Inhibition of immature Ctenocephalides felis felis (Siphonaptera : Pulicidae) development in the immediate environment of cats treated with imidacloprid

The hypothesis that dermally applied imidacloprid may transfer from treated cats, Felis catus L., to their immediate environment in quantities suffici ent to have a significant effect on developing immature cat fleas, Ctenocep halides felis (Bouche), was tested in a controlled experiment. Flea eggs ha rvested from untreated donor cats were incubated on replicated samples from blankets used by treated or untreated cats under standardized conditions. As compared with controls, the percentage of adult flea emergence on blanke ts used by treated animals was reduced by 100% in the 1st wk after treatmen t and by 84, 60, and 74% in subsequent weeks (P < 0.001).