Increased eosinophil numbers have been observed during Giardia infection, and in eosinophil deficient mice, IL-17 levels, as well as serum and luminal IgA levels, are decreased suggesting elevated levels of IL-17 and IgA during Giardia infection are dependent in part on eosinophil activity (Jung et al., 2015). The gene discussed is IL17A; the disease is giardiasis.