HAMILTON & DISTRICT BUDGERIGAR SOCIETY INC.

AVIAN FLU


Source: CDC - Centers For Disease Control And Prevention

Bird Flu Quick Facts

  • 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.
  • 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. This site contains updates & reports.
  • Animal husbandry practices in the United States and Canada 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 and Canada. 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.


    A Tragic Side Effect of The Bird Flu Pandemic
    by Susan Clubb DVM
    Source: The Avicultural Journal Volume 28, Issue #6 2005.

    People are becoming fearful of birds. Remember when the singing of birds was soothing to the soul. With the current worldwide paranoia about Avian Flu panic is replacing joy with fear. People are developing an unreasonable and unfounded fear of birds-all birds. A few facts need to be emphasized in order to try to help people understand what is a threat and what is not. The H5Nl-pathogenic avian flu virus has not been found in the United States. The poultry Industry and the USDA are very vigilant to protect US poultry populations and keep our poultry free of Pathogenic avian Influenza.

    Pathogenic Avian Influenza is a disease of domestic poultry - not all birds. Effective control must focus on the poultry industry in affected countries. Stringent global monitoring programs including immediate culling and correct disposal of infected poultry flocks are necessary. Every effort must be made to limit the spread of the virus to wild waterfowl.

    Avian Flu exists in many strains and is endemic to wild waterfowl such as mallards, but nearly all other varieties of birds have a low incidence of Avian Flu. The presence of Avian Flu in wild waterfowl does not mean that the birds are diseased or that they can spread a virulent form of the virus to poultry or people. The birds that commonly harbour these viruses have developed resistance over many millennia, they rarely suffer illness from Avian Flu viruses. Avian migrations are typically North to South, not from Asia or Europe to the Americas. Insignificant migrations mostly of shorebirds occur from Russia, across the Bering Strait into Alaska but these birds are highly unlikely to come into contact with poultry housed outdoors.

    The pathogenic Avian flu virus will not enter the US in legally imported birds. Since 1972 all birds imported into the United States and Canada undergo mandatory quarantine by The Departments of Agriculture and they are tested for highly pathogenic Avian Influenza virus during quarantine. During that 30-year period, with the entry of many millions of exotic birds, Pathogenic Avian Influenza virus has been found ONLY ONCE in Pekin Robins from China and it was not H5N1. Pathogenic Avian Influenza is an extremely rare disease in pet and exotic birds. Bird's owners should have NO FEAR of contracting pathogenic avian influenza from pet birds. People who are potentially interested in purchasing birds bred in the United States or Canada for pets should have no fear of contracting Avian Influenza.

    In Asia, 120 reported cases and 61 fatalities have occurred in 3 years. In this region it is common for millions of people to live in dose contact with poultry, with the birds often entering their homes. If a bird becomes ill the family will often slaughter it, clean it and I cook it, potentially exposing themselves to the virus. Direct heavy exposure to an infected bird's body fluids is necessary for transmission to people. A favourite Asian dish is raw duck liver. Millions of domestic birds in Asia have become infected and have been destroyed to control the spread of the virus with only 61 human fatalities in 3 years. The case fatality rate may be skewed by the fact that poor people in rural areas who are I most likely to be infected are not likely to seek medical care unless their illness is grave.

    Avian Flu viruses rarely, if ever, jump straight to becoming Human Flu viruses. Typically, Avian Influenza must undergo a series of mutations or a large genetic change to acquire the ability of human-to-human transmission. The potential for genetic mutation associated with exchange of genetic information between strains is higher when an animal or human is simultaneously infected with two different strains of influenza. Simultaneous infections of human and bird flu in a pig may be required for the viruses to interchange their genetic information and become both highly infectious to humans and highly pathogenic. This potential exists in Asia where people often keep poultry and pigs around their home. This is the potential that Public Health officials fear. However, these large changes in genetic makeup are just as likely to result genetic changes that make the virus non-pathogenic.

    Periodic outbreaks of pathogenic Avian Influenza occur in poultry around the world, including the United States. Since 1997, for example, more than 16 outbreaks of pathogenic Avian 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 pathogenic human influenza viruses, yet none of them made the jump from avian virus to human virus. According to CDC records only 2 mild cases of flu have been reported from people in contact with infected poultry during this time. Influenza viruses do not persist in the environment outside of a host for long periods of time.

