As dog owners, many of us routinely give our dogs preventative worm treatments to help protect our beloved pets from becoming infected with any nasty and unpleasant parasites. But do you ever think about whether these treatments are contributing to any environmental damage? And if there is a way to reduce this risk without compromising our pet’s health? 

How dog worming products can contaminate the environment

Many popular worming treatments are sold as broad-spectrum products. This means that one product treats many different parasites including worms, fleas, mites and sometimes ticks. These broad-spectrum treatments usually contain a combination of drugs enabling the product to treat most common parasites in one go. 

So far, research into the environmental effects of worming treatments for dogs is limited. However, imidacloprid, a flea treatment that is routinely combined with many dog worming products has been found to have a concerning effect on the environment. 

Environmental effects of imidacloprid and fipronil 

Research has shown that along with the flea treatment fipronil, imidacloprid has been found in several English rivers. This is concerning because imidacloprid is highly toxic to invertebrates at low doses. So it has the potential to eliminate many invertebrate species. This can consequently result in the decline of aquatic species that feed on invertebrates, disrupting our very delicate ecosystem.

Currently, our knowledge of the true extent of environmental contamination from worming treatments is limited; and we do not know if other worming medications have less environmental impact or not. You should speak to your vet about any concerns you might have about the environmental effects of your pet’s worming treatment. So your vet can help you safely reduce your pet’s preventative parasite usage without compromising their health. 

Topical wormers 

Topical wormers are commonly applied to the skin as a spot-on formulation. These wormers can be easily washed or shed into the environment, resulting in the contamination of watercourses. 

Many dog owners will be aware that swimming is a common way for spot-on medications to enter water. But there are other ways that small amounts of topical wormer can contaminate waterways:

  • Swimming or hydrotherapy
  • Bathing 
  • Rubbing against bedding or soft furnishings, which are then washed 
  • Shedding hair follicles outside, which can potentially make their way into waterways. 
  • Washing hands after stroking fur or applying medication 

Systemic wormers 

Systemic wormers are often given in a tablet form. This formulation may appear to be the safer option for the environment. But environmental contamination can still occur with the use of tablets. This is because certain medications found within tablet wormers can be excreted in faeces or urine. 

There are several ways that systemic wormers can contaminate water courses.

  • Faeces or urine flushed down the toilet can enter wastewater systems 
  • Faeces or urine outside can potentially pass through the soil into waterways or drains and wastewater systems. 
  • Washing hands after giving the medication

How can we limit the harm caused by wormers? 

The environmental effects of worming your dog may seem small but when we consider the size of the pet dog population these effects can quickly build up to significant levels. This means that small changes to our pet’s worming regime can potentially have a positive impact on the environment as increasing numbers of dog owners look at reducing their environmental impact. 

Reduce the use of broad-spectrum parasite treatments

The use of parasite treatments can be reduced for any dogs kept indoors by increasing the treatment interval, as these pets will be at a lower risk of developing infection. During winter, the use of broad-spectrum wormers can also be reduced for some dogs; so flea and tick treatments are not routinely given during lower-risk seasons. Targeted worm treatments can be given during this time if needed. 

Use an individual treatment plan

To help minimise the environmental effects of worming treatments, individual treatment plans can be made by your vet. This enables each pet’s risk factors to be considered, so worming treatments are only given, when necessary, without compromising your pet’s health.

The area of the UK that your pet lives in and their lifestyle may alter their risk for becoming infected with specific worms, enabling worming treatments to be tailored to their needs while ensuring that no unnecessary treatments occur. By working with your vet, a treatment plan can be made for your pet to ensure they have the protection they need without over-treating your dog. 

Choice of wormer 

The most commonly used worming medications are broad-spectrum, so will treat for multiple parasites. This makes it easy to overtreat your dog when using more than one parasite treatment, as so many parasites are covered by each product. However, if you speak to your vet, they can make sure you are not doubling up on specific treatments. So, even if you use over-the-counter products, you should discuss this with your vet to ensure it fits your dog’s treatment plan. This ensures you are only giving your pet the necessary treatments and reduces the risk of environmental contamination.

When worming your dog, it is also important that the right dose is given based on the weight of your pet to ensure the treatment works. Your vet will be able to prescribe all treatments at the correct dose for your pet to prevent any over or under treatment. 

Avoid environmental contamination 

If you are using a topical worming treatment, your pet will need to avoid swimming to reduce environmental contamination. If your dog is regularly in water, whether for swimming or bathing, your vet might advise against using a topical treatment and suggest a tablet version. 

Environmental contamination can also be reduced by returning unused medications to your veterinary practice for safe disposal. You can also wear gloves to apply treatments to prevent getting medications on your hands and contaminating wastewater after hand washing. 

Which is the best wormer for my dog? 

It is currently unknown which wormer is the most environmentally friendly, or even which worming products we should be avoiding. There is no one wormer that is the best choice for every dog, showing how important it is for your vet to make a treatment plan for every individual. 

  • Lifestyle – Is your dog frequently in water? 
  • Temperament – Can the owner easily get their dog to take a tablet? 
  • Geography – Which parasites are commonly found in this location, and are they a risk for your dog? 
  • Other worming medications – Is your dog given any other parasite treatments, such as over-the-counter treatments, to prevent doubling up on treatments? 

When making changes to your dog’s parasite treatment regime it is important that you work with your vet to make sure that any changes are suitable for your pet and will not affect their health (or the risk to yours and your family’s health). 

In the future, research will hopefully provide us with a growing understanding of how worming treatments can contaminate the environment and potentially cause harm to wildlife and our ecosystems. However, in the meantime, you should discuss your concerns with your vet and work together to make the best worming treatment plan for your dog that reduces environmental contamination but keeps your pet healthy. 

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