At the Durham Region Health Department, West Nile virus surveillance and control measures are now in progress for the season. West Nile virus is a mosquito-borne disease that is transmitted to humans by infected mosquitoes, which acquire the virus by feeding on the blood of infected birds. The virus is not transferred from person to person or from bird to person. Since 2001, West Nile virus has been recorded in birds, mosquitoes, horses, and humans in Ontario. In 2022, Durham Region had one confirmed and two possible cases of human West Nile Virus.
To detect West Nile virus, the Health Department collects batches of adult mosquitoes for testing. In 2022, the Health Department found that 15 of their mosquito batches tested positive for West Nile virus, indicating an increase from 2021 when only 10 batches were found positive. The Health Department also conducts larval mosquito surveillance and operates a larviciding program aimed at local catch basins. To avoid mosquito breeding, it’s suggested to cover standing water where mosquitoes lay eggs and use chlorine tablets to sterilize rain barrels.
Residents can also help to reduce mosquito numbers by eliminating potential breeding sites. For example, they should ensure that pools and chair covers, ceramic pots, bird baths, planters, and other items that contain stagnant water are emptied regularly. Removing unused tires from the property, ensuring that drainage ditches are not blocked, and regularly flipping compost piles can help prevent the spread of mosquitoes. Furthermore, to lower the risk of West Nile virus exposure, residents are encouraged to dress in long pants and sleeves and use insect repellent when outside, especially between dusk and dawn when mosquitoes are most active.
For further information about West Nile virus, including the Health Department’s surveillance activities, feel free to call Durham Health Connection Line at 905-668-2020 or 1-800-841-2729, or visit https://www.durham.ca/en/health-and-wellness/west-nile-virus.aspx. Remember to keep the door and window screens in good repair, trim your lawn and shrubs, and adopt other effective measures to control the spread of West Nile virus.
