Flea and tick control in the 21st century: challenges and opportunities

Efficacy and immunogenicity of a veterinary vaccine candidate against tick-borne encephalitis in dogs

Tick-borne encephalitis (TBE) is a severe neuroinfection of humans. Dogs are also commonly infected with tick-borne encephalitis virus (TBEV). These infections are usually asymptomatic, but sometimes show clinical signs similar to those seen in humans and can be fatal. To date, there is no TBEV vaccine available for use in dogs. To address this need, a TBEV vaccine candidate for dogs based on inactivated whole virus antigen was developed. The safety, immunogenicity, and efficacy of the vaccine candidate were tested in mice as the preclinical model and in dogs as the target organism. The vaccine was well tolerated in both species and elicited the production of specific anti-TBEV antibodies with virus neutralising activity. Vaccination of mice provided complete protection against the development of fatal TBE. Immunisation of dogs prevented the development of viremia after challenge infection. Therefore, the developed vaccine candidate is promising to protect dogs from severe TBEV infections.

EVALUATING BAITS WITH LUFENURON AND NITENPYRAM FOR FLEA CONTROL ON PRAIRIE DOGS (CYNOMYS SPP.) TO MITIGATE PLAGUE

Plague, caused by Yersinia pestis, is a widespread threat to endangered black-footed ferrets (Mustela nigripes) and their primary prey, prairie dogs (Cynomys spp.). Wildlife biologists most commonly manage plague using insecticides to control fleas, the primary vectors of Y. pestis. We tested edible baits containing the insecticides lufenuron and/or nitenpyram in prairie dogs. During a laboratory study, we treated 26 white-tailed prairie dogs (Cynomys leucurus) with lufenuron at 300 mg/kg body mass. All animals remained clinically healthy over the 9 wk monitoring period. Although serum lufenuron concentrations were >130 ppb in two treatment groups at week 1, concentrations declined to ≤60 ppb after 3 wk in non-torpid prairie dogs and after 7 wk in torpid prairie dogs. In a field experiment, we tested baits containing a combination of 75 mg lufenuron and 6 mg nitenpyram, respectively, in black-tailed prairie dogs (Cynomys ludovicianus). We uniformly distributed baits at 125 baits/ha on two plots (treated once) and 250 baits/ha on two plots (each treated twice 4.4 wk apart). Following treatments, flea abundance increased on prairie dogs and remained stable in burrows. Our findings indicate that baits containing lufenuron and nitenpyram, at the reported treatment rates, are ineffective tools for flea control on prairie dogs. Future experiments might evaluate efficacy of higher doses of lufenuron and nitenpyram, and repetitive treatments at differing intervals over time to evaluate potentially therapeutic treatments.

Immediate and long-term efficacy of Felpreva®, a new spot-on formulation containing tigolaner, emodepside and praziquantel, applied as a single application to cats artificially infested with the cat flea Ctenocephalides felis

Five studies (two dose determination, two dose confirmation, and one speed of flea kill study) were conducted to assess the immediate (therapeutic) efficacy and long-term persistent (preventive) efficacy of a single spot-on application containing the novel acaricide and insecticide tigolaner in combination with emodepside and praziquantel (Felpreva®, Vetoquinol S.A. Lure, France) applied to cats artificially infested with Ctenocephalides felis. Eight cats per group were randomly allocated to 0, 1×, 1.3× and 2× of the minimum dose (14.5 ​mg/kg body weight) of tigolaner (dose determination studies) or randomly allocated to 0 and 1× of the dosage (dose confirmation studies). Onset of efficacy was assessed in a speed of flea kill study on an existing flea infestation 8, 12 and 24 ​h after treatment and reassessed after monthly flea reinfestation until 13 weeks post-treatment. Efficacy was calculated according to the Abbott formula using arithmetic means. Efficacy was claimed when (i) control groups were adequately infested (flea retention ≥ 50%) at each time-point in the studies; (ii) flea counts in treated groups were significantly lower (P ​≤ ​0.05) than flea counts in control groups; and (iii) calculated efficacy was ≥ 90% (speed of flea kill study) and ≥ 95% (dose determination and dose confirmation studies). Tigolaner at 14.5 ​mg/kg body weight was 100% effective against fleas on Day 1 (immediate, therapeutic efficacy) in both, dose determination and dose confirmation studies. The long-term persistent efficacy in week 13 ranged between 96.3% and 100%. Fleas were rapidly killed within 12 ​h after treatment (100% flea reduction, immediate efficacy). New flea infestations were successfully prevented for 8 weeks (98.9-100% flea reduction) within 8 ​h after reinfestation, and at week 13 (96.3% flea reduction) within 24 ​h after reinfestation.

Dual assessment of transcriptional and metabolomic responses in the American dog tick following exposure to different pesticides and repellents

The American dog tick, Dermacentor variabilis, is a major pest to humans and animals, serving as a vector to Rickettsia rickettsii, a bacterium responsible for Rocky Mountain spotted fever, and Francisella tularensis, which is responsible for tularemia. Although several tactics for management have been deployed, very little is known about the molecular response following pesticidal treatments in ticks. In this study, we used a combined approach utilizing transcriptomics and metabolomics to understand the response of the American dog tick to five common pesticides (amitraz, chlorpyrifos, fipronil, permethrin, and propoxur), and analyzed previous experimental data utilizing DEET repellent. Exposure to different chemicals led to significant differential expression of a varying number of transcripts, where 42 were downregulated and only one was upregulated across all treatments. A metabolomic analysis identified significant changes in acetate and aspartate levels following exposure to chlorpyrifos and propoxur, which was attributed to reduced cholinesterase activity. Integrating the metabolomics study with RNA-seq analysis, we found the physiological manifestations of the combined metabolic and transcriptional differences, revealing several novel biomolecular pathways. In particular, we discovered the downregulation of amino sugar metabolism and methylhistidine metabolism after permethrin exposure, as well as an upregulation of glutamate metabolism in amitraz treated samples. Understanding these altered biochemical pathways following pesticide and repellent exposure can help us formulate more effective chemical treatments to reduce the burden of ticks.

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

Cypermethrin and ivermectin resistance in field populations of Rhipicephalus sanguineus sensu lato (Latrielle, 1806) collected from dogs in south India

The abuse of acaricides for control of Rhipicephalus sanguineus sensu lato ticks led to a strong selection pressure for acaricide resistance. Data on acaricide resistance in R. sanguineus s.l. populations from India is meager though veterinarians frequently report treatment failures. The present study was aimed to characterize the level of resistance in R. sanguineus s.l. against most commonly used drugs, cypermethrin and ivermectin in Andhra Pradesh, south India. Fourteen adult female tick populations were collected from naturally infested dogs at veterinary clinics, residence and stray dog in nine state municipal corporations/municipalities. Information on the history of dog treatment with acaricides was obtained by interviewing dog owners. The larval packet test (LPT) and larval immersion test (LIT) were used on the larvae of ticks to test for resistance to cypermethrin and ivermectin, respectively. Mortality data of each tick population was analyzed by probit analysis. Corresponding to the most susceptible population, thirteen (92.6%) and six (42.9%) tick populations were regarded as resistant to cypermethrin and ivermectin, respectively. The phenotypic level of cypermethrin (resistance ratios at LC50% varied from 1.55 to 13.29) and ivermectin (resistance ratios at LC50% ranged from 1.16 to 4.79) resistance varied distinctly between the populations. Additionally, all the populations were tested using PCR to demonstrate the frequency of the point mutation in sodium channel gene that corresponds with resistance of R. sanguineus s.l. to cypermethrin. A nucleotide substitution (T2134C) on domain III segment VI of the sodium channel gene was noticed in phenotypically resistant tick populations on DNA sequencing. Ivermectin resistance in the brown dog ticks is reported for the first time from India.

Association between Pesticides in House Dust and Residential Proximity to Farmland in a Rural Region of Taiwan

Pesticide drift was reported in many international studies, but rarely studied in Taiwan. We conducted a study in a rural region of Taiwan to examine the associations between pesticides in house dust and nearby agricultural areas using geographic information system (GIS). A questionnaire regarding home characteristics and pesticide use, and indoor and outdoor dust samples were collected from 47 rural homes. Dust samples were analyzed for six pesticides, and agricultural land data for GIS analysis were retrieved from a national website. All but prallethrin were frequently detected from indoor dust samples (>50%), and the maximum concentrations were all below 1000 ng/g. Detection frequencies and concentrations of pesticides in outdoor dust samples were even lower than that in indoor dust samples. Only "work involving pesticides" in the questionnaire was significantly associated with four pesticides in house dust (p < 0.05). Carbofuran and tetramethrin in house dust were significantly correlated with rice cultivation area at certain buffer distances (ρ > 0.33, p < 0.05), and chlorpyrifos was found to be associated with abandoned cultivation area, suggesting the occurrence of pesticide drift. Despite the low levels of pesticides in house dust, residents in the rural region should be cautious of pesticide drift from nearby active or abandoned farmlands.

