Why must flea control target both the host animal and its bedding or nest?

Effective flea control requires simultaneous treatment of both the host animal and its environment because the flea life cycle is not confined to the host's body.1

While adult fleas live on the host, the larva and pupa stages typically develop within the host's bedding, nest, or other haunts. Larvae feed on organic debris found in these areas, such as dried skin and blood, before spinning a cocoon to pupate. Because these immature stages develop away from the animal, treating only the host leaves the breeding site untouched, allowing the infestation to persist.12

To manage an infestation, it is necessary to apply insecticides or growth regulators to both the animal and its living environment to disrupt the development of larvae and adults.1