In the case of interleukin 18 (IL-18), statistically significant differences were only observed at 2 h of infection, with an overexpression of this molecule induced by serotypes b (p < 0.0001) and c (p < 0.0001) with respect to the control condition, and among serotype b (p < 0.0001) and c (p < 0.0001) over the serotype a. The gene discussed is IL18; the disease is infection.