    Under ideal conditions at room temperatures, human flu viruses can remain infective for about one week. Exposure to sunlight drastically reduces the length of time flu viruses can remain infective. As long as the H5N1 virus does not gain the ability to be transmitted from human to human, its impact on human health will continue to be minimal. However, it is important to eliminate the virus from affected poultry populations to protect both people and birds. Culling of uninfected avian populations will not assist in the control of Avian Influenza.

    Because of governmental and media paranoia, wild populations of migrating birds may be culled or disrupted un-necessarily in misguided efforts to control avian influenza. These actions could result in the needless deaths of millions of birds and could endanger species. If pathogenic-human to human transmitted avian influenza does enter the US or Canada, it will be by entry of infected humans, not by infected birds. As in the 2003 outbreak of SARS in Canada, an infected international traveler introduced the disease and subsequent cases occurred in exposed health care workers. This outbreak was brought under control by diligent Public Health response and monitoring of travelers for signs of illness (fever).

    Media reports about Bird Flu have created an unreasonable state of fear that can be detrimental to birds and the relationship of people to birds. A rational response is necessary to avoid further deterioration of public perception.
    People should not be afraid of:

    Pet birds
    Feeding wild birds in their backyards
    Visiting zoos
    Visiting parks where they may contact wild birds
    Migrating birds
    Going to pet stores
    Taking their birds to a veterinarian
    Attending bird shows
    Eating poultry products
    Legal importation of exotic birds
    

    The Avian Flu Captive Bird Policy
    Prepared by the National Avian Welfare Alliance November 2005
    National Avian Welfare Alliance

    What is avian influenza?
    Avian influenza (AI) is a contagious viral infection caused by the influenza virus Type "A", which can affect several species of food producing birds (chickens, turkeys, quails, guinea fowl, etc.), as well as pet birds and wild birds.

    AI viruses can be classified into two categories: low pathogenic (LPAI) and high pathogenic (HPAI) forms based on the severity of the illness caused in birds, with AI causing the greatest number of deaths in birds. Most AI viruses are low pathogenic and typically cause little or no clinical signs in infected birds. However, some low pathogenic viruses are capable of mutating into high pathogenic viruses. There are many influenza subtypes, two of which include H5 and H7. Historically, only the H5 and H7 subtypes are known to have become high pathogenic in avian species.

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

  • quietness and extreme depression;
  • sudden drop in production of eggs, many of which are soft-shelled or shell-less;
  • wattles and combs become swollen and congested;
  • swelling of the skin under the eyes;
  • coughing, sneezing and nervous signs; diarrhea;
  • oedema (swelling) and congestion of the combs; hemorrhages on the hock;
  • a few deaths may occur over several days, but an outbreak may follow, killing hundreds or thousands of birds each day. Diagnosis of avian influenza may be made on the basis of clinical signs and events leading to the disease. However, since the signs and course of avian influenza are similar to other diseases, laboratory diagnosis is essential.

    How is the disease transmitted to birds?
    Wild birds, especially waterfowl, are natural reservoirs for the influenza viruses - yet show no clinical signs - and can be responsible for the primary introduction of infection into domestic poultry.

    The disease can also spread to birds through contact with infected poultry and poultry products, and through manure and litter containing high concentrations of the virus, for example through contaminated clothing and footwear, vehicles and equipment, and feed and water.

    Is avian influenza transmissible to humans?
    Avian influenza viruses, such as the H5 virus present in Asia, may, on rare occasions, cause disease in humans. Human transmission has occurred to people having prolonged contact with heavily contaminated environments. Human to human transmission of avian influenza is extremely limited.

    Due to the potential for human infection, it is recommended that those people working with or in contact with poultry suspected of being infected with avian influenza wear protective clothing, including face masks, goggles, gloves and boots.

