New data indicate that West Nile fever-the most common of West Nile diseases, and long considered benign-has as many long-term health effects as the neuroinvasive diseases West Nile meningitis and encephalitis. Analysts surveyed 49 patients, 38 with West Nile fever and 11 with West Nile meningitis or encephalitis, approximately 13 months postdiagnosis. Forty-nine percent of patients complained of exhaustion; 24% experienced depression. Eight percent reported disabilities ranging from moderate to severe, and 20% had developed new tremors. All patients displayed neuropsychological abnormalities, such as memory and word-finding problems and loss of motor skills and executive functions. Based on these results, researchers have concluded that West Nile virus is an even greater threat to public health than previously realized.

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