Before revision: There has been a discussion in the scientific community as to whether the CNS infection should be termed encephalitis or febrile encephalopathy or vasculitis-associated cerebral infarction, hence some use the broader term "encephalitis syndrome".
After revision: There has been a discussion in the scientific community as to whether the CNS infection should be termed encephalitis or febrile encephalopathy or vasculitis-associated cerebral infarction, hence WHO uses the broader term "encephalitis syndrome".