Most cases of West Nile Virus infection are asymptomatic. 60% to 70% of neuro-invasive cases of West Nile virus infection result in meningitis or encephalitis; however, West Nile encephalitis occurs in less than 1% of patients infected with the West Nile virus.1
Bennin, MD, Charles-Lwanga; Krawitz, MD, Steve; and Weaver, MD, Emma
"West Nile Virus Encephalitis in a Patient with Renal Transplant,"
The Medicine Forum:
Vol. 12, Article 10.
Available at: http://jdc.jefferson.edu/tmf/vol12/iss1/10