Encephalitis literally means an inflammation of the brain, but it usually refers to brain inflammation caused by a virus. It's a rare disease that occurs in approximately 0.5 per 100,000 individuals — most commonly in children, the elderly, and people with weakened immune systems (e.g., those with HIV/AIDS or cancer).
Although several thousand cases of encephalitis (also called acute viral encephalitis or aseptic encephalitis) are reported to the Centers for Disease Control and Prevention (CDC) every year, experts suspect that many more may go unreported because the symptoms are so mild.
Encephalitis is an inflammation of the brain. The usual cause is a viral infection, but bacteria can also cause it. Cases can range from mild to severe. For mild cases, you could have flu-like symptoms. Serious cases can cause
- Severe headache
- Sudden fever
For mild cases, you may just need rest, plenty of fluids and a pain reliever. For severe cases, you might need to be hospitalized. Fortunately, encephalitis is uncommon in the United States.
National Institute of Neurological Disorders and Stroke