Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus
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 Argentin...
| Autores principales: | , , , , , , , , , , |
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| Formato: | Artículo |
| Lenguaje: | Inglés |
| Publicado: |
Elsevier
2025
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| Materias: | |
| Acceso en línea: | 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 |
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| author | 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_browse | Avelar, Barbara Rauta de Azevedo, Thais Ribeiro Correia Ferreira, Priscila Teixeira Klafke, Guilherme Loch, Ana Luiza Morel, Nicolas Nava, Santiago Reck, José Sarli, Macarena Scott, Fabio Barbour Torrents, Jorgelina |
| 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_sort | Klafke, Guilherme |
| collection | INTA Digital |
| 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. |
| format | Artículo |
| id | INTA24059 |
| institution | Instituto Nacional de Tecnología Agropecuaria (INTA -Argentina) |
| language | Inglés |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Elsevier |
| publisherStr | Elsevier |
| record_format | dspace |
| spelling | INTA240592025-10-03T13:21:55Z Standardization of larval bioassays for determination of fluralaner susceptibility in Rhipicephalus microplus 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 Rhipicephalus Ticks Cattle Acaricides Bio-Assays Application Rates Garrapata Ganado Bovino Acaricidas Ensayo Biológico Dosis de Aplicación Rhipicephalus microplus 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 2025-10-03T13:04:00Z 2025-10-03T13:04:00Z 2025-12 info:ar-repo/semantics/artículo info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion 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 eng 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) application/pdf Elsevier Veterinary Parasitology 340 : 110600. (December 2025) |
| spellingShingle | Rhipicephalus Ticks Cattle Acaricides Bio-Assays Application Rates Garrapata Ganado Bovino Acaricidas Ensayo Biológico Dosis de Aplicación Rhipicephalus microplus 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 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 |
| 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_short | 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 |
| topic | Rhipicephalus Ticks Cattle Acaricides Bio-Assays Application Rates Garrapata Ganado Bovino Acaricidas Ensayo Biológico Dosis de Aplicación Rhipicephalus microplus |
| 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 |
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