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Viral Encephalitis


  • Viral encephalitis (en-sef-ah-LI-tis) is an inflammation (swelling) of the brain due to a viral infection. It occurs when a virus (germ) enters the body and goes to the brain, usually through the blood. Many different types of viruses may cause encephalitis. You may get the virus after being bitten by an infected mosquito or tick. There are viruses which are not active in your body for many years, and then cause encephalitis later in life. Viral infections may also cause encephalitis shortly after the illness.
  • Signs and symptoms may include fever, headache, fatigue (tiredness) or confusion (being unable to think clearly). Other symptoms may include a skin rash, nausea (upset stomach), vomiting (throwing up), stiff neck, or neck pain. Viral encephalitis may be diagnosed by a lumbar puncture, blood tests, or magnetic resonance imaging (MRI) of the head. Treatment may include medicine, oxygen, and rest. It may take months to recover from viral encephalitis. Some types of viral encephalitis may be prevented by vaccinations (shots) or by avoiding contact with mosquitos and ticks. With treatment, such as medicine and rest, you may fully recover after having viral encephalitis.


Take your medicine as directed:

Call your primary healthcare provider if you think your medicine is not helping or if you have side effects. Tell him if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.

  • Antiviral medicine: This is given to prevent or treat an infection caused by a germ called a virus. Antiviral medicine may also be given to control symptoms of a viral infection that cannot be cured.
  • Antibiotics: This medicine is given to help treat or prevent an infection caused by bacteria.
  • Steroids: This medicine may be given to decrease inflammation.

Ask for information about where and when to go for follow-up visits:

For continuing care, treatments, or home services, ask for more information.

Preventing viral encephalitis:

  • Avoid bites from mosquitos and ticks:
    • Apply an insect repellant containing DEET (active ingredient) to your clothing and exposed skin. Spray a product that has permethrin (active ingredient) on your clothes. These products help protect you from ticks and mosquitos. Use repellants with 30 percent DEET or less on infants who are younger than 2 months old. Always read and follow the instructions on the label when using an insect repellant. Do not use DEET on the hands of young children or on babies who may rub their eyes or mouth.
    • Do not go outside, especially at dawn (sunrise) and dusk (sunset). Mosquitoes are most active during these times. Avoid being in places where mosquitoes are common. If you sleep outdoors, use a mosquito net.
    • Put screens on all windows and outside doors of your house, and repair screens that have holes in them.
    • Wear long-sleeved shirts and long pants to keep your skin covered.
    • Clearing dead trees and brush away from where you live may also remove the ticks that live in them.
  • Decrease mosquito breeding: Mosquitoes lay their eggs and mature in water. It is important not to have any standing water around. Do the following to decrease mosquito breeding:
    • Avoid leaving containers that can collect water in an uncovered or upright position. These containers may include wheelbarrows, drums, buckets, or cans. Properly store any open containers that are not being used, such as buckets and cans.
    • Change water in animal feeders every few days.
    • Put holes in containers that cannot be thrown out to drain water. Fill in any potholes, patches, and other areas where water is likely to collect or get stagnant. Regularly check ponds, birdbaths, animal feeders, drinking troughs, and other bodies of standing water.
    • Drain or pump out standing water around your house, such as in clogged gutters and ditches.
    • Use aeration as a way to prevent mosquito growth. One way to use aeration is to constantly circulate water, which does not allow water to become stagnant. Circulating water also prevents mosquitoes from laying their eggs and maturing.

Get vaccinated:

Get vaccinated (shots) against infections caused by viruses. These include vaccines against the flu, measles, mumps, rubella, chicken pox, and polio. A flu shot lasts for one year and is usually given in October and November. A vaccine against the Japanese encephalitis virus is also available. You may also get a rabies shot, especially if you work with animals or have been bitten recently. Ask your caregiver which vaccinations are right for you. It is also good to have your pet vaccinated against rabies.


After having viral encephalitis, you may need rehabilitation (rehab). This is a program to help you return to normal life as much as possible. Rehab helps you regain and relearn the skills of everyday living. You may need any of the following:

  • Occupational therapy: Occupational therapy (OT) uses work, self-care, and other normal daily activities to help you function better in your daily life. OT helps you develop skills to improve your ability to bathe, dress, cook, eat, and drive. You may learn to use special tools to help you with your daily activities. You may also learn new ways to keep your home or workplace safe.
  • Physical therapy: You may need to see a physical therapist to teach you special exercises. These exercises help improve movement and decrease pain. Physical therapy can also help improve strength and decrease your risk for loss of function.
  • Speech therapy: A speech therapist may work with you to help or improve how you talk.


Rest when you feel it is needed. Slowly start to do more each day. Return to your daily activities as directed.


  • You have a fever.
  • Your skin is itchy, swollen, or has a rash.
  • You have questions or concerns about your disease, medicine, or care.


  • You become confused, act differently than normal, or become harder to wake up than normal.
  • You have a bad headache, stiff neck, or trouble thinking clearly.
  • You have seizures (convulsions).
  • You have trouble breathing all of a sudden.
  • Your symptoms are getting worse or coming back.
  • You think someone in your family has viral encephalitis.

The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Learn more about Viral Encephalitis (Aftercare Instructions)

Associated drugs

IBM Watson Micromedex