Field study to investigate the effectiveness and safety of a novel orally administered combination drug product containing milbemycin oxime and lotilaner (Credelio® Plus) against natural flea and tick infestations on dogs presented as veterinary patients in Europe

BACKGROUND

A pivotal randomised, blinded, positive-controlled, multicentre, European field study was conducted to evaluate the effectiveness and safety of a novel combination tablet of lotilaner and milbemycin oxime (Credelio® Plus) administered orally to client-owned dogs naturally infested with fleas and/or ticks.

METHODS

In this field study, households with flea- or tick-infested dog(s) were enrolled on Day 0 into the study to provide data for either the tick or flea infestation cohorts. Households were randomised in a 2:1 ratio to receive either the combination investigational product (IP, Credelio Plus® tablets) or the control product (CP: Nexgard Spectra® tablets). Dogs were administered IP (flea cohort n = 135; tick cohort: n = 147) or CP (flea cohort: n = 67; tick cohort: n = 74) once every 4 weeks for a total of three times at a dose rate of 20.0-41.5 mg/kg bodyweight lotilaner and 0.75-1.53 mg/kg bodyweight milbemycin oxime (IP) or as recommended (CP). Percentage reduction was calculated by comparing individual dog flea and tick counts at each assessed post-treatment time point to their respective baseline (pre-treatment) infestation. Resolution of the clinical signs of flea allergy dermatitis (FAD) was assessed in flea-allergic dogs on the days that flea counts were performed.

RESULTS

Flea effectiveness of Credelio Plus® after 3 consecutive monthly treatments was 100% against Ctenocephalides felis, C. canis and Pulex irritans. Tick effectiveness of Credelio Plus® over the same time frame was 99.3% for Ixodes ricinus and 100% against Rhipicephalus sanguineus (s.l.). Flea effectiveness of the CP after three consecutive monthly treatments was 100% against C. felis, C. canis and P. irritans. Tick effectiveness of the CP over the same time frame was 99.8% for I. ricinus and 100% against R. sanguineus. Credelio Plus® was well tolerated based on the safety assessments in all treated dogs in this field study. Within both treatment groups there was a reduction in total FAD scores from baseline.

CONCLUSIONS

This pivotal European field study demonstrated the excellent effectiveness and safety of a combination of lotilaner and milbemycin oxime (Credelio Plus®) administered orally to dogs naturally infested with fleas and/or ticks.

Flea and tick treatment satisfaction, preference, and adherence of US cat owners prescribed topical fluralaner (Bravecto® Topical Solution for Cats)

Background:

Fluralaner is a novel isoxazoline compound and the only systemically distributed ectoparasiticide approved in the United States for redosing at up to 12-week intervals for flea and tick control in cats. Other feline ectoparasiticides, including other systemic isoxazolines, are approved for redosing at monthly intervals. A survey developed in 2016 to assess the satisfaction, preference, and adherence of dog owners prescribed fluralaner as an ectoparasiticide with the treatment and veterinary flea and tick protection recommendations was adapted for completion by cat owners in the USA.

Aim:

The study objective was to use cat-owner survey data obtained at US veterinary practices to assess client satisfaction and utilization practices for fluralaner, and to evaluate owner adherence to current flea and tick control recommendations.

Methods:

US veterinary practices (n = 26) were asked to obtain completed surveys for up to 25 active clients who were currently treating their cats with a topical preparation of fluralaner for flea and tick control. Clients who had previously used flea and tick products for cats other than fluralaner were enrolled in the study. Participating cat owners completed an 11-question survey on their satisfaction with, preference for, and adherence to treatment recommendations for topically applied fluralaner as a feline flea and tick control medication.

Results:

The average cat in this study had a mean (± SD) body weight of 5.1 (± 0.9) kg and was 7.1 (±1.4) years old. Most cats lived in a home versus an apartment and more than half spent some time outside. Satisfaction was assessed with a 5-point Likert scale, with nearly all cat owners (97%) indicating that they were satisfied or very satisfied with fluralaner. Most of them (66%) had previously used other monthly flea and tick products for cats. Owners were not excluded if they had previously used a canine flea and tick product. The extended dosing interval up to 12 weeks was the most frequently selected benefit of fluralaner. Nearly 9 out of 10 respondents indicated they readministered fluralaner mostly on time or delayed by a few days, and most said they were more likely to give a repeat dose of fluralaner at the recommended redosing interval compared to monthly products. 87% of the responding cat owners preferred topical fluralaner over the monthly flea and tick products they had used.

Conclusion:

The extended dosing interval of up to 12 weeks was the leading preference factor and the key driver of user satisfaction with fluralaner leading to improved adherence to redosing recommendations. Cat owners said they were more likely to administer fluralaner at the recommended redosing interval compared to monthly products, indicating that less frequent redosing contributes to improved adherence.

A facile, sensitive and rapid sensing platform based on CoZnO for detection of fipronil; an environmental toxin

A sensitive detection of extremely toxic phenylpyrazole insecticide, 'Fipronil' is presented. Currently, the advancement of approaches for the detection of insecticides at low concentrations with less time is important for environmental safety assurance. Considering this fact, an effort has been made to develop an electrospun CoZnO nanofiber (NF) based label-free electrochemical system for the detection of fipronil. The CoZnO NF were characterized using different techniques including field emission scanning electron microscopy (FE-SEM), Energy Dispersive X-Ray Analysis (EDX), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Raman Spectroscopy. Based on the experimental results, the proposed platform displayed a linear response for fipronil in the attogram/mL range despite the multiple interfering agents. The sensitivity of the device was found to be 3.99 Kῼ (g/ml)^-1 cm^-2. Limit of detection (LOD) and limit of quantification (LOQ) were calculated and found to be 112 ag mL^-1 and 340 ag mL^-1 respectively. Further, this proposed sensor will be implemented in the fields for the rapid and proficient detection of the real samples.

Protecting dogs and cats against the Australian paralysis tick, Ixodes holocyclus (Acari: Ixodidae): A review of the Australian acaricide registration process

Tick control is mainly achieved through the use of effective ectoparasiticides that can be either dermally or systemically distributed in/on the host. Before any acaricide can be legally made available to veterinarians and pet owners, it must demonstrate efficacy in a series of well-designed dose confirmation studies. The data generated during these studies are then reviewed by government regulators and used for the registration of the acaricide. In Australia, the most significant tick species is the Australian paralysis tick, Ixodes holocyclus. This three-host tick produces a potent neurotoxin (holocyclotoxin) that induces a rapidly ascending flaccid paralysis that can be fatal to companion animals and larger mammals such as cattle and horses. The Australian Pesticides and Veterinary Medicines Authority (APVMA) is the national Australian regulator which sets the data requirements for the registration of acaricides. This paper reviews the requirements set by the APVMA and puts them in direct context with the biology, distribution and reported acaricide susceptibility of I. holocyclus. An overview of acaricides currently registered in Australia for the control of I. holocyclus in dogs and cats, their reported efficacy data and the conduct of I. holocyclus efficacy trials are also provided.

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A review of the requirements for the conduct of acaricide efficacy trials for Ixodes holocyclus was undertaken.

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The requirements of the Australian government regulator were put in direct context with the biology of the species.

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The need for the inclusion of Far North Queensland ticks into tick studies needs to be further assessed.

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At present, there is no evidence of acaricide resistance in Ixodes holocyclus.

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.

Laboratory studies evaluating the efficacy of a novel orally administered combination product containing sarolaner, moxidectin and pyrantel (Simparica Trio™) for the treatment and control of flea infestations on dogs

BACKGROUND

Five studies were conducted to evaluate a novel oral combination tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™), for efficacy against induced flea infestations, speed of kill and effects on flea reproduction on dogs.

METHODS

Based on pre-treatment flea counts, dogs were randomly allocated to treatment with a single, oral dose of either placebo or Simparica Trio™ at the minimum label dose of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5 mg/kg pyrantel (as pamoate salt) on Day 0. All dogs were infested with approximately 100 unfed, adult fleas (C. felis or C. canis) prior to treatment and weekly for 5 weeks post-treatment. In Studies 1, 2 and 3, the number of viable fleas were comb-counted at 24 h after treatment and after each weekly infestation; Study 2 also included groups treated with tablets containing sarolaner-alone (1.2 mg/kg), moxidectin-alone (24 µg/kg) or pyrantel-alone (5 mg/kg). In Study 4, flea counts were conducted at 3, 4, 8 and 12 h after treatment and subsequent weekly infestations to establish speed of kill. In Study 5 (flea reproduction), dogs were housed in an enclosure designed to facilitate collection of flea eggs.

