There is much evidence that eosinophilia and IgE hyperproduction caused by infection with tissue-invasive helminth species are controlled by several types of cytokines, especially IL-4 and IL-5, which are produced by Th2 type helper T cells in response to the stimulation with larval excretory/secretory antigen(s) [16–18]. This evidence concerns the gene IL5 and Increased total eosinophil count.