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Neuroinvasive West Nile Virus Disease in Canada. The Saskatchewan Experience

Published online by Cambridge University Press:  23 September 2014

José F. Téllez-Zenteno*
Affiliation:
Division of Neurology, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Gary Hunter
Affiliation:
Division of Neurology, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Lizbeth Hernández-Ronquillo
Affiliation:
Division of Neurology, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Edrish Haghir
Affiliation:
Division of Neurology, Department of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
*
Department of Medicine, Division of Neurology, Royal University Hospital, Saskatoon, Saskatchewan, S7N 0W8, Canada. Email: jftellez@yahoo.com
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Abstract:

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Background:

West Nile virus (WNV) is a virus of the family Flaviviridae. The main route of human infection is through the bite of an infected mosquito. Approximately 90% of WNV infections in humans are asymptomatic, but neurologic manifestations can be severe.

Methods:

This study reviews the clinical profile of cases with neuroinvasive West Nile infection (NWNI) reported by the Surveillance program of the government of Saskatchewan in the Saskatoon Health Region (SHR). In 2007, 1456 cases of human West Nile cases were reported by the government of Saskatchewan in the whole province. One hundred and thirteen cases had severe symptoms of NWNI (8%), 1172 (80%) cases had mild symptoms of WNI and 171 (12%) had asymptomatic disease. Three hundred and fifty six cases were reported in the SHR, where 57 (16%) fulfilled criteria for NWNI.

Results:

From the 57 cases, 39 (68%) were females. Nine (16%) patients had a history of recent camping, two (4%) reported outdoor sports and four (8%) reported outdoor activities not otherwise specified. Twenty five patients had headache (43.9%), 25 confusion (42.1%), 23 meningitis (40.4%), 17 encephalitis (29.8%), 14 encephalopathy (24.6%), 11 meningoencephalitis (19.3%), 10 tremor (17.5%), acute flaccid paralysis 10 (17.5%), myoclonus 1 (1.8%), nystagmus 2 (3.5%), diplopia 2 (3.5%), dizziness 2 (3.5%). Three patients died related with comorbidities during admission.

Conclusion:

During a year of high occurrence of WNI in Saskatchewan, 16% of cases developed NWNI. The recognition of neurological complications associated with WNI is important to improve their referral to tertiary centers.

Contexte:

Le virus du Nil occidental (VNO) est un virus de la famille des Flaviviridae. La principale voie d'infection chez l'humain est la piqûre d'un moustique infecté. À peu près 90% des infections par le VNO chez l'humain sont asymptomatiques. Cependant les manifestations neurologiques peuvent être sévères.

Méthode:

Cette étude revoie le profil clinique des cas atteints de neuroinfection par le VNO (NVNO) rapportés par le programme de surveillance du gouvernement de la Saskatchewan dans la région sanitaire de Saskatoon. En 2007, 1 456 cas d'infection par le VNO dans toute la province ont été rapportés par le gouvernement de la Saskatchewan. Cent treize cas présentaient des symptômes sévères de NVNO (8%), 1 172 (80%) cas présentaient des symptômes légers de NVNO et 171 cas (12%) étaient asymptomatiques. Trois cent cinquante-six cas ont été rapportés dans la région sanitaire de Saskatoon et 57 (16%) respectaient les critères de NVNO.

Résultats:

Parmi ces 57 cas, 39 (68%) étaient des femmes. Neuf patients (16%) rapportaient être allés camper récemment, 2 patients (4%) rapportaient avoir fait des sports à l'extérieur et 4 patients (8%) rapportaient avoir fait des activités non spécifiées à l'extérieur. Vingt-cinq patients présentaient une céphalée (43%), 25 présentaient de la confusion (42,1%), 23 présentaient une méningite (40,4%), 17 (29,8%) présentaient une encéphalite, 14 (24,6%) présentaient une encéphalopathie, 11 (19,3%) présentaient une méningoencéphalite, 10 (17,5%) présentaient du tremblement, 10 (17,5%) présentaient une paralysie flasque, 1 (1,8%) présentait de la myoclonie, 2 (3,5%) présentaient un nystagmus, 2 (3,5%) présentaient de la diplopie et 2 (3,5%) présentaient des étourdissements. Trois patients sont décédés de comorbidités pendant l'hospitalisation.

Conclusion:

Au cours d'une année où la fréquence des infections par le VNO était élevée en Saskatchewan, 16% des cas ont présenté une NVNO. La détection des complications neurologiques associées à l'infection par le VNO est importante pour améliorer l'accès de ces patients à des centres de soins tertiaires.

Type
Research Article
Copyright
Copyright © The Canadian Journal of Neurological 2013

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