Evaluation of sarolaner and spinosad oral treatments to eliminate fleas, reduce dermatologic lesions and minimize pruritus in naturally infested dogs in west Central Florida, USA

An assessment of canine ectoparasiticide administration compliance in the USA

Background

This study evaluated the timing of dog owner ectoparasiticide purchases to estimate administration compliance and assess the consequent impact of dose purchase gaps on the proportion of time that dogs were protected over a 12-month period.

Methods

Ectoparasiticide purchase transactions over a 12-month period were evaluated for 626 US veterinary hospitals to determine dose purchase timing and identify consequent gaps between dose administration in dogs. Orally administered prescription ectoparasitic medications with active ingredients from the isoxazoline family (afoxolaner, fluralaner, lotilaner, or sarolaner) were included in the analysis. A period was calculated for each of the four isoxazoline-containing medications that represented the duration of protection provided by two doses of ectoparasiticide plus the average gap between these two doses. The maximum percentage of time possible for ectoparasiticide protection for this aggregate period was then calculated for each active ingredient.

Results

Ectoparasiticide transaction records of owners were analyzed for 506,637 dogs. These showed that 43% of dog owners purchased just one dose over the 12-month period considered. If a dog owner purchased more than one dose, then the timing of their transactions could create a time gap between the completion of ectoparasite protection from the first dose and onset of protection from the subsequent purchase and administration of the second dose. Such gaps were observed in purchases made by 31–65% of dog owners, depending on the selected active ingredient and number of doses. The average gap duration between dose purchases was calculated for all possible dose combinations over 12 months of ectoparasite protection. Time gaps between the first and second doses are as follows: for sarolaner, 20.3 weeks; for afoxolaner, 12.9 weeks; for fluralaner ,12.8 weeks; and for lotilaner, 8.9 weeks. The proportion of time when protection was provided during the aggregate period between administration of the first and second doses was as follows: for fluralaner, 65%; for lotilaner, 49%; for afoxolaner, 40%; and for sarolaner, 30%.

Conclusions

Dog owner ectoparasiticide purchase transactions showed that there were time gaps between doses leading to reduced ectoparasite protection. The longer re-administration interval for fluralaner, a consequence of its extended duration of activity, resulted in dog owners gaining the greatest proportion of ectoparasite protection time with this medication compared with shorter-acting monthly re-treatment medications.

Graphical Abstract

Prevalence and Factors Associated with Ectoparasite Infestations in Dogs from the State of Tabasco, Mexico

This study was carried out to identify the ectoparasites that infest owned dogs in the state of Tabasco, Mexico. In total, 1,302 dogs were sampled in the 5 ecological regions of Tabasco. The dog owners were surveyed to identify the factors associated with infestations. Ectoparasites were identified using taxonomic keys. Eleven species of ectoparasites were observed. General prevalence was 26.65%. Rhipicephalus sanguineus and Ctenocephalides felis were the most prevalent and abundant ectoparasites. The most important factors associated with ectoparasite infestations in the studied dogs were living outdoors, being a non-purebred, having short hair, being dark-haired, and having a body condition <3. Ectoparasite studies such as the one presented herein generate important information to create control programs focused on decreasing infestations in companion animals and thus the likelihood of zoonotic transmission of pathogens.

Current review of isoxazoline ectoparasiticides used in veterinary medicine

The isoxazolines are a novel class of ectoparasiticides with potent inhibitory activity on glutamate- and gamma-aminobutyric acid-gated chloride channel located in nervous system of invertebrates. In recent years, studies have been performed to evaluate the efficacy and safety of isoxazolines against various types of ectoparasites, including fleas, ticks, and mites. As more single and combined isoxazoline products have been approved by the United States Food and Drug Administration and European Medicines Agency, a more comprehensive understanding of isoxazolines becomes essential for veterinary clinical practitioners. This article provides a complete review of isoxazolines with respect to pharmacodynamics, pharmacokinetics, ectoparasiticidal efficacy, and safety, which will provide veterinarians information to allow them to make the best choice of ectoparasiticide for their clients' specific needs.

Recent Advancements in the Control of Cat Fleas

Simple Summary

The cat flea Ctenocephalides felis felis is the most important pest of domesticated cats and dogs worldwide. This review covers the recent advancements in the control of cat fleas. Over the years, there has been an interest in using ecologically friendly approaches to control fleas. To date, no biological, natural, or cultural means have been discovered that mitigate flea infestations. The recent registration of novel topical and oral therapies promises a new revolution in the control of fleas and ticks and the diseases associated with them.

