Because microglia and macrophages are the major producers of interferon-gamma in the brain following infection with T. gondii (Suzuki et al., 2005) and interferon-gamma is the major effector molecule controlling tachyzoite behavior through the expression of chemokines and MHC antigens (Wang et al., 2004; Wang and Suzuki, 2007; Sa et al., 2015), we suggest that increased microglia in CNS-infected areas may have prevented toxoplasmic encephalitis in BALB/c-infected individuals, limiting parasite proliferation at the early stage of the disease. This evidence concerns the gene IFNG and infection.