Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus

Autores
Klafke, Guilherme; Torrents, Jorgelina; Ferreira, Priscila Teixeira; Sarli, Macarena; Loch, Ana Luiza; Avelar, Barbara Rauta de; Azevedo, Thais Ribeiro Correia; Scott, Fabio Barbour; Morel, Nicolas; Nava, Santiago; Reck, José
Año de publicación
2025
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Fluralaner is an isoxazoline acaricide with potent activity against Rhipicephalus (Boophilus) microplus, a major tick species affecting cattle in South America. In this study, larval bioassays were performed to evaluate the baseline susceptibility of R. microplus populations from Brazil and Argentina to fluralaner. The larval packet test (LPT) was applied to Brazilian laboratory and field populations, while the larval immersion test (LIT) was used in Argentina. Both tests were carried with technical grade and a commercial formulation of fluralaner. LPT results showed consistent LC₅₀ values across two susceptible laboratory strains, with resistance ratios near unity in all field samples. Similar observations were obtained with the LIT, with resistance ratios also near 1 for all tested populations from Argentina. The LIT produced LC₅₀ values approximately 100 times lower than the LPT, a difference consistent with previous studies using systemic acaricides. Both technical and commercial formulations yielded comparable results in both tests. These findings confirm the high susceptibility of R. microplus to fluralaner and establish reliable bioassay parameters for future resistance monitoring. The choice between LPT and LIT and technical grade or commercial formulation of fluralaner should be guided by laboratory infrastructure and logistical needs, as both methods are valid for surveillance purposes.
EEA Rafaela
Fil: Klafke, Guilherme. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); Brasil
Fil: Torrents, Jorgelina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Torrents, Jorgelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Ferreira, Priscila Teixeira. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); Brasil
Fil: Ferreira, Priscila Teixeira. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; Brasil
Fil: Sarli, Macarena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Sarli, Macarena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Loch, Ana Luiza. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); Brasil
Fil: Avelar, Barbara Rauta de. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; Brasil
Fil: Azevedo, Thais Ribeiro Correia. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; Brasil
Fil: Scott, Fabio Barbour. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; Brasil
Fil: Morel, Nicolas. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Morel, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Nava, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Reck, José. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); Brasil
Fuente
Veterinary Parasitology 340 : 110600. (December 2025)
Materia
Rhipicephalus
Ticks
Cattle
Acaricides
Bio-Assays
Application Rates
Garrapata
Ganado Bovino
Acaricidas
Ensayo Biológico
Dosis de Aplicación
Rhipicephalus microplus
Nivel de accesibilidad
acceso restringido
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
INTA Digital (INTA)
Institución
Instituto Nacional de Tecnología Agropecuaria
OAI Identificador
oai:localhost:20.500.12123/24059
Acceder
id INTADig_fae1a66c11da837a634373493d288597
oai_identifier_str oai:localhost:20.500.12123/24059
network_acronym_str INTADig
repository_id_str l
network_name_str INTA Digital (INTA)
spelling Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplusKlafke, GuilhermeTorrents, JorgelinaFerreira, Priscila TeixeiraSarli, MacarenaLoch, Ana LuizaAvelar, Barbara Rauta deAzevedo, Thais Ribeiro CorreiaScott, Fabio BarbourMorel, NicolasNava, SantiagoReck, JoséRhipicephalusTicksCattleAcaricidesBio-AssaysApplication RatesGarrapataGanado BovinoAcaricidasEnsayo BiológicoDosis de AplicaciónRhipicephalus microplusFluralaner is an isoxazoline acaricide with potent activity against Rhipicephalus (Boophilus) microplus, a major tick species affecting cattle in South America. In this study, larval bioassays were performed to evaluate the baseline susceptibility of R. microplus populations from Brazil and Argentina to fluralaner. The larval packet test (LPT) was applied to Brazilian laboratory and field populations, while the larval immersion test (LIT) was used in Argentina. Both tests were carried with technical grade and a commercial formulation of fluralaner. LPT results showed consistent LC₅₀ values across two susceptible laboratory strains, with resistance ratios near unity in all field samples. Similar observations were obtained with the LIT, with resistance ratios also near 1 for all tested populations from Argentina. The LIT produced LC₅₀ values approximately 100 times lower than the LPT, a difference consistent with previous studies using systemic acaricides. Both technical and commercial formulations yielded comparable results in both tests. These findings confirm the high susceptibility of R. microplus to fluralaner and establish reliable bioassay parameters for future resistance monitoring. The choice between LPT and LIT and technical grade or commercial formulation of fluralaner should be guided by laboratory infrastructure and logistical needs, as both methods are valid for surveillance purposes.EEA RafaelaFil: Klafke, Guilherme. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); BrasilFil: Torrents, Jorgelina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); ArgentinaFil: Torrents, Jorgelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); ArgentinaFil: Ferreira, Priscila Teixeira. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); BrasilFil: Ferreira, Priscila Teixeira. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; BrasilFil: Sarli, Macarena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); ArgentinaFil: Sarli, Macarena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); ArgentinaFil: Loch, Ana Luiza. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); BrasilFil: Avelar, Barbara Rauta de. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; BrasilFil: Azevedo, Thais Ribeiro Correia. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; BrasilFil: Scott, Fabio Barbour. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; BrasilFil: Morel, Nicolas. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); ArgentinaFil: Morel, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); ArgentinaFil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); ArgentinaFil: Nava, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); ArgentinaFil: Reck, José. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); BrasilElsevier2025-10-03T13:04:00Z2025-10-03T13:04:00Z2025-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://hdl.handle.net/20.500.12123/24059https://www.sciencedirect.com/science/article/abs/pii/S03044017250021100304-40171873-2550https://doi.org/10.1016/j.vetpar.2025.110600Veterinary Parasitology 340 : 110600. (December 2025)reponame:INTA Digital (INTA)instname:Instituto Nacional de Tecnología Agropecuariaenginfo:eu-repo/semantics/restrictedAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)2025-10-23T11:19:46Zoai:localhost:20.500.12123/24059instacron:INTAInstitucionalhttp://repositorio.inta.gob.ar/Organismo científico-tecnológicoNo correspondehttp://repositorio.inta.gob.ar/oai/requesttripaldi.nicolas@inta.gob.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:l2025-10-23 11:19:47.009INTA Digital (INTA) - Instituto Nacional de Tecnología Agropecuariafalse
dc.title.none.fl_str_mv Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
title Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
spellingShingle Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
Klafke, Guilherme
Rhipicephalus
Ticks
Cattle
Acaricides
Bio-Assays
Application Rates
Garrapata
Ganado Bovino
Acaricidas
Ensayo Biológico
Dosis de Aplicación
Rhipicephalus microplus
title_short Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
title_full Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
title_fullStr Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
title_full_unstemmed Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
title_sort Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
dc.creator.none.fl_str_mv Klafke, Guilherme
Torrents, Jorgelina
Ferreira, Priscila Teixeira
Sarli, Macarena
Loch, Ana Luiza
Avelar, Barbara Rauta de
Azevedo, Thais Ribeiro Correia
Scott, Fabio Barbour
Morel, Nicolas
Nava, Santiago
Reck, José
author Klafke, Guilherme
author_facet Klafke, Guilherme
Torrents, Jorgelina
Ferreira, Priscila Teixeira
Sarli, Macarena
Loch, Ana Luiza
Avelar, Barbara Rauta de
Azevedo, Thais Ribeiro Correia
Scott, Fabio Barbour
Morel, Nicolas
Nava, Santiago
Reck, José
author_role author
author2 Torrents, Jorgelina
Ferreira, Priscila Teixeira
Sarli, Macarena
Loch, Ana Luiza
Avelar, Barbara Rauta de
Azevedo, Thais Ribeiro Correia
Scott, Fabio Barbour
Morel, Nicolas
Nava, Santiago
Reck, José
author2_role author
author
author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Rhipicephalus
Ticks
Cattle
Acaricides
Bio-Assays
Application Rates
Garrapata
Ganado Bovino
Acaricidas
Ensayo Biológico
Dosis de Aplicación
Rhipicephalus microplus
topic Rhipicephalus
Ticks
Cattle
Acaricides
Bio-Assays
Application Rates
Garrapata
Ganado Bovino
Acaricidas
Ensayo Biológico
Dosis de Aplicación
Rhipicephalus microplus
dc.description.none.fl_txt_mv Fluralaner is an isoxazoline acaricide with potent activity against Rhipicephalus (Boophilus) microplus, a major tick species affecting cattle in South America. In this study, larval bioassays were performed to evaluate the baseline susceptibility of R. microplus populations from Brazil and Argentina to fluralaner. The larval packet test (LPT) was applied to Brazilian laboratory and field populations, while the larval immersion test (LIT) was used in Argentina. Both tests were carried with technical grade and a commercial formulation of fluralaner. LPT results showed consistent LC₅₀ values across two susceptible laboratory strains, with resistance ratios near unity in all field samples. Similar observations were obtained with the LIT, with resistance ratios also near 1 for all tested populations from Argentina. The LIT produced LC₅₀ values approximately 100 times lower than the LPT, a difference consistent with previous studies using systemic acaricides. Both technical and commercial formulations yielded comparable results in both tests. These findings confirm the high susceptibility of R. microplus to fluralaner and establish reliable bioassay parameters for future resistance monitoring. The choice between LPT and LIT and technical grade or commercial formulation of fluralaner should be guided by laboratory infrastructure and logistical needs, as both methods are valid for surveillance purposes.
