ANTIFEEDING EFFECT OF SEVERAL INSECTICIDAL FORMULATIONS AGAINST CTENOCEPHALIDES-FELIS ON CATS

Evaluation of insecticidal activity of flea products is generally base d on counting live fleas in the animal's coat 24 and 48 hours followin g artificial infestation. This approach, however, does not allow to sp ecify whether the fleas have had the opportunity to bite and lake a bl oodmeal prior io their death. To address this question, 30 cats were a lloted to six groups of five animals. Each cat was housed in a separat e cage. Al Day 0, each group of cais received a single treatment as fo llows: Group 1: spot-on application of imidacloprid: cats < 4 kg: 40 m g/cat, cats greater than or equal to 4 kg: 80 mg/cat (Advantage(R)). G roup 2: spot-on application of fipronil: 50 mg/cat (Frontline spot-on( R). Group 3: spray application of fipronil: 7.5 mg/kg b.w (frontline s pray(R)). Group 4: foam application of permethrin 40/60: 50 mg/kg b.w. (Defencat(R)). Group 5: aerosol spray application of dichlorvos+fenit rothion: one second/kg b.w, (NuvanTop(R)). Group 6: control group. cat s were left untreated. One hour after treatment, each cat was infested with 50 unengorged young adult fleas, Ctenocephalides felis, deposite d along the dorsal midline. One hour later, each cai was carefully com bed using a fine-toothed comb (13 teeth/cm). Collected fleas were swat ted to detect blood in their abdomen. To the manufacturers respective product use instructions and efficacy claims, reeinfestations were mad e al Days 3, 7, 14 in ail groups; at Days 21 and 30 in Groups 1,2, 4, 6; at Days 35 and 42 in Groups 3 and 6. The cats were combed one hour after each reinfestation. The results indicate that the topical applic ation of imidacloprid or fipronil does not prevent fleas from biting a nd feeding within the first hour after infestation prior to being kill ed while the topical application oi dichlorvos/fenitrothion and permet hrin let to a better than 80% decrease oi the number of engorged fleas for three and seven days post treatment, respectively.