Eastern Canada Avian Association

Promoting the Human Avian Bond

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 Avian Flu

History of the NAWA

When the USDA was forced to regulate birds under the Animal Welfare Act, they informed various bird-keeping organizations of the need for input in drafting the regulations since they had no prior experience with regulating birds. To facilitate a coordinated effort, AFA president, Dr. Benny Gallaway, invited representatives from various avicultural organizations to a meeting in Houston in May, 2003 to establish a group to respond to the USDA's request. As a result, the National Avian Welfare Alliance (NAWA) was formed with representatives from a broad cross-section of bird specialty groups including, bird trainers and avian veterinarians, as well as organizations for keepers of racing pigeons, waterfowl and pheasants, finches, softbills, and parrots. It was decided that NAWA would function as a roundtable between these organizations.
 

 

Avian Flu and Captive Birds

Prepared by the National Avian Welfare Alliance  (NAWA) November 2005

An outbreak of Avian Flu in the United States has great potential to cause the loss of valuable breeding stock and rare bloodlines of captive birds. This is not because Avian Flu will devastate captive bird facilities. It is because there is likely to be an overreaction to the presence of avian flu as a result of media hype and unwarranted public fear. The biggest threat to our captive birds during the Avian Flu scare will not come from the virus itself, but from government officials who are likely to react to its presence by calling for the euthanasia of every bird within a specified radius of any Avian Flu case in order to appear like they are doing something about a perceived human health threat.

Avian Flu can become a Human Flu with the proper genetic changes. This change is what epidemiologists are concerned about with the H5N1 flu virus. But what we don't often hear in media reports is that once the flu becomes a human flu, it is humans that will be spreading the virus not birds. It is very difficult to catch Avian Flu from birds because the virus is adapted to avian biology. Once the virus becomes adapted to human biology and gains the ability to be transmitted from human to human, birds will no longer be a factor in its spread. As long as the virus is an AVIAN flu, it will only infect humans on very rare occasions under extreme contact with infected bird body fluids.

Avian Flu exists in many strains and is endemic to wild waterfowl with local rates of up to 60% positive for some waterfowl, such as mallards, but nearly all other varieties of birds have a low rate of Avian Flu incidence. The presence of Avian Flu in wild bird populations does not mean that the birds are diseased. Because wild waterfowl commonly harbor these viruses they have developed resistance over many millennia. They rarely suffer illness from Avian Flu viruses. Instead, they act as the natural reservoir of Avian Flu viruses. Migrating waterfowl can spread the virus over vast distances. Although wild waterfowl regularly harbor avian flu, they do not come in close enough contact with humans or with most captive birds in this country to pose a serious threat to human or captive bird health.

Avian Flu does pose a serious threat to the poultry industry and it is one of the reasons for an effective biosecurity program on poultry ranches. Avian Flu in poultry can result in anything from decreased egg production to significant mortality. The disease was first described over 125 years ago and periodic outbreaks of avian flu in poultry have frequently occurred around the world, including the United States. Since 1997, for example, more than 16 outbreaks of H5 and H7 influenza have occurred in poultry within the United States. When Avian Flu is identified in poultry, the infected flock is quickly culled to prevent the virus from spreading to additional poultry facilities.

Most Avian Flu strains are not highly lethal, but Influenza viruses undergo frequent mutations that change the pathogenicity of the virus strains. There are two categories of pathogenicty; Highly Pathogenic Avian Influenza (HPAI) and Low Pathogenic Avian Influenza (LPAI). HPAI outbreaks can cause mortality in wild waterfowl and can also cause significant losses to domestic poultry. If poultry is infected with LPAI they will be culled to prevent the opportunity for the virus to mutate to HPAI.

Commercial poultry flocks are maintained in high density environments of genetically similar birds. When this is coupled with the close contact these birds have with fecal and other secretions, it allows for rapid viral transmission and dispersal through the flock. The lack of genetic variation in domestic poultry contributes to their susceptibility to disease and increases their mortality rate. If a virus can easily infect one chicken on a facility, it is likely to be able to infect the rest since their immune systems will be genetically very similar.

Exotic and native captive birds are kept under very different circumstances than domestic poultry. The density, or number of birds per square foot, is much lower. Non-poultry avian immune systems are also much more capable of fending off a viral infection. This does not mean that birds other than poultry are immune to the virus, but that they are less likely to suffer the losses that poultry will if exposed to avian flu. Proper biosecurity can easily prevent avian flu from infecting our birds.

