West Nile virus linked to acute flaccid paralysis. (Disease Watch).

Acute flaccid paralysis (AFP) syndrome has been associated with the West Nile virus (WNV), according to a series of six cases described in the Sept. 20 issue of the Morbidity and Mortality Weekly Report. Dr. A. Leis and colleagues from the Centers for Disease Control and Prevention (CDC), who studied the six cases, recommend that patients presenting with acute weakness should be screened for WNV before beginning treatment for presumed Guillain-Barre syndrome (GBS). In the cases of WNV-associated AFP, clinical, laboratory, and electrophysiologic findings suggested pathology localized to anterior horn cells and motor axons, similar to that seen in acute poliomyelitis. All six patients had acute onset of asymmetrical weakness without pain or sensory loss, and four of five who had cerebrospinal fluid (CSF) analysis had pleocytosis. To help differentiate AFP from GBS, the authors point out that GBS usually exhibits symmetrical weakness, sensory changes or paresthesias, and elevation of CSF protein in the absence o f pleocytosis. The onset of GBS usually follows signs of acute infection by several days, and prognosis is good, with rapid improvement in strength. To date, patients with AFF have had little improvement over one and a half to two months, but doctors cannot predict how long symptoms will last, according to Dr. Jim Sejvar of the CDC.