Study of the effect of parasite replacement on the anthelmintic resistance of Haemonchus contortus in sheep breeds

• Grant number: 22/07720-8
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: August 01, 2022
• End date: July 31, 2026
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Ana Carolina de Souza Chagas
• Grantee: Hornblenda Joaquina Silva Bello
• Host Institution: Embrapa Pecuária Sudeste. Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA). Ministério da Agricultura, Pecuária e Abastecimento (Brasil). São Carlos , SP, Brazil
• Associated research grant: 21/02535-5 - Parasite-host-environment approach to control anthelmintic resistance in sheep flocks, AP.TEM

Abstract

Studies indicate that the efficacy of Anthelmintics (AH) can be restored by replacing the parasite population in sheep, here called Worm Replacement (WR). Thus, we intend to evaluate and monitor the effect of partial and total replacement of the population of Haemonchus contortus in different sheep breeds (White Dorper, Santa Inês e Texel) on the anthelmintic resistance status for five years, also clarifying the role of refugia in different WR situations. The differences inherent to each breed in terms of susceptibility to parasites, evaluated in genomic studies, in association with the partial and total replacement of parasites, will bring understanding about the ability to dilute resistance in different breeding conditions and the possible use of this strategy/tool/technology by producers. In addition, Fecal Egg Count Reduction Test (FECRT), in vitro tests (RESISTA-Test©) and molecular tests will help to verify and monitor the phenotypic and genotypic susceptibility of eggs and L3 of H. contortus obtained from experimental animals before, during and after the WR process. The safety of the treatment will be verified by histological and induced inflammatory response studies in sheep. Molecular resistance marker to benzimidazoles in H. contortus will be evaluated to monitor changes in allelic and genotypic frequencies and to monitor the dilution of resistance genes in the population evaluated. Thus, it is expected to develop tools that can be incorporated into the integrated control of parasites, adding advantages such as: reduction in the number of AH applications, reduction of environmental impacts of AH, increase in food security and longevity of AH, providing sustainability and potential of growth for the small ruminant production chain. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

KAPRITCHKOFF, RAFAELA TAMI IKEDA; OKINO, CINTIA HIROMI; NICIURA, SIMONE CRISTINA MEO; BELLO, HORNBLENDA JOAQUINA SILVA; MATOS, RENATA SILVA; MELITO, GLAUCIA ROBERTA; BRESSANI, FLAVIA ALINE; ESTEVES, SERGIO NOVITA; CHAGAS, ANA CAROLINA DE SOUZA. Association of β-globin polymorphisms and tolerance to haemonchosis in ewes and lambs of different sheep breeds. Veterinary Parasitology, v. 328, p. 8-pg., 2024-03-21. (22/00776-8, 21/02535-5, 22/07720-8)

CHAGAS, ANA CAROLINA S.; RIBEIRO, DAVID M.; OSORIO, HUGO; ABREU, ANA A. P.; OKINO, CINTIA H.; NICIURA, SIMONE C. M.; AMARANTE, ALESSANDRO F. T.; BELLO, HORNBLENDA J. S.; MELITO, GLAUCIA R.; ESTEVES, SERGIO N.; et al. Molecular signatures of Haemonchus contortus infection in sheep: A comparative serum proteomic study on susceptible and resistant sheep breeds. Veterinary Parasitology, v. 331, p. 11-pg., 2024-08-08. (22/12536-1, 21/02535-5, 22/07720-8)