Catalyzes the hydrolysis of the N-glycosidic bond of commonly occurring purine and pyrimidine nucleosides into ribose and the base, but has a preference for inosine and uridine as substrates. Is not active on thymidine and 2'-deoxynucleosides. Functions in purine salvage from the blood of the host, a fundamental pathway since protozoan parasites such as C.fasciculata are incapable of de novo purine biosynthesis. H2O + inosine = D-ribose + hypoxanthine H2O + uridine = D-ribose + uracil kcat is 32 sec(-1) with inosine as substrate. kcat is 243 sec(-1) with 5-methyluridine as substrate. Purine metabolism; purine nucleoside salvage. Homotetramer. Belongs to the IUNH family.