West Nile virus is a viral infection primarily spread by mosquitoes. It was first identified in Uganda in 1937 and has since spread to many parts of the world, including North America. Most people infected with the virus do not show symptoms, but some may experience mild flu-like symptoms such as fever, headache, and body aches. In rare cases, West Nile virus can lead to severe neurological diseases, including meningitis and encephalitis. People over 50 years old and those with weakened immune systems are at higher risk for serious complications. Preventive measures include using insect repellent and eliminating standing water where mosquitoes breed.