MEMO: Heightened Surveillance for West Nile Virus (WNV)

TO: Health Care Professionals in the Niagara Region

FROM: Infectious Disease Program, Niagara Region Public Health

REFERENCE: Heightened Surveillance for West Nile Virus (WNV)

DATE: Sept. 21, 2021

Niagara Region Public Health (NRPH) has received a confirmed report of West Nile Virus (WNV) in September. Please be on heightened surveillance for any additional cases of WNV.

WNV is most commonly transmitted through the bite of an infected mosquito.

Clinical Presentation

Average incubation period is 3 to 14 days after infected mosquito bite
Only 20% of people will develop symptoms
Mild Symptoms of WNV can include:
- Fever
- Myalgia
- Arthralgia
- Headache
- Nausea and vomiting
- Lymphadenopathy
- Maculopapular rash
About 1 in 150 infected people will have a severe infection, including West Nile virus Neurological Syndrome. Symptoms can include:
- Headache / high fever
- Neck stiffness
- Disorientation
- Coma / unconsciousness
- Tremors / convulsions
- Muscle weakness / paralysis

Diagnosis and Management

Symptoms listed above may be related COVID-19. If someone tests negative for COVID-19 consider testing for WNV if symptoms are compatible. There is no specific treatment, medication or vaccine for WNV.

Reporting

WNV is reportable to the Medical Officer of Health under Ontario Regulation 135/18 and amendments of the Health Protection and Promotion Act. If you have a probable case of WNV, report it to Public Health by the next business day:

Call 905-688-8248 ext. 7554, (Mon-Fri, 8:30 a.m. to 4:30 p.m.)
Toll free: 1-888-505-6074

More Information

For further information, please contact NRPH, Infectious Disease program at 1-888-505-6074 or 905-688-8248 ext. 7554/7543 Monday to Friday 8:30 a.m. to 4:30 p.m. or visit our website.