Control of immature stages of the flea Ctenocephalides felis (Bouche) in carpets exposed to cats treated with imidacloprid

Fleas cause allergic dermatitis in cats and dogs and therefore warrant cont rol. It has been demonstrated previously that there is marked inhibition of the development of the immature stages of the cat flea Ctenocephalides fel is on fleece blankets exposed to cats treated with imidacloprid. This study reports on the efficacy of imidacloprid in suppressing adult flea emergenc e in carpet exposed to treated cats. Circular discs of carpet pre-seeded wi th flea eggs and larvae were exposed to 6 untreated control and 6 topically treated (imidacloprid 10 % m/v) cats 1 to 2 days after treatment and subse quently fortnightly for 6 weeks. Exposure times on alternate days were eith er 1 or 6 hours. Adult flea yield from carpets was determined 35 days after exposure. Differences between flea yield on control carpets and those expo sed for 1 hour were significant only for days fl and +14. For the 6-hour ex posure, differences were significant at all times except on Day +43. The ab ility of imidacloprid to suppress the yield of adult fleas on carpets (6-ho ur exposure) steadily declined from 82 % (Day +2) to 12 % (Day +43). For th e 1-hour exposure it varied inconsistently between 0 and 83 % over the 6-we ek study period.