Dynamics of distribution and efficacy of different spot-on permethrin formulations in dogs artificially infested with Dermacentor reticulatus

Abstract

BackgroundVarying reports concerning the duration and reliability of different permethrin preparations' efficacy can be found in the literature. The aim of this study was to investigate the dynamics of the distribution and efficacy of four different spot-on formulations with permethrin as the active ingredient formulated with different solvents. To examine the influence of these solvents on the speed of distribution and the acaricidal activity of permethrin in the coat, an in vivo study under laboratory conditions was performed. Six dogs per test period were treated with the recommended dose and 1, 14 and 28 days after treatment dogs were infested with Dermacentor reticulatus ticks: a) on the back, near the application site, and b) on the hind leg, the greatest possible distance from the application site. Efficacies were determined 6 hours after tick infestation to examine the repellent effect and the speed of kill of the products which plays an important role in the context of tick transmitted diseases.ResultsAfter six hours of exposure, a significant acaricidal efficacy (p < 0.001) could be observed in all treated groups over the whole duration of the study, regardless of which product was used. While the arithmetic mean of attached ticks was < 3 on Day 1, numbers increased over the course of the study to a mean of > 9 on Day 28. However, most of these ticks were dead even 28 days after treatment, as the mean of live attached ticks was still < 2. Significant differences could neither be found between the different permethrin spot-on formulations, nor between the two parts of the body (p > 0.05).ConclusionsAll products were able to kill ticks within six hours following infestation from Day 1 to Day 28 after treatment. Additionally, no significant difference between the tick numbers on the back and the hind leg could be found at any time, which implies a homogenous distribution of permethrin over the body. The efficacy of all four products was comparable during the whole study period, showing that the different solvents do not significantly affect the dynamics of distribution.

Prevalence of antibodies to Rickettsia conorii in human beings and dogs from Catalonia: a 20-year perspective

“…sanguineus, but it does not suppress infestation completely [20]. However, Lüssenhop et al demonstrated that in dogs treated with permethrinimidacloprid spot-on, most ticks were dead 6 h after experimental infestation with ticks of the genus Dermacentor reticulatus [21]. In fact, many dogowners who use the spot-on treatment report that it is not uncommon to find ticks attached to the dog, but that usually these ticks are dead.…”

Seasonal and spatial distribution of ixodid tick species feeding on naturally infested dogs from Eastern Austria and the influence of acaricides/repellents on these parameters

“…The assumption that tick biting behaviour is not influenced with increasing distance from the application site [12] could thus be confirmed.…”

“…Furthermore, no shift of the feeding ocation on treated dogs to places further away from the acaricide application sites (neck) was expected. According to Lüssenhop et al [12] the effect of acaricides is distributed homogeneously on the dog’s skin, indicating that there is no reduction of the concentration of the active component with increasing distance from the application site.…”

Distribution of permethrin in hair and stratum corneum after topical administration of four different formulations in dogs

“…As this study was conducted with beagles only, the possibility of different results in other dog species with different coat lengths can not be excluded. In spite of the low concentration towards the end of the study, a sufficient acaricidal effect could be shown in a study with ticks which was simultaneously conducted on the same dogs (Lüssenhop et al. , 2011).…”

“…In conclusion, the additives 1-methoxypropan-2-ol, isopropyl myristate and 1-methyl-2-pyrrolidon do not significantly differ in their effect on the distribution and thus efficacy (Lü ssenhop et al, 2011) of permethrin in four commercially available formulations.…”