What happens to fleas after applying drops to cats? - briefly
The topical medication spreads across the cat’s skin, killing fleas on contact and preventing further development of eggs and larvae. Within hours, the infestation collapses as the insects are eradicated and no new fleas can emerge.
What happens to fleas after applying drops to cats? - in detail
Topical flea medication applied to a cat is absorbed through the skin and enters the bloodstream. The active ingredients spread over the body via the cat’s natural oil layer and reach the hair follicles, where adult fleas and developing stages reside.
When a flea contacts the treated coat, the insect contacts the insecticidal compound. The compound interferes with the flea’s nervous system, causing rapid paralysis and death within minutes to a few hours, depending on the specific product and flea resistance levels.
The life‑cycle disruption occurs at several stages:
- Adult fleas: Immediate intoxication leads to loss of mobility, inability to feed, and death.
- Eggs: Females that die before laying eggs reduce the number of new eggs deposited on the host.
- Larvae and pupae: Some products contain insect growth regulators (IGRs) that prevent immature stages from maturing, halting development into reproductive adults.
Because the medication circulates systemically, fleas that bite the cat later ingest the toxin, extending the lethal effect beyond the initial contact. Re‑infestation from the environment is still possible, but the reduced number of viable fleas on the host lowers the likelihood of re‑establishment.
Effective control depends on applying the correct dose, using a product formulated for the cat’s weight and age, and following the recommended re‑application interval to maintain therapeutic levels in the animal’s system.