Avian Influenza

What is avian influenza?

Avian influenza (AI), often called “bird flu,” is caused by the Type “A” influenza virus. This virus can affect:

• several species of food-producing birds (chickens, turkeys, quails, guinea fowl, etc.); as well as,
• pet and wild birds.

AI viruses can be broadly classified into two types, based on the severity of the illness caused in chickens:

• low pathogenic (LPAI)
• highly pathogenic (HPAI)

Most AI viruses are low pathogenic. These typically cause little or no signs of illness in infected birds. Highly pathogenic viruses can cause severe illness and death in birds.

AI viruses are further divided by sub-types based on two proteins found in the viruses: hemagglutinin, or “H” protein, and neuraminidase, or “N” protein. There are 16 H types and 9 N types that can exist in any combination. Only the H5 and H7 subtypes are known to have become highly pathogenic in avian species.

Studies have shown that a small number of mammals are susceptible to natural infection with AI viruses. These include:

• ferrets;
• mink;
• pigs;
• seals;
• whales; and
• humans

Is avian influenza a risk to human health?

AI viruses, such as the highly pathogenic H5N1 virus present in Asia, can, on rare occasions, cause disease in humans.

Transmission to humans has occurred when people have had close contact with infected birds or heavily contaminated environments. Due to the potential for human infection, it is recommended that those people working with poultry suspected of being infected with AI, or in contact with such poultry, wear protective clothing. This includes, face masks, goggles, gloves and boots.

What are the clinical signs of avian influenza?

Some or all of the following clinical signs are evident in infected birds:

• a drop in production of eggs, many of which are soft-shelled or shell-less;
• diarrhea;
• haemorrhages on the hock;
• high and sudden mortality rate;
• quietness and extreme depression;
• swelling of the skin under the eyes; and
• wattles and combs become swollen and congested.

The incubation period of AI ranges from 2 to 14 days.

The signs of AI are very similar to those seen with virulent Newcastle disease and other diseases of poultry.

Where is avian influenza found?

AI viruses can be found around the world.

For detailed information on the distribution of the H5N1 subtype and highly pathogenic AI, please refer to the following links:

• http://www.fao.org/avianflu/en/index.html
• http://www.healthmap.org/promed

How is avian influenza transmitted and spread?

Wild birds, especially waterfowl, are natural reservoirs of influenza viruses. They are not normally affected by the disease, but can still transmit it to domestic birds.

The disease can spread to birds through contact with infected poultry and poultry products. It can also spread through contaminated manure, litter, clothing and/or  footwear, vehicles, equipment, feed and water.

It is essential for commercial poultry producers to use strict biosecurity practices. This will prevent introduction of the virus in their flock. Farmers should do the following:

• keep poultry away from areas frequented by wild fowl;
• keep strict control over access to poultry houses;
• keep equipment cleaned and disinfected before taking it into poultry houses;
• do not keep bird feeders or create duck ponds close to poultry barns as they attract wild birds; and
• maintain high sanitation standards.

How is avian influenza diagnosed?

AI should be suspected on the basis of clinical signs.

Laboratory testing is needed to confirm the presence of the AI virus. Contact your local veterinarian or provincial veterinary laboratory for assistance.

How is avian influenza treated?

There is no treatment for the disease.

Vaccination may play a role in reducing the spread of the disease but does not eliminate the virus from birds.

What is done to protect domestic poultry in Canada from AI?

The Canadian Food Inspection Agency (CFIA) imposes strict regulations on the import of animals and animal products from countries where AI is known to occur. These regulations are enforced through port-of-entry inspections done either by the Canada Border Services Agency or the CFIA.

The CFIA has enhanced its AI surveillance for commercial poultry flocks in Canada with the launch of the Canadian Notifiable Avian Influenza Surveillance System (CanNAISS). This surveillance program was developed in collaboration with provincial and territorial governments, poultry farmers and other industry representatives.

The Government of Canada, provincial and territorial governments, and animal health experts conduct an annual surveillance program of AI in wild birds. Through this program, live and dead birds are sampled and tested for AI viruses.

AI is a “reportable disease” under the Health of Animals Act. This means that all suspected cases must be reported to the CFIA for immediate investigation by inspectors.

How would the CFIA respond to an outbreak of AI?

Canada’s emergency response strategy to an outbreak of AI would be to:

• eradicate the disease; and
• re-establish Canada’s disease-free status as quickly as possible.

In an effort to eradicate AI, the CFIA would use its “stamping out” policy, which includes:

• the humane destruction of all infected and exposed animals;
• surveillance and tracing of potentially infected or exposed animals;
• strict quarantine and animal movement controls to prevent spread;
• strict decontamination of infected premises; and
• zoning to define infected and disease-free areas.

Owners whose animals are ordered destroyed may be eligible for compensation.

What can travellers do to help protect Canadian livestock from an outbreak of AI?

While out of the country, travellers should avoid visiting areas where they may come into contact with live birds, including:

• poultry farms;
• live bird markets; or
• any other area where birds congregate.

This is most important in countries experiencing an outbreak of HPAI. An updated list of countries affected by this disease can be found at the World Organisation for Animal Health web site at: http://www.oie.int/eng/en_index.htm

If you are in contact with live birds infected with the AI virus, the virus may persist on your clothing, footwear and in your hair. Take appropriate personal hygiene measures including:

• washing hands and showering;
• washing clothing; and
• cleaning and disinfecting footwear.

When you return home, do the following:

• Avoid contact with farmed animals (including poultry), zoo animals or wildlife for five days after you return if you were exposed to similar animals while you were abroad.
• Do not visit Canadian farms for 14 days if you visited a farm or had contact with wild birds while abroad.
• Be sure the footwear you wore to the farm or when you had contact with wild birds is disinfected and your clothing is washed thoroughly and dried at a high temperature.
• Complete the appropriate areas of your Customs Declaration Card regarding farm visits.
• Ensure all birds and poultry products you bring into Canada are eligible for entry. Declare all animal products upon arrival.

For more information

Contact your CFIA Area office:

Atlantic Area: 506-851-7651

Quebec Area: 514-283-8888

Ontario Area: 519-837-9400

Western Area: 403-292-4301

You can find your local CFIA District office on the CFIA Web site or by consulting the blue pages of your local phone directory.