Is Seresto flea and tick collar unsafe for dogs?

Over the course of nearly a decade, Seresto, one of the most popular flea and tick collars on the market, has been the subject of a whopping 75,000 reports of incidents involving dogs, cats and humans harmed by its use or handling. These reports were sent to the Environmental Protection Agency (EPA) which oversees the pesticide-containing products. These incidents include 1,698 pet deaths and nearly 1,000 documented personal injury cases.

Has the EPA made the public aware of the risks of the collar? No it doesn’t. The problem has now emerged in a Midwest Center for Investigative Reporting story jointly published with USA Today, based on documents received from the Center for Biological Diversity, an EPA watchdog.

In 2019, the EPA released an internal memo investigating flumethrin, one of the active ingredients in the collar, and reviewing the human incidents that had been reported to that agency. In humans, the clinical symptoms varied widely: rashes or skin lesions; Numbness, tingling, or pain; and irritation of the nose, eyes or throat. These signs occurred after the collar was put on the pet, after the pet was cuddled, or after the pet was slept. More serious events were also reported. In many cases, clinical symptoms improved after the collar was removed. Unfortunately, animal deaths seem to have occurred very suddenly.

In addition to flumethrin (4.5%), Seresto collars contain a second chemical active ingredient: imidacloprid (10%). Imidacloprid belongs to the neonicotinoid class of insecticides that are most commonly used in crops in the United States. Although neonicotinoids have been linked to massive bee and butterfly deaths, last year the EPA suggested re-approving imidacloprid and other class members.

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Seresto, which is advertised for eight month protection against fleas and ticks, is the only product that contains flumethrin, and it is speculated that the problem could be the combination of the two pesticides. So far nothing has been confirmed.

As with most pesticides, data on the registration of Seresto was only collected from the company that made it – in this case Bayer AG, a massive German agricultural and pharmaceutical company. The majority of the studies looked at each pesticide individually. According to the Midwest Center report, a 2012 Bayer study found that these two ingredients flumethrin and imidacloprid together have a “synergistic effect,” meaning they are more toxic together. The study found that the “unique pharmacological synergism” started working after just six hours to prevent ticks from sticking and feeding and preventing the transmission of disease.

Karen McCormack, a retired EPO employee who served as both a scientist and a communications officer, was quoted in Midwest Center history as saying that the collars have the most pesticide pet product incidents she has ever seen.

“The EPA seems to be turning a blind eye to this issue and after seven years of increasing incidents, they are telling the public that they are continuing to monitor the situation,” she said. “But I think this is a significant problem that needs to be addressed sooner rather than later.”

In 2019, Bayer sold its Animal Health business to Elanco Animal Health for a combination of US $ 7.6 billion and Elanco shares. This means Seresto is now an Elanco product, but Bayer continues to have a stake in it. As the story goes, Keri McGrath, a spokesman for Elanco, said in an email that the company “takes the safety of our products very seriously and is thoroughly investigating potential concerns related to their use.” McGrath pointed out that regulators have approved the product in more than 80 countries and that the EPA is in the final stages of re-approving both pesticides. (There is no timeline for the final decision.)

It is likely that even this high number of reports is only the tip of the iceberg. Few people, including myself, would consider reporting a flea collar incident to the EPA. Incidentally, it is unclear how the public would know which government agency to report to.

We reached out to the FDA Veterinary Medicine Center (CVM) of the United States Food and Drug Administration (FDA) for more information. According to Siobhan DeLancey of the CVM, the EPA is responsible because the Seresto collar is classified as a pesticide. DeLancey also says the FDA is in control of flea and tick products that are classified as medicinal products and that their regulation is separate from that of the EPA.

Still, she says: “We strongly encourage people whose dogs have had side effects to report their experience to the company and / or us. Manufacturers must provide us with the reports they receive, but staff can also report directly to the FDA if they prefer. Here’s how. “

Bottom Line: If you are using the Seresto collar on your dog or cat and if you or your pets experience harmful effects, contact the EPA and FDA today. Remove the collar and dispose of it responsibly. For the most part – and despite what the company says on the product information sheet – it means you don’t throw it in the trash. Better to take it to the hazardous waste dump near you.

For more information, see the Midwest Center for Investigative Reporting and USA Today reports.

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