Birds that are housed indoors are extremely unlikely to become exposed to the virus since they are not in contact with wild waterfowl. Outdoor captive bird facilities are not likely to become exposed provided biosecurity practices are in place and due to the fact that these birds do not leave their enclosures to commingle with wild waterfowl. Sunlight and fresh air also inhibit the ability of the virus to survive long enough to infect a new host.

All imported birds must go through USDA quarantine. During quarantine, the birds are tested for Avian Influenza, among other diseases. In the many years that testing has been performed on exotic birds in USDA quarantine, there has been only one isolation of Pathogenic Avian Influenza in an exotic bird (a Pekin Robin with H7N1), ref: Dennis Senne et al. in Avian Diseases 40:425-37(1996). The isolated strain was not pathogenic to poultry or humans. Imported and domestic exotic birds have never been a source of HPAI infections in the United States. Exotic birds are not a significant public health risk for Avian Influenza.

There is a good chance that H5N1 Avian Flu could make it here to the United States via migrating waterfowl. The threat this poses to our birds must be kept in perspective. Avian Flu, of one variety or another, arrives every year in the United States via migrating waterfowl. We do not see Avian Flu infections of captive birds as a result. H5N1 is no more likely to infect our captive birds than any other strain of Avian Flu.

Proper biosecurity should always be in place to protect our birds from the various health threats that are omnipresent. The possibility of the arrival of H5N1 flu should serve as a reminder to practice proper biosecurity, but it should not be something to panic about.

 

Bird Flu Prevention and Protection Through Bio-security Measures

Prepared by the National Avian Welfare Alliance November 2005

Bird Flu Carriers: Wild migratory waterfowl, ducks and geese, are the primary carriers of a variety of strains of bird flu viruses, including the H5N1 subtype which can be dangerous to humans. New strains of H5 and/or H7 bird flu viruses have always arrived every year. H5N1 is not in North America at this time.

H5N1, is rarely transmissible from infected poultry to humans. Only people who have contact with H5N1 infected poultry, their feces, or water contaminated by their droppings may become infected.

H5N1, is NOT transmissible from human to human at this time, but it is feared that H5N1 might mutate into a form that is transmissible from human to human. If H5N1 becomes transmissible from human to human, birds will no longer be a source of infection.

Standard biosecurity measures can protect your birds from infection by various diseases including the H5N1 virus. The following simple measures can be taken to protect your birds from exposure to H5N1 and other infectious diseases.
  1. If your birds are housed inside a building or your home, and you have no poultry at your home and you do not have any free roaming poultry with access to your facilities, your birds will have no opportunity to contract the disease. If you handle other birds away from home or visit an area with free-roaming waterfowl, it is recommended to shower, change clothing and disinfect shoes before handling your birds.
  2. If you do not visit or frequent feed stores or other sites frequented by individuals or farmers with free ranging chickens, or other poultry, you should have no opportunity to pick up viral particles on your shoes to track into your home or facility.
  3. If you have a small flock of poultry that is contained in a building or a securely fenced area with wire enclosing the top portion so that wild birds cannot enter, your poultry will be protected from exposure to bird flu from wild birds. However, if you DO have any poultry located at your facility, it is recommended that you routinely wear special footwear outside when feeding the poultry, and remove that footwear prior to entering your house or exotic bird facility.
  4. If you have a neighbor with free ranging poultry, especially if they have a pond which is visited by wild waterfowl during migration, it is recommended that you put in place a security fence so that the free ranging poultry cannot enter your property.
  5. If you have a pond on your property which provides access to wild waterfowl, and you have a flock of ducks or geese or swans, it is recommended that you corral the domestic or exotic waterfowl so that they cannot access the pond and contact the wild migratory waterfowl or their feces.
  6. If you have family or friends who own poultry or waterfowl, it is recommended that you have them remove their footwear prior to entering your home or bird facility.
  7. If you are feeding wild songbirds at bird feeders, it is unlikely that you will come into contact with a bird carrying bird flu. However, it is wise to wash your hands well after handling and refilling the feeder.
  8. If you find a dead wild bird near your birds, wear disposable gloves to pick it up. Take it to a vet or state lab for necropsy and testing.

Bird Flu is for the Birds!

Prepared by the National Avian Welfare Alliance November 2005

Human influenza is a highly contagious disease. Most of us have had the flu multiple times in our lives. In the United States, influenza epidemics occur nearly every winter and are responsible for a substantial amount of illness and deaths. Approximately 114,000 hospitalizations and 20,000-50,000 deaths occur in the U.S. on an annual basis as a result of the flu (http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5107a1.htm).

If influenza is so easily transmissible, why aren't more people catching the bird flu directly from birds? The reason is that birds and humans are different. The qualities that allow the virus to easily infect birds don't work well on humans.

Although it's true that avian flu viruses can become human flu viruses, the typical way a flu virus makes the jump from birds to humans is by infecting a pig that just happens to have a concurrent infection of human flu virus - 2 different viruses in the same animal at the same time. Pigs are more easily infected by both types of viruses and they serve as a sort of mixing pot. Different types of influenza viruses can exchange genetic material when they are exposed to each other in the same host. This is called antigenic shift.

Antigenic shift allows for large amounts of new genetic information to be acquired by the avian flu from the human flu virus when they are exposed to each other. If the avian flu virus acquires the genetic factors that allow it to easily pass from human to human, then it is possible for the avian virus to make the jump to become a human influenza.

Because birds and humans are very different, there are generally multiple factors that must be acquired in order for the virus to make the transition from avian to human flu. The actual factors that allow an avian flu virus to easily infect birds may prevent it from easily infecting humans. Additionally, the factors that allow the avian flu viruses to easily infect humans are likely to alter more than just the viruses' ability to infect humans. It is also likely to alter the virus's impact on the human body. In the case of H5N1, this means it is just as likely to become nothing more than the standard flu, as opposed to the killer flu, if it makes the jump to human influenza.

One of the reasons Asia is a breeding ground for influenza is the animal husbandry practices that are used there. Poultry can be brought to markets where they are exposed to poultry from other farms, and live birds are brought back home if unsold. Ducks, poultry and pigs are allowed to commingle on the farms where there is very little biosecurity. Poultry are allowed to free-range and domestic ducks are allowed to graze in open wetlands where wild waterfowl visit. This increases the likelihood that avian flu viruses which are common in wild waterfowl can mix with human flu viruses which are common in pigs. This allows for a shuffling of genetic traits between the different strains of viruses which creates new strains as a result. If the new strains have the ability to infect humans easily, then the farmer, or other people around the livestock, will catch it and the virus spreads through the human population from there.

Animal husbandry practices in the United States are not conducive to the mingling of avian flu strains with human flu strains. If H5N1 arrives in the United States via migrating waterfowl, it is not going to have the opportunity to acquire the traits necessary to become a human flu virus here.

Influenza viruses also change their genetic properties by simple random mutations. This process is called antigenic drift, in contrast to antigenic shift. Antigenic drift is responsible for small changes in the genetic properties of the virus. All influenza viruses mutate regularly and thereby undergo antigenic drift constantly. This is the reason we can't carry immunity to the flu from one year to the next. This year's flu will be different enough from last year's flu so that our immune system will not recognize it or have the proper antibodies to fight it off. Although antigenic drift can result in changes in pathogenicity in avian flu virus strains, it rarely, if ever, results in the significant genetic changes required to allow an avian flu virus to make the jump to becoming a human flu virus.

It is theoretically possible for an avian flu virus to accumulate enough mutations through antigenic drift to gain the ability to infect humans easily, without antigenic shift or an intermediate host involved, but this generally requires a specific series of mutations to happen. Because more than a single mutation is involved, the odds of this happening are very small. Any single mutation in the direction that may lead to an avian flu becoming a human flu is likely to cause that avian flu strain to be less capable of infecting birds and thereby surviving long enough to gain the additional mutations necessary to complete the jump. Even if an avian virus strain was capable of accumulating the correct series of mutations to become a human influenza, those genetic changes are also just as likely to reduce the impact the virus has on the human body.

In order for an influenza virus to be easily spread throughout the human population and result in a pandemic, it must be mild enough for people to be able to go out and spread the virus once they are infected. If the virus kills its victims quickly, as is the case with the current strain of H5N1, there will be dramatically less opportunities for the virus to be transmitted from the victim to a new host. The infection becomes what epidemiologists call "self-limiting". Because a victim quickly becomes too sick to get out in public, the virus does not have the chance to spread to a large number of people. This further illustrates why the genetic changes required for H5N1 to become a human flu virus are unlikely to cause it to become the deadly killer that the media is playing it up to be.

The current pattern displayed by H5N1 illustrates how difficult it is for avian flu viruses to infect humans. Despite the fact that there have been millions of H5N1 infected poultry in Asia in the past few years, only a little over one hundred human H5N1 cases have been reported. This is a very small number in comparison to the probability of numerous human exposures resulting from the husbandry practices there. Keep in mind that in Asia poultry are frequently sold live to the consumer who must butcher and prepare the bird themselves.

Since 1997, more than 16 outbreaks of H5 and H7 influenza have occurred in poultry within the United States. The virus strains in each of these outbreaks were just as likely as H5N1 to become human influenza viruses, yet none of them made the jump from avian virus to human virus. Of all the people exposed to the avian flu during these 16 outbreaks, according to the CDC (http://www.cdc.gov/flu/avian/), only 2 mild cases of human infection in the U.S. resulted.

Despite the media attention to Bird Flu, there is no increased risk of catching the flu from exposure to birds, other than poultry in Asia. There have been no documented cases of humans catching Avian Flu from pet birds such as parrots, finches and other commonly kept species (http://www.cdc.gov/flu/avian/).

All birds imported into the United States have been routinely tested for pathogenic Avian Influenza since 1974. Of the many millions of birds imported during this 30 year period, pathogenic Avian Influenza was only found in 1 shipment of birds from China. Exotic birds being legally imported into the United States represent virtually NO risk of introducing pathogenic Avian Influenza virus as they are ALL tested during quarantine.

Exotic birds being bred for sale in the United States represent virtually NO risk for Pathogenic Avian Influenza unless they are co-mingled with infected poultry and at this time pathogenic Avian Influenza (H5 or H7 strains) are not known to exist in the United States. USDA is continually monitoring for the presence of Influenza and New Castles Disease in domestic "backyard" and commercial flocks.

It is important to understand that Bird Flu or Avian Influenza is a disease of birds (mostly poultry), and it is not readily transmitted to humans. For many millennia, Avian Influenza has existed in North America. It is found in migrating waterfowl on an annual basis. H5N1 is no more likely to infect humans than the Avian Flu strains that arrive every year yet do not infect humans.

If H5N1 gains the ability for human to human transmission, it will be humans spreading the disease to humans, not bird to human transmission. A human version of the virus will most likely enter the US by infected persons arriving from outside the US on airplanes. The virus will not arrive by imported birds which are quarantined, and not by migrating birds. And example of this type of disease transmission was the spread of SARS into Canada. This disease introduction was quickly recognized and brought under control due to vigilance of medical and regulatory personnel.

The fear of contracting bird flu from pet, companion, or zoo birds in the United States is totally unfounded. The chance of contracting bird flu from native birds is also extremely remote. Attention needs to be appropriately placed on surveillance of incoming international travelers if and when the virus shifts sufficiently to maintain virulent human to human transmission.


 

 

• All influenza A viruses originated in birds.

• Influenza epidemics occur nearly every winter and are responsible for approximately 114,000 hospitalizations and 20,000-50,000 deaths in the U.S. on an annual basis. ( http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5107a1.htm).

• Although the annual influenza viruses may have originated in birds, birds are not involved in the spread of the influenza viruses that infect humans.

• For many millennia, new strains of Avian Flu have been arriving in North America via migrating waterfowl on an annual basis. H5N1 is no more likely to infect humans than the Avian Flu strains that arrive every year yet do not infect humans.

• The typical way a flu virus makes the jump from birds to humans is through an intermediate host such as a pig. Once the virus becomes a human virus, it is humans, not birds, which spread the disease.

• Pet birds are NOT a risk factor for catching the flu. There have been no documented cases of humans catching Avian Flu from pet birds such as parrots, finches and other commonly kept species ( http://www.cdc.gov/flu/avian/gen-info/avian-flu-humans.htm).

• Animal husbandry practices in the United States are not conducive to the mingling of avian flu strains with human flu strains.

• Since 1997, more than 16 outbreaks of H5 and H7 influenza have occurred in poultry within the United States. The virus strains in each of these outbreaks were just as likely as H5N1 to become human influenza viruses, yet none of them made the jump from avian virus to human virus.

• Although there have been millions of H5N1 infected poultry in Asia in the past few years, only a little over one hundred human H5N1 cases have been reported. This is an extremely small number in comparison to the large numbers of human exposures there.