health

Most cases of encephalitis in the United States are caused by viruses:

• Herpes simplex virus (HSV) 1 and 2. This is the virus responsible
  for cold sores and genital herpes.
  
• Poliovirus.
  
• Arboviruses. The arboviruses are a family of viruses transmitted to
  humans by infected mosquitoes, ticks, or other blood-sucking
  insects. These types of encephalitis include West Nile virus,
  Japanese encephalitis, equine encephalitis, La Crosse encephalitis,
  and St. Louis encephalitis.
  
• The rabies virus.

Toxoplasmosis, a disease caused by a parasite, and Lyme disease, a
bacterial infection, can cause encephalitis.

Symptoms of encephalitis in infants may include:

• Vomiting
  
• Body stiffness
  
• Crying that increases when the baby is picked up or held
  
• A fullness or bulge in the soft spot at the top of the baby’s head

In addition to the symptoms of encephalitis in adults discussed earlier,
people with severe infections may also have:

• Visual hallucinations
  
• Seeing double
  
• Personality changes
  
• Loss of sensation in some parts of the body
  
• Impaired judgment
  
• Muscle weakness