In this study, co-infection of T. gondii and C. jejuni further increased the levels of IFN-γ and IL-6 caused by T. gondii, much in the same way as the changes in cytokines induced by C. jejuni in gnotobiotic mice (Bereswill et al., 2011), which suggests that T. gondii infection promotes C. jejuni infection symptoms. Here, IL6 is linked to coinfection.