The predicted amino acid sequence of Smek CatB (GenBank:KP317840) was aligned to compare sequence identity with other cathepsin B reported in other related trematode parasites includ-ing S. mansoni cathepsin B1 (GenBank: CAD44624.1), S. mansoni cathepsin B2 (GenBank: CAC85211.2), S. japonicum cathepsinB (GenBank: CAA50305.1), F. gigantica Cathepsin B (GenBank:AAO73002.1), F. hepatica cathepsin B (GenBank: ABU62925.1) and Opisthorchis viverrini cathepsin B2 (GenBank: ACT99885.1).