Dr. Risser's Column: June 2007

Dr. Risser's Column: June 2007

Occasionally I check out the bumpy and pock-marked backyard, victims of the countless moles that call the underground world of my beloved grassy yard home. The neighbors try assorted efforts to banish them (often in vain or, worse, into my yard), but I get incredibly nervous when I hear of anyone using rodent poisons to try to kill moles or other rodents. The recent pet food recalls and tragic poisonings of dogs and cats created some confusion about rodenticides, as such poisons are called. The chemical found in the contaminated food was sometimes called, by the media, a rodenticide, for which it, in fact, is used in Asia, though not typically in North America. This chemical, which works by causing kidney failure, can be distinguished from the “anticoagulant” rodenticides used here. These poisons, by contrast, are extremely potent and effective at blocking the normal blood clotting mechanisms in the body. Unfortunately, they are also readily available in homes and yards, and their sweet taste is appealing to dogs and cats. While dogs are more likely to directly eat the poison itself, cats more commonly indirectly take it in by eating a rodent that has itself eaten the rodenticide. This can make it extremely difficult to even know if a cat has been poisoned until he or she is showing symptoms.

Symptoms of toxicity with anticoagulant rodenticides come from their effects on blocking the body’s production of Vitamin K, a vital part of the so-called clotting cascade. As Vitamin K levels drop over a few days following ingestion of the poison, “routine” knocks and bumps cause an animal’s body to start bleeding uncontrollably. Initial signs can be bruising on large areas of the skin, gums, or eyes. Some animals have nosebleeds or vomit blood. Untreated, animals that are showing symptoms will die. Even with aggressive treatment, if diagnosed too late in the course of the illness, many animals do not survive.

Important considerations with animals that have, or may have, ingested rodenticides is EARLY and AGGRESSIVE treatment. Even a very small amount of poison can be fatal. The first goal of treatment is removal of any rodenticide that is still in the animal’s stomach, if it was recently eaten, by inducing vomiting. Contact your veterinarian for recommendations on how to best do so. Further treatment often involves administering activated charcoal or other toxin adsorbents, and starting Vitamin K therapy. Vitamin K usually starts as an injection, followed by at least 4 weeks of daily oral medication. Even animals suspected of ingesting anticoagulant rodenticides should be treated prophylactically.

Animals already displaying clinical signs may require intensive care and blood transfusions. These animals should be minimally-handled to avoid further trauma that could start an additional bleeding episode. These are challenging and often sad cases.

If you have pets, or know of animals that have access to your home or property, be extremely cautious with rodent poisons, or avoid them altogether. Take any possible exposure very seriously. For my part, I’ll just continue, grudgingly, to view my mole-riddled yard as a current fact of life.