West Nile Virus cases analyzed for prevalence and symptoms

Researchers from Chicago have identified focal neurological deficits as a major group of presenting symptoms among patients with West Nile Virus infection, which became epidemic in the United States in 2002. Focal neurological deficits included visual loss, muscle weakness, paralysis of one half of the body, abnormally slow movement, tremor with rigidity, numbness or tingling and unstable gait. Findings of their study are being presented at the American Academy of Neurology Annual Meeting in Honolulu, March 29-April 5, 2003.

West Nile Fever, generally transmitted to humans through the bite of an infected mosquito, is usually a relatively mild infection. It is estimated that about 20 percent of those infected will develop West Nile Fever, characterized by mild, flu-like symptoms, a skin rash on the trunk of the body and swollen lymph nodes. West Nile fever typically lasts only a few days and does not appear to cause any long-term health effects.

The more severe form of the disease is the West Nile encephalitis or meningitis, characterized by high fevers, headache, stiff neck, disorientation, seizures, coma and focal neurological deficits. The death rate among West Nile virus infection cases from the summer of 2002 was 5 to 6 percent according to the latest Center for Disease Control reports.

Illinois experienced a higher incidence of West Nile Virus infection cases than any other state: 836, or 20 percent of all U.S. cases reported by January 2003. To aid in diagnosis and treatment, researchers from three Chicago area medical centers were interested to know more about presenting symptoms. Detailed analysis of 28 cases from three hospitals between the months of August through October of 2002, revealed that more than half (54 percent) of their patients exhibited a neurological symptom that mimicked other neurological diseases such as stroke, Parkinson’s, Bells’ palsy, polio and Guillain-Barre syndrome. The remainder of their cases presented with a meningitis or encephalitis without any focal symptoms. “As West Nile virus cases continue to be seen across the U.S., we hope neurologists and patients benefit from the findings of our study by being aware of the varied presentations of the West Nile virus,” concluded study author Nidhi K. Watson, MD of Rush Medical Center, Chicago, Ill.

The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. For more information about the American Academy of Neurology, visit its online press room at http://www.aan.com/press/index.cfm.

For more information contact:
Kathy Stone, 651-695-2763, kstone@aan.com
March 29-April 5, 808-792-6630
Marilee Reu, 651-695-2789, mreu@aan.com