Efficacy of Emodepside/Praziquantel Spot-on (Profender®) against adult Aelurostrongylus abstrusus Nematodes in Experimentally Infected Cats

The adulticidal efficacy of a topical combination of emodepside 2.1 % (w/v) plus praziquantel 8.6 % (w/v) (Profender® spot-on for cats, Bayer) against adult Aelurostrongylus abstrusus nematodes was evaluated in two randomised, placebo-controlled laboratory efficacy studies. Each study involved 16 cats experimentally inoculated with L3 (800 and 600 each in studies no. 1 and 2, respectively) and randomised into two study groups of 8 cats each after onset of patency. While cats in the treatment group in study no. 1 received a single spot-on application at the minimum therapeutic dose (3 mg/kg emodepside and 12 mg/kg praziquantel), cats in study no. 2 were treated twice with an interval of 14 days. The faecal output of first stage larvae was monitored throughout the study. Necropsy was conducted 4 or 5 weeks after the (first) treatment and the worm counts were used for efficacy calculations. The control groups showed a geometric mean of the total worm count (live and dead worms) of 28.8 (study no. 1) and 17.6 (study no. 2), respectively. All control animals were infected. While the single treatment in study no. 1 resulted in a reduction of the total worm burden by 73.0 % (p = 0.0070), the treatment protocol in study no. 2 was 99.2 % effective (p = 0.0035). Based on live worm counts, the efficacy in study no. 2 was 100 % (p = 0.0030). It is concluded that two applications of Profender® spot-on given two weeks apart represent a safe and highly efficacious treatment regime against feline aelurostrongylosis.