

Murray Valley Encephalitis virus

What is Murray Valley encephalitis?

Murray Valley encephalitis (MVE) is a disease caused by a virus that is spread through mosquito bites. Most people who are infected with the virus do not feel sick. Some people do develop symptoms such as fever, headache, nausea, vomiting, and tiredness. People who get the virus may also develop severe disease. Symptoms of severe disease are confusion, sleepiness, trouble speaking, lack of coordination, and brain infection. In very rare cases, long-term disability or death can occur.

Who is at risk?

Travelers to New Guinea and remote northwestern Australia or southeastern Australia are at risk of getting MVE virus. (See map.) The virus is more common during heavy rainfall, flooding, and hot weather. Travelers who plan to spend a lot of time outdoors or will be in an area with a lot of mosquitoes are at increased risk of getting the virus.

What can travelers do to prevent Murray Valley encephalitis?

There is no vaccine or medicine that prevents MVE. Travelers can protect themselves from MVE by preventing mosquito bites.

Prevent mosquito bites:

man spraying insect repellent on his arm
  • Use an appropriate insect repellent as directed.
  • Always follow product directions and reapply as directed:
    • If treating items yourself, follow the product instructions carefully.
    • Do not use permethrin directly on skin.
  • Stay and sleep in screened or air conditioned rooms.

If you are bitten by mosquitoes:

  • Avoid scratching mosquito bites.
  • Apply hydrocortisone cream or calamine lotion to reduce itching.

If you feel sick and think you may have MVE:

  • Get lots of rest, and drink plenty of liquids.
  • Avoid spreading the disease by preventing more mosquito bites.

Traveler Information

Clinician Information