RESULTS

Efficacy of Simparica Trio™ against C. felis was ≥ 99.7% and against C. canis was 100% at 24 h after treatment and after subsequent infestations for at least 35 days. Treatment with sarolaner-alone had similar efficacy to Simparica Trio™, while moxidectin-alone and pyrantel-alone were no different from placebo at most time points. In Study 4, significant flea killing started at 4 h after treatment; by 8 h after treatment, all treated dogs were free of fleas. Following weekly re-infestation, the combination product reduced fleas by ≥ 97.8% within 12 h for 28 days. Simparica Trio™ reduced flea egg-laying by 100% for 35 days. No treatment-related adverse reactions occurred in any study.

CONCLUSIONS

A single dose of Simparica Trio™ at the recommended minimum dose provided highly efficacious and rapid treatment within 4 h of existing flea infestations and persistent control of fleas on dogs for 5 weeks. The efficacy against fleas resulted in 100% prevention of flea reproduction for over a month following a single oral dose.

Efficacy of a novel oral chewable tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against natural flea and tick infestations on dogs presented as veterinary patients in Europe

Background

A novel chewable oral tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) has recently been developed to provide persistent protection against flea and tick infections for a month, treatment of hookworm and roundworm infections and prevention of heartworm and lungworm disease in dogs. Two field studies were conducted to evaluate the safety and efficacy of Simparica Trio™ against natural flea and tick infestations on dogs in Europe.

Methods

Dogs with natural flea or tick infestations were allocated randomly to treatment on Day 0 with either Simparica Trio™ tablets (flea study: n = 297; tick study: n = 189) to provide 1.2–2.4 mg/kg sarolaner, 24–48 µg/kg moxidectin and 5–10 mg/kg pyrantel (as pamoate salt) or with NexGard® Spectra (afoxolaner + milbemycin oxime) according to the label instructions (flea study: n = 164; tick study: n = 91). Efficacy was calculated based on the mean percent reduction in live parasite counts compared to the respective pre-treatment counts on Days 14 and 30 in the flea study and on Days 7, 14, 21 and 30 in the tick study. To count the fleas, the dog’s entire coat was systematically combed using an extra fine-tooth flea comb until all fleas were removed. For the tick counts, the dog’s entire coat was searched manually. Resolution of the clinical signs of flea allergy dermatitis (FAD) was assessed in flea allergic dogs in the flea study. Palatability was assessed in both studies.

Results

Simparica Trio™ was well tolerated in both studies. Efficacy against fleas was ≥ 97.9% in the Simparica Trio™ group and ≥ 96.1% in the NexGard® Spectra group. Efficacy against ticks was ≥ 94.8% in the Simparica Trio™ group and ≥ 94.4% in the NexGard® Spectra group. Clinical signs of flea allergy dermatitis improved following treatment with Simparica Trio™. Simparica Trio™ tablets were voluntarily and fully consumed on ≥ 78% of the 485 occasions they were offered.

Conclusions

A single oral dose of Simparica Trio™ was safe and highly efficacious against naturally occurring flea and tick infestations for 1 month on dogs. Clinical signs of FAD improved following treatment. Simparica Trio™ was voluntarily and readily consumed by most dogs.

Safety and efficacy of a novel oral chewable combination tablet containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against natural flea infestations in client-owned dogs in the USA

BACKGROUND

One randomized, controlled clinical field study was conducted in 18 general veterinary practices throughout the USA to evaluate the safety and efficacy of a novel oral chewable combination tablet, Simparica Trio™, containing sarolaner, moxidectin and pyrantel for the treatment and prevention of fleas on dogs.

METHODS

Client-owned dogs, from households of three or fewer dogs were eligible for enrollment. Four hundred and twenty-two dogs from 251 households were enrolled. Households were randomly assigned in a 2:1 ratio to treatment with either Simparica Trio™ at the minimum label dose of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5 mg/kg pyrantel (as pamoate salt) or afoxolaner (NexGard®, Boehringer-Ingelheim) at the label dose. One dog per household was selected as the primary dog for efficacy evaluations. Treatments were dispensed and dogs were dosed in their home environment on Day 0 and on approximately Day 30. Flea counts and examination for clinical signs of flea allergy dermatitis (FAD) were performed at the initial visit the day before or on Day 0 prior to treatment and on Days 30 and 60. Additionally, all dogs were examined for general health at each visit and blood and urine were collected for clinical pathology at screening and Day 60.

RESULTS

Simparica Trio™ reduced geometric mean live flea counts by 99.0% by Day 30 and by 99.7% by Day 60. As a result of the rapid reduction in flea infestations, clinical signs associated with FAD substantially improved following treatment. Simparica Trio™ was well-tolerated and a diverse range of concomitant medications were administered to dogs during the course of the study. Simparica Trio™ chewable tablets were well-accepted by dogs, with the majority of flavored chewable tablets (91.9%) voluntarily consumed by free choice without, or when offered in food.

CONCLUSIONS

Simparica Trio™ administered orally once monthly for two consecutive treatments was safe and effective against natural flea infestations and substantially improved clinical signs associated with FAD in client-owned dogs in a field study conducted in the USA.

Efficacy of a novel orally administered combination product containing sarolaner, moxidectin and pyrantel (Simparica Trio™) against induced infestations of five common tick species infesting dogs in the USA

Background

The efficacy of a novel oral combination product, Simparica Trio™, containing sarolaner, moxidectin and pyrantel was evaluated against five tick species that commonly infest dogs in the USA, Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, Ixodes scapularis and Rhipicephalus sanguineus.

Methods

Laboratory studies were conducted against two different strains of each tick species. In each study, 10 purpose-bred Beagle or mixed-breed dogs were randomly allocated to one of two treatment groups based on pre-treatment host-suitability tick counts. Dogs were infested with approximately 50 (45–55) unfed adult ticks on Days -2, 5, 12, 19, 26 and 33. On Day 0, dogs received either a single oral dose of Simparica Trio™ at the minimum label dose of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5 mg/kg pyrantel (as pamoate salt) or placebo. Tick counts were conducted at 48 h post-treatment and after each subsequent weekly re-infestation for A. maculatum, D. variabilis, I. scapularis and R. sanguineus studies and at 48 hours or at 72 h post-treatment and after weekly re-infestation in the first and second A. americanum studies, respectively.

Results

No treatment-related adverse reactions occurred in any study. In all studies, placebo-treated dogs maintained infestations throughout the entire study duration, and dogs treated with Simparica Trio™ had significantly lower (P ≤ 0.0010) mean live tick counts than placebo-treated dogs at all time-points. Against A. maculatum, D. variabilis, I. scapularis and R. sanguineus, a single oral dose of Simparica Trio™ evaluated at 48 h post-treatment provided ≥ 98.9% efficacy against existing infestations, and within 48 h of re-infestation efficacy was ≥ 90.4% through at least Day 28 (except for R. sanguineus on Day 14 in a single study with an efficacy of 89.7%). Against A. americanum, Simparica Trio™ provided ≥ 99.4% efficacy at ≤ 72 h after treatment of existing infestations and maintained ≥ 98.4% efficacy at ≤ 72 h after re-infestation through at least Day 35.

Conclusions

A single dose of Simparica Trio™ administered orally at the minimum label dosage of 1.2 mg/kg sarolaner, 24 µg/kg moxidectin and 5 mg/kg pyrantel provided treatment and control of the common tick species infesting dogs in the USA for at least one month.

Evaluation of a plant-based food supplement to control flea populations in dogs: A prospective double-blind randomized study

A prospective double-blind randomized placebo-controlled study evaluated the tolerance and efficacy of the biological plant-based food supplement Bioticks® (extracts of thyme, rosemary, melissa, fenugreek, absinthe and lemongrass) as a flea-control product. Twelve dogs were used as placebo controls (group A). Ten dogs under similar housing conditions received the same food daily but supplemented with Bioticks® (group B). Flea counts were performed on D0 and 14, then 1, 2, 3, 4 and 5 months after the beginning of the study. No flea treatment was given or environmental modifications made during the 6 months prior to beginning and throughout the duration of the study. Efficacy was calculated according to Abbott's formula. No adverse event was recorded. At inclusion, dogs in groups A and B hosted a mean ± standard deviation of 7.9 ± 3.3 and 9.5 ± 3.6 fleas, respectively. The mean flea population in group A steadily increased until 4 months after D0 (21.5 ± 4.9 fleas/dog). Meanwhile, the mean flea population in group B dogs remained stable for the first month but then steadily decreased to reach an average of 3.1 ± 1.7 fleas/dog at D0+5 months. The percentage efficacy in the treated group as compared to the non-treated group was 33%, 51%, 71%, 80% and 82% at 1, 2, 3, 4 and 5 months, respectively.

Bioticks® was shown to be safe and effectively limited the flea population in dogs with a moderate flea infestation in conditions that were highly favourable to flea development. This is the first study to evaluate a plant-based product as an oral supplement for flea control.

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There is a growing demand for non-chemical, biological or “natural” flea products.

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In vivo studies assessing the efficacy of plant extracts are lacking in animals.

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The food supplement Bioticks® (Biodevas) contains several plant-extracts.

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Two groups of flea-infested dogs underwent a double-blind placebo-controlled study.

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Dogs fed with Bioticks® had a flea population reduced by 80% after 4 months.

