Western equine encephalitis is a viral infection that is transmitted to humans and horses by mosquitoes. Most cases arise during the late summer months, when there are many Culex tarsalis mosquitos, which is the main type of mosquito responsible for transmitting the virus. Western equine encephalitis is more common in the United States west of the Mississippi and in rural South American locations. While it the virus can affect anyone, children and the elderly are usually affected most severely.
Infection with western equine encephalitis is often asymptomatic. Severe cases may begin with the symptoms of sudden fever, stiff neck, headache, vomiting, and tiredness. Symptoms can progress to disorientation, irritability, seizures, and coma. Those with severe cases are at risk for developing encephalitis, or inflammation of the brain. Children who have severe cases of western equine encephalitis may be at risk for additional complications and may have cognitive impairment.
There is currently no vaccine available for western equine encephalitis. Infection can be prevented by protecting yourself from mosquito bites such as by avoiding being outdoors during times of peak mosquito activity at dawn and dusk, wearing long sleeves, and using mosquito repellant. If you have been diagnosed with western equine encephalitis, talk to your doctor about the most current treatment options.