Prevention of Flea Egg Development in a Simulated Home Environment by Frontline® Gold (fipronil, (S)-methoprene, pyriproxyfen) Applied Topically to Cats.

A single topical application of a combination of fipronil, (S)-methoprene, pyriproxyfen (Frontline® Gold, Merial, now part of Boehringer Ingelheim) on cats significantly prevented flea egg development (Ctenocephalides felis) in a simulated home environment for 15 weeks. Six healthy male cats were treated and then split in two groups of 3, and each group was housed in separate, identical rooms. For the duration of the study, the cats had free access to three sites in rooms that were covered by a carpet to allow contact with the animals' fur during resting. A portion of the original carpet was retained for use as control carpet. In order to assess the prevention of flea egg development, carpet discs of 48 mm in diameter were sampled on a weekly basis from each carpet, i.e., 6 discs/week, for 15 weeks, and placed into vials with 60 C. felis eggs and flea growth medium and were then incubated for 35 to 37 days. In parallel, six identical discs of carpets without any contact with treated cats were used as untreated controls. During the 15 weeks of the study, an average of 41.0 newly emerged adult fleas (36.5 - 45.3) were recovered weekly from the control carpets, and an average of 2.6 fleas (0.7 - 5.7) were recovered from the carpets in contact with the treated cats. Significantly fewer adults fleas were recovered from the carpets in contact with FRONTLINE Gold treated cats than the control carpets at all time-points (p<0.005). A single administration of FRONTLINE Gold administered topically to cats reduced flea egg development by an average of 93.6% for 15 weeks in this simulated environment. [ABSTRACT FROM AUTHOR]