Cathepsins and other cysteine proteases from parasites as well as viruses may become good targets for major diseases such as arthritis, osteoporosis, AIDS, immune-related diseases, atherosclerosis, cancer, and for a wide variety of parasitic diseases such as malaria, amebiasis, chagas disease, leishmaniasis, or African sleeping sickness (Petrov et al., 2000; Lecaille et al., 2002; Gills et al., 2007; Salminen-Mankonen et al., 2007; Hirai et al., 2013). This evidence concerns the gene CTSB and parasitic infectious disease.