RT Journal Article
SR Electronic
T1 West Nile virus infection in 2002: morbidity and mortality among patients admitted to hospital in southcentral Ontario
JF Canadian Medical Association Journal
JO CMAJ
FD Canadian Medical Association
SP 1399
OP 1405
VO 168
IS 11
A1 Caitlin Pepperell
A1 Neil Rau
A1 Sigmund Krajden
A1 Ralph Kern
A1 Atul Humar
A1 Barbara Mederski
A1 Andrew Simor
A1 Donald E. Low
A1 Allison McGeer
A1 Tony Mazzulli
A1 Jodie Burton
A1 Cheryl Jaigobin
A1 Margaret Fearon
A1 Harvey Artsob
A1 Michael A. Drebot
A1 William Halliday
A1 James Brunton
YR 2003
UL http://www.cmaj.ca/content/168/11/1399.abstract
AB Background: In August and September 2002 an outbreak of West Nile virus (WNV) infection occurred in southern Ontario. We encountered a number of seriously ill patients at our hospitals. In this article we document the clinical characteristics of these cases. Methods: We conducted a retrospective chart review of patients who came to the attention of infectious disease or neurology consultants or the microbiology laboratories at 7 hospitals in the municipalities of Toronto, Peel and Halton, Ont. Patients were included if they had been admitted to hospital or stayed overnight in the emergency department, had serological evidence of WNV infection and had clinical evidence of WNV fever, aseptic meningitis, encephalomyelitis or motor neuronopathy. Results: In all, 64 patients met the inclusion criteria; 57 had encephalitis or neuromuscular weakness or both, 5 had aseptic meningitis, and 2 had WNV fever. The mean age was 61 years (range 26–87). The patients were predominantly active, middle-aged or elderly people living independently in the community. Seven patients were immunocompromised A febrile prodromal illness preceded the neurological symptoms in almost all cases. The most common neurological abnormality was decreased level of consciousness; this frequently evolved to severe lower motor neuron neuromuscular weakness. Ataxia and swallowing disorders were frequent and important problems. Sixteen patients (25%) required intubation and mechanical ventilation because of a decreased level of consciousness, inability to clear secretions or respiratory muscle weakness; 9 others had disabling muscle weakness of one or more limbs. Ten patients died. The study patients were in hospital a total of 1856 patient-days, including 532 patient-days in an intensive care unit. Only 28% (13/47) of the patients who survived encephalitis or neuromuscular weakness, or both, were discharged home without additional support. Slow turnaround time for serological test results resulted in delayed diagnosis. Interpretation: The 2002 WNV infection outbreak in Ontario caused serious morbidity and mortality in the subset of patients who had encephalitis or neuromuscular weakness severe enough to require hospital admission.