What are the symptoms of West Nile infection?
Approximately 80% of WNV infections are mild and may go unnoticed. Perhaps 20% of WNV infections will result in West Nile fever, an illness characterized by fever, headache, body aches, and occasionally skin rash and swollen lymph glands. A serious complication of WNV infection is encephalitis or other neuroinvasive disease. Symptoms can include severe headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, paralysis, and, rarely, death. How does WNV cause severe illness in humans? Once a person is infected, WNV may multiply in the person’s blood system and cross the blood-brain barrier to reach the brain. Once there, the virus can interfere with normal functioning of the central nervous system and causes inflammation of brain tissue (encephalitis), with sometimes-fatal results. The risk of serious illness or death is greatest among the elderly or among individuals with weakened immune systems. It is important to realize that less than
