Health Department begins 2020 West Nile virus surveillance activities
Whitby, Ontario - Durham Region Health Department has started West Nile virus (WNV) surveillance and control activities for the 2020 season. WNV is a mosquito-borne disease that is spread to humans through the bite of an infected mosquito. Mosquitoes become infected by feeding on the blood of birds that carry the virus. The disease is not passed from person to person or from bird to person.
As part of ongoing WNV surveillance, the Health Department will conduct a number of activities to monitor WNV concerns across the Region, including implementing a weekly adult mosquito-trapping program, a larval mosquito surveillance program and a larviciding program involving regional catch basins, as well as identifying stagnant water sites where mosquitoes could breed.
The Health Department also routinely traps batches of adult mosquitoes, known as mosquito pools, which are then tested for the virus. In 2019, one mosquito pool trapped by the Health Department tested positive for WNV. This represents a decrease from seven positive mosquito pools that tested positive in 2018. In addition to testing adult mosquitoes for the virus, the Health Department also uses indicators such as larval mosquito surveillance to determine the risk of the virus for area residents.
The Health Department advises area residents to remove or cover any standing water around their homes to help reduce or eliminate the opportunity for mosquitoes to lay eggs that develop into larvae and, ultimately, become mosquitoes which can spread the virus.
Since 2001, WNV has been found in birds, mosquitoes, horses and humans in Ontario. For 2019, the Public Health Agency of Canada reported 19 human cases of the virus in Ontario, compared to 126 human cases in 2018. Durham Region did not have any confirmed human cases of WNV in 2019, compared to five human cases in 2018.
The Health Department recommends the following specific steps to help minimize potential breeding sites for mosquitoes:
- Chlorinate rain barrels or cover them with mosquito screening.
- Drain water from areas such as pools and chair covers, and from containers such as ceramic pots, wading pools, bird baths, planters, etc.
- Check that roof gutters are cleared and draining properly.
- Clean and properly maintain swimming pools and outdoor hot tubs.
- Remove all unused tires from your property.
- Ensure that drainage ditches are not backed up and holding stagnant water.
To help reduce the possibility of being exposed to WNV, residents are encouraged to take the following precautions:
- Wear shoes, socks and light-coloured clothing with long sleeves and full-length pants when outside, especially overnight, between dusk and dawn, when mosquitoes are most active.
- Use insect repellent containing DEET on exposed skin, following Health Canada’s safety tips on using personal insect repellents. More information on using insect repellents containing DEET can be found at https://www.canada.ca/en/health-canada/services/about-pesticides/insect-repellents.html?_ga=1.190416748.61038264.1464190033.
- Ensure doors and windows have screens that are tight-fitting and in good repair.
- Keep grass, shrubs and hedges trimmed.
- Turn over compost piles regularly.
For more information about West Nile virus and the Health Department’s surveillance activities, please call Durham Health Connection Line at 905-668-2020 or 1-800-841-2729, or visit durham.ca/WestNile.
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For more information, please contact the Health Department.
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