Efficacy of Broadline® in cats against induced infections with developing fourth-stage larval and adult Ancylostoma ceylanicum hookworms

ABSTRACT Ancylostoma ceylanicum hookworms parasitize dogs and cats in subtropical and tropical South East Asia and Pacific region, the Arab Peninsula, southern Africa and South America but cause patent infections in humans too. To evaluate the efficacy of Broadline®, a combination product comprising eprinomectin, fipronil, (S)-methoprene and praziquantel, against developing fourth-larval stage (L4) and adult A. ceylanicum in cats, a blinded, induced infection study was conducted. Following oral inoculation of 24 purpose bred cats with ∼300 infectious A. ceylanicum larvae each, cats were allocated to one of three groups of eight animals, each which served either as untreated controls or received Broadline® (once topically at the minimum label dose of 0.12 mL per kg bodyweight) when the hookworms were L4 (five days post inoculation, dpi) or adults (25 dpi). Efficacy was determined on nematode counts conducted following necropsy of the cats. Fecal examination at 22 dpi confirmed all cats of the control group and of the group to be treated when the hookworms were adult excreting hookworm eggs (range, 100 to 1,000 eggs per gram) while no eggs were recovered from the feces of the cats treated with Broadline® 5 dpi. Nematode counts established 35 dpi demonstrated that Broadline® treatment was 100% efficacious against both developing L4 and adult A. ceylanicum: no hookworms were recovered from any Broadline®-treated cat while the all control animals harbored A. ceylanicum (range, 8 to 35) (p  No health problems were observed throughout the study.