Are Seresto Flea and Tick Collars Harmful to Dogs?

On March 2, USA Today published an article about the Seresto collar, originally developed and brought to the market by Bayer Animal Health in 2012. The article highlighted the fact that the United States Environmental Protection Agency (EPA) has received nearly 1,700 reports of animal deaths associated with use of the collar. Worried pet owners have been flooding their veterinarians’ offices with calls about whether to remove their pets’ Seresto collars.

Dog owners should be aware that every effective pesticide will cause adverse effects in some animals; that’s the nature of products that are meant to kill parasites. But there are a number of things you can do to reduce the potential for harm to your dog:

• Don’t use any flea- and/or tick-killing or –repelling pesticides unless your dog needs that protection. If you are lucky enough to have never observed fleas in your home or on your dog, you may have no need for flea-control products; don’t buy them unless you need them! In some parts of the country, fleas and/or ticks are a fairly constant threat to pets and pesticides are needed to control and manage infestations. (I put the collars on my dogs when I am planning to hike with them in areas where ticks are numerous, or when my dogs get exposed to a dog with fleas. The rest of the year, they go without!)
• Use an integrated pest management (IPM) plan to control persistent flea infestations, so you can use pesticides less frequently in the future. This link provides a good source of information on how to do that.
• If the pets in your home repeatedly get infested with fleas, try to identify the source of reinfestations. Indoor/outdoor cats are often the culprits, as they may rest in places frequented by flea-infested mice, rats, squirrels, or chipmunks, picking up fleas there and inadvertently bringing them back home to reproduce.
• If you have used a particular flea/tick-control product and your dog had an adverse reaction to that product, note the information in any place that will help remind you to avoid that product or its active ingredients in the future. My granddog Cole had an adverse reaction to Frontline once, vomiting once or twice on the day after the spot-on was applied and exhibiting diarrhea for a day or two after that. About a year later, my son, misremembering which product had caused the adverse response, inadvertently used Frontline on Cole again (after getting fleas from a visit to a friend’s infested home), with the same response. Aghast, he called me to confirm that Frontline was the culprit. Now we both remember, and avoid that product for Cole.
• It’s easy to respond if your dog, like Cole, has an acute adverse response to a particular pesticide. (In the case of an adverse response to a spot-on pesticide, you can give your dog a series of baths to help eliminate all of the pesticide that was not yet absorbed into his skin. If your dog has an adverse response after you have put a Seresto collar on him, remove the collar and bathe him well.) But if your dog has chronic health problems, you may need to more deliberately consider whether any of the topical or oral pesticides you have administered to him may be connected to his health problems. We wouldn’t recommend giving dogs with cancer or those who suffer from seizures any pesticides whatsoever. Instead, we’d use whatever IPM tactics were at our disposal to control fleas if necessary, and would avoid tick habitats at all costs.
• If you have used a particular pesticide product on your dog with great success (fleas disappeared, walks in areas known to be infested with ticks did not result in any or just a few tick-attachments) and without any adverse events, stick to that pesticide if you need one in the future. Don’t introduce an entirely new pesticide that may pose potential side effects for your dog without a solid reason to do so.

That last tip is why I’m not going to stop using Seresto and start using some new product. Neither of my dogs has had an adverse response of any kind to the collars. If either one had, I would avoid that product, but I’m not going to expose them to a new pesticide; I have evidence that Seresto is not causing them harm, but I’d be starting from scratch with a new pesticide.

It’s easy to forget what life was like before we had effective, relatively safe, long-lasting pesticides to kill fleas and ticks on our dogs. Many dogs suffered much more than their modern counterparts. Tick-borne diseases kill many dogs annually, and make many more suffer from chronic effects; without the measure of control offered by pesticides, these numbers would be much higher. Also, prior to the modern age of pesticides, it was very common to see dogs whose front teeth were worn to the gums from just chewing their own bodies in an effort to relieve the horrible itching caused by flea bites. While we would like people to use pesticides more sparingly and carefully, we wouldn’t like to go back to having none of these substances at our disposal.