Our dogs love to cool off in hot weather, but a dip in the river could reduce their flea and tick protection. Many spot-on treatments wash off in water, forcing dog owners to spend more time and money to keep their pet safe.

These treatments can also do serious harm to a river’s wildlife. Because they are insecticides, they can kill the larvae of species like mayflies, damselflies, and dragonflies. As a food source for fish, bats, and birds, these insects are crucial to the health of our rivers.

If you have a dog, ask your vet about flea treatment tablets, which don’t wash off in water. If you stick with spot-on treatments, explore other ways to beat the heat. A cooling vest can keep your dog refreshed during a walk, while a shallow paddling pool is great for at home.

As we seek to protect both our dogs and our wildlife, it might be time for a new approach to flea and tick treatment. A recent paper from Imperial College London notes that some ingredients have been banned in farming, and highlights the risk of parasites becoming immune to their effects.

One of the paper’s authors, Veterinary Surgeon Dr Andrew Prentis, suggests asking your vet “what is best for [your] pet, what is safe for the environment and whether such regular preventative treatments are needed. In the same way that we only take antibiotics when we’re ill - not every month - we may need to apply the same principle to parasite treatments for our pets."