IL13 and infection: Immunocompetent mice usually expel the adult worms by day 10 after infection by a process that requires IL-4- or IL-13-mediated activation of STAT6 in intestinal epithelial cells and smooth muscle cells to induce goblet cell hyperplasia, mucus secretion, and increased intestinal peristalsis causing a “weep and sweep” mechanism of worm expulsion (5, 6).