Western equine encephalitis (WEE) is a virus spread by a bite from an infected mosquito. While WEE is rare, an infection can be serious or fatal.
Factors that may increase your chance of WEE include:
- Living in or visiting the plains regions of western and central United States
- Doing activities outdoors and not using insect repellent
Most people with WEE do not have any symptoms.
If symptoms do occur, they appear within 5-10 days after infection and include:
- Neck stiffness
- Joint and muscle pain
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.
In addition to taking your medical history and doing a physical exam, your doctor will ask you:
- What kind of symptoms you are experiencing
- Where you have been living or traveling
- Whether you have been exposed to mosquitoes
Your doctor may need to test your bodily fluids. This can be done with:
- Blood tests
- Cerebrospinal fluid tests to evaluate the fluid that surrounds the brain and spinal cord
Imaging tests to evaluate the brain 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:
- IV fluids
- Antiseizure medications
- Medications to decrease brain swelling
- Breathing support—mechanical ventilation
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:
- Stay inside between dusk and dark, when mosquitoes are most active.
- Wear long pants and long-sleeved shirts when outside.
- Use an insect repellent with DEET.
- Repair screens to prevent mosquitoes from entering the house.
- Use proper mosquito netting at night. Look for netting treated with insecticide.
- Remove standing water (such as birdbaths, clogged gutters) to prevent mosquito breeding.
- Reviewer: David L. Horn, MD
- Review Date: 11/2015 -
- Update Date: 12/20/2014 -