Abstract

With the advent of imidacloprid and fipronil spot-on treatments and the oral ingestion of lufenuron, the strategies and methods to control cat fleas dramatically changed during the last 25 years. New innovations and new chemistries have highlighted this progress. Control strategies are no longer based on the tripartite approach of treating the pet, the indoor environment, and outdoors. The ability of modern therapies to break the cat flea life cycle and prevent reproduction has allowed for the stand-alone treatments that are applied or given to the pet. In doing so, we have not only controlled the cat flea, but we have prevented or reduced the impact of many of the diseases associated with ectoparasites and endoparasites of cats and dogs. This review provides an update of newer and non-conventional approaches to control cat fleas.

Update on pathogenesis, diagnosis, and treatment of atopic dermatitis in dogs

Improved understanding of the pathogenesis of atopic dermatitis in dogs has led to more effective treatment plans, including skin barrier repair and new targeted treatments for management of allergy-associated itch and inflammation. The intent of this review article is to provide an update on the etiologic rationale behind current recommendations that emphasize a multimodal approach for the management of atopic dermatitis in dogs. Increasing knowledge of this complex disease process will help direct future treatment options.

Evaluation of a topical sarolaner-selamectin combination to control flea populations on naturally infested cats in private residences in West Central Florida

Historic data show that home flea infestations can be managed by treating all animals on the premises with a highly effective flea control product. The use of effective products has also been shown to reduce pruritus and minimize dermatologic lesions in both cats and dogs. Therefore, an in-home study was conducted in West Central Florida USA to evaluate the efficacy of a topically applied selamectin-sarolaner formulation to control fleas in naturally infested cats over a 12-week period. Thirty-seven cats in 21 households were treated once monthly with the selamectin-sarolaner topical solution. In the topical fluralaner treatment (positive control) group, forty-three cats in 20 households were treated once on day 0. A combined total of thirty dogs in both groups were treated once monthly with oral sarolaner. Fleas on cats were counted by flea combing, fleas on dogs were counted using visual area counts and fleas in the indoor premises were assessed using intermittent-light flea traps. Blinded-assessments of feline dermatologic lesions (modified-SCORFAD) were conducted monthly by a boarded-dermatologist and pruritus severity was evaluated by pet owners. Three consecutive monthly treatments of selamectin-sarolaner reduced flea populations on cats by 96.3 % within 7 days and by 100% from week 6 to the end of the 12-week study. The topical application of fluralaner reduced flea populations by 98.1 % within 7 days and efficacy reached 100% by week 12. At the end of the study, fleas were completely eradicated (from cats, dogs and homes) in every home regardless of treatment group. Owner reported cat pruritus was reduced by > 87 % in both treatment groups by week 12. Significant improvements in dermatologic lesion scores (> 81 %) were achieved by both products by the end of the study. Monthly applications of topical selamectin-sarolaner or topical fluralaner to cats living in the heavy flea challenge environment of West Central Florida USA were effective in eradicating flea infestations, reducing pruritus and improving dermatologic lesions.

In-home assessment of flea control and dermatologic lesions in dogs provided by lotilaner (Credelio®) and spinosad (Comfortis®) in west central Florida

Post-launch field investigations of recently-approved flea control products establish an efficacy baseline and in subsequent years can detect any efficacy decline suggestive of emerging resistance. As part of a continuing program of yearly assessment of flea control products in west central Florida, this study, using client-owned dogs, investigated the efficacy of lotilaner and spinosad in controlling fleas and in alleviating dermatologic signs likely associated with flea infestations. Forty-four qualifying households were randomized to either a lotilaner (Credelio®) (minimum dose rate 20 mg/kg) or a spinosad (Comfortis®) (30 mg/kg) group, with 33 and 36 dogs in each group, respectively. On Days 0 and 28 (±2) all dogs in each household were treated with the allocated product according to label directions, and all household cats received spinetoram (Cheristin®). On Day 0 and at weekly intervals through Day 56 (±2), on-animal and premises flea burdens were enumerated, a veterinary dermatologist scored integumental changes using canine atopic dermatitis extent and severity index (CADESI)-4 and flea allergy dermatitis (FAD) scales, and owners scored pruritus using the validated canine pruritus severity scale (CPSS). At study entry geometric mean flea counts were 33.2 and 29.9 in the lotilaner and spinosad groups, respectively. For both groups, reductions in flea counts were > 99% at the first post-treatment assessment (Week 1), and 100% from Week 6 through the final assessment (Week 8) when all study dogs were flea-free. For both groups, at each timepoint, flea counts on dogs and in traps were significantly reduced compared to the initial assessment (p < 0.001), as were improvements in median CADESI-4, FAD and CPSS scores (p ≤ 0.001). At Week 4, the geometric mean flea count on dogs in the lotilaner group (0.1) was significantly lower than that of dogs in the spinosad group (0.6) (p = 0.027), significantly fewer dogs in the lotilaner group were found to have fleas (p = 0.034), and mean owner-rated pruritus scores were significantly lower (p = 0.025). Under field conditions favoring heavy flea challenge, two consecutive monthly treatments of dogs with either lotilaner or spinosad produced a 100% reduction in canine flea infestations and dramatic improvements in dermatologic lesions and pruritus, based on scoring by a veterinary dermatologist and by dog owners. Household flea burdens were driven to extinction in all but one home in each treatment group.

