Canada's Wild Bird Influenza Survey now in its third year

Canada's national inter-agency survey for influenza in wild birds began in 2005. The impetus for the survey stemmed from a major outbreak of influenza in the Canadian poultry industry which coincided with the spread of a particular strain of avian influenza (Asian H5N1) from Asia to Europe and Africa.

The purpose of the survey is to identify strains of North American influenza viruses found in wild birds (known as the "natural reservoir") and to monitor for influenza strains that might harm people or domestic animals, including the highly pathogenic (ability to harm) Asian H5N1 strain. The Canadian Cooperative Wildlife Health Centre coordinates the survey, which involves Canada's veterinary colleges and diagnostic laboratories, as well as federal, provincial and territorial agencies responsible for the health of domestic animals, the public and wildlife. The survey will continue until 2011.

Canada's survey has made good progress in three years. Canada has established an Avian Influenza Virus Laboratory Network and national communications protocols for responses to important disease occurrences. Canadians can be assured that Asian H5N1 has not been identified in North America to date.

Results from the survey have also confirmed the importance of understanding avian influenza viruses in wild duck populations. In addition, scientists have developed a complex data management system -- a powerful tool for assessing changes in the status of avian influenza in coming years.

Avian influenza viruses often cause no noticeable illness in wild birds but can cause illness in poultry infected by the viruses. Most people become infected through close contact with sick or dead poultry, not wild birds.

Surveillance in 2006

In 2006, approximately 10,000 live birds -- mainly ducks -- were safely trapped in the field, swabbed to collect samples for testing, and then released unharmed. About 40% of the healthy wild birds tested carried one or more avian influenza viruses, all native to North America. In addition, approximately 2,400 dead birds were submitted by researchers working in the field and by members of the public. Of these, 99 tested positive for North American influenza strains.

Surveillance in 2007

This year's field season was underway in early June. As in 2005 and 2006, researchers will collect samples from live ducks at sites where birds are routinely captured and given leg bands to monitor bird populations and health. An international project with the United States brings a new focus on ducks and geese in the Canadian Prairies.

Researchers will also sample inter-American migrants -- blue-winged teal, Franklin's gulls, double-crested cormorants and American white pelicans -- on their breeding grounds in the Canadian Prairies to detect any strains introduced from Mexico, Central America and South America.

In Canada, surveillance in the North Atlantic region is the primary opportunity for early detection of foreign strains of avian influenza - such as Asian H5N1 - introduced by birds migrating from Europe, Asia and Africa. In response, researchers are in the High Arctic surveying very remote areas and collecting samples as part of an international project in Iceland.

Reporting sick and dead birds

In 2007, there is renewed emphasis on reporting sick and dead birds, and submitting carcasses to diagnostic laboratories. Dead birds are examined by veterinary specialists to determine cause of death and to test for established or emerging diseases. Wild birds found dead or sick in unusual numbers, or at unusual times or locations, are of special interest, although even routine deaths are important.

If you see sick or dead wild birds, call the Canadian Cooperative Wildlife Health Centre at 1-866-544-4744. A bilingual message will provide contacts and information for your area.

Fast Facts:

• The Canadian Wild Bird Influenza survey includes samples from primarily wild ducks, as well as geese, gulls, terns, cormorants, shorebirds, and any species of wild bird found dead.
• Wild ducks are the main species surveyed because they are thought to be the "natural reservoir" of the full gene pool of avian influenza viruses.
• Only mild avian influenza strains that produce little or no disease in wild birds are maintained in the wildlife reservoirs.
• Avian influenza strains only acquire virulence (the ability to cause disease) when circulating in poultry, or when mixed with human-adapted influenza strains.
• Urban-nesting Canada Geese that were surveyed were free of influenza viruses.

Related Links:

• Canada's Inter-Agency Wild Bird Influenza Survey
• Canadian Wildlife Service "Avian Influenza and Migratory Birds"
• Reporting and Submitting Dead Birds
• Recommendations for Safe Practices When Handling Wild Birds (Public Health Agency of Canada)

Print Version

E-mail this Story