Efficacy of lotilaner (Credelio™) against the adult cat flea, Ctenocephalides felis and flea eggs following oral administration to dogs

BACKGROUND

A blinded, randomized, negative controlled laboratory study was conducted to evaluate the efficacy of lotilaner (CredelioTM, Elanco) when administered orally to dogs, against experimentally induced adult flea infestations and flea egg production.

METHODS

Twenty dogs were selected for the study and allocated to two treatment groups. Ten dogs were treated with lotilaner (at the lower half of the recommended dose range of 20-43 mg/kg) on Day 0. Ten dogs treated with placebo tablets served as the control group. Each dog was infested with 100 unfed adult C. felis fleas on days -1, 6, 13, 20 and 29. At 24 h post-treatment or post-infestation, each dog was combed for the removal and counting of adult live fleas. Flea eggs were also collected and counted from the pan under each dog cage.

RESULTS

Dogs in the lotilaner treated group received a mean dose of 22.6 mg/kg (range 20.2-25.9 mg/kg) and no adverse events were observed in any dog in this study. At each evaluation time point, the lotilaner group provided 100% efficacy against adult live flea counts as compared to the placebo control group. Egg production from lotilaner treated dogs was reduced by 98.5% (geometric mean; 97.4% arithmetic mean) 24 h post-treatment (and 48 h post-flea infestation). No eggs (100% efficacy) were available for collection following infestations on Day 6 onwards from the lotilaner treated dogs. At each evaluation time point, adult live flea counts from the lotilaner treated dogs were significantly lower (P < 0.0001) than from the placebo control group.

CONCLUSIONS

In dogs treated with a single dose of lotilaner (mean dose 22.6 mg/kg), 100% of adult fleas were killed within 24 h post-treatment or post-subsequent infestations as compared to the placebo control group, thereby demonstrating that lotilaner kills fleas before they can lay eggs thus preventing subsequent flea infestations for 30 days after treatment. There were no reported adverse events in any dogs, demonstrating that lotilaner tablets were well tolerated at the dose rates assessed in this study.

Dog owner flea/tick medication purchases in the USA

Background

Veterinary clinic transaction records from the USA were examined to determine dog owner purchase patterns for three prescription ectoparasiticides. In-clinic purchases of formulations of fluralaner (with 12-week duration per dose) were compared with dog owner purchases of afoxolaner and spinosad (both with 4 week duration per dose) in a population of 231,565 dogs over a 12 month period. Prior studies in human and animal medicine have suggested that patients more closely adhere to prescriber dosing recommendations when they receive a longer-duration medication.

Results

Veterinary clinic transaction records were examined for the period June 2014 through March 2017 using records from approximately 650 veterinary clinics. Ectoparasiticide purchase patterns were compared for two products (afoxalaner and spinosad) with monthly dosing and one product (fluralaner) with an extended (12 week) dosing interval. The average dog owner who obtained fluralaner purchased significantly more months of flea/tick protection (5.7 months) over the 12-month study period than the average dog owner that selected either afoxolaner (4.6 months) or spinosad (3.3 months). The proportion of dog owners who obtained only one dose of ectoparasiticide per 12-month period was 42% for fluralaner, 30% for afoxolaner and 37% for spinosad. The proportion of dog owners who obtained 2 doses or less per 12-month period was 67% for fluralaner, 52% for afoxoalaner and 67% for spinosad. Owners that obtained fluralaner were significantly more likely to obtain 7.0–12.0 months of flea and tick protection and significantly less likely to purchase 1.0–6.9 months compared with dog owners who purchased afoxolaner or spinosad.

Conclusions

Dog owners who obtained a flea and tick medication with a longer duration of action acquired significantly more months of protection in a year than dog owners who obtained shorter duration (1 month) products. Dog owners were better able to adhere to veterinary recommendations on ectoparasites control with a longer-acting flea/tick medication.

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.

Evaluation of an 11.2% spinetoram topical spot-on solution for the control of experimental and natural flea (Ctenocephalides felis) infestations on cats in Europe

Spinetoram is the newest member the spinosyn-class of natural products to be commercialized for flea control on cats in the United States under the tradename Cheristin^® for cats. This report describes results from two laboratory studies and a multi-center clinical field trial designed to confirm the efficacy of a topical spot-on solution containing spinetoram (11.2% w/w, 130 mg/mL) against European strains of the cat flea, Ctenocephalides felis. In the laboratory studies, cats were allocated to one of two treatment groups of eight animals each: negative control (mineral oil) or spinetoram, both applied as a topical spot-on at the base of the skull on Day 0. Cats were infested with ∼100 newly emerged, unfed adult fleas on Days -2 or -1, 7, 14, 21, 28 and 35. To calculate efficacy, fleas were counted and removed 48 h after treatment, and 48 h after each subsequent infestation through week 5. Spinetoram treatments provided 100% efficacy through at least day 16 and ≥ 97% efficacy (arithmetic mean) for one month. For the field trial, 23 clinics from Northern and Southern Europe participated in the study that compared the effectiveness and safety of spinetoram and fipronil/(S)-methoprene treatments over a period of two months. There were 258 and 248 evaluable efficacy cases for month 1 and month 2, respectively, with 300 total evaluable cases for safety. Treatments were administered on Day 0 and again on Day 30 (±3 days). The effectiveness of treatments was calculated based on reduction in live flea counts on Days 14, 30, 44 and 60 (±3 days) relative to flea counts obtained on Day 0. Efficacy (geometric mean percent flea reduction) on Days 14, 30, 44 and 60 was 97.0%, 95.0%, 99.3% and 99.1% for spinetoram, respectively, and 86.1%, 80.9%, 92.4% and 92.3% for fipronil/(S)-methoprene, respectively. Spinetoram was deemed non-inferior at all intervals and superior to fipronil/(S)-methoprene at Days 30 and 60. Clinical signs of flea allergy dermatitis (FAD) were markedly improved following spinetoram treatment, as demonstrated through statistically significant reductions in severity of FAD scores for most of the clinical signs when compared to fipronil/(S)-methoprene treatment. There was a lower overall adverse event incidence rate for spinetoram (5.1%) versus fipronil/(S)-methoprene treatment (11.5%).

The Biology and Ecology of Cat Fleas and Advancements in Their Pest Management: A Review

The cat flea Ctenocephalides felis felis (Bouché) is the most important ectoparasite of domestic cats and dogs worldwide. It has been two decades since the last comprehensive review concerning the biology and ecology of C. f. felis and its management. Since then there have been major advances in our understanding of the diseases associated with C. f. felis and their implications for humans and their pets. Two rickettsial diseases, flea-borne spotted fever and murine typhus, have been identified in domestic animal populations and cat fleas. Cat fleas are the primary vector of Bartonella henselae (cat scratch fever) with the spread of the bacteria when flea feces are scratched in to bites or wounds. Flea allergic dermatitis (FAD) common in dogs and cats has been successfully treated and tapeworm infestations prevented with a number of new products being used to control fleas. There has been a continuous development of new products with novel chemistries that have focused on increased convenience and the control of fleas and other arthropod ectoparasites. The possibility of feral animals serving as potential reservoirs for flea infestations has taken on additional importance because of the lack of effective environmental controls in recent years. Physiological insecticide resistance in C. f. felis continues to be of concern, especially because pyrethroid resistance now appears to be more widespread. In spite of their broad use since 1994, there is little evidence that resistance has developed to many of the on-animal or oral treatments such as fipronil, imidacloprid or lufenuron. Reports of the perceived lack of performance of some of the new on-animal therapies have been attributed to compliance issues and their misuse. Consequentially, there is a continuing need for consumer awareness of products registered for cats and dogs and their safety.

Usefulness of a topical combination of dinotefuran and pyriproxyfen for long-term control of clinical signs of allergic dermatitis in privately-owned cats in Ile-de-France region

BACKGROUND

The present study assessed the activity of a combination of dinotefuran and pyriproxyfen (Vectra® Felis) for long-term control (3 months) of allergic dermatitis (AD) in privately-owned cats under common household conditions in Ile-de-France region.

METHODS

This was an open pre-treatment vs post-treatment study. Twenty-eight client-owned cats with clinical signs of AD were enrolled in the study. They received topical application of the combination of dinotefuran and pyriproxyfen on days 0, 28, 56 and 84. Two parameters (clinical signs and pruritus severity) were used to assess the animals' condition on days 0, 28 and 84. Fleas were counted if they were observed.

RESULTS

Of the 28 cats initially enrolled, 26 were presented on day 28 and 20 for the final evaluation on day 84. A significant improvement in clinical signs and pruritus was observed in cats for which fleas and/or flea feces were detected on day 0. Globally, the post-treatment AD clinical scores on days 28 and 84 were different from that of the pre-treatment on day 0, with a reduction of 30% and 71%, respectively. For cats with fleas and/or flea feces, the reduction on days 28 and 84 was 33% and 85%, respectively. The improvement of clinical signs and pruritus was not significant in cats with no visible fleas and no flea feces at the beginning of the trial (n = 8).

