What happens to fleas after applying flea drops for dogs? - briefly
The active ingredients spread over the dog’s coat, contacting fleas and interfering with their nervous system, causing swift paralysis and death. Immobilized insects then detach and are removed by the dog’s grooming or by cleaning the environment.
What happens to fleas after applying flea drops for dogs? - in detail
After a topical flea treatment is applied to a dog’s skin, the active ingredients spread across the coat through the natural oils of the animal. Within minutes, the chemicals reach the parasites that are either walking on the fur or feeding on the host’s blood.
- Contact exposure: Fleas that land on the treated area absorb the insecticide through their exoskeleton. The compound interferes with nerve transmission, causing rapid paralysis and death, typically within 15–30 minutes.
- Ingestion route: While feeding, fleas ingest the substance present in the blood. Systemic action further disrupts their nervous system, leading to mortality within a few hours.
- Reproductive inhibition: Many formulations contain insect growth regulators (IGRs) such as methoprene or pyriproxyfen. These agents do not kill adult fleas directly but prevent eggs from hatching and larvae from developing, breaking the life cycle for up to several weeks.
- Residual protection: The medication remains active on the skin for 30 days (or the label‑specified period). New fleas that jump onto the dog encounter a hostile environment and are eliminated before they can reproduce.
- Environmental impact: Dead fleas fall off the animal, reducing the number of parasites in the home. However, eggs and larvae already present in the environment may continue to develop until the IGR component suppresses them.
The combined immediate kill and long‑term disruption of development result in a swift decline of the flea population on the dog and in the surrounding area. Proper dosing according to the animal’s weight ensures sufficient concentration to achieve these effects while minimizing risk to the host.