First report of multiple anthelmintic resistance in nematodes of sheep in Colombia.

Carlos M.B Gárcia,Efraín B Ortiz,Marcelo B Molento,Lew K Sprenger

doi:10.1590/0001-3765201620140360

Abstract

This study aimed to report the presence of parasites resistant to the most used anthelmintic drugs in sheep in Colombia. Four farms (denominated farm 1, 2, 3 and 4) were selected where the animals were not treated with anthelmintics for two months before the trial. Animals with faecal egg count (FEC) above 150 and of different ages were allocated into six groups, each consisting of at least 5 animals. The drugs and dosages used were: ivermectin 1% (0.2 mg/kg), albendazole 25% (5 mg/kg), fenbendazole 10% (5 mg/kg), levamisole 10% (5 mg/kg), and moxidectin 1% (0.2 mg/kg). Anthelmintic efficacy was determined by the FEC reduction test (FECRT) with a second sampling 14 days post-treatment. The efficacy of albendazole and fenbendazole at farm 1 was above 95%, which was different from the others farms. The FECRT indicated the presence of multidrug resistance in the other farms where no tested drugs showed activity higher than 79% (albendazole: 0 to 55%, fenbendazole: 51.4 to 76.6%, ivermectin: 67.3 to 93.1%, levamisole: 0 to 78.1%, and moxidectin: 49.2 to 64.1%).Haemonchus contortus was the predominant (96%) species, followed by a small presence of Trichostrongylus sp. (3%) andCooperia sp. (1%). Therefore, we report for the first time the existence of multiple anthelmintic resistance in gastrointestinal nematodes of sheep in Colombia.

Highlights

Colombia is considered a livestock country and currently a great interest in sheep farming is occurring (Ospina et al 2011)
Initial faecal samples were taken from all animals, to perform parasite egg counts per gram (EPG) according to Gordon and Whitlock (1939)
Groups with a minimum of five animals were treated with Ivermectin (IVM) 1% 0.2 mg/ kg ( Mk®, Technochemistry, Cali, Colombia), Albendazole (ABZ) 25% 5 mg/kg (Insubenzol®, Insuvin, Bogota, Colombia), Fenbendazole (FBZ) 10% 5 mg/kg (Panacur®, MSD Salud Animal, Bogota, Colombia), Levamisole (LEV) 10% 5 mg/ kg (Levamisol®, Vicar Pharmaceutical, Bogota, Colombia), Moxidectin (MOX) 1% 0,2 mg/ kg (Cydectin®, Wyeth Inc., Fort Dodge, Bogota, Colombia) and a Control group that received no treatment

Summary

Introduction

Colombia is considered a livestock country and currently a great interest in sheep farming is occurring (Ospina et al 2011). Gastrointestinal parasitism is one of the most important negative economic factors of the small ruminant industry of Colombia. Herrera et al (2013) have reported that Haemonchus contortus is the most prevalent nematode, followed by Trichostrongylus spp., Cooperia spp., Strongyloides spp. and Oesophagostomun spp. In Colombia there are only a few studies relating small ruminants and parasite infections. These infections have been described as being responsible for decreasing weight gain, delaying puberty, causing anemia and even death (Ensuncho-Hoyos et al 2014)

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Results