CONCLUSIONS

The present study indicated that the treatment with a combination of dinotefuran and pyriproxyfen should be considered as useful in controlling fleas on cats without additional environmental treatment and useful for long-term control of clinical signs and pruritus in allergic cats.

Efficacy of a new spot-on formulation of selamectin plus sarolaner for cats against adult Ctenocephalides felis, flea egg production and adult flea emergence

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.

Assessment of the efficacy of a topical combination of fipronil-permethrin (Frontline Tri-Act®/Frontect®) against egg laying and adult emergence of the cat flea (Ctenocephalides felis) in dogs

This study was conducted to assess the prevention of egg laying and the inhibition of the emergence of the cat flea (Ctenocephalides felis) resulting from the application of a combination of fipronil and permethrin (Frontline Tri-Act^®/Frontect^®, Merial) on dogs. Sixteen healthy dogs were included after pre-treatment live flea counts and randomly allocated to two groups. Eight dogs served as untreated controls and 8 dogs were treated on Day 0 and Day 30 with topical application of fipronil/permethrin at the minimum dose of 6.76 mg/kg fipronil and 50.48 mg/kg permethrin. On days −2, 7, 21, 28, 42 and 56, each dog was infested with 100 fleas. Flea eggs were collected from each dog in individual trays from 12 to 36 h after treatment or each flea re-infestation. All fleas were removed by combing and counted 36 h after treatment or infestations. The collected eggs were counted and incubated for 28 days for larval development and adult emergence assessment. The curative efficacy of Frontline Tri-Act^®/Frontect^® against adult fleas 36 h after treatment was 95.3% and the efficacy remained 100% after subsequent flea infestations for 8 weeks. Compared to the control group, the treatment reduced egg laying by 84.5% within 36 h after first treatment and was 99.9%, 100%, 100%, 100%, 100% on collection days 7, 21, 29, 43 and 57, respectively. Frontline Tri-Act^®/Frontect^® reduced by 28.7% the emergence of new adult fleas from eggs laid during the 48 h of pre-treatment infestation. The inhibition of adult emergence from incubated flea eggs could not be assessed after flea re-infestation in the treated group as no eggs were collected.

A comparative laboratory trial evaluating the immediate efficacy of fluralaner, afoxolaner, sarolaner and imidacloprid + permethrin against adult Rhipicephalus sanguineus (sensu lato) ticks attached to dogs

Background

Acaricides are used to treat and prevent tick infestations, and a common clinical scenario is to administer an acaricide on observing an attached tick. Consequently, immediate acaricidal efficacy (onset of activity and speed of kill) results are clinically valuable. This study evaluated the immediate efficacy of four commercially available acaricides against adult Rhipicephalus sanguineus (sensu lato).

Methods

Forty dogs were blocked on hair length and tick carrying capacity, then randomly assigned to receive one of four treatments (fluralaner, sarolaner, imidacloprid + permethrin, or afoxolaner) or left untreated as controls. All dogs were challenged with 50 adult R. sanguineus (s.l.) ticks 48 h prior to treatment. After treatment, in situ tick thumb counts were conducted at 2, 4, 8, 12 and 24 h; thereafter ticks were removed and counted at 48 h.

Results

Imidacloprid + permethrin had the earliest onset of activity at 2 h (36.9% efficacy) followed at 4 h by fluralaner (60.2% efficacy) and sarolaner (48.2% efficacy), and lastly afoxolaner at 8 h (90.8% efficacy). Three oral treatments had an 8 h speed of kill (>90% efficacy) threshold; with corresponding efficacies as: fluralaner (99.6%), sarolaner (94.7%) and afoxolaner (90.8%). Fluralaner and sarolaner achieved 100% efficacy at 12, 24 and 48 h; afoxolaner achieved 100% efficacy at 48 h. Imidacloprid + permethrin achieved 80.1% efficacy at 48 h, therefore, failing to attain the speed of kill 90% efficacy threshold.

Conclusion

The systemically distributed isoxazolines performed much better than cutaneously distributed imidacloprid + permethrin and are optimal treatment choices against attached ticks based on the combination of earlier onset of activity and speed of kill. Fluralaner had a 4 h onset of activity, an 8 h speed of kill and achieved 100% efficacy at 12 h.

Initial evaluations of the effectiveness of spinetoram as a long-acting, oral systemic pulicide for controlling cat flea (Ctenocephalides felis) infestations on dogs

Spinetoram is a semi-synthetic, spinosyn class natural product derived from fermentation by the actinomycete, Saccharopolyspora spinosa. Based on LD₅₀ (50% lethal dose) values against adult cat fleas (Ctenocephalides felis) using an in vitro contact assay, spinetoram was approximately 4-fold more potent than spinosad. Subsequently, two parallel-arm, randomized block design laboratory studies were conducted to evaluate the effectiveness of orally administered spinetoram against experimental C. felis infestations on dogs, when administered as a single dose or multiple doses over a 6-12h interval. In the first study, 16 mixed-breed dogs were allocated to two treatment groups of eight dogs each, based on pre-treatment flea retention rates: negative (placebo) control; and a single dose of spinetoram at 30mg/kg. In the second study, 32 mixed- and pure-breed dogs were allocated to four treatments groups of eight dogs each, based on pre-treatment flea retention rates: negative (placebo) control; a single dose of 60mg/kg; three sequential 20mg/kg oral doses evenly administered over a 6h period; and three sequential 20mg/kg oral doses evenly administered over a 12h period. In both studies, treatments were administered to dogs in a fed state in order to enhance absorption of spinetoram. Therapeutic efficacy was assessed 24h after treatment and persistent efficacy was assessed 48h after each subsequent flea infestation. The duration of effectiveness was assessed at approximate weekly intervals beginning on Day 5 through Day 56 in the first study, or through Day 105 in the second study. In both studies, treatment efficacy was ≥99% (geometric means) through 44 d, with ≥99% efficacy continuing through 72 d for all three treatments in the second study. Efficacy remained ≥90% for at least 8 weeks with a single 30mg/kg dose; through 13 weeks with three sequential 20mg/kg doses; and through 15 weeks with a single 60mg/kg dose. For all time points and in both studies, spinetoram-treated groups had significantly fewer live fleas relative to their respective negative control group (p<0.05). The pharmacokinetic profile in dogs revealed that the mean plasma concentration of spinetoram required for effectiveness against fleas was maintained for at least 3 months regardless of whether the 60mg/kg total body dose was administered as a single bolus or in three sequential 20mg/kg doses administered over a 6-12h period of time. The results of preliminary in vitro and in vivo studies demonstrate that orally administered spinetoram was well tolerated, and provides long lasting effectiveness against C. felis infestations on dogs.

Systemically and cutaneously distributed ectoparasiticides: a review of the efficacy against ticks and fleas on dogs

Acaricidal (tick) and insecticidal (flea) efficacy of systemically and cutaneously distributed ectoparasiticide products for dogs are compared based on permethrin and fluralaner as representative molecules. Results of efficacy studies against fleas and ticks are reviewed that show generally good to excellent results. Both externally and systemically distributed treatments have benefits and weaknesses in potentially preventing pathogen transmission by these arthropod vectors.

Four general properties are considered related to the goal of providing optimal reduction in the risk of vector-borne pathogen transmission. These are:

Owner adherence to the recommended treatment protocol;

Rapid onset of activity following administration;

Uniform efficacy over all areas of the treated dog at risk for parasite attachment;

Maintenance of high efficacy throughout the retreatment interval.

In considering these four factors, a systemically distributed acaricide can offer an option that is at least as effective as a cutaneously administered acaricide with regard to the overall goal of reducing the risk of vector-borne pathogen transmission.

Evaluation and comparison of a flumethrin-imidacloprid collar and repeated monthly treatments of fipronil/(s)-methoprene to control flea, Ctenocephalides f. felis, infestations on cats for eight months

Background

This controlled laboratory study was designed to evaluate the efficacy of the 10 % imidacloprid/4.5 % flumethrin collar (Seresto®, Bayer Animal Health) against fleas (Ctenocephalides f. felis) on cats, when compared to fipronil (9.8 %w/w)/(s)-methoprene (11.8 % w/w) topical spot-on formulation (Frontline® Plus for Cats and Kittens, Merial).

Methods

Thirty cats were randomized into three groups of ten animals based on pre-treatment flea counts: Group 1: imidacloprid/flumethrin collar; Group 2: fipronil/(s)-methoprene topical spot-on and Group 3: non-treated controls. The imidacloprid/flumethrin collars were applied one time on Day 0, while the fipronil/(s)-methoprene spot-on was administered every 30 days from Day 0 through Day 210. Cats were infested with 100 fleas on study days 0, 7, 14, 29, 59, 89, 119, 149, 179, 209 and 239. All flea counts were conducted by combing to remove fleas on post-treatment days 2, 8, 15, 30, 60, 90, 120, 150, 180, 210 and 240.

