The dysfunctional intestinal epithelial barrier during Giardia infection is characterized by altered expression of TJ proteins (i.e., ZO-1, claudins, occludin), increased intestinal permeability, and reduced transepithelial electrical resistance (TEER) in both murine models of giardiasis as well as in humans (51, 53). This evidence concerns the gene TJP1 and giardiasis.