INDEPTH: AVIAN FLU
Canada's poultry industry faces avian flu
CBC News Online | October 20, 2005
 A Canadian Food Inspection Agency official decontaminates a truck before it leaves a free-range geese and duck farm in Abbotsford, B.C., Wednesday, May 12, 2004. The birds on the farm were slaughtered. (CP Photo/Richard Lam)
The Canadian Food Inspection Agency says it began when one farm near Abbotsford, B.C., was infected by two different forms of the bird flu in the winter of 2004.
The first was an H7 virus “of low pathogenicity.” The farm was quarantined and the birds slaughtered. But a few weeks later, in March, the “repopulated” chickens on the farm again became sick, this time with what the CFIA called “highly pathogenic avian influenza” H7N3, which was also detected on a nearby farm.
By the middle of May 2004, the CFIA says, birds on 42 commercial and 11 backyard premises had been declared infected. The CFIA investigation could find no definite cause for the outbreak but the agency says on its website that the scientific literature recognizes wild waterfowl “as natural reservoirs of avian influenza virus.”
Other problems included “farm-to-farm movement of people, equipment or birds likely to spread the virus over long distances” and “once the virus was introduced into a densely populated region, airborne transmission through dust or feathers may have infected nearby flocks.”
No flu was detected in the lower Fraser Valley after June 3, 2004, and the farms were permitted to restock in July 2004.
CFIA Bio-security Precautions
The Canadian Food Inspection Agency recommends that poultry farms take these precautions:
Clothing
Clean coveralls or other clothing should be provided for all visitors. Require all visitors to wear these over their clothes while on your premises. Clean these clothes each day using normal laundering practices.
Hygiene
Require all visitors to wash their hands before entering your barns.
Footwear
Require all visitors to wear footwear you supply while on your premises. If this is not feasible, thoroughly clean all debris from footwear with soap and water followed by disinfectant. As an added precaution, footbaths containing disinfectant should be placed at the entrance of poultry houses to clean entering and exiting footwear.
Vehicles
Place a standard pump sprayer containing disinfectant at the entrance to your property. Require all visitors to thoroughly spray their vehicles – particularly the tires, wheel wells and undercarriage – before driving onto your premises.
Equipment
Ensure all equipment brought onto your premises is clean. To further protect against avian influenza spread, spray equipment with disinfectant.
Disinfectant:
The Canadian Food Inspection Agency recommends using a solution of equal parts bleach and water.
The flu in B.C.'s Fraser Valley, combined with the possible threat from the H5N1 virus that has killed a number of people in Southeast Asia, has led to increased “bio-security” at poultry farms across Canada.
In Nova Scotia, chicken farmer Bruce Fuller has put up a stop sign at his farm and locked the doors. No visitors are allowed inside without taking precautions, such as dipping shoes in disinfectants.
"This is basically entering a controlled access zone ... that we require you to get authorization before you enter our farms to help control people from spreading pathogens from farm to farm," Fuller says.
About a thousand people in Nova Scotia work in slaughterhouses, earning $30 million in wages.
Abbotsford, B.C., poultry farmer Ray Nickel has already been hit by it once, and that's why nobody goes in to see his birds without suiting up and going through a bio-security routine. Nickel lost 60,000 birds, and he was one of dozens of producers affected by the H7N3 virus.
Now poultry farms are closely monitored
Andrew Larder, the medical health officer for the Fraser Valley, says, “The outbreak that we had in Abbotsford, if you'll excuse the phrase, it was a wonderful dry run for having to deal with something like an H5 virus.”
In B.C., that virus affected two people working on the cleanup, but their illnesses were not serious.
“We were making sure they were being tested. We were making sure that they were getting appropriate treatment, and we were making sure that they were staying away from all the people,” Larder says.
Some officials say it's possible that migratory birds with the H5N1 virus might not stop in Canada. Says Jim Clark of the Canadian Food Inspection Agency, “The majority of the birds involved in flying or migrating in North and South America are a very distinct group of birds and do not have a great deal of opportunity to commingle or interact with the birds that are in Asia. I'm not saying that it's not possible, but it's highly unlikely at this point in time that separate population is going to be infected.”
Vancouver Airport is one of the most likely access routes for the virus to enter Canada because 2½ million people fly there from Asia every year.
Dr. Cornelius Kylie of the CFIA says travellers are being checked, and so are any products that might be infected. “We are doing all we can to stop it now. By having policies in place, we do not allow live poultry, poultry products, and we're talking about feathers and material like that, to come from Asia to Canada.”
Health officials say regular influenza is, overall, a much bigger threat than the avian kind.
Avian influenza
In birds, the CFIA says, influenza viruses can be classified into two categories: low pathogenic (LPAI) and high pathogenic (HPAI) forms, based on the severity of the illness caused in domestic birds. The first causes mild illness, including ruffled feathers or reduced egg production. The second form, known as "high pathogenic avian influenza," is of greater concern. This form is extremely contagious in birds and rapidly fatal.
Most avian influenza viruses are low pathogenic and typically result in little or no clinical signs in infected birds.
The H5 and H7 viruses are the most dangerous forms of the virus that infects domestic birds. Both the H5 and H7 mutate into high pathogenic forms and affect birds at a higher rate. All other subtypes (H1 through H4, H6, and H8 through H15) may cause disease and death in domestic birds, but the illness spreads at a much slower rate than H5 and H7. “Depopulation of birds infected with the H5 or H7 virus contributes significantly to reducing the amount of virus in the environment, therefore preventing the spread of the virus.”
How many variations have been associated with illness in humans?
Some variations of the H5, H7 and H9 subtypes have also been associated with illness and disease in humans. Specifically H5N1 (most recently in Asia), H7N7 (previously in the Netherlands) and H9N2 (previously in Southern China and Hong Kong) have been known to cause illness in people.
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What you can do:
- Get a flu shot. There is no vaccine for avian flu but it may boost your overall immunity, health officials say.
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Definition:
The flu is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to death. Bird flu is an infection caused by avian influenza viruses. (Source: CDC)
Symptoms of flu/avian flu:
Fever, fatigue, cough, sore throat, eye infections, muscle aches.
Transmission:
Infected birds shed flu virus in their saliva, nasal secretions and feces. Avian flu may have passed to humans by contact with infected poultry or contaminated surfaces. In human-to-human cases, flu viruses spread in respiratory droplets caused by coughing and sneezing. (CDC)
Prevention:
Get a seasonal flu shot, wash your hands, cover your mouth when sneezing, stay home if you are sick, consult your doctor.
Avian flu vaccine:
It is under development but cannot be finalized until the pandemic version of the virus appears.
Cure: A healthy body's immune system can often combat the flu. Antiviral drugs may help. Antibacterials are ineffective because the flu is a virus.
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DEFINITION
Vaccines and antivirals are different. A vaccine is designed to procure immunity from a disease.
An antiviral drug is commonly used to treat an existing illness. Antivirals can also be used in a preventive way, but they are not vaccines, and do not provide immunity.
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