West Nile Virus Response Plan 2009
Alberta's Response Plan
An interdepartmental plan
Under the leadership of Alberta Health and Wellness, a provincial plan to respond to West Nile virus (WNv) was developed with support from the following Alberta government departments:
- Agriculture and Rural Development;
- Environment;
- Health and Wellness; and
- Sustainable Resource Development.
Purpose of the plan
To minimize the risk of WNv infection to humans.
Basis of the plan
Alberta’s WNv plan has been modified for 2009 based on:
- WNv activity from 2003-2008 in Alberta;
- What has been learned about WNv in the USA and other parts of Canada since it was first identified in North America in 1999;
- Public Health Agency of Canada Management of Patients with West Nile Virus: Guidelines for Health Care Providers (2005).
Key components
| Communications |
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| Humans |
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| Mosquitoes |
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Birds |
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Horses |
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Communications
Specific objectives
To inform Albertans of the potential consequences of a WNv infection, about the steps they can take to prevent being bitten by mosquitoes and the most effective means of reducing the risk of infection.
Albertans notified
The Government of Alberta will inform Albertans of the evidence of WNv in the province when there is confirmation of the virus in humans.
Weekly updates of evidence of WNv in humans will be posted on the Alberta Health and Wellness website.
Messages to the public
Information about WNv and the steps people can take to protect themselves will be made available to Albertans in a number of ways:
- A public awareness campaign will remind all Albertans throughout the summer about the simple steps they can take to protect themselves, and direct them to reliable information through the Alberta Health and Wellness WNv website.
- Albertans can also call Health Link Alberta for more information.
Humans
All cases reported
Under the authority of the Public Health Act, human cases of WNv infection are reported to public health officials in Alberta.
The milder form of the infection, West Nile Non-Neurological Syndrome (formerly known as West Nile Fever) and the more serious form of the disease known as West Nile Neurological Syndrome are both reported to regional Medical Officers of Health, Alberta Health and Wellness, Public Health Agency of Canada and if necessary, to the Canadian Blood Services.
Blood supply protected
The Canadian Blood Services will be notified when it is suspected that an individual has WNv and there is a history of either donating or receiving blood or blood products. Measures will then be taken by Canadian Blood Services to prevent the possibility of WNv transmission through blood.
Physicians alerted
Once WNv is confirmed in Alberta in a person who does not have a history of travel to an area with WNv, physicians will be notified of this information through the local Medical Officer of Health. Physicians will also be asked to consider WNv when someone presents with specific symptoms and ensure laboratory testing is ordered as appropriate.
Laboratory testing
All WNv testing in Alberta will be carried out by the Provincial Laboratory for Public Health.
Prevention stressed
A public awareness campaign will remind Albertans of WNv, how the virus is spread and the measures they can take to protect themselves and their families.
Ongoing coordination
Alberta Health and Wellness will participate in the national meetings that address WNv in Canada. Alberta’s Interdepartmental Committee will continue to evaluate Alberta’s WNv plan within the context of what is happening in this province, nationally and internationally.
Messages to the public
Alberta Health and Wellness will monitor and report on the number of cases of WNv human infections in Alberta on an ongoing basis.
The numbers of cases of WNv will be posted on a weekly basis on the Alberta Health and Wellness WNv website.
Mosquitoes
Role in surveillance
The mosquito surveillance program will not continue in Alberta in 2009.
The mosquito surveillance plan was initiated in 2003 with the objectives of performing West Nile virus testing on mosquito pools in different areas of the province, determining the presence of West Nile virus in mosquitoes, and to assist in determining the point where transmission from mosquitoes to humans is of greatest risk.
Since its arrival in Alberta, the virus has exhibited a consistent pattern of occurrence. Information collected over the past six years indicates the period of greatest risk of WNv transmission to humans is between mid-July and mid-August. This is related to the presence and activity of the mosquito Culex tarsalis. The success of this mosquito acting as a transmitter of the virus is dependent on consistent warm weather from early June through mid-August.
Messages to the public
Messaging to the public on personal protective measures will occur throughout mid-July and mid-August to coincide with the period of greatest risk of WNv infection.
Birds
Role in surveillance
Alberta is no longer conducting WNv surveillance in wild birds. The surveillance program was originally designed to provide an early warning system to alert the public and officials to the presence of the WNv. Since its arrival in Alberta in 2003, the virus has exhibited a consistent pattern of occurrence, so there is no need to submit individual dead birds for testing.
WNv expected in 2009
Similar to the past five years, limited bird mortality is likely to occur largely in the Grassland Natural Region of southeastern Alberta where conditions are most favourable for development of the Culex tarsalis mosquito, the only mosquito that effectively transmits the virus in Alberta.
The number of dead birds infected with WNv has declined significantly since 2003. However, the populations of birds such as crows and magpies have not declined. It is likely that these birds, as well as other bird species exposed to the virus, adapted to the presence of WNv in the ecosystem and developed protective immunity.
Messages to the public
Information on how to handle dead birds and answers to frequently asked questions are available on the Alberta Health and Wellness website and Sustainable Resource Development’s, Fish and Wildlife website.
Horses
Role in surveillance
Cases of WNv in horses will be monitored, used to identify the presence of the virus and provide information to alert the public.
Low risk / serious illness
Although the risk of an individual horse becoming infected with WNv is very low, a small proportion of horses infected with WNv will develop varying degrees of clinical disease. Up to 35 per cent of these sick horses will die or have to be euthanized because of complications resulting from the illness.
Reporting
Under the federal Health of Animals Act, WNv in any species is an immediately Notifiable Disease and the laboratory making the diagnosis must report it to the Canadian Food Inspection Agency.
Under Alberta’s Livestock Diseases Act, anyone knowing or suspecting WNv infection in a horse must report the occurrence to the chief provincial veterinarian as soon as possible.
Information for owners
Alberta Agriculture and Rural Development and the Alberta Veterinary Medical Association provide information to veterinarians informing them of the surveillance and reporting protocols.
Information is available for horse owners about the precautions they can take to minimize the risk of WNv to their animals. This includes steps that can be taken to reduce exposure to mosquitoes that may carry WNv (e.g. reducing mosquito breeding sites, ensuring barns have screening in good repair, applying repellents containing DEET, regularly changing water in water tanks etc).
Horse owners are advised to consult their veterinarian regarding the use of vaccination to prevent WNv in their horses.
Messages to the public
Alberta Agriculture and Rural Development provides a fact sheet, articles in Agri-News, public information spots on “Call of the Land” and materials for various stakeholder publications.
Information regarding any positive cases will be posted on the Alberta Health and Wellness WNv website and the Chief Provincial Veterinarian website.