Results

The efficacy of the imidacloprid/flumethrin collar ranged from 98.2 to 100 % for eight months. The efficacy of fipronil/(s)-methoprene spot-on ranged from 68.2 to 99.9 %. Efficacy was < 85 % for fipronil/(s)-methoprene on Days 90, 150 and 210. The flea counts in both treatment groups were significantly fewer than those in the non-treated control group at every post-treatment study day (P < 0.0001). In addition, there were significantly fewer fleas in the imidacloprid/flumethrin collar group when compared to the fipronil/(s)-methoprene group on Days 90, 150 and 210 (P < 0.0001).

Conclusions

This study demonstrated that the imidacloprid/flumethrin collar (Seresto®, Bayer Animal Health) maintained excellent ( > 98.2 %) efficacy against fleas on cats for the entire 8 month study. Monthly applications of fipronil/(s)-methoprene (Frontline® Plus for Cats and Kittens, Merial) generally had high, but variable (68.2 to 99.9 %) efficacy over the course of the eight month study. Based on the very high residual efficacy achieved by the imidacloprid/flumethrin collar in this study, veterinarians should expect that this collar will control and eliminate existing flea infestations on cats and in their in-home premises as long as every flea infested host is treated.

Comparative speed of kill of sarolaner (Simparica and fluralaner (Bravecto) against induced infestations of Ctenocephalides felis on dogs

Background

Fleas are the most common ectoparasite infesting dogs globally and cause direct discomfort, induce allergic reactions, and transmit pathogenic agents. Rapid speed of kill is an important characteristic for a parasiticide in order to alleviate the direct deleterious effects of fleas, reduce the impact of allergic responses, and break the flea life cycle. In this study, the speed of kill of a novel, orally administered isoxazoline parasiticide, sarolaner (Simparica^™), against fleas on dogs was evaluated and compared with fluralaner (Bravecto^®) over a 3-month period.

Methods

Based on pretreatment flea counts, 24 dogs were randomly allocated to treatment with oral sarolaner at the label rate (2 to 4 mg/kg), once a month for 3 months, or oral fluralaner (25 to 50 mg/kg), once per label directions, or placebo. Dogs were combed and live fleas counted at 8, 12, and 24 h after treatment and subsequent re-infestations on Days 14, 29, 44, 59, 74 and 90. Efficacy was determined at each time point relative to counts for placebo dogs.

Results

There were no adverse reactions to treatment. Three monthly doses of sarolaner provided ≥97.6 % efficacy (based on arithmetic means) within 8 h of treatment or subsequent weekly re-infestations of fleas for 3 months. By 12 h, fleas were eradicated from all dogs (100 % efficacy). Significantly greater numbers of live fleas were recovered from fluralaner-treated dogs at 8 h on Days 74 and 90 (P ≤ 0.0043) when efficacy (based on arithmetic means) was only 80.7 and 72.6 %, respectively.

Conclusions

In this controlled laboratory evaluation, sarolaner had a significantly faster speed of kill against fleas than fluralaner at the end of its claimed treatment period. The rapid and consistent kill of fleas within 8 to 12 h after monthly oral doses of sarolaner indicates that this treatment will provide rapid and highly effective control of flea infestations, and suggests that it will provide relief for dogs suffering from flea allergy dermatitis, and should reduce the risk of flea-borne pathogen transmission.

Comparative speed of kill of sarolaner (Simparica) and spinosad plus milbemycin oxime (Trifexis) against induced infestations of Ctenocephalides felis on dogs

Background

Fleas are a ubiquitous ectoparasite infesting dogs and cause direct discomfort, allergic reactions and are responsible for the transmission of several pathogens. The rapid speed of kill of a parasiticide is important to alleviate the direct deleterious effects of fleas, reduce the impact of allergic responses, and break the flea life cycle. In this study, the speed of kill of a novel orally administered isoxazoline parasiticide, sarolaner (Simparica^™) against fleas on dogs was evaluated and compared with spinosad in combination with milbemycin oxime (Trifexis^®) for 5 weeks after a single oral dose.

Methods

Twenty-four dogs were randomly allocated to treatment with a single oral dose per product label of sarolaner (2 to 4 mg/kg), spinosad/milbemycin oxime (30 to 60 mg/kg / 0.2 to 0.4 mg/kg), or placebo based on pretreatment flea counts. Dogs were combed and live fleas counted at 8, 12, and 24 h after treatment and subsequent re-infestations on Days 7, 14, 21, 28, and 35. Efficacy (reduction in live flea counts) of each treatment was determined at each time point relative to counts for placebo dogs.

Results

There were no adverse reactions to treatment. A single oral dose of sarolaner provided ≥94.0 % efficacy (based on geometric means) within 8 h of treatment or subsequent weekly re-infestations of fleas to Day 35. By 12 h, fleas were eradicated from all dogs and they remained flea free at 24 h. Significantly greater numbers of live fleas were recovered from spinosad/milbemycin oxime-treated dogs at 8 h from Day 21 to Day 35 (P ≤ 0.0085), and at 12 and 24 h on Day 35 (P ≤ 0.0002).

Conclusions

In this controlled laboratory evaluation, dogs treated with sarolaner had significantly fewer live fleas than spinosad/milbemycin oxime- treated dogs at 8 h after re-infestation from Day 21 after a single oral dose. The rapid and consistent kill of fleas after a single oral dose of sarolaner over 35 days indicates that this treatment should provide highly effective control of flea infestations, relief for dogs afflicted with flea allergy dermatitis, and also reduce the risk of transmission of flea-borne pathogens.

Comparative speed of kill of sarolaner (Simparica) and afoxolaner (NexGard) against induced infestations of Ctenocephalides felis on dogs

BACKGROUND

Fleas are the most common ectoparasite infesting dogs globally. The many possible sequellae of infestation include: direct discomfort; allergic reactions; and the transmission of pathogens. Rapid speed of kill is an important characteristic for a parasiticide in order to alleviate the direct deleterious effects of fleas, reduce the impact of allergic responses, and break the flea infestation cycle. In this study, the speed of kill of a novel orally administered isoxazoline parasiticide, sarolaner (Simparica) against fleas on dogs was evaluated and compared with afoxolaner (NexGard) for 5 weeks after a single oral dose.

METHODS

Twenty-four dogs were randomly allocated to treatment with a single oral dose at label rate of either sarolaner (2 to 4 mg/kg) or afoxolaner (2.5 to 6.8 mg/kg) or placebo, based on pretreatment flea counts. Dogs were combed and live fleas counted at 8, 12 and 24 h after treatment and subsequent re-infestations on Days 7, 14, 21, 28 and 35. Efficacy was determined at each time point relative to counts for placebo dogs.

RESULTS

There were no adverse reactions to treatment. A single oral dose of sarolaner provided ≥98.8% efficacy (based on geometric means) within 8 h of treatment or subsequent weekly re-infestations of fleas to Day 35. By 12 h, fleas were virtually eradicated from all dogs, with only two fleas recovered from a single sarolaner-treated dog on Day 7; efficacy was 100% at all other time points. Significantly greater numbers of live fleas were recovered from afoxolaner-treated dogs at 8 h on all days and at 12 h on Days 28 and 35 (P < 0.05).

CONCLUSIONS

In this controlled laboratory evaluation, sarolaner had a significantly faster speed of kill against fleas than afoxolaner. This was noticeably more evident towards the end of the treatment period. The rapid and consistent kill of fleas within 8 to 12 h after a single oral dose of sarolaner over 35 days indicates that this treatment will provide highly effective control of flea infestations, relief for dogs afflicted with flea allergy dermatitis, and should reduce the risk of flea-borne pathogen transmission.

Evaluation of the speed of kill of sarolaner (Simparica™) against induced infestations of three species of ticks (Amblyomma maculatum, Ixodes scapularis, Ixodes ricinus) on dogs

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.

Efficacy of fluralaner flavored chews (Bravecto) administered to dogs against the adult cat flea, Ctenocephalides felis felis and egg production

Background

Fluralaner is a potent insecticide and acaricide with rapid and persistent efficacy. This study measured the efficacy of fluralaner flavored chews (Bravecto®, Merck Animal Health) administered to dogs against adult Ctenocephalides felis felis and egg production.

Methods

Twelve purpose-bred dogs were randomly allocated to two groups of six dogs each. Dogs in treatment group 1 were administered a single fluralaner flavored chew to achieve a minimum dose of at least 25 mg/kg while treatment group 2 served as untreated controls. On Days −2, 28, 56, 84, 91, 98, 105, 112, and 120 post-treatment, each dog was infested with approximately 200 unfed cat fleas, C. felis felis (KS1 strain). Forty-eight hours after treatment and 48 h after each infestation, eggs were collected over a 3-h period, counted and viability determined. Dogs were combed to remove any remaining fleas.

