COMPARATIVE ACTIVITY IN DOGS OF DELTAMETHRIN-IMPREGNATED AND DIAZINON-IMPREGNATED COLLARS AGAINST CTENOCEPHALIDES-FELIS

Objective-To compare effectiveness of deltamethrin- and diazinon-impre gnated collars against fleas (Ctenocephalides felis) in an experimenta l infestation. Animals-30 Beagles. Procedure-Dogs were housed in separ ate cages. Dogs were infested with 50 fleas each, and fleas were count ed 24 hours later. Dogs were then fitted with a collar containing 4% d eltamethrin (group 1) or 15% diazinon (group 2). Dogs in group 3 were controls. Fleas were counted 24 and 48 hours after collars were applie d, and fleas were then removed. Dogs were reinfested with fleas on day s 7, 14, 28, 60, 90, 120, 150, and 210. Fleas were counted 24 and 48 h ours after each reinfestation. Results-48 hours after applying collars , flea counts were not notably decreased. Effectiveness in groups 1 an d 2 was 24 and 29%, respectively. Infestation on day 7 was controlled, to a comparable extent, by both insecticides (effectiveness approx 85 %). Effectiveness > 97% was obtained after collars had been worn for 1 4 days. Between days 14 and 91, both collars had comparable effectiven ess (> 93%) that did not differ significantly. After day 91, effective ness of the collar containing diazinon decreased sharply, whereas that of the collar containing deltamethrin remained > 90% until day 152. C onclusions and Clinical Relevance-The collar containing deltamethrin c ontrolled flea populations on dogs beginning 14 days after application and continuing until day 150. The collar containing diazinon controll ed infestation for 90 days. Deltamethrin-impregnated collars are a new formulation that can be introduced into a program to easily control f leas.