During larval ascariasis, both in a simple infection model [9], and in the present study, an increase in the cytokine IL-5 was observed in lung tissue, which is probably related to the higher number and activity of eosinophils in reinfected mice, since IL-5 increases the differentiation, maturation and survival of eosinophils derived from bone marrow precursors [63,64]. The gene discussed is IL5; the disease is infection.