Medical Advisory - Heightened Surveillance for West Nile Virus Infections

Released August 10, 2017

Issued by: M. Mustafa Hirji, MD, MPH, FRCPC, Associate Medical Officer of Health

  • Public Health has received its first confirmation of the virus in two mosquito pools
  • On average, 5 to 10 mosquito pools test positive in the Niagara region every year
  • There have been no identified infections in humans as of this time
  • All health care providers are encouraged to be on heightened surveillance of WNV infection
Clinical Presentation

WNV infection can present as one of three syndromes:
  • Asymptomatic (79%)
  • WNV Fever (20%), a flu-like illness with some of the following symptoms:
    • Fever
    • Headache
    • Myalgias / body aches
    • Fatigue
    • Nausea / vomiting
    • Diarrhea
    • Swollen lymph nodes
    • Maculopaopular rash (below neck and above waist)
  • Neurological disease (1%), presenting as meningitis / encephalitis, acute flaccid paralysis, or Parkinson-like symptoms

Please consider WNV infection in patients presenting as above who have had mosquito bites within the preceding 14 days.


Please report all confirmed and suspected cases of WNV infection using the online Human Surveillance Patient Report Form​

For further information, please contact Niagara Region Public Health, Infectious Disease Program at 1-888-505-6074 or 905-688-8248 ext. 7330 Monday to Friday 8:30 a.m. to 4:30 p.m., after hours 905-984-3690.
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