    Does avian influenza occur in Canada?
    In the sixties, when turkeys were often raised in ranges (outdoors), cases of low pathogenic avian influenza were often reported in the autumn. One of the viruses isolated in 1966 was later found to meet the modern criteria of a high pathogenic influenza virus. Since the sixties, the majority of turkeys have been raised in closed poultry houses to control other diseases and are managed under more stringent bio-security conditions. As a result, the cases of low pathogenic avian influenza have been rare. Canada has had three cases of low pathogenic H5 and H7 since 1975, the latest of which was reported in 2000.

    In February 2004, the Canadian Food Inspection Agency (CFIA) identified the presence of a low pathogenic H7 avian influenza in the Fraser Valley area of southern British Columbia. Subsequent tests revealed the presence of highly pathogenic H7 avian influenza in British Columbia in March 2004. The CFIA depopulated all infected premises (42 commercial and 11 backyard premises) on which highly pathogenic avian influenza was found and pre-emptively destroyed all birds in the surrounding three kilometre areas.

    What is the CFIA’s role in controlling and preventing this disease from entering Canada?
    AI is a reportable disease under the Health of Animals Act. This means that all suspected cases must be reported to the CFIA. All reported suspect cases are immediately investigated by inspectors from the agency. The CFIA imposes strict regulations on the import of poultry and poultry products from foreign countries. These regulations are enforced through port-of-entry inspections.

    Canada’s emergency response strategy in the event of an outbreak of a foreign animal disease is to eradicate the disease and re-establish the country’s disease-free status as quickly as possible. In an effort to eradicate AI, the CFIA would employ its "stamping out" policy, which would include:

    The humane destruction of all infected and exposed animals; 
    Surveillance and tracing of potentially infected or exposed animals; 
    Strict quarantine and animal movement controls; 
    Thorough decontamination of infected premises; 
    Zoning to define infected and disease-free areas. 
    

    What can travellers do to avoid bringing the disease into the country?

  • While out of the country: Avoid visiting areas where you may come into contact with live birds, such as poultry farms, live bird markets or any other area where birds congregate. This is most important in countries experiencing an outbreak of high pathogenic avian influenza. (An updated list of countries affected by AI 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 clothing, footwear and in hair. Take appropriate personal hygiene measures including thorough hand washing and showering, wash clothing, and clean and disinfect footwear.

  • On returning home: Ensure all birds and poultry products you wish to bring into Canada are eligible for entry and declare all animal products upon arrival. If you visit an area where you have been in contact with live birds while abroad and/or you plan to go onto a live bird premises shortly after your return to Canada, make sure that any clothing and footwear you wear are free from soil and manure before entering Canada. Also, take appropriate personal hygiene measures including thorough hand washing and showering, wash clothing, and clean and disinfect footwear after arrival.

    What can livestock producers do to prevent infection on their farm?
    Wild bird populations are the natural reservoir for the influenza viruses. Therefore, it is essential for commercial poultry producers to maintain strict bio-security practices.

    On a farm:

  • Keep away from areas frequented by wild fowl;
  • Keep strict control over access to your poultry houses by people and equipment;
  • Keep equipment cleaned and disinfected before taking it into poultry houses;
  • Do not keep bird feeders and duck ponds on your farm. This will discourage wild birds.
  • Maintain high sanitation standards.

    If clinical signs are noticed or suspected in poultry, contact your veterinarian or the CFIA office in your area. Producers are obligated to report any suspicion of AI because it is a reportable disease under the Health of Animals Act.

    There are reports of H5N1 infections in domestic cats. Is it possible for household pets to contract avian flu? Avian influenza typically affects species of food producing birds (chickens, turkeys, quails, guinea fowl, etc.), as well as pet birds and wild birds. Studies have shown that a small number of mammalian species, including pigs, seals, whales, mink, and ferrets, are susceptible to natural infection with avian influenza viruses. However, of these species, the pig is the only one that has significance for human health. While there have been recent reports of avian influenza infection in domestic cats in Thailand, this is a rare event. The World Health Organization continues to investigate the case in Thailand but reports that is unlikely that H5N1 infection in cats presents a risk to human health.

    Background
    All Influenza A viruses can infect birds. Influenza A viruses that can infect birds, but cannot easily infect humans are called Avian Flu viruses. Influenza A viruses that have the ability to easily infect humans and can be transmitted from human to human are called Human Influenza A viruses. The Avian Flu disease was first described in Italy in 1878, and the Avian Flu virus was first identified in 1955.

