How do flea drops for cats affect fleas? - briefly
Flea drops applied to a cat’s skin release an insecticide that penetrates the flea’s exoskeleton, causing rapid paralysis and death. The medication spreads through the coat, eliminating fleas that later come into contact with the animal.
How do flea drops for cats affect fleas? - in detail
Flea drops applied to a cat’s skin contain insecticidal or insect growth‑regulating compounds that act on contact and through the animal’s lipid layer. After application, the solution spreads across the coat, forming a thin film that remains active for weeks. When a flea lands on the treated area, the chemical penetrates the exoskeleton, disrupting the nervous system or metabolic processes, leading to rapid paralysis and death, typically within a few hours.
The active agents also affect immature stages:
- Adult fleas: immediate knock‑down and mortality.
- Newly emerged fleas: exposure to residual concentration prevents feeding, causing fatal intoxication.
- Eggs and larvae in the environment: certain ingredients inhibit development, reducing the emergence of new adults.
Systemic components, such as nitenpyram, enter the bloodstream and are ingested during blood meals, providing an internal lethal dose that kills fleas within minutes. This dual action—contact toxicity and systemic effect—breaks the flea life cycle, lowers infestation pressure, and prevents re‑infestation for the duration of the product’s efficacy, usually four to twelve weeks depending on the formulation.
Resistance management relies on rotating products with different modes of action, as repeated use of a single class can select for tolerant flea populations. Proper dosing according to the cat’s weight ensures adequate distribution of the active substance, maximizing both immediate kill and long‑term suppression.