Phylogenetic relationships among G. duodenalis MLGs. The phylogenetic tree was constructed using a concatenated dataset of the bg, tpi, and gdh gene sequences and Neighbor-Joining analysis with the Tamura–Nei model. MLGs with unambiguous sequences identified in this study (Table 5) were analyzed with reference isolates. Bootstrap values greater than 50% from 1000 replicates are shown at the nodes. HN: Henan; SX: Shaanxi; JX: Jiangxi; HS: Hu sheep; EN: Environment.