Anthelmintic resistance of Haemonchus contortus from sheep flocks in Brazil: concordance of in vivo and in vitro (RESISTA-Test©) methods

Author(s)

Yousmel Alemán Gainza ^[1] ; Isabella Barbosa dos Santos ^[2] ; Amanda Figueiredo ^[3] ; Leonardo Aparecido Lima dos Santos ^[4] ; Sérgio Novita Esteves ^[5] ; Waldomiro Barioni-Junior ^[6] ; Alessandro Pelegrine Minho ^[7] ; Ana Carolina de Souza Chagas ^[8]

Affiliation

^[1] Universidade Estadual Paulista. Faculdade de Ciências Agrárias e Veterinárias - Brasil

^[2] Universidade Estadual Paulista. Faculdade de Ciências Agrárias e Veterinárias - Brasil

^[3] Universidade Estadual Paulista. Faculdade de Ciências Agrárias e Veterinárias - Brasil

^[4] Centro Universitário Central Paulista - Brasil

^[5] Embrapa Pecuária Sudeste - Brasil

^[6] Embrapa Pecuária Sudeste - Brasil

^[7] Embrapa Pecuária Sudeste - Brasil

^[8] Embrapa Pecuária Sudeste - Brasil

• Document type: Journal article
• Source: Revista Brasileira de Parasitologia Veterinária; v. 30, n. 2 2021-05-03.

Abstract

Abstract This study evaluated the resistance status of Haemonchus contortus from sheep flocks in the state of São Paulo, Brazil, through comparison between the fecal egg count reduction test (FECRT) and the larval development test (LDT). For the FECRT, 35 sheep were selected in each of five flocks and divided into groups treated with: benzimidazole, levamisole, ivermectin, monepantel and control. Feces were collected for EPG and fecal cultures. The LDT was performed using thiabendazole (TBZ), levamisole (LEV), ivermectin aglycone (IVM-A) and Zolvix (ZLV). Resistance to all drugs was detected using FECRT in 100% of the flocks, except in relation to ZLV (40% resistant and 20% suspected of resistance). LDT indicated resistance to TBZ and IVM-A in all flocks, to LEV in 80% of flocks and to ZLV in 10%. Total agreement was obtained between the two tests for TBZ and IVM (k = 1.0), while for LEV (k = 0.8) and ZLV (k = 0.9), substantial and almost perfect agreement were obtained, respectively. The concordance between the tests was significant, thus showing that it is possible to use the outcome of the LDT to predict the FECRT, and hence validating the former as a fast diagnostic test for use by sheep farmers in Brazil. (AU)

• FAPESP's process: 14/25821-0 - Genomics of anthelmintic resistance in Haemonchus contortus and evidences for DNA methylation
• Grantee: Simone Cristina Méo Niciura
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/13249-8 - Nanotechnology applied to elaboration of synthetic acaricides associated with plant isolates for the control of Rhipicephalus (b.) microplus
• Grantee: Amanda Figueiredo
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/16070-1 - Study of the impact of gastrointestinal nematodes infection on the performance of Morada Nova Lambs for development of a targeted selective treatment
• Grantee: Isabella Barbosa dos Santos
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/07132-8 - Development and validation of a diagnostic kit of parasitic resistance to anthelminthics for resistance monitoring in sheep flocks
• Grantee: Yousmel Alemán Gainza
• Support Opportunities: Scholarships in Brazil - Doctorate