Title:	Resista-Test© as an in vitro tool for Haemonchus contortus resistance diagnosis in small ruminant flocks.
Authors:	CHAGAS, A. C. de S. BELLO, H. J. S. GAINZA, Y. A. SANTOS, L. A. L. dos MINHO, A. P. NICIURA, S. C. M.
Affiliation:	ANA CAROLINA DE SOUZA CHAGAS, CPPSE; HORNBLENDA JOAQUINA SILVA BELLO, FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO; YOUSMEL ALEMÁN GAINZA, UNIVERSIDADE ESTADUAL PAULISTA JÚLIO DE MESQUITA FILHO; LEONARDO APARECIDO LIMA DOS SANTOS, UNIVERSIDADE ESTADUAL PAULISTA JÚLIO DE MESQUITA FILHO; ALESSANDRO PELEGRINE MINHO, CPPSE; SIMONE CRISTINA MEO NICIURA, CPPSE.
Date Issued:	2025
Citation:	In: INTERNATIONAL CONGRESS BIOPHARM NONCLINICAL DEVELOPMENT, 4., 2025, VERADERO, CU. Abstract... Veradero: CIGB, 2025. BioNCID 2025.
Description:	Absctract: Haemonchus contortus is the most pathogenic nematode in small ruminants, and the excessive use of anthelmintics has resulted in treatment failure. Diagnostic techniques less dependent on in vivo tests are extremely important for the 3Rs principles in experimental animals. This study aimed to monitor anthelmintic resistance in a sheep flock before and after the worm replacement technique (WR). Ewes (n = 60) received anthelmintics to remove parasites, were artificially infected with a H. contortus-susceptible isolate (Echevarria1991), and grazed on worm-free paddocks. For resistance diagnose, animals were monitored by molecular tests (F200Y and S168T polymorphisms for benzimidazole and levamisole resistance, respectively), in vitro test (RESISTA-Test©, set in 96-well plates to determine the critical wells through LC50) and in vivo test (Fecal Egg Count Reduction Test (FECRT), for albendazole and levamisole ecacy evaluation 14 days after anthelmintic treatment). Echevarria91 presented 86.4% (9.1%RS, 77.3%SS) individuals susceptible to albendazole and 100% (100% SS) susceptible to levamisole. RESISTA-Test© detected susceptibility for both anthelmintics, and FECRT performed in sheep-hosts achieved > = 95% eficacy for both as well. For the parasites from the flock previous to the artificial infection, molecular tests showed 58.6% (49.4%RS, 9.2%SS) individuals susceptible to albendazole and 70% (45%RS + 25%SS) susceptible to levamisole. RESISTA-Test© indicated resistance for all anthelmintics, while 0% and 81% eficacy for albendazole and levamisole were obtained in FECRT, respectively. After artificial infection, susceptible H. contortus were 92.3% (15.4%RS, 76.9%SS) for albendazole and 100% (7.7%RS, 92.3%SS) for levamisole. RESISTA-Test© detected resistance for albendazole and suspected resistance for levamisole. FECRT indicated 78.3-95.7% eficacy for the albendazole+levamisole (combination adopted after artificial infection). The concordance among the tests indicates that the RESISTA-Test© outcomes predict the FECRT results, which is a laborious and time consuming test. Although molecular tests can detect resistance earlier, RESISTA- Test© is cheaper, allowing routine use to delay resistance occurrence and preserve anthelmintic eficacy.
Thesagro:	Cultura In Vitro Diagnostico Haemonchus Contortus Rebanho Ruminante Nematóide Ovelha
NAL Thesaurus:	In vitro culture Haemonchus Nematode control
Keywords:	Resista-Test FECRT
Type of Material:	Resumo em anais e proceedings
Access:	openAccess
Appears in Collections:	Resumo em anais de congresso (CPPSE)