Fluralaner Research Articles

Enzootic stability of tick fever in Holstein calves grazing in a tropical region, subjected to strategic cattle tick control with fluralaner

BackgroundIn 2022, fluralaner was launched on the market for use in the control of the cattle tick Rhipicephalus microplus after showing 100% efficacy in registration trials against the causative agents of cattle tick fever (TFAs). The aim of the present study was to determine whether a strategic control regimen against R. microplus using fluralaner (FLU) in Holstein calves grazing in a tropical region would alter the enzootic stability status of cattle tick fever, triggering outbreaks in these animals up to 22 months age.MethodsIn this study, a group of calves treated with FLU was compared with a control group treated with the regimen currently being used on the farm, which consisted of the fipronil + fluazuron formulation (FIFLUA). In the first experiment, the efficacy of the FIFLUA pour-on formulation was evaluated in a field study. In the second experiment, which lasted 550 days, two experimental groups (n = 30/group) of Holstein calves naturally infested with R. microplus were analyzed. Calves aged 4 to 10 months received either a specific treatment regimen with FLU (experimental group) or FIFLUA (control group). During this period, tick counts, animal weight measurement, feces collection (to determine eggs and oocysts per gram of feces), tick fever monitoring, blood smears (to ascertain enzootic stability of the herd), PCR testing for TFAs and serology (indirect enzyme-linked immunosorbent assay [iELISA]) were performed. All calves were evaluated for signs of tick fever between ages 11 and 22 months.ResultsFIFLUA showed an acaricidal efficacy of > 90% from post-treatment days 14 to 35. Regarding treatments against the TFAs, the average number of treatments was similar between groups, but animals treated with FLU had a smaller reduction in packed cell volume on some of the evaluation dates of the second and third treatment against TFAs. In calves aged 10 months in the FLU group, B. bovis was not detected by PCR (0/15 samples), 40% of the samples had antibody titers and 33% (10/30) of the samples had positive blood smears. Regarding B. bigemina, > 86% of the samples in both groups tested positive for B. bigemina DNA and antibodies; there was no difference in the antibody titers between the groups. There were no clinical cases of cattle tick fever in calves aged 11 to 22 months.ConclusionsIn comparison with the control treatment, the strategic control regimen against R. microplus with FLU that was implemented in the present study did not negatively affect the enzootic stability status of A. marginale and B. bigemina in the herd up to 22 months of age. The enzootic stability status of B. bovis was not reached by either group. These results likely represent a characteristic of the local tick population, so further studies should be performed.Graphical

Usability Comparison Study of Spot-on Formulations of Parasiticides in Cats

The aim of this study was to evaluate the usability of spot-on parasiticides for cats from the aspects of their stickiness and drying time after application. Eighteen client-owned healthy, munchkin cats (3 males, 15 females), between 9-month-old and 6-year-old, weighing from 1.5-2.9 kg were used in the study. Six spot-on parasiticides which are commercially available in Thailand including selamectin (SE), moxidectin + imidacloprid (MI), praziquantel + emodepside(PE), fipronil + (S)-methoprene + eprinomectin + praziquantel (FMEP), fluralaner (FL) and fipronil + (S)-methoprene (FM) were assessed after their respective application to the skin between shoulder blades of the 18 cats. Stickiness scores (STS) and drying time scores (DTS) were evaluated and recorded at 0.5, 1, 3, 6, 9, 12, 24 and 48 h after drug administration (DA). SE and MI groups showed the most satisfying scores of STS at 3 h after DA, STS in all groups was zero (not sticky) at 48 h after DA. For DTS, the SE and FL groups had the most satisfying score at 0.5 and 1 h after DA, DTS in all groups were zero (dry) at 24 h after DA. Some skin lesions such as erythema and alopecia were found in the MI and FMEP groups but the lesions completely recovered and all cats had normal general health throughout the study. From the study results, all of the 6 spot-on parasiticides are safe for cats and are acceptable for cat owners.

Chemoinformatic Approaches in the Study of Fluralaner and Afoxolaner-mediated Inhibition of l-glutamate-gated Chloride Channels

This work showcased the chemoinformatic study of isoxazoline ectoparasiticides: Fluralaner (FLU) and Afoxolaner (AFO) interactions with l-glutamate-gated chloride channels (3RHW). In order to evaluate inhibition thermodynamics, computational approaches such as molecular docking were employed. Results evidenced that FLU-3RHW highest scoring pose presented lower Gibbs free energy and henceforth, lower K i values than AFO-3RHW. The findings herein reported suggest therefore that computational methods might be useful to study the thermodynamic features of ectoparasiticides used in veterinary care, what might shed further light on their chemical and pharmacological properties.