MUC5AC and giardiasis: Using murine models of infection with either G. muris or G. duodenalis, the present findings reveal that Giardia infection can alter mucin glycosylation and the expression of mucin-associated glycosyltransferases in both the small intestines, at the site of parasite colonization, and in the distal colon, where Giardia trophozoites are absent.