This was further corroborated by pathway analysis of the differentially expressed genes during infection and by the down-regulation in cluster 4 of components of the somatotropic axis (GHR-I, GHR-II, IGF-II, IGFBP4) of importance in intestinal growth and repair [59], that can be considered a prelude to the severe cachectic episodes typically associated with more advanced stages of E. leei infection. This evidence concerns the gene IGF2 and infection.