Parasiticide use needs overhaul – study co-author

A vet and co-author of a new study into the environmental impact of parasiticide treatments has called for significant change in the profession’s attitude towards the products.

Medicine regulators have welcomed the findings, despite warning about enduring knowledge gaps, while the BVA has called for vets to consider animals’ own risks when making treatment decisions.

But Oxfordshire-based vet Martin Whitehead believes enough is already known about the risks of harm the products pose to justify a change of approach by both clinicians and clients.

He said: “The whole system is just wrong. We don’t need to be treating animals that don’t have fleas and ticks.”

Analysis

The analysis, led by researchers from Imperial College London and the University of Sussex, estimated that as much as 9.1% of the imidacloprid administered through spot-on treatments of dogs, plus 6% of fipronil, was discharged through washoff from bathing the animals and the washing of both their bedding and owners’ hands. Further studies are expected to follow, and Dr Whitehead said there were likely to be more avenues of discharge that have not previously been accounted for.

But he is worried that the problem may be being exacerbated by both the use of more powerful products and the trend of offering worm, flea and tick treatments within longer-term pet health plans.

He argued the plans discourage discussion of whether the treatments are needed, adding: “They need to stop.”

A joint policy position developed by the BVA, BSAVA and British Veterinary Zoological Society three years ago urged vets to be “mindful” of the potential for harm arising from parasiticide use and to avoid what it described as “blanket treatment”.

‘Important role’

Responding to the latest paper, BVA president Anna Judson said: “Parasiticides play an important role in preventing and treating parasites in animals, which if left unaddressed can lead to bigger health and welfare issues in both animals and people.

“But it’s important they are used responsibly, and we have called for more research into how parasiticides affect the environment so we can further minimise the impact.

“In the meantime, we encourage vets to consider the risks of an animal’s exposure to fleas or ticks when prescribing or recommending parasiticides, such as evaluating if a single house cat needs treatment at all.”

Dr Judson also urged pet owners who choose to purchase parasiticides in shops or online, rather than through their veterinary practice, to discuss appropriate use and disposal of them with their vet.

Meanwhile, the VMD, which supported work on the study, said it considered the findings to be “key evidence” that will be discussed by the cross-government Pharmaceuticals in the Environment group.

But a spokesperson insisted that a “balanced approach” to the subject was still needed, adding: “It is important to highlight that there are several evidence gaps remaining, including the need to improve understanding of the impacts that flea and tick treatments have on aquatic ecosystems, animal health and human health.”

Campaigners who are calling for an outright ban on the use of several pesticides in veterinary medicines, including fipronil and imidacloprid, have argued that the paper’s findings endorse their position.

But, despite his misgivings about current usage, Dr Whitehead stressed he remains cautious about the idea, partly due to a lack of understanding about the potential impacts of alternative products.

He said: “I’m not thinking of a ban. We still do need to treat the cats and dogs that have got fleas and ticks.

“You could ban them, but what will people use instead? We’ve got all these other treatments and there’s no reason to think they would be toxic. We just haven’t tested them.”