Incremental Value of Species-Resolved Molecular Diagnostics in Faecal Egg Count Reduction Testing for Anthelmintic Resistance in Small Ruminants: A Scoping Review

Anthelmintic resistance in gastrointestinal nematodes of sheep and goats is commonly evaluated by the faecal egg count reduction test (FECRT), but aggregate reduction may conceal heterogeneous responses within mixed-species infections. This scoping review assessed when species-resolved molecular information changes, refines, or explains FECRT interpretation. PubMed, Lens, and Dimensions were searched for literature published mainly from January ۲۰۲۱ to August ۲۰۲۶. Of ۱۱۹ acquired full-text records, ۴۲ underwent formal processing and ۳۱ unique publications were assessed after deduplication; three cattle-only studies were excluded. The analytical evidence base comprised ۳۰ sources (۱۷ CORE and ۱۳ SUPPORTING), supplemented by ۱۶ contextual citations. DNA-based species identification reclassified ۲۴ of ۹۵ broader taxonomic assessments initially considered susceptible, while integration of qPCR with conventional egg counts revealed an aggregate FECR of ۷۹.۳% but a Haemonchus contortus-specific FECR of only ۴.۴% in one goat farm. Nemabiome analyses showed simultaneous poor and near-complete responses among constituent species, and resistance-marker assays added genotypic information, particularly for beta-tubulin-associated benzimidazole resistance. FECRT should remain the phenotypic anchor, with molecular testing used selectively to resolve taxonomic attribution, quantify taxon-specific efficacy, detect masked resistant minorities, or evaluate validated resistance-associated genotypes.

کلیدواژه ها:

Anthelmintic resistance ، Faecal egg count reduction test ، Species-resolved diagnostics ، Gastrointestinal nematodes ، Nemabiome ، Quantitative PCR ، Resistance-associated SNPs ، Small ruminants