Efficacy of a novel topical combination of fipronil, (S)-methoprene, eprinomectin and praziquantel against experimental infections of Toxascaris leonina in cats

The efficacy of a novel topical fipronil, (S)-methoprene, eprinomectin and praziquantel combination product (BROADLINE®, Merial) was evaluated against adult Toxascaris leonina ascarids in experimentally infected cats in two controlled studies under an identical protocol. For each study, 30 nematode-naive, purpose-bred European Short Hair cats were inoculated orally with approximately 300 larvated T. leonina eggs. Twenty-two and 24 cats, respectively, that were shown to be positive for Toxascaris eggs by pre-treatment faecal examination were subsequently included in the two studies. In each study, the animals were allocated randomly to an untreated (control) group or to a treatment group. The treatment was a novel topical combination: fipronil (8.3%, w/v), (S)-methoprene (10%, w/v), eprinomectin (0.4% w/v) and praziquantel (8.3% w/v). Treatment was applied on Day 0 at 0.12 mL/kg bodyweight. For parasite recovery and count, cats were euthanized humanely seven days after treatment and necropsied. All untreated cats harboured adult T. leonina (range, 1-31 nematodes). The treatment provided a high level of efficacy against adult T. leonina in both studies (95.8% and 98.1%, respectively p < 0.001). All cats accepted the treatment well based on hourly post-treatment observations for 4 h and daily observations thereafter. No adverse experiences or other health problems were observed throughout the studies. Thus the data indicate that this novel combination product will provide a safe and effective treatment against T. leonina in cats.