How does West Nile virus (WNV) affect humans?
West Nile virus infection in humans ranges from infection without symptoms to serious brain illness and death. About 80% of people who are infected will experience no symptoms and will not be aware of the infection. Most people who get sick will have a mild illness called West Nile fever that includes fever, headache, joint pain, muscle pain, and fatigue. In less than 20% of cases, swollen lymph nodes and rash may be present. West Nile fever typically lasts for 2-7 days. Some individuals experience the more severe forms of the illness, West Nile encephalitis and meningitis, in which either the brain or its outer covering become inflamed. The brain illnesses include the symptoms of West Nile fever described above PLUS stiff neck, altered mental status, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent in some cases. While ANYONE can be infected and/or
