Algoma Public Health
- West Nile Virus (WNv)
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West Nile Virus (WNv)
This virus is spread to humans through the bite of an infected mosquito. The virus has been identified in birds, mosquitoes, horses and humans in Ontario since the summer of 2001.
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Frequently Asked Questions
- Fever
- Fatigue
- Muscle weakness and or aches
- Achy joints
- Swollen glands of the face/neck
- Rash
- 70-80% of people will not have any symptoms
- Usually from 2-6 days but can range from 2-14 days and can be as long as 21 days in a person considered to be immune compromised
WNv is spread to humans through the bite of an infected mosquito. A mosquito becomes infected by biting a bird that carries the virus. WNv is mostly a disease of birds but can spread to humans by mosquitoes that have fed on both birds and humans. The virus is not known to spread from person-to-person, nor from bird-to person. There have been rare cases from blood/organ transmission and transmission from pregnant mothers to their newborn child. Breast feeding may also spread the infection although this has not been confirmed.
If you are bitten by a mosquito, no treatment or tests are needed unless symptoms develop. There is no specific treatment or vaccine for WNv. Some people with severe illness may require hospitalization. Most people who are infected with West Nile virus recover fully.
Studies indicate that following infection, antibodies and “memory” white blood cells (T-lymphocytes) are produced in the body. Therefore, it is assumed that immunity will be lifelong, however, it may diminish in later years.
How to Protect Yourself
- Limit your time outdoors when mosquitoes are most active (from May to September, from dusk to dawn).
- Cover Up: wear protective clothing such as long pants, long sleeves, shoes and socks, when mosquitoes are active.
- Wear light-coloured clothing. Mosquitoes are attracted to dark, more intense colours.
- Use an insect repellent, or bug spray, that says “DEET” or “icaridin” on it. Put it on your clothes and exposed skin. Always read the label for directions on how to use it.
- Repair damaged doors and window screens.
- Reduce standing water where mosquitoes like to breed.
NOTE: Vitamin B, ultrasonic devices, incense, citronella plants and bug zappers have NOT been shown to be effective in preventing mosquito bites.
Female mosquitoes tend to lay their eggs in or around water that is stagnant, shallow and high in organic matter. Eliminating potential breeding sites is the primary control measure in reducing mosquito populations.
The following are simple steps that can be taken to eliminate potential breeding sites in and around your home and prevent you from getting a mosquito bite:
- Remove unused objects, garbage or refuse that could collect stagnant water (tires, flowerpots, etc.).
- When not in use, turn over items such as wading pools, recycling boxes, wheelbarrows and boats/canoes.
- Clean and chlorinate swimming pools, outdoor saunas and hot tubs. Cover if not in use.
- Weekly draining of water that collects on pool covers, window boxes, flower pots, etc.
- Weekly changing of water in wading pools, bird baths and pet food/water dishes.
- Aerate ornamental ponds, or stock self-contained ponds with mosquito-eating fish (gold fish, koi, etc.).
- Cover rainwater barrels with a fine mesh or screen.
- Do not wash grass clippings or leaves down roadside catch basins.
- Turn compost over on a regular basis.
- Do regular landscape maintenance of weeds, tall grasses and shrubs.
- Regular maintenance of roof gutters to prevent clogging.
- Ensure that doors and windows have tight fitting screens and are in good repair.
Monitoring in Algoma
Adult mosquito surveillance is carried out with the use of Centers for Disease Control (CDC) light traps, baited with carbon dioxide (CO2). Traps are set at 14 designated locations on a bi-weekly basis for 24 hours throughout the summer months. Upon collection mosquitoes are sent to a laboratory for where they are identified, and tested for both West Nile Virus and Eastern Equine Encephalitis Virus. The last positive pool in Algoma was in 2017.
Tracking Across Ontario
WNv tracking week by week for all public health units in Ontario can be found on Public Health Ontario’s website.
Dead Bird Submissions
Algoma Public Health does not accept dead birds. If you find a dead bird on your property, you can contact the Canadian Wildlife Health Cooperative to learn more about their surveillance and submission programs.