Surveillance activities for this season will focus on birds, horses, mosquitoes and humans. Surveillance is done to detect the presence of the virus as early as possible in any given area so that communities can take steps to reduce their risk. Surveillance activities will vary by region depending on the level of West Nile Virus seen in the region in previous years, and provincial and local surveillance strategies.
For details, see PHAC's West Nile Virus Monitor under Maps & Stats.
The Canadian Cooperative Wildlife Health Centre, along with provincial laboratories and the PHAC's National Microbiology Laboratory in Winnipeg, will test dead birds for West Nile virus from late April until the first hard frost.
When West Nile virus first came to North America, bird surveillance was used as an early indicator of the presence of the virus in animals. Experience from past outbreaks showed that crows, jays, magpies and ravens were highly susceptible to West Nile virus, making them a good indicator for determining whether people in particular areas are at risk. Some of the provinces/territories are no longer conducting dead bird surveillance, instead focussing their efforts on other surveillance activities.
For more information on dead bird surveillance in your region, visit the Canadian Cooperative Wildlife Health Centre Web site.
Of all large land mammals, horses are particularly susceptible to West Nile virus. The Canadian Food Inspection Agency, along with Provincial Veterinary Laboratories, veterinarians and other members of the animal health community, will take the lead in monitoring for West Nile virus in horses. For the most recent information about West Nile virus and horses, visit the Canadian Food Inspection Agency Web site.
Mosquito surveillance this year will depend on the level of anticipated or current West Nile virus activity in a particular area. In areas where West Nile virus has never been found, surveillance will likely focus on establishing which mosquito species are present and how many there are in the area.
In areas where West Nile virus has been found, mosquitoes may also be tested for West Nile virus. This information would help identify the role different species play in spreading the virus to birds, animals and people. It would also be used to determine if, where and how to best intervene to reduce the risk of infection.
As in previous years, health care providers will watch for symptoms of West Nile virus infection in their patients. They will request laboratory tests where appropriate. They will also report all probable and confirmed cases of West Nile virus infection to local/provincial health authorities.
Human surveillance information is used in a number of important ways. Knowing that West Nile virus is in an area puts doctors and the general public on alert. It also provides more clues about who may be at risk for serious health effects from West Nile virus. In addition, human surveillance provides information to help ensure the safety of the blood supply in Canada. See the fact sheet West Nile Virus: Transmission through Blood for more information.
The Public Health Agency of Canada and key stakeholders are providing general information and advice on reducing risks through brochures, posters, fact sheets, media briefings, news releases, Web sites and toll-free numbers.
People looking for information about West Nile activity in specific locations, including surveillance activities and proposed prevention and response plans, should contact their provincial or local health authority. If West Nile virus is detected in an area, health authorities will alert the local media and will provide the public with details on specific prevention and response measures.
Provincial and local health authorities are providing information to people whose jobs may put them at risk for West Nile virus infection. In addition, Health Canada has issued an Occupational Health Advisory.
Prevention and response plans will vary across the country, depending on the level of risk. When West Nile virus is found in an area, provincial and municipal health authorities will make sure people get the information they need to reduce their risk. In some cases, local and provincial authorities may consider using pesticides to control mosquito populations.
For more information, see the fact sheet West Nile Virus: Using Pesticides to Control Mosquitoes.