West Nile Virus–associated Flaccid Paralysis

摘要

The causes and frequency of acute paralysis and res-piratory failure with West Nile virus (WNV) infection areincompletely understood. During the summer and fall of2003, we conducted a prospective, population-based studyamong residents of a 3-county area in Colorado, UnitedStates, with developing WNV-associated paralysis. Thirty-two patients with developing paralysis and acute WNVinfection were identified. Causes included a poliomyelitis-like syndrome in 27 (84%) patients and a Guillain-Barré–like syndrome in 4 (13%); 1 had brachial plexusinvolvement alone. The incidence of poliomyelitislike syn-drome was 3.7/100,000. Twelve patients (38%), including 1with Guillain-Barré–like syndrome, had acute respiratoryfailure that required endotracheal intubation. At 4 months, 3patients with respiratory failure died, 2 remained intubated,25 showed various degrees of improvement, and 2 werelost to followup. A poliomyelitislike syndrome likely involvingspinal anterior horn cells is the most common mechanismof WNV-associated paralysis and is associated with signif-icant short- and long-term illness and death