EEA Rafaela
Fil: Klafke, Guilherme. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); Brasil
Fil: Torrents, Jorgelina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Torrents, Jorgelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Ferreira, Priscila Teixeira. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); Brasil
Fil: Ferreira, Priscila Teixeira. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; Brasil
Fil: Sarli, Macarena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Sarli, Macarena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Loch, Ana Luiza. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); Brasil
Fil: Avelar, Barbara Rauta de. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; Brasil
Fil: Azevedo, Thais Ribeiro Correia. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; Brasil
Fil: Scott, Fabio Barbour. Universidade Federal Rural do Rio de Janeiro. Instituto de Veterinária. Seropédica; Brasil
Fil: Morel, Nicolas. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Morel, Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Nava, Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Nava, Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación de la Cadena Láctea (IdICaL); Argentina
Fil: Reck, José. Instituto de Pesquisas Veterinárias Desidério Finamor (IPVDF); Brasil
description Fluralaner is an isoxazoline acaricide with potent activity against Rhipicephalus (Boophilus) microplus, a major tick species affecting cattle in South America. In this study, larval bioassays were performed to evaluate the baseline susceptibility of R. microplus populations from Brazil and Argentina to fluralaner. The larval packet test (LPT) was applied to Brazilian laboratory and field populations, while the larval immersion test (LIT) was used in Argentina. Both tests were carried with technical grade and a commercial formulation of fluralaner. LPT results showed consistent LC₅₀ values across two susceptible laboratory strains, with resistance ratios near unity in all field samples. Similar observations were obtained with the LIT, with resistance ratios also near 1 for all tested populations from Argentina. The LIT produced LC₅₀ values approximately 100 times lower than the LPT, a difference consistent with previous studies using systemic acaricides. Both technical and commercial formulations yielded comparable results in both tests. These findings confirm the high susceptibility of R. microplus to fluralaner and establish reliable bioassay parameters for future resistance monitoring. The choice between LPT and LIT and technical grade or commercial formulation of fluralaner should be guided by laboratory infrastructure and logistical needs, as both methods are valid for surveillance purposes.
publishDate 2025
dc.date.none.fl_str_mv 2025-10-03T13:04:00Z
2025-10-03T13:04:00Z
2025-12
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/20.500.12123/24059
https://www.sciencedirect.com/science/article/abs/pii/S0304401725002110
0304-4017
1873-2550
https://doi.org/10.1016/j.vetpar.2025.110600
url http://hdl.handle.net/20.500.12123/24059
https://www.sciencedirect.com/science/article/abs/pii/S0304401725002110
https://doi.org/10.1016/j.vetpar.2025.110600
identifier_str_mv 0304-4017
1873-2550
dc.language.none.fl_str_mv eng
language eng
dc.rights.none.fl_str_mv info:eu-repo/semantics/restrictedAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv restrictedAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Elsevier
publisher.none.fl_str_mv Elsevier
dc.source.none.fl_str_mv Veterinary Parasitology 340 : 110600. (December 2025)
reponame:INTA Digital (INTA)
instname:Instituto Nacional de Tecnología Agropecuaria
reponame_str INTA Digital (INTA)
collection INTA Digital (INTA)
instname_str Instituto Nacional de Tecnología Agropecuaria
repository.name.fl_str_mv INTA Digital (INTA) - Instituto Nacional de Tecnología Agropecuaria
repository.mail.fl_str_mv tripaldi.nicolas@inta.gob.ar
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score 12.982451

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