For the past few months, our household has been battling some unwanted tenants. Those of you who live in the country may empathize with our situation, especially after the farmers harvest their crops. The pesky critters I speak of are field mice.
With having two large cats in the house, we generally had no issues with mice in the past. Apparently, years of being spoiled house cats have made Smokey and Bandit “soft” and unreliable in catching the mice. A word of advice to cat owners — female cats tend to be better mousers.
After no success in nabbing the critters with the live or snap traps, we realized we had “smart” mice on our hands. Therefore, our next plan of attack was to purchase mice/rat poison, also known as rodenticide. Knowing the risk rodenticides pose to pets, I was reluctant to purchase the poison, but I was determined to rid our house of the unwanted guests.
Working in an emergency clinic, I regularly see pets that have ingested rat poison. There are many rodenticide products available commercially, and each of them has different active ingredients. One thing I have learned is the ingredient of a rodenticide cannot be identified based on the color or shape of the product. However, in order to treat the pet appropriately, we must have the package with list of ingredients.
The most common active ingredients in rodent poisons are anticoagulants. These products interfere with the body’s ability to recycle Vitamin K, an essential part in clotting. Internal bleeding occurs throughout the body, eventually killing the animal. Symptoms begin two to three days after ingesting the poison, and depending on the active ingredient, may last up to four weeks. Cats are much more resistant to the affects of anticoagulants compared to dogs.
Effective in 2010, the Environmental Protection Agency mandated decreasing the usage of anticoagulants in rodent poisons. Therefore, companies began making different active ingredients that have proven even more deadly to pets. These newer products contain bromethalin or cholecalciferol.
Bromethalin is a non-anticoagulant rodenticide that causes swelling and death of cells in the brain, spine and nerves. Cats are very sensitive to these products so even a small amount can be lethal. Signs may be seen within two to 24 hours and include abnormal behavior, instability walking or hind limb paralysis, seizures and coma.
Cholecalciferol, the chemical name for vitamin D3, is one of the most deadly rodenticides to pets. Vitamin D3 is also present in prescription vitamins, psoriasis and eczema creams. Ingestion of cholecalciferol results in excess calcium in the blood that will calcify or “harden” the soft tissues of the body, most commonly the kidneys. This mineralization of the kidneys leads to acute, and potentially irreversible, kidney failure. Clinical signs often do not develop for one to three days, once the kidneys have begun to fail, and include increased drinking and urinations, lack of appetite, vomiting and diarrhea.
Lastly, phosphide rodenticides have been used since the 1930s and are still readily available on the market, but are generally used by professional exterminators. Signs begin suddenly with vomiting, abdominal pain, severe diarrhea (usually bloody) and a garlic-like odor to the breath. Zinc phosphide also carries a public health risk. If a pet vomits, phosphine gas is released into the air that can result in poisoning of the pet owner or the veterinary staff.
If you suspect your pet has consumed rat poison, call your veterinarian immediately! If the poison has been ingested recently, your veterinarian may recommend you to induce vomiting at home. Most likely, you will be instructed to get to the veterinary clinic right away where your veterinarian can induce vomiting and start treatment immediately. Before heading to the veterinarian’s office, be sure to grab the rodenticide product packaging and to have an approximate amount that your pet has ingested.
After your pet has vomited, your veterinarian will begin the appropriate treatment. Treatment will differ depending on the active ingredient of the poison which is why it is so important to have the packaging information. Prognosis for your pet will depend on the type of poison, the amount eaten and the time passed since it was ingested. Remember, time is of the essence so do not wait to contact your veterinarian.
The best way to prevent rodenticide toxicity is to avoid keeping the poison on your property. However, if you must use rat poison (as in our case), never place it in an area that is accessible to your pet and always discard dead rodents before your pet has a chance to eat them. In addition, always keep a good relationship with your veterinarian and know what their after-hours policy is. You can never be too prepared!
Dr. April Shattuck is a 2004 graduate from the Ohio State College of Veterinary Medicine, an army wife and proud mother of two beautiful daughters. She practices small animal emergency medicine at the West Central Ohio Veterinary Emergency Services Hospital. Any comments or questions may be directed to her at firstname.lastname@example.org.