MedGen

Japanese encephalitis is an arboviral disease (<i>i.e.</i> a disease due to a virus transmitted by an arthropod). [from ORDO]

An inflammatory process affecting the brain parenchyma. Causes include viral infections and less frequently bacterial infections, toxins, and immune-mediated processes. [from NCI]

An inflammation of brain parenchyma due to infection with a virus. Viral encephalitis can occur as a rare complication of common infections (eg, herpes virus infections) or can occur as a characteristic presentation of rare viruses (eg, rabies virus infection). Encephalitis may be the only neurologic manifestation of infection, or may occur in association with meningitis, myelitis, radiculitis, or neuritis. Viral encephalitis is associated with neurological dysfunction. [from HPO]

A disorder of the brain caused by an infectious agent that presents with fever, headache, and an altered level of consciousness. There may also be focal or multifocal neurologic deficits, and focal or generalized seizure activity. [from HPO]

Viral infections of the brain, spinal cord, meninges, or perimeningeal spaces. [from MeSH]