West Nile virus transmission cycle
West Nile virus is an infection transmitted by mosquitoes. If you become infected with West Nile virus, you may not experience any signs or symptoms, or you may experience only minor ones such as fever and mild headache. However, some people who become infected with West Nile virus develop a life-threatening illness that includes inflammation of the brain.
Mild infection signs and symptoms
About 20 percent of people develop a mild infection called West Nile fever. Common signs and symptoms of West Nile fever include:
Find out about more about symptoms, causes and treatment: West Nile Virus