    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 the birds that commonly harbor these viruses 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

    Higher mortality is seen when bird species are infected with virus subtypes that are not normally found in that species of bird resulting in low resistance levels to that virus subtype. Transmission is primarily by fecal material and also via respiratory/nasal secretions.

    Most Avian Flu strains are not highly lethal, but Influenza viruses undergo frequent mutations that change the pathogenicity of the virus strains. This is called antigenic drift. 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.

    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 effortless viral transmission and dispersal through the flock. The poor immunity these domestic birds have towards any disease contributes to the high mortality rates on poultry farms.

    Imported exotic birds (non-domesticated birds that are kept in captivity that are not native to this country) 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 and Canada. Exotic birds are not a significant public health risk for Avian Influenza. Other than from poultry, there have been no documented cases of humans contracting 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). Pigeons have also been shown to be resistant to Avian Influenza infection.

    Influenza viruses do not persist in the environment outside of a host for long periods of time. Under ideal conditions at room temperatures, human flu viruses can remain infective for about one week. Exposure to sunlight drastically reduces the length of time flu viruses can remain infective. For cross infection of Avian Flu viruses to human hosts, it is likely that direct heavy exposure to an infected bird's body fluids is necessary.

    Influenza viruses are classified by the types of proteins on their surface. There are 16 types of hemaglutinin (H) proteins and 9 types of neuraminidase (N) proteins. These 2 protein types can be combined in many different ways to create a great number of unique subtypes. Within each subtype there are also numerous strains with varying disease properties.

    Influenza A viruses are H5, H7, or H9. HPAI (High pathogenic) has only occurred with H5 and H7 subtypes. H9 has only produced LPAI (Low pathogenic) cases. Each of these 3 H-types could potentially be paired with any of the nine N proteins to yield 27 different Influenza A subtypes, all of which can infect birds.

    Currently there are only 3 recognized subtypes of Influenza A viruses that circulate in the human population. It is clear that Avian Flu viruses rarely, if ever, jump straight to becoming Human Flu viruses. Typically, Avian Influenza must undergo a series of mutations or a large genetic change to acquire the ability of human to human transmission. Larger genetic changes to a virus can happen when an animal or human is infected with two different strains of influenza (H5N1 mixing with H1N1 for example). Due to the nature of viruses, genetic information between these two strains can be interchanged and potentially create a new strain unique from either parent; this is referred to as antigenic "shift" (in contrast to antigenic "drift" explained above). These new strains are what concerns health officials, in that they can potentially lead to viral transmission in pandemic proportions. However, these large changes in genetic makeup are just as likely to result in significant differences in pathogenicity.

    Human flu strains are not able to be passed easily from bird to bird. The genetic changes necessary for a virus to become efficient at infecting humans generally preclude it from being efficient at infecting birds. These genetic changes also change the pathogenicity of the virus, most often resulting in a less pathogenic strain.

    Avian Flu is a concern since the various strains can cause mortality and/or low production in poultry and under certain specific conditions can infect and cause illness in humans. The most likely route of infection occurs when free-range domestic ducks or poultry commingle with wild ducks, the natural reservoir, and then carry the virus back to domestic poultry housing where it can spread to the rest of the poultry flock. Pathogenic forms of Avian Flu can cause significant mortality in domestic poultry since these birds do not posses the level of resistance that wild waterfowl have to these viruses. Commercial poultry are also genetically very similar so disease can spread rapidly through an infected flock. Humans can become exposed to the virus by handling infected poultry or contaminated surfaces.

    Periodic outbreaks in poultry have occurred around the world, including the United States and Canada, since the disease was identified over one-hundred-twenty-five years ago. Since 1997, for example, more than 16 outbreaks of H5 and H7 influenza have occurred in poultry within the United States and Canada. 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. Members of clean up crews for Avian Flu infected barns in Canada were all tested for signs of the influenza virus, amazingly none tested positive for the virus, even after prolonged periods of exposure.

