Morphological and molecular characterization of gastrointestinal nematodes in sheep

Abstract

A study was set out to investigate the distribution of gastrointestinal nematode parasites in sheep farms of Hassan district, Karnataka and to ascertain which species are involved in the anthelmintic resistance. In the study 26 farms were treated with fenbendazole and 19 farms were treated with ivermectin. The pre and post treatment faecal cultures were prepared for each farms. The larvae identified in the pre-treatment faecal culture were Haemonchus sp, Trichostrongylus sp, Oesophagostomum sp, Bunostomum sp and Cooperia sp based on the morphological keys. During the study 15 farms showed resistance to fenbendazole whereas 2 farms were resistant to ivermectin. Among 15 farms, 12 farms had Haemonchus sp as a predominant larvae followed by Trichostrongylus sp in 3 farms. The ivermectin resistant farms had Haemonchus sp as pre dominant larvae. The post treatment faecal cultures revealed Haemonchus sp. as the predominant gastrointestinal nematode followed by Trichostrongylus sp. The ones mentioned were identified as Haemonchus contortus and T. colubriformis by PCR. The PCR tool used for epidemiological studies supported the investigations of conventional parasitological techniques