The efficacy of a single oral treatment with sarolaner (Simparica™, Zoetis), a novel isoxazoline compound, was evaluated against five tick species known to infest dogs in the United States. A total of 10 laboratory studies, two against each species, were conducted using adult purpose-bred mongrels or Beagle dogs. In each study, 16 dogs were randomly allocated to one of two treatment groups based on pre-treatment host-suitability tick counts. Dogs were infested with approximately 50 unfed adult Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, Ixodes scapularis or Rhipicephalus sanguineus ticks on Days -2, 5, 12, 19, 26 and 33. On Day 0, dogs were treated with a placebo or a sarolaner tablet providing a minimum dose of 2 mg/kg. Tick counts were conducted 48h after treatment and after each subsequent weekly re-infestation. There were no treatment-related adverse reactions during any of the studies. Dogs in the placebo-treated group maintained tick infestations throughout the studies. Geometric mean live tick counts were significantly lower (P≤0.0001) in the sarolaner-treated group compared to the tick counts in the placebo group at all timepoints. Treatment with sarolaner resulted in ≥99.6% efficacy against existing infestations of all five tick species within 48h. The efficacy against weekly post-treatment re-infestations of all tick species was ≥96.9% for at least 35 days after treatment. Thus, a single dose of sarolaner administered orally at the minimum dosage of 2mg/kg, resulted in excellent efficacy within 48h against existing tick infestations, and against weekly re-infestations for 35 days after treatment. These studies confirmed that administration of the minimum dose of sarolaner will provide rapid treatment of existing infestations and give at least one month of control against re-infestation by the common tick species affecting dogs in the US.
Background: Recent reports indicated that increasing the monthly oral dosage and the number of consecutive monthly doses of moxidectin improved the efficacy against macrocyclic lactone (ML)-resistant Dirofilaria immitis. The two laboratory studies reported here evaluated the efficacy of four or six monthly oral doses of 24 µg/kg moxidectin compared to six monthly doses of either Heartgard ® Plus (ivermectin/pyrantel) or Interceptor ® Plus (milbemycin oxime/praziquantel) against ML-resistant D. immitis strains. Methods: Dogs were inoculated 30 days prior to first treatment with 50 third-stage (L 3) larvae of a ML-resistant strain of D. immitis, ZoeLA or JYD-34. In each study, dogs (six per group) were randomized to treatment with six monthly doses of placebo, four or six monthly doses of 24 µg/kg moxidectin, or six monthly doses of Heartgard ® Plus or Interceptor ® Plus at their label dose rates. Efficacy was evaluated by adult heartworm counts approximately nine months after L 3 inoculation. Results: All negative-control dogs were infected with adult heartworms (geometric mean, 35.6; range, 24-41) for ZoeLA and (geometric mean, 32.9; range, 30-37) for JYD-34. Efficacies against ZoeLA for moxidectin, Heartgard ® Plus and Interceptor ® Plus were ≥ 96.1%, 18.7% and 21.2%, respectively. Adult counts for both moxidectin-treated groups were significantly lower than negative control (P < 0.0001), significantly lower than Heartgard ® Plus and Interceptor ® Plus (P < 0.0001), but not significantly different from each other (P = 0.5876). Counts for Heartgard ® Plus and Interceptor ® Plus were not significantly different than negative control (P ≥ 0.2471). Efficacies against JYD-34 were ≥ 95.9%, 63.9% and 54.6% for moxidectin, Heartgard ® Plus and Interceptor ® Plus, respectively. Counts for all groups were significantly lower than negative control (P ≤ 0.0001). Counts for six monthly doses of moxidectin were significantly
The rapid speed of kill of sarolaner (Simparica™, Zoetis), a novel isoxazoline compound, was demonstrated against three tick species known to infest dogs in Europe or the United States. Efficacy was measured against an existing infestation and against subsequent weekly re-infestations for 35 days after treatment. Dogs were randomly allocated to treatment with a single oral dose of either placebo or sarolaner (2mg/kg) based on pre-treatment host-suitability tick counts. Dogs were infested with approximately 50 unfed adult Ixodes scapularis, Ixodes ricinus or Amblyomma maculatum ticks on Days-2, 7, 14, 21, 28 and 35. Tick counts were conducted at 4 (I. scapularis only), 8, 12 and 24h after treatment on Day 0 and after each subsequent re-infestation. No treatment-related adverse reactions occurred during any of these studies. Dogs in the placebo-treated groups maintained adequate tick infestations (recovery of 20-70% of applied ticks) throughout the duration of the studies. Following treatment, live tick counts were significantly reduced relative to placebo at the 8h post treatment counts indicating that sarolaner started killing existing infestations of ticks rapidly after treatment. Efficacy was 90.1% against I. ricinus, 98.8% against I. scapularis, and 99.2% against A. maculatum within 12h, and 100% efficacy was achieved at 24h after treatment against all three tick species. This speed of kill was maintained throughout the month with ≥95.7%, ≥98.7% and ≥89.6% efficacy against I. scapularis, I. ricinus, and A. maculatum, respectively, at 24h after re-infestation at least through Day 28.
A new spot-on formulation of selamectin plus sarolaner was evaluated against fleas for adulticidal efficacy, and for the effect on egg production and hatching when applied to flea-infested cats. Ten male and ten female adult domestic shorthair cats were randomly assigned to one of two treatment groups based on pre-treatment flea counts. Cats received topical treatment on Day 0 in a single spot to the dorsal scapular area with either a placebo formulation or with the combination formulation at the minimal dose of 6.0mg selamectin plus 1.0mg sarolaner per kg bodyweight. On Days -1, 5, 12, 19, 26 and 33, cats were infested with approximately 100 (±5) unfed Ctenocephalides felis fleas. At 24h after treatment or 48h after subsequent flea infestation, cats were housed for a 20-h period in a cage to allow collection of flea eggs. At the end of this period, flea eggs were collected from the cages and cats were combed to remove and count live fleas. Emerged viable larvae and emerged adult fleas were counted 3days and 35days, respectively, after egg collection. The new spot-on formulation of selamectin plus sarolaner provided 100% efficacy against adult fleas up to Day 36 following a single application. Fleas on placebo-treated cats produced large numbers of eggs throughout the study, with individual counts ranging from 110 to 1256 eggs. Following treatment, four flea eggs were collected from a single selamectin/sarolaner-treated cat on Day 29, but there were no eggs collected from any other selamectin/sarolaner-treated animal during the study. No larvae or adult fleas developed from these four eggs. From the eggs collected from the placebo-treated cats, the mean percentage of live larvae and adults that emerged ranged from 67.3% to 84.2% and from 50.7% to 81.8%, respectively. A single topical treatment with a new spot-on formulation of selamectin plus sarolaner at the minimum label dose thus controlled fleas on cats and was 100% effective in preventing flea reproduction for over one month after treatment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.