The use of ITS-2 rDNA nemabiome metabarcoding to enhance anthelmintic resistance diagnosis and surveillance of ovine gastrointestinal nematodes.

摘要: A lack of quantitative information on the species composition parasite communities present in fecal samples is a major limiting factor for sensitivity, accuracy and interpretation diagnostic tests commonly used to assess anthelmintic efficacy resistance. In this paper, we investigate ability ITS-2 rDNA nemabiome metabarcoding enhance egg count reduction testing by providing effect drug treatments individual species. Application from ewes over 90 flocks across western Canada revealed high gastrointestinal nematode infection intensities many with Haemonchus contortus being most abundant followed Teladorsagia circumcincta then Trichostrongylus colubriformis. Integration pre- post-treatment counting consistently poor producer-applied ivermectin benzimidazole against H. contortus, but much better T. colubriformis, except small number flocks. Fecal Egg Count Reduction Tests (FECRT), undertaken farm visits, confirmed that fenbendazole resistance widespread currently less common colubriformis Canada. FECRT/nemabiome did not detect moxidectin any GIN suggested early emergence levamisole specifically circumcincta. It also although closantel was relatively common, based total counts, due its narrow spectrum activity rather than This study illustrates value improve testing, perform large-scale surveillance direct more targeted rational use.