Title:	Haemonchus contortus isolates assessed for anthelmintic resistance using RESISTA-test©
Authors:	BASSETTO, C. C. CHOCOBAR, M. L. E. BELLO, H. J. S. SILVA, N. M. M. da AMARANTE, A. F. T. do CHAGAS, A. C. de S.
Affiliation:	CÉSAR CRISTIANO BASSETTO, UNIVERSIDADE ESTADUAL PAULISTA JÚLIO DE MESQUITA FILHO; MARIANNA LAURA ELIS CHOCOBAR, UNIVERSIDADE ESTADUAL PAULISTA JÚLIO DE MESQUITA FILHO; HORNBLENDA JOAQUINA SILVA BELLO, FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO; NAIARA MIRELLY MARINHO DA SILVA, UNIVERSIDADE ESTADUAL PAULISTA JÚLIO DE MESQUITA FILHO; ALESSANDRO FRANCISCO TALAMINI DO AMARANTE, UNIVERSIDADE ESTADUAL PAULISTA JÚLIO DE MESQUITA FILHO; ANA CAROLINA DE SOUZA CHAGAS, CPPSE.
Date Issued:	2025
Citation:	In: CONFERENCE OF THE WORLD ASSOCIATION FOR THE ADVANCEMENTS OF VETERINARY PARASITOLOGY, 30., 2025, Curitiba. Abstract book. Curitiba: Universidade Federal do Paraná, 2025. p. 235-238.
Description:	Abstract: RESISTA-Test© is a larval development test to detect anthelmintic resistance for thiabendazole (TBZ), ivermectin (IVM), levamisole (LEV), and monepantel (MPT). Two isolates of Haemonchus contortus were assessed to confirm the anthelmintic status (Echevarria1991 - HcEc91, susceptible and Botucatu - HcBot, resistant) were kept in two donor lambs each. Eight lambs were artificially infected with each isolate and kept in separate paddocks (field lambs) for 160 days. To calculate the resistance factor (RF), faecal samples of the donor and field lambs of each isolate was examined using RESISTA-Test©. The results were analysed using logit dose-response by the Probit model. The RF was calculated as the LC50 values of the studied isolate divided by the respective susceptible isolate values. For the HcEc91 isolate in the field lambs, the RF values were TIA = 0.7, IVM = 0, LEV = 1.1 and MPT = 0.9. The RF values for the HcBot isolate in the donor lambs were TIA = 147, IVM = 176, LEV = 931, and MPT = 53 and for the field lambs the RF values were TIA = 141, IVM = 196, LEV = 822, and MPT = 34. The results confirmed with accuracy the anthelmintic resistance status of the two isolates since the RF values for the susceptible isolate were below 3 and the contrary was observed for the resistant isolate, with RF values above 3. Moreover, RF values for the donor and field lambs infected with HcBot isolate were quite similar for all chemical groups demonstrating that both isolates can be kept successfully in the field as long as lambs graze different paddocks. In conclusion, RESISTA-Test© is applicable in laboratory routines to ascertain the anthelmintic resistance status of H. contortus without necessitating superfluous anthelmintic treatments such as those employed in faecal egg count reduction test (FECRT). This tool would be utilised in farm’s parasite management initiatives, facilitating a more precise, and sustainable control of gastrointestinal nematodes.
NAL Thesaurus:	Haemonchus Heteropogon contortus Anthelmintics Lambs Pastures Gastrointestinal nematodes
Type of Material:	Resumo em anais e proceedings
Access:	openAccess
Appears in Collections:	Resumo em anais de congresso (CPPSE)