Results

Treatment of dogs with oral fluralaner provided a 100 % reduction in flea counts 48 h after treatment and within 48 h of every post-treatment infestation through Day122. Egg production from fluralaner treated dogs was reduced by 99.9 % (two eggs from one dog) within 48 h after treatment and not a single egg (100 % efficacy) was thereafter collected from treated dogs. Adult flea counts and egg production from the fluralaner-treated dogs were significantly lower than for non-treated controls at all post-treatment evaluations (P < 0.001). The two eggs collected from the single treated dog 48 h after treatment did not produce any adult fleas. As no additional eggs were collected from treated dogs, no viability assessment was performed.

Conclusions

A single oral dose of fluralaner flavored chews provided 100 % efficacy against repeated flea infestations on dogs for 4 months. Fluralaner reduced egg production of activity reproducing female fleas by 99.9 % and then killed every single female flea before any eggs could be produced following each subsequent re-infestation for the entire 122-day evaluation period.

Evaluation of spinosad for the oral treatment and control of flea infestations on cats in Europe

METHODS

An ectoparasiticide containing spinosad was evaluated as an oral formulation for cats. Two European laboratory studies and a European multicentre field efficacy and safety study assessed the use of a chewable tablet formulation of spinosad at a dose range of 50-75 mg/kg for treatment and control of flea infestations on cats.

RESULTS

The studies with experimentally infested cats consistently demonstrated persistent activity against Ctenocephalides felis with >98 per cent efficacy at four weeks post-treatment. In the field study with naturally infested client-owned cats from 18 clinics across Germany and Italy, two monthly doses of spinosad were administered; selamectin was the comparator product. Safety was evaluated in 226 cats, each receiving at least one dose of spinosad or selamectin; both products were well tolerated. 113 spinosad-treated cats and 71 selamectin-treated cats showed >97 per cent reductions in geometric mean flea counts within 14 days post-treatment and at 60 days post-treatment efficacy was >98 per cent in both groups. Analysis of success rates showed 96 per cent in spinosad-treated cats compared with 90.9 per cent in selamectin-treated cats at day 60. The spinosad tablets were successfully administered to over 98 percent of cats. These studies indicate that this formulation of spinosad is safe and efficacious for treatment and prevention of flea infestations in cats.

Efficacy of spinosad tablets administered to a colony of 15 indoor cats naturally infested with fleas

The aims of the study were (i) to describe adult fleas distribution in a strictly indoor cat colony composed of cats with flea allergy dermatitis (FAD) and non-FAD cats and (ii) to evaluate the efficacy of spinosad used alone. Skin lesions were scored according to the SCORing Feline Allergic Dermatitis lesion severity scale (SCORFAD) on days 0, 15, 30, 45, 60, and 90. Cats were combed prior to the treatment (days 0, 30, and 60) and on days 15, 45, and 90; collected fleas were replaced on the animals. All cats received flavored spinosad tablets (Comfortis) at a dosage of 50-75 mg/kg on days 0, 30, and 60. Cats were fed immediately afterwards. On day 0, a total of 60 fleas were collected (mean: 4 ± 4). Cats with FAD had a SCORFAD of 6, 8, 12, and 13 and harbored 0, 2, 1, and 0 fleas, respectively. Tablets were taken voluntarily by 8, 11, and 12 cats on days 0, 30, and 60, respectively. No adverse event was recorded. From day 15 to day 90, no fleas could be collected. SCORFAD was reduced by 40%, 71%, 80%, 89%, and 98% on days 15, 30, 45, 60, and 90, respectively.

Insecticide/acaricide resistance in fleas and ticks infesting dogs and cats

This review defines insecticide/acaricide resistance and describes the history, evolution, types, mechanisms, and detection of resistance as it applies to chemicals currently used against fleas and ticks of dogs and cats and summarizes resistance reported to date. We introduce the concept of refugia as it applies to flea and tick resistance and discuss strategies to minimize the impact and inevitable onset of resistance to newer classes of insecticides. Our purpose is to provide the veterinary practitioner with information needed to investigate suspected lack of efficacy, respond to lack of efficacy complaints from their clients, and evaluate the relative importance of resistance as they strive to relieve their patients and satisfy their clients when faced with flea and tick infestations that are difficult to resolve. We conclude that causality of suspected lack of insecticide/acaricide efficacy is most likely treatment deficiency, not resistance.

Efficacy of a combination of 10% imidacloprid and 4.5% flumethrin (Seresto®) in slow release collars to control ticks and fleas in highly infested dog communities

Background

Dog communities living in kennels are at high risk of being infected by ticks and fleas. In spite of the indubitable efficacy of several topical ectoparasiticides registered for the control of ectoparasites in dogs, the short period of action and the price of these products limit their use in dog communities. This paper reports on the efficacy of imidacloprid/flumethrin slow release collars to cure dogs highly infested with ectoparasites and to prevent infestations for 8 months in a refuge with a history of unsuccessful environmental treatments.

Methods

A total of 82 dogs were collared with slow release collars containing a formulation of imidacloprid 10% / flumethrin 4.5%. Dogs were followed-up for ectoparasite presence after 2, 7 and 14 days and thereafter biweekly up to 90 days. Furthermore, dogs were examined for ectoparasites whilst replacing collars 8 months after their application.

Results

At the time of treatment 79 (96.3%) out of 82 included dogs were heavily infested by ticks and 53 (68.8%) out of the 77 combed dogs were infested by fleas. Tick infested dogs had an estimated mean intensity of 46.9 (± 65.7), while flea infested animals had a load between 20 and 50 fleas. In addition, some of the flea infested dogs (18.9%) were presenting signs of flea allergic dermatitis (FAD). Two days after treatment, 49 (60.5%) and 9 (11.7%) dogs were still infested by live ticks and fleas, respectively. However, the mean intensity of ticks decreased to 3.5 (± 4.3) with a reduction of 92.5%. Except for sporadic cases, no attached ectoparasites were found on dogs from the day 14 visit until the end of the investigation. Cases of FAD resolved without any other treatment within 30 days.

Conclusions

Ticks and fleas represent a constant hazard for dog populations. Therefore, in particular settings, such as dog refuges, sustainable and long-term strategies to control ectoparasite infestations are needed. Based on the observed evidence of efficacy, long-term duration and safety, the imidacloprid/flumethrin slow release collars can be regarded as an efficacious and sustainable means for ectoparasite control and for treatment of FAD in high-risk dog communities.

Evaluation of the efficacy of selamectin spot-on in cats infested with Aelurostrongylus abstrusus (Strongylida, Filariodidae) in a Central Italy cat shelter

In recent years Aelurostrongylus abstrusus has often been reported in Italy. This lungworm is very common in cat colonies due to its route of transmission. Deciding a therapeutic approach can be difficult in such colonies, because there is no certainty whether oral medicines administered with food, or with what dose, will be taken. In this field study, stool samples were taken from 42 cats and analysed for A. abstrusus L1 larvae with Baermann technique. Ten cats testing positive were treated with a spot-on formulation of selamectin 45 mg. Clinical examinations and laboratory tests, repeated four times in two months, demonstrated the success of the treatment in 9 of the 10 cats. Improvements in respiratory signs and general clinical condition were reported after treatment.

Efficacy of indoxacarb applied to cats against the adult cat flea, Ctenocephalides felis, flea eggs and adult flea emergence

Background

A study was conducted to evaluate the effect of indoxacarb applied to cats on adult cat fleas, Ctenocephalides felis, flea egg production and adult flea emergence.

Methods

Sixteen cats were selected for the study and allocated to two treatment groups. Eight cats were treated with a 19.5% w/v topical spot-on solution of indoxacarb on day 0 and eight cats served as untreated controls. Each cat was infested with 50 fleas on Days -2, 7, 14, 21, 28, 35 and 42. On Days 1, 2, and 3, and at 2 and 3 days after each post treatment reinfestation flea eggs were collected from the pan under each cat cage. Eggs were counted and viability assessed by evaluating adult flea emergence 28 days after egg collection. Three days after treatment or infestation, each cat was combed to remove and count live fleas.

Results

Treatment with indoxacarb provided 100% efficacy following infestations on day -2, 7, 14, 21 and 28 and efficacy was 99.6% following infestations on days 35 and 42. Egg production from indoxacarb treated cats was reduced by 99.9% within 72 hours of treatment. For subsequent infestations no eggs were produced from treated cats from day 8 through day 30. Egg production was still reduced by ≥95.8% through day 45. Indoxacarb treatment also reduced adult flea emergence from eggs for 5 weeks after treatment. The combination of reduction in egg numbers and egg viability from indoxacarb treated cats reduced predicted flea emergence by 100% from days 2 – 31 and 99.9%, 100%, 96.4% and 99.0% on days 37, 38, 44 and 45, respectively.

Conclusions

A topical spot-on formulation of indoxacarb provided ≥99.6% efficacy against flea infestations on cats for 6 weeks following a single treatment. Indoxacarb also eliminated or markedly reduced egg production for the entire evaluation period and reduced the viability of the few eggs that were produced from Day 1 through Day 38. Given indoxacarb’s effect on adult fleas, egg production and egg viability; this formulation can interrupt flea reproduction on treated cats for at least 6 weeks after treatment.

Efficacy of selamectin, spinosad, and spinosad/milbemycin oxime against the KS1 Ctenocephalides felis flea strain infesting dogs

Background

A study was conducted to evaluate and compare the efficacy of selamectin, spinosad, and spinosad/milbemycin oxime against the KS1 strain of Ctenocephalides felis on dogs.

Methods

Forty-eight dogs were selected for the study and two batches of 24 were blocked and allocated randomly to treatment groups and flea count times. There were four treatment groups of 12 dogs each: negative control, topical selamectin, oral spinosad/milbemycin oxime, and oral spinosad. Each dog was infested with 100 fleas on Days -2, 7, 14, 21 and 28. Within each treatment group, six dogs were flea counted at 24 hours and six at 48 hours after treatment or post-infestation. On Day 0, dogs received a single treatment of the appropriate drug according to the approved commercial label.

Results

Efficacy of selamectin against an existing flea infestation was 60.4% and 91.4% at 24 and 48 hours, respectively, whereas spinosad/milbemycin oxime and spinosad were 100% at both time points. All products were >90% effective within 24 hours after subsequent infestations on Days 7, 14 and 21. Following the Day 28 flea infestation, selamectin was 93% and 95.7% effective at 24 and 48 hours, respectively. Whereas the efficacy of spinosad/milbemycin oxime following the day 28 infestation was 84.7% and 87.5% at 24 and 48 hours, respectively and spinosad alone was 72.9% and 76.3% effective at 24 and 48 hours, respectively.

Conclusions

After initial application, the two oral spinosad products had a more rapid onset of flea kill than topical selamectin which took up to 48 hours to control (>90%) the existing infestation. However, for subsequent weekly flea infestations selamectin had similar or better efficacy than spinosad or spinosad/milbemycin oxime at 24 and 48 hours after infestation. Spinosad/milbemycin oxime and spinosad were >90% effective against the KS1 strain from Day 1 to Day 23. Whereas, selamectin was >90% effective against the KS1 strain of C. felis from Day 2 to Day 30.

Fleas infesting pets in the era of emerging extra-intestinal nematodes

Modifications in climatic conditions, movements of hosts and goods, changes in animal phenology and human behaviour and increase of wildlife, are presently concurring in the geographic spread of vectors and cardio-respiratory nematodes, e.g. Dirofilaria immitis, Angiostrongylus vasorum, Aelurostrongylus abstrusus and Capillaria aerophila. All these factors may also influence dispersion and clinical significance of fleas, thus posing relevant challenges in those regions where other parasites are emerging at the same time. Ctenocephalides felis, Ctenocephalides canis and Pulex irritans cause discomfort, nuisance, allergic reactions, anaemia, and may transmit several pathogens, some of them are of importance for public health. The present article reviews the importance of fleas in small animal practice and their sanitary relevance for dogs, cats and humans, and discusses current control methods in the present era of emerging extra-intestinal nematodes, towards a possible changing perspective for controlling key parasites affecting companion animals.

Comparative efficacy on dogs of a single topical treatment with fipronil/(S)-methoprene or weekly physiological hygiene shampoos against Ctenocephalides felis in a simulated flea-infested environment

Flea infestations of pets continue to persist due to the lack of knowledge of flea biology and ecology. It is not unusual that pet owners believe regular hygiene, such as shampooing their dogs can replace regular insecticidal treatment. The objective of this study was to compare in a flea simulated environment, modelling exposure similar to that found in a home, that the use of regular physiological shampoo does not control fleas adequately when compared to a long acting topical formulation. Three groups of six dogs were formed: one untreated control group, one group treated monthly with the topical formulation of fipronil/(S)-methoprene, and a third group treated weekly with a hygiene shampoo. All dogs were infested with adult unfed Ctenocephalides felis fleas (200 ± 5) on Days -28 and -21. Each animal’s sleeping box was fitted with a plastic cup mounted to the inside roof of the box. The sleeping bench of each animal was covered with a carpet to accommodate flea development. The dogs were maintained in their kennels throughout the study. In order to maintain the environmental flea challenge, C. felis pupae (100 ± 5) were placed in the plastic cup in each animal’s sleeping box on Days -14, -7, 0, 7, 14, 21, 28, 35 and 42. The dogs were combed and fleas counted weekly on Days -1, 3, 10, 17, 24, 31, 38, 45, and 51. The fleas were placed immediately back on the dogs. On Day 60, fleas were counted and removed. Flea infestations in the untreated control group at each count averaged between 46.2 and 74.2 fleas throughout the study. The average number of fleas infesting dogs was significantly different (p < 0.05) between the untreated and the two treatment groups and between the two treatment groups at all counts throughout the two months study (Days 3, 10, 17, 24, 31, 38, 45, 51 and 60). The efficacy was never below 99.1% in the fipronil/(S)-methoprene group, and efficacy in the shampoo group was never above 79.2%. Weekly shampooing in treatment group 3 was intentionally delayed after Day 42, to evaluate wether missing a weekly bath would affect the flea population. The Day 48 data indicate that forgetting or delaying a single weekly shampooing resulted in a clear increase in flea numbers and a significant decrease in efficacy from 68.2% to 34.8%. The fipronil(S)/methoprene treatment allowed a continuous control as demonstrated by the high efficacy against fleas, and also the number of flea-free dogs on seven of the nine weekly assessments, in spite of what was essentially a continuous flea challenge model.

Efficacy of a novel fipronil spot-on for the treatment and control of induced infestations of adult cat fleas (Ctenocephalides felis) and castor bean ticks (Ixodes ricinus) on cats

Cat fleas (Ctenocephalides felis) and the castor bean tick (Ixodes ricinus) cause discomfort and health effects due to bites and ingestion of blood and they serve as vectors for several animal and human pathogens. Effectiveness of a novel 10 % w/v fipronil spot-on (Eliminall®/Exproline vet™, marketed by Pfizer Animal Health and registered and manufactured by Krka, d.d., Novo mesto) was confirmed against these parasites on experimentally infested cats. Two parallel, unicentre and masked controlled studies were conducted with European mixed breed and mixed sex cats. Cats were allocated randomly to one of two treatment groups based on either pre-treatment flea counts (study 1) or pre-treatment tick counts (study 2). In each of the study, eight animals served as control, while another eight animals were treated once topically with the unit label dose of 50 mg fipronil per cat (10.6-23.8 mg/kg). At each reinfestation, animals were infested with approximately 100 fleas or 60 ticks to achieve adequate infestation rates. Parasites were removed and counted on days 2, 9, 16, 23, 30 and 37, 48 h after the treatment or experimental infestation. Excellent effectiveness was demonstrated on day 2 (100 and 94 % efficacy against fleas and ticks, respectively) and lasted for up to 5 weeks (efficacy ≥96 %) against fleas and up to 4 weeks against ticks (efficacy ≥94 %). The product was well tolerated and no adverse reactions were observed.

Comparative efficacy on dogs of a single topical treatment with the pioneer fipronil/(S)-methoprene and an oral treatment with spinosad against Ctenocephalides felis

In the study reported here, the pioneer fipronil/(S)-methoprene topical product (FRONTLINE^® PLUS, Merial Limited, Duluth, GA) was compared to the oral spinosad product (COMFORTIS^® Elanco, Greenfield, IN) for efficacy against adult fleas and preventing egg production. The product presentations, doses and labelling were the one applicable in the USA. Using a standard protocol, 200 cat fleas of mixed sex were applied to dogs on Days 1, 7, 14, 21, 28, 35, and 42. Dogs were combed to remove fleas 24 hours post-infestation, the fleas were counted, collected, and then reapplied to each dog following completion of their respective count. At 48 hours post-infestation, comb counts were performed and fleas were removed. No fleas were collected from any dog in the fipronil/(S)-methoprene group at any 24 or 48 hours post-infestation assessment throughout the six weeks study, yielding a preventive efficacy of 100%. For the spinosad treatment, efficacy was 100% at 24 hours and 48 hours through Day 16, and thereafter declined. The results observed in the spinosad-treated dogs were highly variable between animals. At the 24 and 48 hours counts following the Day 21 infestation, only five of eight spinosad-treated dogs (62.5%) were flea-free. Following the Day 28 infestation, spinosad efficacy fell to 85% and 89%, for the 24 hours and 48 hours counts, and only two dogs (25%) were flea free, compared to 100% flea-free dogs in the fipronil/(S)-methoprene group. No fleas were collected from the fipronil/(S)- methoprene treated dogs throughout the entire study, therefore, no eggs were collected at any time from any dog in the group. However, in the spinosad group adult fleas were found on dogs starting on Day 21 and by Day 30, 42 eggs were collected from one dog that had 107 adult fleas counted at 48 hours. At Day 37 and Day 49, more than 100 eggs were collected from each dog in the spinosad-treated and control groups.