Fleas are an itchy nuisance! They can also cause nasty skin problems, anaemia, and transmit tapeworm as well as bacteria (such as Bartonella). I think we can all agree that flea infestations are best avoided. However, recent studies have highlighted the impact which some flea preventatives may be having on the environment. So how do we balance the health and welfare of our cats with the ever growing need to protect our environment?

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Are flea treatments bad for the environment?

Recent research has found that English rivers are contaminated with fipronil and imidacloprid, two pesticides commonly used in cat (and dog) flea products. Alarmingly, fipronil levels were found to be five times the safety threshold! The risk to aquatic wildlife from fipronil was classed as high, with imidacloprid not far behind, classed as ‘moderate’.

These products are very effective against fleas because they are toxic at even a low dose, can survive for months and they are soluble in water. However, these products are not specific for fleas, meaning they will be harmful to a wide range of other species too. The potential impact on aquatic wildlife, food chains, natural pest controller insects, and crucial pollinating insects such as bees is not to be ignored. 

How are these chemicals reaching our rivers? We know that water contamination can occur from dogs and cats being bathed, with the run-off water ending up in our rivers. Washing of pets’ bedding, and people washing their hands after touching a product or stroking their pet may also contribute to the pollution. Another possibility is that the pesticides are excreted in urine and faeces, and then leach into the soil and groundwater. Some people also choose to flush their pet’s faeces down the toilet, providing another possible source.

Do I need to treat my cat for fleas?

The simple answer is yes! Fleas are uncomfortable for your cat and reproduce at an alarming rate. An infestation doesn’t take long to develop, but can take months to resolve. Heavy flea burdens can cause anaemia, especially in kittens. Fleas can also transmit tapeworm and various infections to your cat. 

Let’s not forget that fleas can bite people too! Flea bites are itchy, and the thought of fleas in our home is not a pleasant one. Although uncommon, they can potentially transmit tapeworm and other infections to humans too. So flea control is not only important for your cat’s health, but also your own. It is especially important for households in which someone is immune compromised.

What can we do about the environmental impact?

One suggestion for reducing the environmental impact has been to move away from year-round flea preventatives. The suggestion being to focus on the times of year when we see the most fleas, so spring and summer. In theory this is a good idea. However, milder winters and central heating mean that we are now seeing flea problems year-round. 

So, how do we balance protecting our cat’s health and our own health, while also protecting the environment? It’s certainly a complex problem, with no easy answer. The veterinary industry is working to come up with solutions, such as more targeted treatment protocols, moving away from multi-drug treatments and making more flea treatments prescription-only. The latter allows greater regulation of these products, alongside proper administration and disposal advice. 

While more research is clearly needed, there are a few points we can all consider at home:

  • You could consider encouraging your cat to use a litter tray, so that their urine and faeces cannot contaminate the soil. (Although never flush their waste down the toilet.)
  • Ensure you administer the product correctly, so that your hands don’t become contaminated. Your vet or vet nurse will be happy to show you if you aren’t sure!
  • If you do bathe your cat, avoid doing so after application of a flea treatment, for the time-period recommended in the manufacturer’s instructions.
  • Don’t use topical treatments on cats who are undergoing hydrotherapy or are bathed frequently.
  • Dispose of any packaging responsibly.

Any decisions based on when, and how often, your cat needs flea treatment need to be decided with your veterinary team.

Are flea tablets better for the environment? 

There are so many options when it comes to flea control! There are spot-ons, flea collars, tablets and injectables. 

Some topical treatments are absorbed into the skin, where they sit and are released from the hair follicles. This means the pesticide may end up on the animal’s bedding, contaminating the water ways when the bedding is washed. The product is also more likely to end up on our hands, which we then wash. 

Flea tablets, injectables and some topical treatments are absorbed through the skin into the body, so are less likely to contaminate the environment by being washed off (directly, via the bedding or our hands). However, unless completely broken down in the liver (rare for products used in cats), the pesticide can still be excreted in the urine and faeces. So they still have the potential to contaminate the environment, although likely to a lesser extent. 

It would make sense that flea tablets, injectables and topical treatments which act systemically (i.e., are absorbed into the body rather than working on the surface of the skin) are better for the environment. Provided that any packaging, faeces and urine is disposed of responsibly. However, more research is needed before we know for sure.

At the moment, there is no definitive answer. Until the research becomes clear, decision making is best done on a case-by-case basis. This means having a discussion with your vet about the best options, tailored for your cat and your family.

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