West Nile encephalitis is a viral infection caused by the West Nile virus, primarily transmitted to humans through the bite of infected mosquitoes. Most people infected with the virus do not show symptoms, but some may develop mild flu-like symptoms or more severe neurological issues. In rare cases, the infection can lead to encephalitis, an inflammation of the brain, which can cause symptoms such as fever, headache, confusion, and seizures. Those at higher risk include the elderly and individuals with weakened immune systems. Prevention focuses on reducing mosquito exposure and controlling mosquito populations.