In accordance, when IL-6-/- 129/SvJ mice were infected with RRA strain by the oral route with 20 cysts, they were more susceptible, with high mortality until 28 days p.i. and high parasite load with high IFN-γ serum levels on day 7–8 of infection, with high inflammation in the brain with necrotic areas [71]. The gene discussed is IFNG; the disease is infection.