Evaluation of efficacy of selamectin, fipronil, and imidacloprid against Ctenocephalides felis in dogs.
OBJECTIVE
To evaluate efficacy of monthly administration of selamectin, fipronil, and imidacloprid against Ctenocephalides felis in dogs.


METHODS
Randomized controlled trial.


METHODS
44 healthy dogs.


METHODS
Dogs known to be free of fleas were infested with 100 unfed adult fleas on days -28 and -21. On days 0, 30, 60, 90, and 120, dogs (12/group) were treated by topical administration of selamectin (6 mg/kg [2.7 mg/lb] of body weight), fipronil (7.5 mg/kg [3.4 mg/lb]), or imidacloprid (10 mg/kg [4.5 mg/lb]); 8 untreated dogs were used as controls. On day -6 and every 2 weeks after initial treatment, comb counts of viable adult fleas were made, and fleas (< or =50/dog) were replaced onto the dog from which they were removed. On day 89, fleas were not replaced. On day 91 and every 7 days until the end of the study, dogs were challenged with 20 adult fleas.


RESULTS
14 days after initial treatment, geometric mean flea counts were reduced by 97.5 to 99.1 % for all treatments, compared with pretreatment counts on day -6. Selamectin, fipronil, and imidacloprid reduced geometric mean flea counts by 99.7 to 100% from day 29 to the end of the study.


CONCLUSIONS
Selamectin is as effective as fipronil and imidacloprid in reducing C felis infestation in dogs housed for 3 months in a flea-infested environment under conditions known to support the flea life cycle, and in protecting against subsequent weekly challenges with C felis for an additional 2 months.
Ritzhaupt
L K
LK
Animal Health Group, Pfizer Inc., New York, NY 10017, USA.
Rowan
T G
TG
Jones
R L
RL
D000287:Administration, Topical; D000818:Animals; D000977:Antiparasitic Agents / Q000008:administration & dosage* / Q000592:standards; D004283:Dog Diseases / Q000188:drug therapy* / Q000469:parasitology; D004285:Dogs; D004478:Ectoparasitic Infestations / Q000188:drug therapy / Q000662:veterinary*; D005260:Female; D007093:Imidazoles / Q000008:administration & dosage* / Q000592:standards; D007306:Insecticides / Q000008:administration & dosage* / Q000592:standards; D007559:Ivermectin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000592:standards; D016018:Least-Squares Analysis; D008297:Male; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011720:Pyrazoles / Q000008:administration & dosage* / Q000592:standards; D005423:Siphonaptera / Q000254:growth & development
D000977:Antiparasitic Agents; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011720:Pyrazoles; C082359:imidacloprid; D007559:Ivermectin; C414354:selamectin; C082360:fipronil