Viral Encephalitis

Often resulting in swelling of the brain, viral encephalitis is a group of diseases transmitted to humans by an insect bite. Different types include West Nile virus, Japanese encephalitis, and St. Louis encephalitis. Symptoms of encephalitis typically begin with fever and severe headache, and may then progress to symptoms such as vomiting, sensitivity to light, and seizures. There are no human vaccines for this group of illnesses, except for a Japanese encephalitis vaccine that is available only to travelers.

Types of Encephalitis

What Is Viral Encephalitis?

Viral encephalitis is a group of illnesses that can cause swelling of the brain (encephalitis). The illnesses are transmitted to humans by insects that bite, such as ticks and mosquitoes.

Types

Types of viral encephalitis include:

West Nile virus
Herpes encephalitis
Japanese encephalitis
St. Louis encephalitis
LaCrosse encephalitis
Equine encephalitis (eastern equine encephalitis, western equine encephalitis, and Venezuelan equine encephalitis).

Symptoms of Viral Encephalitis

Symptoms of viral encephalitis usually begin with fever and a severe headache.

Symptoms that follow the fever and severe headache may include:

Sensitivity to light
Nausea and vomiting
Stiff neck and back
Lack of energy
Drowsiness
Seizures or tremors
Change in personality
Memory loss
Trouble learning and/or understanding
Restlessness
Confused speech
Hallucinations
Coma.

Milder viral encephalitis symptoms are often caused by less serious diseases and normally should be no cause for alarm. In general, symptoms that develop suddenly and are severe from the start tend to be associated with more severe, life-threatening cases of encephalitis.

Early encephalitis may also cause symptoms similar to meningitis, a serious illness that causes inflammation of the tissues surrounding the brain and spinal cord.

(Viral Encephalitis Continued: Page 2)