Longtime objectors to the Environmental Protection Agency’s (EPA’s) 2008 prohibition of second-generation anticoagulants in domestic-use rodenticides, rodent control brand d-CON has finally agreed to come into compliance. A new line of rodenticide baits containing the first-generation anticoagulant diphacinone will be introduced in 2015.
“I’m thankful for that as a veterinarian,” says Ahna Brutlag, DVM, MS, DABVT, a diplomate of the American Board of Toxicology and assistant director of veterinary services for Pet Poison Helpline. In the wake of the EPA reforms, which required compliance by 2011, most manufacturers chose to use bromethalin, a neurotoxin with no known antidote, as their active ingredient.
Brutlag and others saw greater potential for harm in companion animals and children with the new toxin. Pet Poison Helpline initiated a study to document bromethalin exposures from October 2012 through February 2013. The study looked at details of exposure, consumer behaviors related to product use, dose ingested, treatment referral frequency and medical outcome.
“Since the EPA regulations went into effect—since the summer of 2011—from that point on we’ve seen 65 percent more cases of bromethalin [exposure]. We’re seeing quite an increase of calls.”
Brutlag says while she believes the majority of dogs are being treated correctly for bromethalin exposure with appropriate intensive medical care—90 percent of the study cases were successfully treated with early medical intervention and remained asymptomatic—she still believes an anticoagulant such as diphacinone is a better choice. Bromethalin exposure leaves veterinarians with just hours to intervene before clinical signs associated with central nervous system edema develop, which often makes treatment more difficult and expensive.
In contrast, veterinarians have up to five days after ingestion of a traditional anticoagulant before bleeding begins, and the antidote—vitamin K—is effective and inexpensive, Brutlag says. “It’s rare to find a clinic that doesn’t stock it,” she says. In fact, she is currently examining if diphacinone will take less time to treat. While d-CON’s traditional anticoagulants usually required three to four weeks of treatment, Brutlag says that with diphacinone, “We may be able to treat for a shorter length of time—possibly two weeks.”
Veterinarians need to be aware of the different types of rodenticide exposure, she says, because despite the EPA’s efforts to make bait stations pet-proof, the Pet Poison Helpline study found that bait stations and bittering agents don’t deter dogs from rodenticide ingestion. Plus, consumers are often noncompliant when it comes to proper use of rodenticide products.
Brutlag says consumers are buying a bag of product and scattering blocks freely around the house as only one “pet-proof” bait station is included per bag. Usually, she says, dogs will eat one or two blocks in that scenario. However, sometimes dogs will get into the package itself. Packaging is often flimsy cardboard or a plastic bag and dogs will sometimes consume up to a pound of rodenticide. “Of those who get into the package directly, it is a 90 percent emergency room referral rate,” Brutlag says. “That’s where my prime concern is.”
Few other rodenticide manufacturers seem inclined to follow d-CON back to anticoagulants at this time. But because d-CON is one of the largest manufacturers of rodenticides, Brutlag is pleased that the company went against the grain. “d-CON remains committed to ensuring that the rodent population is effectively controlled without impact to the health and safety of children, pets and non-target wildlife,” a release from the company states. “We will work closely with the EPA, state agencies and interested environmental groups to accomplish this mission.”