Fluralaner (Bravecto\xae) induces long-term mortality of Lutzomyia longipalpis after a blood meal in treated dogs

Tamyres Bernadete Dantas Queiroga,Henrique Rafael Pontes Ferreira,Ana Beatriz Lourenço De Assis,Paulo Marcos Matta Guedes,Romeika Karla Dos Reis,Antônia Cláudia Jácome Da Câmara,Renata Antonaci Gama,João Ciro Fagundes Neto,Manuela Sales Lima Nascimento,Vicente Toscano De Araújo Neto,Wilo Victor Dos Santos

doi:10.1186/s13071-020-04489-1

Tamyres Bernadete Dantas Queiroga, Henrique Rafael Pontes Ferreira + Show 9 more

Open Access

https://doi.org/10.1186/s13071-020-04489-1

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Abstract

BackgroundLeishmania infantum is the etiological agent of visceral leishmaniasis (VL) in the New World, where the sand fly Lutzomyia longipalpis and domestic dogs are considered the main vector and host reservoirs, respectively. Systemic insecticides have been studied as an alternative to control vector-borne diseases, including VL. Fluralaner, an isoxazoline class compound, is a systemic insecticide used in dogs, with proven efficiency against different species of phlebotomine sand flies. However, to date no studies have demonstrated the efficacy of fluralaner on Lu. longipalpis. The aim of this study was to evaluate the insecticidal effect of fluralaner (Bravecto®) on the sand fly Lu. longipalpis after blood meal in treated dogs.MethodsHealthy mongrel dogs (n = 8) were recruited from the Zoonoses Control Center in the city of Natal, Rio Grande do Norte, Brazil, and randomized into two groups: fluralaner treated (n = 4) and non-treated control (n = 4). Colony-reared female specimens of Lu. longipalpis (n = 20) were allowed to feed on all dogs for 40 min before treatment (for fluralaner-treated dogs), at day 1 after treatment and then monthly until 1 year post-treatment.ResultsIn the treatment group, there was 100% mortality of Lu. longipalpis for up to 5 months after treatment initiation, decreasing to 72.5% at 6 months post-treatment initiation. The efficacy of fluralaner ranged from 100% at day 1 (P = 0.0002) to 68% ( P = 0.0015) at 6 months, decreasing to 1.4% at 1 year post-treatment. Sand fly mortality carried out blood meal in non-treated control dogs remained constant at ≤ 15%.ConclusionsTaken together, our results suggest that fluralaner may be used as a control strategy for VL in dogs in VL endemic areas.Graphical

Highlights

Leishmania infantum is the etiological agent of visceral leishmaniasis (VL) in the New World, where the sand fly Lutzomyia longipalpis and domestic dogs are considered the main vector and host reservoirs, respectively
No side effects were observed in dogs treated with fluralaner The assays were conducted between November 2018 and November 2019
Fluralaner (Bravecto®) induces 100% mortality of Lu. longipalpis up to 5 months after treatment in dogs All female Lu. longipalpis specimens used in the assays were engorged, with 100% feeding success

Summary

Introduction

Leishmania infantum is the etiological agent of visceral leishmaniasis (VL) in the New World, where the sand fly Lutzomyia longipalpis and domestic dogs are considered the main vector and host reservoirs, respectively. Dogs are the main domestic reservoir and play an important role in maintaining the disease cycle due to the high prevalence of L. infantum infection in dogs, the presence of amastigote forms in their skin and their proximity to humans [4,5,6,7]. For this reason, dogs are considered to be strategic targets for disease control. The control actions currently used to target the vector and its main reservoir are controversial and appear to have a limited impact on the incidence of human and canine VL cases due to several limitations, including inefficiency of diagnostic methods, absence of a treatment that eliminates the parasite and/or lack of an effective vaccine to prevent infection in humans and dogs [13, 14]

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