Preferences of Pet Owners in Regard to the Use of Insecticides for Flea Control

A survey conducted from 2002 to 2012 of 759 customers from 84 veterinary practices allows us to examine the habits of dog and cat owners regarding the use of insecticides for flea control. The results indicate that the percentage of animals treated during the 12 mo prior to the survey was not very high (71% in dogs and 50% in cats), considering that 100% of animals included in the study were flea-infested. Statistical analysis shows that animals older than 4 mo are treated more frequently and that dogs are more likely to be treated than cats. Among cats, those living in houses with gardens or farms are treated at a higher rate than those that live in houses without gardens or in flats. The main variable associated with the degree of satisfaction and product loyalty is the active ingredient, and the choice of a commercial product is generally associated with high-efficacy products. The mode of application of a flea treatment does not seem to have a strong influence on pet owner satisfaction or loyalty. Likewise, we do not find a clear correlation between owners' satisfaction and loyalty, so pet owners may find the results of the selected product more or less satisfactory for reasons other than simple effectiveness. Finally, because of the complexity of the life cycle of these ectoparasites, the importance of the advice of a veterinarian when planning flea control is emphasized.

In-home assessment of either topical fluralaner or topical selamectin for flea control in naturally infested cats in West Central Florida, USA

Background

An investigation was conducted in West Central Florida, USA to evaluate the efficacy of either topically applied fluralaner or topically applied selamectin to control flea infestations, minimize dermatologic lesions and reduce pruritus in naturally flea infested cats over a 12-week period. When dogs were present in the households, they were treated with either oral fluralaner (if household cats were treated with topical fluralaner) or oral sarolaner (if household cats were treated with topical selamectin).

Methods

Thirty-one cats in 20 homes were treated once with fluralaner topical solution on day 0 and 18 dogs in these homes were administered a single fluralaner chewable. Twenty-nine cats in 18 homes were treated once monthly with a selamectin topical solution for 3 treatments and 13 dogs in these same homes were treated once monthly for 3 treatments with a sarolaner chewable. Fleas on cats were counted by flea combing, fleas on dogs were estimated using visual area counts and fleas in the indoor premises were assessed using intermittent-light flea traps. Blinded-assessments of feline dermatologic lesions were conducted monthly and pruritus severity was evaluated by pet owners.

Results

A single topical application of fluralaner reduced flea populations on cats by 96.6% within 7 days and by 100% at 12 weeks post-treatment. This efficacy was significantly greater than selamectin treatment where single topical application reduced flea populations on cats by 79.4% within 7 days of initial treatment and 3 consecutive monthly treatments reduced flea populations by 91.3% at the end of 12 weeks. At the end of the 12-week study, all fluralaner-treated cats were flea-free and this was significantly greater than the 38.5% of selamectin treated cats that were flea-free. At the end of the study, fleas were completely eradicated (from cats, dogs and homes) in 95.0% of fluralaner treatment group homes, significantly greater than the 31.3% of selamectin/sarolaner treatment group homes with complete flea eradication. Owner reported cat pruritus was reduced similarly in both treatment groups. Significant improvements in dermatologic lesion scores were achieved by day 30 in fluralaner treated cats and by day 60 in selamectin treated cats.

Conclusions

An in-home investigation in subtropical Florida found that 1 application of topical fluralaner eliminated flea infestations on cats and in homes significantly more effectively than 3 consecutive monthly doses of selamectin.