Western equine encephalitis (WEE) is a virus spread by a bite from an infected mosquito. While WEE is rare, an infected person can become seriously ill and even die from the virus.
WEE is caused by being bitten by a mosquito that is infected with the virus.
Factors that may increase your risk of WEE include:
Most people with WEE do not have any symptoms.
If symptoms do occur, they appear within 5-10 days after infection and include:
WEE can lead to more serious, life-threatening symptoms like inflammation of the brain (encephalitis), seizures, and coma. These serious symptoms are more common in infants and older adults.
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In addition to taking your medical history and doing a physical exam, your doctor will ask you:
Your doctor may need to test your bodily fluids. This can be done with:
Your doctor may need pictures of structures inside your head. This can be done with:
Because the infection is viral, there is no specific treatment for WEE. Treatment will focus on managing your symptoms and related complications through:
There is no vaccine for humans. There is a vaccine for horses. Prevention of WEE focuses on controlling mosquitoes and avoiding mosquito bites. Steps you can take to avoid mosquito bites include:
Centers for Disease Control and Prevention
National Institute of Allergy and Infectious Diseases
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Western equine encephalitis fact sheet. Minnesota Department of Public Health website. Available at: http://www.health..... Accessed January 4, 2013.
10/1/2013 DynaMed Systematic Literature Surveillance https://dynamed.ebscohost.com/about/about-us: Reimer LJ, Thomsen EK, Tisch DJ, et al. Insecticidal bed nets and filariasis transmission in Papua New Guinea. N Eng J Med. 2013 Aug 22; 369(8):745-753.
Last reviewed December 2013 by David L Horn, MD, FACP
Last Updated: 1/13/2014