You are here
What is Avian Influenza?
Avian Influenza Virus (AIV), often called 'bird flu' is a contagious viral infection causes by avian influenza type A viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and pet birds. Avian flu viruses have caused sporadic human infections.
The Asian H5N1 virus, known as 'Highly Pathogenic Avian Influenza A' (HPAI) virus, causes severe disease in poultry. The 'Asian Bird Flu' is unusual because it is extremely deadly for poultry. It has spread to many different countries in Asia, Africa and Europe, has caused disease outbreaks in wild birds, and it has caused a number of human infections and deaths.
The mild form of AIV is known as Low Pathogenicity Avian Influenza or LPAI, and typically causes a respiratory infection in chickens and other poultry species. Outbreaks of H5, H7 and H9 viral infections have occurred in Canadian poultry barns. Avian Influenza is now a reportable disease under the Health of Animals Act in Canada in order to track the incidence of infection.
Avian influenza in humans
Since 2003 human illness has been on the rise. The factors are not completely understood but include increasing human travel to affected countries, bird migration and genetic mutation of influenza viruses. Almost all of the infected people have had close, direct contact with poultry infected with AIV. Birds infected with AIV can shed large amounts of virus in feces and other bodily secretions that can result in human infections.
The main global human health concern is that outbreaks, particularly in domestic poultry flocks, present an opportunity for ongoing genetic mutation or viral reassortment. If a person becomes infected with both human influenza and avian influenza viruses at the same time, this situation provides an opportunity for an exchange of genes possibly leading to a new influenza virus with pandemic potential.
Public health officials have plans for control of any large scale human outbreak with vaccines and antiviral medications, but prevention would be the preferred solution. The latest update on human infections by the World Health Organization can be found on their site.
Can I get avian influenza from eating or handling poultry products?
There is no danger of acquiring AIV from properly cooked poultry or poultry products. Avian influenza virus is easily destroyed by the heat of normal cooking. Standard good food handling practices for raw poultry are sufficient.
There is a risk if handling dead birds that were affected with avian influenza. Protective clothing including gloves and masks should be worn if handling dead infected birds.
Movement of infected poultry or poultry products
The importation of birds or bird products from affected areas has been banned or placed under strict control by the Canadian government. Illegal or inadvertent movement (smuggled birds, food on airplanes, etc) remains a threat, and that is why customs agents are active at all major entry points into Canada.
Movement by Wild Birds
One of the unique features of the Avian Influenza virus is that wild birds can be infected, and increasing evidence suggests that they can spread the virus within and between countries. Control of wild bird movements, particularly migrating birds, is not possible. There exists some overlap of migrating birds from the infected countries and North American birds, but the risk of movement of the virus by this route is not known. Surveillance programs to test wild birds for AIV are ongoing and increasing to provide an early warning system whether wild birds pose a risk to Canadian poultry.
Clinical Signs of Avian Influenza in birds
Clinical signs of avian influenza vary widely and include:
- loss of appetite
- sudden drop in egg production
- purplish-blue colouring of the wattles and combs, possibly with blisters
- coughing, sneezing, swollen eyes
- nervous signs such as incoordination or the inability to stand or walk
Current or Future Response Plans for Avian Influenza in Canada
Monitoring and surveillance for avian influenza is performed constantly at many different levels:
- Canadian Food Inspection Agency (CFIA) National Avian On-Farm Biosecurity Standard
- Canadian Wildlife Health Cooperative
- Alberta Agriculture and Forestry testing and prevention program
The policy of the poultry industry and provincial and federal governments is to eradicate avian influenza outbreaks as quickly as possible after detection. This is performed by the rapid detection of infected flocks and then the quarantine and ultimately the humane euthanasia of any flocks where virulent avian influenza virus has been identified. All birds are humanely euthanized according to CVMA standards and disposed of through environmentally sound methods.