Encephalitis is an acute inflammation of the brain, usually caused by an infection. The infection could be viral, bacterial, fungal or due to autoimmune causes. Primary encephalitis occurs when an infection or inflammation directly affects the spinal cord or the brain. Secondary encephalitis is when an infection starts in another part of the body, and spreads to the brain or the spine through the blood stream. Encephalitis can cause cognitive problems, vision loss, hearing loss, seizures or movement problems. Encephalitis is a relatively rare disease, but it can be life-threatening.