Pet owners could be banned from buying monthly over-the-counter flea and tick treatments in a bid to reduce their use, due to environmental contamination.

Ministers are considering restricting access to spot-on treatments and collars to prescriptions provided by vets and medical professionals, and avoiding preventative treatment where possible.

The move comes amid evidence the poisons are killing songbirds, which like to feather their nests with dog and cat hair, as well as contaminating rivers, killing aquatic life.

This is because the powerful toxins are water-soluble, so they easily wash into rivers if a dog goes swimming, and into water when a pet owner washes their hands after application.

A Department for Farming and Rural Affairs (Defra) spokesperson said research from their Veterinary Medicines Directorate (VMD) had found residues in fish tissue, wild bird nests, aquatic insects,and coastal waters, suggesting widespread contamination.

Water Minister Emma Hardy is now considering only allowing vets and other medically-trained professionals to prescribe parasiticides, launching an eight-week consultation with the sector.

“This government is committed restoring nature and cleaning up our rivers,” she said.

“We are making progress on reducing the presence of forever chemicals in our waterways and this call for evidence is another important step.

“These treatments play a vital role in pet health and welfare, but it is right that we look at whether they should only be made available for sale via medical practitioners who can advise the public on their correct usage.”

Animal welfare remains paramount, Defra said, and continued access to effective flea and tick treatments for pet owners is a key priority.

A full ban on the sale of fipronil and imidacloprid, is not being considered, for pets.

However, their use in agriculture outdoors has been banned in the UK since 2017 because of the chemicals’ link to declining bee, butterfly and insect populations.

Research funded by VMD highlights fipronil and imidacloprid as an “overlooked” and “important” source of continuing water pollution, due to “many of the UK’s 22 million cats and dogs receiving routine, year-round preventative doses”, suggesting this may be unnecessary.

These scientists recommend a “systematic review” of “prescribing practices”, with the drugs currently given to cats and dogs as “repeated, and often monthly, parasiticide treatment, with some veterinary parasitologists advocating routine year-round preventative flea treatment of all dogs and cats”.

Another report found fipronil in 100% of bird nests tested and imidacloprid in 89% of them and recommended re-evaluation of the “potent and persistent insecticides” on pets as a result.

The authors stated: “Overall, a higher number of either dead offspring or unhatched eggs was found in nests containing a higher number of insecticides… suggesting that contact exposure of eggs to insecticides in nest lining may lead to mortality and lower reproductive success.”

The British Veterinary Association president Rob Williams said these treatments are “important tools” that must be “used responsibly”.

He added: “A tailored, rather than blanket, approach to using these treatments is needed, ensuring an animal’s individual needs are met whilst minimising the impact on the environment.”

The Society of Practising Veterinary Surgeons have “strongly encouraged” a shift from blanket preventative use to individualised risk assessments, considering factors like a pet’s lifestyle, seasonality, and the prevalence of specific parasites in the local area.

Most pet owners could replace routine flea treatments with regular combing and testing to see if fleas are present, an SPVS factsheet suggests, adding: “phasing-out routine prophylaxis where patent infections are not suspected or likely” would allow “reserving preventative treatment regimes for higher risk patients”.

Trade body Noah said flea treatments should be made “more accessible, not more expensive”.

Noah chief executive Dawn Howard said: “Parasite control is a cornerstone of responsible pet ownership.

“While we support a thorough and transparent review, it is essential that decisions are grounded in sound science and a full understanding of the real-world impacts on animal health and welfare.

“Pet owners are already under financial pressure, and affordability directly influences whether animals receive the treatments they need.”

The RSPCA and company Bob Martin have been approached for comment.

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