ABSTRACT
Fleas are very small and annoying blood-sucking pests, capable of spreading serious human diseases. We come in contact with fleas primarily through our pet cats and dogs. Fleas have a complex life cycle and reproduce rapidly, so flea control is an important issue in any household with pets. A common insecticide used to kill fleas on cats is imidacloprid. This insecticide is also used to control sucking insects such as aphids, whiteflies, termites and a range of other soil insects, and some beetles. It is also very toxic to bees. Imidacloprid is toxic to the nervous system, causing an overstimulation of acetylcholine nicotinic nerves, resulting in the insect’s paralysis and death. When used to control fleas, it is typically applied to the back of the cat’s neck. Imidacloprid is absorbed through the skin and circulates in the blood. The flea dies after biting the cat and consuming the cat’s blood, which contains this toxic chemical. The cat appears to be unaffected by this chemical primarily because it receives a very small amount of pesticide relative to the cat’s body weight. Effects of overexposure on the cat would include muscle weakness, fatigue, and twitching. The flea, because of its very small size, receives a much larger dose because of its small body weight. The average flea weighs between 0.5 mg and 1 mg and can double its body weight when feeding. It takes only a very small amount of pesticide in the blood of the animal to kill the flea.