    In 1997, transmission of Avian Influenza A H5N1 resulted in the deaths of 6 people in Hong Kong. Since then, a total of approximately 60 people have died from H5N1. Millions of domestic birds in Asia have become infected and have been destroyed to control the spread of the virus. Although over 100 reported people have become infected with H5N1 in Asia, this is a very small number in comparison to the probability of numerous human exposures resulting from poor husbandry practices there.

    To date, all cases of H5N1 infection in humans can be traced to direct contact with infected poultry. Husbandry practices in Asia are a major factor in its presence there. Many families keep small poultry flocks for their own consumption and for income. Poultry are allowed to roam freely, often in yards where children play, and poultry often enter human dwellings. At the first signs of illness in poultry, the birds are frequently slaughtered for consumption. Exposure during slaughter, de-feathering and butchering of infected birds is considered most likely to result in human infection and this practice has been tied to a number of the human cases in Asia.

    Other than certain species of ducks, all species of birds that can be infected with the H5N1 subtype of Avian Flu will exhibit high rates of mortality and morbidity within 48 hours of infection with this virus. Exotic birds have had zero incidence of H5N1 and are not likely to become a source of infection.

    Response to H5N1
    The threat to human health and to poultry production in the United States and Canada necessitates an organized plan of action to be in place prior to the possible arrival of H5N1 here. Although H5N1 has not been found in captive birds, it may become necessary to examine or monitor captive birds for the virus. It is important to enhance cooperation between captive bird owners and public health officials.

    Media reports about H5N1 have created an unreasonably heightened state of public fear that any bird could cause Avian Flu. Any government response to H5N1 will likely be influenced by public perception and demand. In the face of irrational fears, a rational response is necessary to avoid further deterioration of public perception.

    Culling of infected flocks is a vital means to control the spread of the virus among susceptible birds. It should be obvious and made clear that culling birds that are not infected or that are not likely to become infected will not enhance our ability to control the spread of Avian Flu.

    As long as the H5N1 virus does not gain the ability to transmit from human to human, its impact on human health will continue to be minimal. However, it is important to eliminate the virus from the avian population to protect both birds and people. In the unlikely event that this virus gains the ability for human to human transmission, it must be recognized that culling birds will no longer have an impact on controlling the spread of the virus. If the virus arrives in the United States and Canada in a state that allows it to spread directly from human to human, any government response that includes culling of birds will only drain vital resources away from vital human health services.

    Because imports of most exotic birds were halted in 1992 under the Wild Bird Conservation Act, much of the breeding stock available to aviculturists is irreplaceable. Many of these birds are endangered in their native habitats and the captive birds may represent a valuable genetic resource for the survival of that species. To prevent unnecessary culling of valuable and irreplaceable birds, the following policy is formulated to establish guidelines to protect captive bird facilities and pet bird owners, yet allow for appropriate measures should H5N1 arrive in the United States and Canada.

    Part 1 (Human H5N1) If H5N1 arrives in the United States and Canada in a form that can be transmitted from human to human, culling of captive birds to control H5N1 will have no impact on the spread of the virus. Under this scenario, H5N1 is a human health issue that is not affected by birds. Therefore, culling of captive birds to control Human H5N1 shall not occur.

    Part 2 (Avian H5N1) Bird Marts and Bird Exhibitions, where live birds are brought together from separate facilities, will be cancelled or postponed within a county with any positive cases of H5N1. Such events will remain cancelled or postponed until such time as the county remains H5N1 free for 30 days.

    An Avian H5N1 eradication program includes surveillance for infected birds and euthanasia of all birds testing positive for Avian H5N1. Typically all birds on a premise will be destroyed if any bird on that premise tests positive for H5N1. Exceptions to this policy are outlined below.

    Captive birds housed in cages within enclosed structures or housed in outdoor caging under specified conditions should be exempted from euthanasia according to the following policy.

    An Avian H5N1 eradication program includes surveillance for infected birds and euthanasia of all birds testing positive for Avian H5N1. Typically all birds on a premise will be destroyed if any bird on that premise tests positive for H5N1. Exceptions to this policy are outlined below.

    Captive birds housed in cages within enclosed structures or housed in outdoor caging under specified conditions should be exempted from euthanasia according to the following policy.

    Birds qualified for exemption from euthanasia include: