West Nile Virus

Mosquitoes can become infected with West Nile virus when they feed on the blood of birds infected with West Nile virus. Because mosquitoes feed on infected birds, it is possible to detect  the virus in mosquitoes through laboratory testing. Mosquitoes are captured  using a trap that is baited with  carbon dioxide, using a black  light and a fan to draw mosquitoes into  the trap. Traps are set up overnight across pre-established sites in the City and are collected the next morning. Mosquitoes collected in the traps are counted; species and sex  identified and tested to determine if the mosquitoes are carrying West Nile virus.

Trapping and testing mosquitoes helps the City determine where infected mosquitoes can likely be found, the different types of mosquitoes and the amount of mosquitoes trapped each week.  We use this data to establish our controls which could be include larvaciding, reducing standing water in the area and activities to increase public awareness.

Mosquitoes breed in standing water and tend to stay close to their breeding site throughout their life. If the number of breeding areas can be reduced, we can reduce the number of mosquitoes and West Nile virus in our community.

Report standing Water

Standing water surveillance starts on April 1 each year and continues until October 31, under Hamilton’s Standing Water By-law No. 03-173(PDF, 61.33 KB).  We do not investigate complaints outside of these dates.

If you want to report standing water:

• Email [email protected]
• Phone 905-546-2489

We accept complaints for standing water that is more than 2 ½ cm deep at the deepest point with no movement of the water.  If water has been treated to prevent insects from breeding, it is not considered standing water. Treatment may include continuous movement of the water or appropriate pesticide treatment or other actions approved by the Medical Officer of Health.

Public land complaints

We follow up on public land complaints within five business days. The City looks for mosquito larvae at several hundred surface water sites from June to the fall each year.  We treat sites when necessary to reduce or eliminate the amount of mosquitoes developing in the water. This helps control the mosquito population in Hamilton.

Private land complaints

We follow up on private land complaints within five business days. The City investigates and enforces private land complaints that fall within the scope of Hamilton’s Standing Water By-law No. 03-173.

The City of Hamilton is committed to reducing the risk of West Nile virus within our community by using strategies with the least negative impact on human health, nature and the environment.  We do many things to control West Nile virus such as:

• public education
• reducing mosquito breeding sites and standing water on City land
• enforcing Hamilton's Standing Water By-law No. 03-173(PDF, 61.33 KB)
• surveillance for West Nile virus in mosquitoes
• monitor for West Nile virus in humans 

Adult mosquito control

We have a contingency plan for using an ultra-low volume insecticide called malathion to control the adult mosquito population.  This could be used if the Medical Officer of Health determines that it is needed to decrease the risk of West Nile virus to human health.  Spraying to control adult mosquitoes has not yet been required in Hamilton or any other municipality in Ontario for West Nile virus control. 

If we are going to use malathion, Public Health Services will notify residents in the affected areas a minimum of 48 hours before application. Notification will be through the media such as newspapers, television, radio or door-to-door notices.

Sign up for the Adult Mosquito Control Registry

If you want to receive personal advance notification of plans to apply malathion in your area because of health-related concerns, sign up for the adult mosquito control registry. Let Public Health Services know your:

• Name
• Preferred method of contact - phone, fax or email
• Contact information – phone, fax and/or email

You can submit this information to Public Health by:

• Phone: 905-546-2489
• Fax: 905-546-2787
• Email: [email protected]

We will use an automated system to electronically contact each person registered on the adult mosquito control registry by their chosen method of phone, email, fax or a combination of these to notify them of any adulticiding plans in their area. 

Personal information collected for the purpose of administering the Adult Mosquito Control Registry is being collected under the authority of the Health Protection and Promotion Act, R.S.O. 1990, c. H.7.

If you have any questions regarding this collection, contact the West Nile Virus program, Public Health Services, City of Hamilton, 110 King Street West, Hamilton, Ontario, L8P 4S6 or by Phone: 905-546-2424 ext. 3576.