Infection of BALB/c mice with different DENV serotypes has also been studied [16, 50, 100], and a previous study showed that infection of adult BALB/c mice with mouse-adapted DENV-3 resulted in lethality, the rate of which increased with increasing inoculum, with increased IFN-γ expression preceded by increased IL-12 and IL-18 expression [27]. This evidence concerns the gene IL18 and infection.