IL18 and infection: At the time of euthanasia (ChD acute phase), a statistically significant increase (** p ≤ 0.05) was recorded in TNF-α, IFN-γ, IL-12, and IL-18 concentrations in only-infected groups, immunized, or not immunized (groups II, IV, VI and VIII); while in the groups that did not have the stimulus produced by the parasite infection (groups III, V, and VII), levels of these cytokines remained similar to those during post-immunization/pre-infection time (p > 0.05).