Fly Bait Toxicity in Dogs & Cats

Dogs and cats can have varying degrees of sensitivity to pyrethrins, which are the pesticides used in fly bait. These pesticides are also widespread in agriculture as they are used commonly in corn, wheat and alfalfa crops to prevent infestation by flies and other insects damaging to crops. These insecticides may also be used in poultry farming. Permethrin is the product name of the pyrethrin-containing pesticide used in fly bait and agriculturally used pesticides. Additionally, drug companies have produced Federal Drug Administration-approved products with permethrin-containing pesticides for topical use on dogs to rid them of fleas. Permethrin poisoning often occurs in cats when flea medicine for dogs is used in an off-label method for cats.

  1. Symptoms

    • Cats tend to be more sensitive to fly-bait ingestion than dogs due to their generally smaller size as well as their inability to process the substance in their livers. Small dogs may be more susceptible to fly bait than larger dogs, as well.

      Dogs exhibiting allergies to fly-bait contact or ingestion may have swelling of the skin and/or hives. Veterinarians may prescribe baths, including topical and/or internal antihistamines, as well as steroids to reduce inflammation of the skin.

      Cats that exhibit symptoms of fly-bait poisoning often have more severe symptoms that may affect their neurological functioning, such as tremors, vomiting and convulsions.

    Identification

    • More specifically, cats which have ingested fly bait or products containing permethrin may have tremors, difficulty walking, or other signs that nerve impulses have been affected. For example, 30 percent of cats that have ingested fly bait or other permethrin-containing products may exhibit symptoms such as small muscle contractions, twitching, increased sensory stimulation and convulsions. Other less common neurological symptoms may include drooling, altered gait, dilation of pupils, blindness, loss of body temperature, altered blood chemistry, low protein count and breathing difficulties.

    Treatment

    • Veterinarians treat the symptoms of fly-bait poisoning rather than directly counteracting their source. For example, the vet will empty the cat's stomach and give activated charcoal in order to to prevent further absorption of the toxic material. In addition, veterinarians prescribe anti-convulsive medications, such as methocarbamol to ease seizures following fly-bait poisoning.

    Expert Insight

    • An Australian study in the Journal of Feline Medicine and Surgery reported fewer than one death in 40 cases of cat permethrin ingestion. However, the article reported that toxicity from permethrin exposure was severe in cats, and that a common cause of this exposure was due to improper use of dog flea medicine in felines.

    Considerations

    • Keep pets apart when the family dog has been treated for fleas in order to prevent contamination in the family cat. The ASPCA has reported that a single dose of a permethrin treatment for a greater than 40 pound dog has caused cause toxic tremors in ordinary house cats weighing approximately 10 pounds.