Cysteine protease is a candidate diagnostic antigen with good specificity for some helminth infections, including Angiostrongylus cantonensis [33], Necator americanus [39], Toxocara canis [15], Paragonimus westermani [14], Schistosoma japonicum [40], Clonorchis sinensis [41], Taenia solium [42], and S. erinaceieuropaei [17]. This evidence concerns the gene CTSB and helminthiasis.