Viral Encephalitis

Side view of head and brain.

Encephalitis is inflammation of the brain. It may cause:

  • Headache

  • Stiff neck

  • Irritability

  • Fever

  • Drowsiness

  • Nausea and vomiting

  • Confusion

  • Bizarre behavior

  • Paralysis

  • A seizure

It can be caused by infection from a virus. This includes viruses such as:

  • Rabies

  • Herpes

  • Measles

  • Mumps

  • Chickenpox

  • West Nile virus

  • Zika virus

  • HIV

  • Other viruses

The virus may be spread to a person by other people, animals, ticks, or insects. Mosquito bites are a common way to get a virus that causes encephalitis.

You may be given:

  • Antiviral medicine

  • Anti-seizure medicine

  • Steroid medicine

You will likely need to stay in the hospital until you are stable. In mild cases, most people recover fully in 2 to 4 weeks. But more severe cases may cause long-term (permanent) disability.


  • Get all vaccines for common viral illnesses.

  • Drain areas of water where mosquitoes can breed.

  • Use insect repellent that works on mosquitoes and ticks. Wear protective clothing when in areas where mosquitoes and ticks are found.

  • Be cautious around stray cats and dogs, and wild animals.

  • Try not to have close contact with people who have viruses.

Home care

  • Rest in bed until you feel better. Stay home from school or work for at least 1 week to prevent spreading the virus to others.

  • If you were taking antiviral medicines in the hospital, you may need to continue them at home. Take any medicines as directed.

  • Ask your healthcare provider before you take medicines for fever and headache. This includes ibuprofen or acetaminophen. Tell your provider if you have chronic liver or kidney disease. Tell them if you have ever had a stomach ulcer or digestive bleeding.

  • If you have a fever, drink plenty of fluids. This is to prevent dehydration. Drink water, sports drinks, or other fluids.

Follow-up care

Follow up with your healthcare provider during the next week as directed by our staff. This helps make sure that the medicines are working.

When to get medical care

Call the healthcare provider if you have any of these:

  • Fever of 100.4°F (38°C) or higher that does not get better with medicine

  • Headache or stiff neck doesn't get better

  • Headache or stiff neck gets worse

  • Not able to keep fluids down due to vomiting

Call 911

Call 911 if any of the following occur:

  • Increasing drowsiness, confusion, or bizarre behavior

  • Weakness of an arm or leg or 1 side of the face

  • Trouble with speaking

  • Trouble seeing

  • Trouble walking

  • Seizure

  • Fainting

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