Conference Agenda

Session

S2: Canines Symposium sponsored by Elanco

Time:

Tuesday, 30/June/2026:

11:00am - 11:30am

Session Chair: Swaid Abdullah, The University of Queensland
Session Chair: Liisa Ahlstrom, Elanco

Location: Lecture Theatre 2

Boulevard Room 2

Presentations

Speed-of-kill comparison of isoxazolines in the combination endectocide products Credelio™ PLUS (lotilaner), NexGard Spectra^® (afoxolaner) and Simparica^® Trio (sarolaner) against the Australian paralysis tick (Ixodes holocyclus) throughout one month

Liisa Ahlstrom¹, Rachel Lyons¹, Claudia Ellenberger¹, Kim Baker¹, Melissa Pittorino¹, Scott Wiseman², Bettina Schunack³

¹Elanco Animal Health, Australia; ²Elanco Animal Health, United Kingdom; ³Elanco Animal Health GmbH, Germany

Paralysis ticks (Ixodes holocyclus) cause a severe, potentially fatal, toxicosis in dogs. A fast and sustained speed-of-kill throughout the dosing interval is a valuable acaricidal characteristic. Lotilaner has the longest half-life (35 days) of the oral isoxazolines¹, and a single dose kills paralysis ticks for over 11 weeks.²

A randomised, blinded, controlled study was conducted to compare the speed-of-kill of the monthly-dosed combination isoxazoline products Credelio™ PLUS (lotilaner, milbemycin oxime), NexGard Spectra^® (afoxolaner, milbemycin oxime) and Simparica^® Trio (sarolaner, moxidectin, pyrantel) against Ixodes holocyclus. Dogs (n=7/group) were treated (or left as untreated controls) on Day 0 and infested with 10-12 unfed adult female ticks on Days -2, 21, 28 and 35. Tick counts were performed 12, 18 and 24 hours post-treatment and post-reinfestation.

The initial speed-of-kill efficacy (12 h post-treatment) was rapid and similar for lotilaner and sarolaner (>80%), and significantly greater than afoxolaner (50%; P<0.004). On Day 21, efficacies of lotilaner, sarolaner and afoxolaner were 95.6%, 66.1% and 26.0%, respectively, 12 hours after reinfestation, with lotilaner and afoxolaner exceeding 97% and sarolaner nearly reaching 95% by 24 hours. On Day 28, efficacies of lotilaner, sarolaner and afoxolaner were 86.4%, 21.6% and 3.6%, respectively, 12 hours after reinfestation, with all products exceeding 96% and lotilaner reaching 100% by 24 hours. On Day 35, efficacies of lotilaner, sarolaner and afoxolaner were 76.6%, 23.4% and 6.9%, respectively, 12 hours after reinfestation. Lotilaner exceeded 95% efficacy already by 18 hours, sarolaner by 24 hours, while afoxolaner remained below 90%.

Lotilaner killed reinfesting ticks faster (P<0.01 at 12 hours) than sarolaner and afoxolaner and sustained its rapid speed-of-kill and efficacy beyond the label claim of one month. This offers reassurance to veterinarians and dog owners, addressing concerns about the potential increased risk of tick paralysis towards the end of the dosing interval of acaricides.

References:

¹Toutain CE., et al. The intravenous and oral pharmacokinetics of lotilaner in dogs. Parasit Vectors. 2017;10(1):522.

²Baker, K., et al. Laboratory evaluations of the 3-month efficacy of oral lotilaner (Credelio™) against experimental infestations of dogs with the Australian paralysis tick, Ixodes holocyclus. Parasit Vectors. 2018;11(1):487.