500,000 Pet Cats Nationwide at Risk of Adverse Reactions from Parasite Medication [Study]

Pet cats across the United States could be at risk from common drugs containing a certain ingredient called "eprinomectin." This is according to a February 2024 study by Washington State University (WSU) researchers, who estimated that half a million US cats could potentially suffer from adverse reactions from parasite medication containing the said ingredient. These parasiticides are widely used against fleas and ticks.

Cats, along with dogs, are the two most common household pets across the US and even in some other countries worldwide. While our feline and canine pets may appear healthy, experts warn that they are still vulnerable to blood-sucking pests that can carry harmful pathogens. While parasite medications have been used in response to this threat, our furry pets also face the threats posed by pesticide chemicals.

Pet Cats at Risk from Parasiticides

500,000 US pet cats are potentially in danger from experiencing either severe or deadly neurological reaction from eprinomectin-based parasite medication. The conclusion was made by researchers from WSU's Program for Individualized Medicine who found the ingredient is present in various popular common drugs against pests. The findings of the study were published in the Journal of Veterinary Pharmacology and Therapeutics on February 17.

The authors of the research paper specify that eprinomectin-containing parasiticides at some label doses can cause "neurological toxicosis" in pet cats. The findings highlight that not all cats are vulnerable. However, there are some cats that have been found to develop a genetic mutation called MDR1. Under this condition, some cats lack a mechanism that prevents eprinomectin from entering the brain.

Pesticide Poisoning

According to health authorities, neurotoxicity is a condition that occurs when a biological, chemical, or physical substance cause an adverse reaction to an organism's central or peripheral nervous system. According to the Centers for Disease Control and Prevention (CDC), the adverse neurological reaction is also caused by pesticide poisoning, where humans are also at risk, especially after being exposed to nerve agents.

For pet cats, this area is not yet fully explored but experts assert that pesticide poisoning can also be damaging or lethal for some cats. In the WSU study, researchers collected samples from 33 cases that were submitted due to cats suspected of being exposed to eprinomectin toxicosis. In some of the cases, which includes 11 US states, there are some pet cats that recovered and died, with some being euthanized.

Following their findings, the researchers hope that their findings will result in the inclusion of warning labels on medical products containing the ingredient eprinomectin. Unlike other diseases, the only way to ensure that a cat is at risk from parasite medication is through genetic testing. This method can help identify if the feline has developed MDR1 that causes the ingredient to enter the brain, as mentioned earlier.