title: Lack of efficacy of monepantel against Trichostrongylus colubriformis in sheep in Brazil.
abstract: Multiple drug resistance of nematodes against anthelmintics has become one of the most important economic problems in sheep production worldwide. The aim of this experiment was to evaluate the efficacy of monepantel (2.5mg/kg) against gastrointestinal nematodes in fecal egg count reduction test (FECRT) and controlled efficacy test (CT) in naturally infected sheep. We used 30 sheep for the FECRT and 20 sheep for the CT, equally divided into control and treated groups. In the FECRT, the reduction was 98%. Larval identification of pre-treatment coprocultures revealed 100% Haemonchus spp. for both control and treated groups. Post-treatment culture of treated sheep was 100% Oesophagostomum spp., but only few larvae were recovered. In the control group, they were 99% Haemonchus spp and 1% Oesophagostomum spp. larvae. Based on the FECRT, Haemonchus spp. was considered susceptible to monepantel. The efficacy of monepantel in the CT against Haemonchus contortus and Trichostrongylus axei was 100% and against Cooperia curticei was 99.7%. For Trichostrongylus colubriformis, the efficacy was -21.5%. In both treated and untreated animals, Oesophagostomum columbianum was recovered from the large intestines. Based on FECRT and CT and in accordance with WAAVP standards, monepantel was ineffective against T. colubriformis and O. columbianum, but effective against H. contortus, T. axei and C. curticei in the studied flock.
authors.affiliation: Graduate Program in Animal Science, School of Agricultural Sciences and Veterinary Medicine-Pontifícia Universidade Católica do Paraná (PUCPR), São José dos Pinhais, Paraná 83010-500, Brazil. Electronic address: christinemary89pitty@hotmail.com.
authors.forename: M C R
authors.initials: MC
authors.lastname: Cintra
authors.affiliation: School of Agricultural Sciences and Veterinary Medicine-Pontifícia Universidade Católica do Paraná (PUCPR), Brazil. Electronic address: valeria.natascha@pucpr.br.
authors.forename: V N
authors.initials: VN
authors.lastname: Teixeira
authors.affiliation: Graduate Program in Animal Science, School of Agricultural Sciences and Veterinary Medicine-Pontifícia Universidade Católica do Paraná (PUCPR), São José dos Pinhais, Paraná 83010-500, Brazil. Electronic address: ligiavaleria.nascimento@gmail.com.
authors.forename: L V
authors.initials: LV
authors.lastname: Nascimento
authors.affiliation: Graduate Program in Animal Science, School of Agricultural Sciences and Veterinary Medicine-Pontifícia Universidade Católica do Paraná (PUCPR), São José dos Pinhais, Paraná 83010-500, Brazil. Electronic address: cristina.sotomaior@pucpr.br.
authors.forename: C S
authors.initials: CS
authors.lastname: Sotomaior
mesh_terms: D000018:Abomasum / Q000469:parasitology; D000284:Administration, Oral; D000607:Aminoacetonitrile / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D000969:Antinematodal Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D001938:Brazil; D004351:Drug Resistance; D005243:Feces / Q000469:parasitology; D005260:Female; D006189:Haemonchus / Q000187:drug effects; D007422:Intestines / Q000469:parasitology; D008297:Male; D009815:Oesophagostomum / Q000187:drug effects; D012756:Sheep; D012757:Sheep Diseases / Q000188:drug therapy* / Q000469:parasitology; D014251:Trichostrongyloidea / Q000187:drug effects; D014253:Trichostrongylosis / Q000188:drug therapy / Q000662:veterinary*; D014254:Trichostrongylus / Q000187:drug effects*
chemical_list: D000969:Antinematodal Agents; D000607:Aminoacetonitrile; C533978:monepantel
keywords: Anthelmintic resistance; Gastrointestinal nematodes; Monepantel; Small ruminants