fleming warned that inappropriate use of antibiotics could lead to resistance, which could prove fatal, as pathogens can then not be treated.
‘A greater threat to human health
than cancer’
DAVID RENDLE
“That was more than 70 years ago; we’ve been a bit slow to embrace concerns over antibiotic resistance,” Mr Rendle said.
Citing the coverage of the issue in humans in national media, he said opinion is that this is a “greater threat to human health than cancer”, and that annually,
700,000 people die as a result, a number expected to increase to 10million by 2020 to 2030.
“We hear cynics saying this is politically motivated, and ask whether it affects us in equine practice, but it really is an issue we need to tackle,” he said. “A report in 2016 showed overwhelming evidence that unnecessary use in animals is a significant concern for human health.”
Mr Rendle said resistance can spread not only through the food chain, but via physical contact between humans and animals, so companion animals such as horses are a source of resistant bacteria that threaten human health.
“The problems are out there,” he said. “There’s a general concern that our adoption of antimicrobial stewardship is so slow; it’s possible that’s due to lack of knowledge but I don’t think the concepts are difficult to grasp; the main issues seem to be cultural inertia and fear of client perception when we don’t use antimicrobials even if we know they aren’t truly indicated.”
Mr Rendle said there is often a perception that a vet’s first duty is to an individual horse, which “sometimes trumps” duty to the species, and our own species,
“but this is an increasing issue for equines, and us.”
He said there can be reluctance to change but the Netherlands has reduced its antibiotic use by about 50% in farm animals, and GPs their use in humans by 6.5% from 2011 to 2014.
“We have to face the potential for those 10million human deaths annually, and take collective responsibility,” he said.“As healthcare professionals we have to pull in the same direction as our medical colleagues.”
Celia Marr, a fellow specialist in equine internal medicine from Rossdales Equine Hospital in Newmarket, said antibiotics must be used appropriately, and there are situations in which they are prescribed when monitoring may be a better option.
She added that educating the equestrian community is key, and when looking at alternatives to antibiotics, “there is no doubt we need better evidence from trials — and we need braver vets.”
Tim Brazil, another equine internal medicine specialist from Gloucestershire, spoke of resistance to wormers which, although not related to human health, can have serious implications for equines.
“For a long time we worked on the basis that an ounce of prevention is better than a pound of cure,” he said. “We thought we were preventing worms by giving these drugs fairly willy-nilly but on many occasions we weren’t really treating or preventing.”
Mr Brazil said that when he was training, large strongyles were notorious for causing colic, so this was combated with regular interval dosing, telling clients to “every so often rotate products, without great justification”.
He added that ivermectin was recommended to treat ascarids (roundworm), and that many foals in some stud farms were routinely given this every four to six weeks.
“Now ivermectin resistance is pretty much ubiquitous on some farms,” he said, adding that he has dealt with farms which “have resistance to pretty much every product on the market.
“We need to try to come up with good plans for sensible and cost-effective practice to try to preserve the use of these medicines,” he said.