Recovery from clinical West Nile virus infection: A longitudinal study

Abstract

Context. Minimal data exists on the long-term sequelae of clinical WN virus infection.;Objectives. To document the physical, cognitive, functional and psychosocial effects of WN virus over the eighteen months after acute illness. To formulate a multifaceted definition for recovery in order to examine how the severity of the initial clinical syndrome, age and underlying illness affect recovery, and the extent to which psychosocial variables such as social support, social functioning, and dispositional optimism influence this process.;Design. A cohort follow-up design conducted in New York City, NY.;Subjects. All surviving New York City residents with laboratory-confirmed WN virus diagnosed in the summer of 1999 were recruited to participate in the prospective study. Of the 46 WN cases from 1999, 42 survived the acute illness.;Main outcomes and measures. Data collection included subjective information on current symptoms, changes in activities of daily living and a series of psychosocial parameters, including social support measures and the Revised Life Orientation Test. Recovery was defined in six ways from reported symptoms and self-assessment questions.;Results. WN virus can result in significant convalescence immediately following the acute phase of illness; approximately 40% of the hospitalized cases were not discharged to their own homes and 45% of the cases required physical therapy. Regardless of the severity of the acute clinical presentation, difficulty walking, muscle weakness, fatigue, and insomnia were reported by over 40% of cases eighteen months after illness. The most prominent cognitive complaints of memory loss, confusion, depression and irritability were reported by over 30% eighteen months after illness. Physical and cognitive symptoms persisted with minimum recovery to baseline (prior to WN viral infection) at one and a half years after acute illness. Eighteen months after illness, 30% of cases still reported needing assistance with a number of daily activities, but mostly with activities involving increased strength such as heavy chores.;Conclusion. Individuals with severe acute WN meningoencephalitis experienced a constellation of residual symptoms including fatigue, muscle weakness, difficulty walking, depression, irritability and memory loss eighteen months after acute illness. Long-term recovery was best predicted by age and social functioning.