Under stressful conditions, such as, in the presence of infection or inflammation, microglia are activated (Graeber and Streit, 2010), and secrete a variety of inflammatory mediators, such as, tumor necrosis factor-alpha (TNF-α), and interleukin (IL)-10, and mediators of inflammation, such as, reactive oxygen species (ROS), nitric oxide (NO) and prostaglandin E2 (PGE2; Streit et al., 2004; More et al., 2013). This evidence concerns the gene TNF and infection.