With respect to CNS inflammation, the expression of cytokines and chemokines within the CNS may be required to fully explain encephalitis, because encephalitis caused by neurotropic viruses is indirectly derived from CNS degeneration caused by robust immunological responses, such as the uncontrolled secretion of cytokines, including TNF-α, and the resultant activation of microglia and astrocytes [22, 23]. Here, TNF is linked to encephalitis.