Flea treatment is toxic to wildlife: Here are the facts
Peter Cairns/2020VISION
Fleas are a primary cause of skin issues and both dogs and cats. Their bites can lead to allergic reactions and can also carry flea tapeworm. Severe infestations can lead to anaemia due to blood loss. Fleas lay lots of eggs and a small number getting into the house can quickly escalate.
There are various treatments on the market for dealing with fleas. Spot on treatments, tablets and injections are preferred. Some attack adult fleas, others interrupt flea development and many new products on the market do both. As a pet owner, we don’t really have time to review all the different brands and chemicals used. With over 1,334 parasiticide products on the veterinary market (as of October 2023), we just trust our vet to know best!
What harm does flea treatment do?
Not all flea treatments are harmful. The Pesticide Action Network warn us about two chemicals which are harmful to human health; fipronil and permethrin. These have both been found to have links to cancer and suspected endocrine disruption which means they can interfere with your hormone system.
Some chemicals are also harmful to wildlife. Researchers at Sussex University in 2021 found fipronil in 100% and imidacloprid in 70% of English rivers they tested. These active substances have been banned from use in agriculture for several years for the harm they do to wildlife such as bees. Concentrations of these substances were found to exceed safe levels on all accounts for fipronil and on 7 out of 20 sites for imidacloprid. The highest levels of pollution were found downstream of wastewater sites which increases the likelihood that these chemicals are coming from household drainage systems and linking the source back to pets. Imidacloprid, a neonicotinoid is both highly mobile and persistent in the environment, able to stay present in water for several years after it has been applied.
This increased concentration in our aquatic systems is thought to be a factor in the ever-decreasing numbers of aquatic invertebrates such as caddisflies and mayflies. These are important species at the bottom of the food chain and their slow extinction has knock on effects on whole ecosystems.
Worming treatment isn’t getting off that easily!
Worming treatments are another class of parasiticides known as endectocides. Some studies have found that the active ingredient of these medications can still be found in the faeces. We know from livestock studies that reducing these chemicals leads to greater diversity in livestock dung such as an increase in the very important dung beetle.
What can be done?
Twenty-four environmental and veterinary organisations – including The Progressive Veterinary Association, Veterinary Poisons Information Service, RSPB and The Wildlife Trusts – have written an open letter calling on the UK Government to ban five toxic pesticides from being included in medicines for cats and dogs. These include:
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fipronil
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permethrin
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imidacloprid
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dinotefuran
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nitenpyram
They’re also calling on the government to close a current loophole which would mean any chemical deemed too harmful to be used in crops is automatically banned from appearing in veterinary medicines. Please share this message with your MPs and make sure that when you next buy flea, tick and worming treatment for your pet, you ask your vet to ensure that the above chemicals are not the active ingredient in your product.
The British Veterinary Association (BVA), the British Small Animal Veterinary Association (BSAVA) and the British Veterinary Zoological Society (BVZS) issues their policy position on the use of parasiticide products. They say that veterinary professionals should always take a risk-based approach to prescribing medicines.
The following tips give an example of how their policy position document recommends patients are advised:
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Do not use topically applied products in dogs that swim, are bathed regularly or do hydrotherapy regularly. Do not flush the faeces or urine of orally treated animals down the lavatory and always dispose of faeces responsibly.
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Treat pets at lower risk of infestation less frequently, or not at all – that includes indoor cats all year, and all pets during winter and early spring (the lower risk times of year).
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For preventative treatments, prolong the interval between applications. You can ask your vet about minimum and maximum durations of very high- level protection, but there is likely to be substantial protection for longer durations.
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Avoid using multiple-ingredient products where they are not necessary. Treat for worms or fleas rather than worms and fleas at once.
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Consider not using prophylactic parasiticide treatments at all, and instead regularly monitor for fleas (flea-comb regularly) and ticks (check dogs after walks and use a tick hook) and then treat with parasiticides if they are seen to prevent an infestation building up.
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A flea trap can also be used to monitor for fleas in the home. Although not very useful for clearing an infestation, in the absence of an infestation, a trap being set regularly (overnight, perhaps once a week) in the area a pet frequents and a flea being caught suggests a need for treatment.
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Bathe untreated dogs regularly.
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Hot-wash pet bedding weekly and regularly vacuum areas where pets lie.
At Kent Wildlife Trust, we would add a couple more to this list:
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Talk to your vet – if you’re unsure about what to do and would like to try something with a less environmentally heavy footprint, ask for advice and best practice which will be tailored to your pet.
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Footpaths and leads – keep your dog on footpaths and on a lead in wildlife sensitive areas such as nature reserves.