Assessment of the in vitro acaricidal activity of Bravecto ® (fluralaner) and a proposed orange oil-based formulation vehicle for the treatment of Sarcoptes scabiei

Kotaro Takano; Scott Carver; Yolandi Vermaak; Katja Fischer; Robert J Harvey; Kate E Mounsey

doi:10.1186/s13071-024-06275-9

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Assessment of the in vitro acaricidal activity of Bravecto ® (fluralaner) and a proposed orange oil-based formulation vehicle for the treatment of Sarcoptes scabiei

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Assessment of the in vitro acaricidal activity of Bravecto ® (fluralaner) and a proposed orange oil-based formulation vehicle for the treatment of Sarcoptes scabiei

Kotaro Takano, Scott Carver, Yolandi Vermaak, Katja Fischer, Robert J Harvey and Kate E Mounsey

Parasites & Vectors, Vol.17, pp.1-9

2024

DOI: https://doi.org/10.1186/s13071-024-06275-9

PMCID: PMC11046784

PMID: 38664829

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Abstract

Sarcoptes scabiei

Sarcoptic mange

scabies

bare-nosed wombat

Vombatus ursinus

fluralaner

citrus oil

essential oil

Background Sarcoptic mange is a serious animal welfare concern in bare-nosed wombats (Vombatus ursinus). Fluralaner (Bravecto®) is a novel acaricide that has recently been utilised for treating mange in wombats. The topical ‘spot-on’ formulation of fluralaner can limit treatment delivery options in situ, but dilution to a volume for ‘pour-on’ delivery is one practicable solution. This study investigated the in vitro acaricidal activity of Bravecto, a proposed essential oil-based diluent (Orange Power®), and two of its active constituents, limonene and citral, against Sarcoptes scabiei. Methods Sarcoptes scabiei were sourced from experimentally infested pigs. In vitro assays were performed to determine the lethal concentration (LC50) and survival time of the mites when exposed to varying concentrations of the test solutions. Results All compounds were highly effective at killing mites in vitro. The LC50 values of Bravecto, Orange Power, limonene and citral at 1 h were 14.61 mg/ml, 4.50%, 26.53% and 0.76%, respectively. The median survival times of mites exposed to undiluted Bravecto, Orange Power and their combination were 15, 5 and 10 min, respectively. A pilot survival assay of mites collected from a mange-affected wombat showed survival times of < 10 min when exposed to Bravecto and Orange Power and 20 min when exposed to moxidectin. Conclusions These results confirm the acaricidal properties of Bravecto, demonstrate acaricidal properties of Orange Power and support the potential suitability of Orange Power and its active constituents as a diluent for Bravecto. As well as killing mites via direct exposure, Orange Power could potentially enhance the topical delivery of Bravecto to wombats by increasing drug penetration in hyperkeratotic crusts. Further research evaluating the physiochemical properties and modes of action of Orange Power and its constituents as a formulation vehicle would be of value.

Details

Title: Assessment of the in vitro acaricidal activity of Bravecto ® (fluralaner) and a proposed orange oil-based formulation vehicle for the treatment of Sarcoptes scabiei
Authors: Kotaro Takano - University of the Sunshine Coast, Queensland, School of Science, Technology and Engineering
Scott Carver - University of Georgia
Yolandi Vermaak - Wombat Support and Rescue NSW/ACT Inc. (Australia)
Katja Fischer - QIMR Berghofer Medical Research Institute
Robert J Harvey - University of the Sunshine Coast, Queensland, School of Health
Kate E Mounsey (Corresponding Author) - University of the Sunshine Coast, Queensland, School of Health - Biomedicine
Publication details: Parasites & Vectors, Vol.17, pp.1-9
Publisher: BioMed Central Ltd.
Date published: 2024
DOI: 10.1186/s13071-024-06275-9
ISSN: 1756-3305
PMID: 38664829; PMC11046784
Copyright note: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
Data Availability: All data generated or analysed are included in this published article.
Grants: Developing treatment for feasible control of mange disease in wombat populations, LP180101251, Australian Research Council (Australia, Canberra) - ARC
Organisation Unit: School of Health - Biomedicine; School of Health; School of Science, Technology and Engineering
Language: English
Record Identifier: 991016462202621
Output Type: Journal article

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