Efficacy of an adulticide used alone or in combination with an insect growth regulator for flea infestations of dogs housed in simulated home environments

Objective-To determine the effect of an adulticide on flea populations of d ogs and to evaluate efficacy of combined use of the adulticide and an insec t growth regulator (IGR)in dogs with experimentally induced flea infestatio ns. Animals-40 adult Beagles. Procedure-Each group of 5 dogs was housed in a sep arate room. Each dog was infested 3 times with 50 fleas, and fleas were counted beginning on day -2 1. Groups of dogs and treatments (initiated on day 0) were as follows: 1, a dulticide once; 2, adulticide on days 0 and 7; 3, adulticide on days 0, 3, and 7,4, sham treatment; 5, IGR monthly; 6, IGR monthly plus adulticide onc e weekly for 6 weeks;7, IGR monthly plus adulticide twice weekly for 6 week s; 8, sham treatment. Flea counts were compared between treated and control dogs. Results-By 24 hours after initial treatment, all adult fleas but 1 were dea d in treated dogs; In groups 1 and 3, populations increased to 15 to 20 fle as/dog 2 months after treatment, compared with 48 fleas/dog in group 4. Aft er treatment, mean flea counts were significantly lower for groups 1,, and 3, relative to group 4. Efficacy of treatment for group 5, relative to grou p 8, was > 94% after day 84. Efficacy of treatment for groups 6 and 7 was 9 9% after day 28. Conclusions and Clinical Relevance-Treatment with adulticide alone or in co mbination with an IGR had better efficacy, compared with sham treatment or IGR atone. Administration of adulticide twice weekly was not more efficacio us than treatment once weekly.