Clinical Characteristics and Functional Outcomes of West Nile Fever

7 September 2004 | Volume 141 Issue 5 | Pages 360-365

Background: West Nile fever, considered a nonsevere manifestation of West Nile virus infection, has not been clinically well described in the United States. In 2002, Illinois had 884 documented cases of West Nile virus infection with 66 associated deaths.

Objective: To describe the symptoms and functional outcomes of West Nile fever.

Design: Case series.

Setting: Illinois.

Patients: 98 community-dwelling patients with laboratory evidence of West Nile virus infection but no history of clinical evidence of meningitis, encephalitis, or acute flaccid paralysis.

Intervention: Outpatient interviews.

Measurements: Presence and duration of patient-reported symptoms of infection, symptom-associated absenteeism, health care use, and impact on daily activities.

Results: Of 98 patients, 96% had fatigue for a median of 36 days, 81% had fever for a median of 5 days, 71% had headache for a median of 10 days, 61% had muscle weakness for a median of 28 days, and 53% had difficulty concentrating for a median of 14 days. Thirty respondents reported hospitalization, with a median stay of 5 days. At 30 days after onset, 63% of respondents continued to have symptoms. Duration did not vary significantly with increased age. Among the 72 patients who normally attended work or school, 57 (79%) could not attend because of illness (median absence, 10 days).

Limitations: Recall bias could have been introduced by the delay between illness onset and interview and by self-reporting of illness information.

Conclusions: West Nile fever is a more severe illness than has previously been documented. Mandatory reporting of West Nile fever cases in addition to West Nile meningoencephalitis cases could allow more accurate and timely recognition of the geographic distribution of West Nile virus infections and could inform public health interventions.

Editors' Notes Context The frequency of infection with West Nile virus is increasing rapidly in the United States. While the most fatal and closely studied manifestations of the disease are meningitis and encephalitis, little is known about the symptoms and clinical outcomes of West Nile fever. Contribution The authors interviewed 98 people with nonparalytic West Nile fever following recovery. Muscle weakness, fatigue, headache, difficulty concentrating, and fever were common manifestations. Approximately one third of patients required hospitalization. Median time to full recovery was 60 days. Implications Even in the absence of neurologic manifestations, West Nile virus infection is a potentially severe and debilitating illness. –The Editors

 

Author and Article Information

From Chicago Department of Public Health, Chicago, and Illinois Department of Public Health, Springfield, Illinois; and Centers for Disease Control and Prevention, Atlanta, Georgia.

Potential Financial Conflicts of Interest: None disclosed.

Corresponding Author: John T. Watson, MD, Chicago Department of Public Health, 2160 West Ogden, Chicago, IL 60612; e-mail, watson_john{at}cdph.org.

Current Author Addresses: Drs. Watson, Paul, and Gerber, Mr. Jones, and Ms. Siston: Chicago Department of Public Health, 2160 West Ogden, Chicago, IL 60612.

Dr. Pertel: Bayer Pharmaceuticals, 400 Morgan Lane, West Haven, CT 06516.

Dr. Austin: Illinois Department of Public Health, 525 West Jefferson Street, Springfield, IL 62761.

Author Contributions: Conception and design: J.T. Watson, P.E. Pertel, R.C. Jones, W.S. Paul, S.I. Gerber.

Analysis and interpretation of the data: J.T. Watson, P.E. Pertel, R.C. Jones, A.M. Siston, S.I. Gerber.

Drafting of the article: J.T. Watson, P.E. Pertel, R.C. Jones.

Critical revision of the article for important intellectual content: J.T. Watson, P.E. Pertel, R.C. Jones, A.M. Siston, W.S. Paul, C.C. Austin, S.I. Gerber.

Final approval of the article: J.T. Watson, P.E. Pertel, R.C. Jones, A.M. Siston, W.S. Paul, C.C. Austin, S.I. Gerber.

Provision of study materials or patients: C.C. Austin.

Statistical expertise: R.C. Jones, A.M. Siston.

Collection and assembly of data: J.T. Watson, P.E. Pertel.

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