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Western Equine Encephalitis
Major complications, including brain damage, are reported in about 13 percent of infected people overall and in about a third of infants diagnosed with this disease.
Western equine encephalitis is fatal to about 3 percent of those who develop severe symptoms.
There is no specific treatment for western equine encephalitis. Antibiotics are not effective against viruses, and no effective antiviral drugs have been discovered. Caring for patients with western equine encephalitis involves treating the symptoms and complications.
Western equine encephalitis is a relatively rare disease in humans that can occur in isolated cases or in epidemics. Since 1964, 639 human cases of western equine encephalitis have been confirmed in the United States. Fewer than five cases are reported each year. In the United States, western equine encephalitis cases in humans are usually first seen in June or July.
The risk of exposure to western equine encephalitis has been increasing in recent years as people move into previously undeveloped areas where the western equine encephalitis virus lives.
Expansion of irrigated agriculture in the North Platte River Valley during the past several decades has created habitats and conditions that favor increases in the number of grain-eating birds and mosquitoes that spread western equine encephalitis.
A vaccine is available for horses but not for humans. Prevention focuses on public health action to control mosquitoes and individual action to avoid mosquito bites. To avoid being bitten by the mosquitoes that carry the western equine encephalitis virus:
- Stay inside between dusk and dark (when mosquitoes are most active)
- When outside, wear long pants and long-sleeved shirts
- Spray exposed skin with an insect repellent.
Written by/reviewed by: Arthur Schoenstadt, MD
Last reviewed by: Arthur Schoenstadt, MD