Chemosensory tuft cells of the intestinal epithelium were recently identified as the major source of IL-25 in the intestine during parasite infection.162, 163, 164 Remarkably, tuft cell–deficient mice show extremely abrogated immunity to N brasiliensis infection, with all tuft cell–deficient mice retaining productive infections up to 42 days after infection,162 whereas IL-25–deficient mice show only a slightly delayed response.161. Here, IL25 is linked to infection.