Larvicidal efficacy of nitenpyram on the treatment of myiasis caused by Cochliomyia hominivorax (Diptera: Calliphoridae) in dogs.

The purpose of our study was to evaluate the larvicidal efficacy of nitenpyram for the treatment of screwworm myiasis caused by Cochliomyia hominivorax in naturally infested dogs. Seven Beagle dogs presenting with myiasis were treated with nitenpyram twice at an interval of 6 h. The animals received dosages between 1.43 and 4.42 mg/kg body weight of nitenpyram in each given treatment. The criteria used to determine the drug efficacy were larval expulsion and fall. These were quantified at 15 min intervals within the first hour followed by 2, 3, 4, 6, and 18 h post-treatment. The highest larval expulsion happened between 1 and 2 h post-treatment. The spontaneous larval expulsion percentages were 86% and 94.11% for 6 and 18 h after the first treatment, respectively. Larvae were expelled until 18 h post-treatment. After this period the remaining dead larvae were mechanically removed. Nitenpyram showed 100% efficacy on the treatment of myiasis by C. hominivorax in naturally infested dogs.