Nov. 15, 2016

Avian Influenza in the North American Poultry Industry

Animal Welfare

In late 2014, a very highly pathogenic form of avian influenza (H5N2) was found in some domestic poultry on the West Coast of Canada and the USA.  Highly pathogenic refers to the virus’s ability to produce severe disease including death of the bird.  With the arrival of spring, the disease moved east into the central parts of the USA.

H5N2 is spread by migratory birds

This disease is moving through North America by wild birds as they migrate north through the migratory flyways.  The only Flyway not affected is the Atlantic.  As of the end of May 2015, more than 35 million laying hens as well as several million turkeys have become infected with this disease and had to be humanely euthanized in the USA.  This is over 10% of the USA egg supply.  Comparatively, there has been little infection in Canada. This is the largest outbreak since 1983/84 when 17 million hens were infected in Pennsylvania.  This strain of avian influenza (AI) is of great concern because it is extremely contagious.  Domestic chickens and turkeys have no immunity to the disease and many die quickly once infected.  Since the mortality of chickens and turkeys infected with this virus is very high (up to 50% within 48 hours), this virus can be categorized as a highly pathogenic Avian Influenza virus. To learn more about the origin of the H5N1/H5N2 virus click here .

How does AI affect domestic poultry flocks?

Movement of poultry, wild birds or contaminated materials (like wild bird feces on boots or clothing) associated with poultry production can facilitate the movement of this very contagious virus.  Wild aquatic birds (waterfowls, ducks and geese) worldwide are considered the natural 'reservoirs' for the avian flu viruses. 'Reservoirs' are those that carry the virus without showing any clinical or noticeable signs. Domestic chickens and turkeys coming in contact with these reservoirs increase the risk of poultry contracting the virus. Therefore, poultry farms require very strict biosecurity practices to limit the exposure of their birds to the outside and thus to wild birds (particularly ducks and geese) and rodents, which carry the virus.  It is said that secure farm driveways and barn entrances are a farmer’s best line of defence against diseases. Presently, there are no poultry vaccines that can be used to help prevent this disease, so the only tools in our biosecurity tool box are practices that keep the virus from entering our farms. To learn more about Burnbrae Farm’s biosecurity practices click here .

Dr. Ravi Kulkarni, from the Poultry Health Research Network at the University of Guelph comments: “The avian flu viruses do not usually infect humans. Scientifically, it is observed that human airways lack certain specific receptors that are critically required by the avian influenza viruses to establish infections in people. However, there have been human cases of avian influenza virus in earlier and most of these infections have resulted from contact with infected poultry or fomites. Therefore, strict on-barn biosecurity measures put in place can prevent the spread of the virus beyond the infected flocks.”

Is it safe to consume eggs from AI infected hens?

The CFIA and other government officials are working hard to enforce restrictions on movement of poultry within infected zones and strict biosecurity measures on and around farms help contain the spread. It is very important to note that products from infected flocks do not reach our food supply. Flocks that are diagnosed with AI are quarantined and humanely euthanized on farm.  Furthermore, influenza viruses are susceptible to heat. Therefore proper cooking of meat and egg products would eliminate the risk of possible viral transmission.

How does AI affect our Canadian egg supply?

This disease episode has had far reaching impacts on the poultry industry in the United States especially.  Shortages of eggs and egg products and likely turkey products will be a consequence. The price of eggs is already rising in the United States.  The good news is Canadian poultry operations have not been so dramatically affected.  So far, following strict biosecurity procedures has been the best strategy to reduce the risk of infection and spread of disease.  Currently, this is our best defence because there are no vaccines available yet to protect poultry against this virus.

Researchers at universities across the continent (e.g. University of Guelph and members of the Poultry Health Research Network) are actively researching the virus and its properties to find a control method such as vaccination.  Also, here in Canada, we have dedicated farmers practicing good biosecurity and taking good care of their poultry; thus working hard every day to ensure a safe and abundant food supply.