Avian Flu: Frequently Asked Questions
Ducks Unlimited is providing the information below to address the most frequently asked questions we have received about avian flu.
What is avian influenza (avian flu/bird flu)?
Avian influenza, or avian flu, is a common, naturally occurring virus in birds that has many forms or subtypes. Scientists believe all birds are susceptible to infection by some form of avian flu. Some birds, like waterfowl, can be infected with the virus but develop no signs of illness. In addition, the potency (virulence) varies greatly among the various subtypes of the avian flu virus.
Virulence is classified as either low pathogenic avian influenza (LPAI) or high pathogenic avian influenza (HPAI). Most avian flu subtypes are LPAI and cause little or no signs of illness in domestic or wild birds and pose no threat to human health. These subtypes are found every year in waterfowl. HPAI viruses are associated with the H5 and H7 subtypes. Some strains of the H5 and H7 subtypes may be extremely infectious and fatal to domestic poultry, sometimes posing a threat to human health, too.
If I hunt waterfowl in Saskatchewan, can I bring harvested birds back across the U.S. border?
Yes. The Canadian Food Inspection Service Agency confirmed a North American strain of an H7N3 highly pathogenic avian influenza virus on September 27. The positive results came from samples collected at a commercial broiler breeder farm in Saskatchewan.
This is not the highly pathogenic Asian H5N1 virus that has spread through commercial poultry in Asia, Europe and Africa.
The U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) placed a temporary ban on the importation of poultry and commercial shipments of live birds, hatching eggs, and unprocessed (not fully cooked) avian products from Saskatchewan. This action follows agreed upon protocols between the U.S. and Canada.
APHIS will allow the entry of hunter harvested birds and wild bird commodities from the Saskatchewan into the U.S. This decision is consistent with World Organization for Animal Health guidelines. As customary, hunters bringing their game back into the U.S. must show a license to hunt in Canada.
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What is the high pathogenic Asian H5N1 strain of the a vian flu virus?
The high pathogenic Asian H5N1 strain is a particularly virulent strain of avian flu that was first detected in Southeast Asia in 1997.
Is the high pathogenic Asian H5N1 strain of avian flu a risk to humans?
To date, the high pathogenic Asian H5N1 strain of the avian flu virus has resulted in the deaths of millions of domestic birds. Despite the millions of people who have had close contact with domestic fowl during the past nine years in Asia, more than 320 people have been infected worldwide. This is an extremely low rate of infection. However, human health officials are concerned with the 61 percent mortality rate of people that have been infected. This is much higher than what normally occurs with more typical flu infections.
There is no evidence that the high pathogenic Asian H5N1 strain of avian flu is present in North America or that wild birds easily transmit this H5N1 strain of avian flu to humans. In almost every case in which the route of transmission has been detected, direct contact between people and domestic fowl has been the probable cause. Only one incident of transmission from wild birds to humans has been recorded. In the spring of 2006 in Azerbaijan, several villagers contacted the Asian strain of H5N1 after plucking feathers from swans that had died from the disease. This is a very similar form of direct contact with infected fowl that has been the prevalent route of infection wherever it has occurred. Hunters and all others have always been advised never to handle randomly found birds they find dead in the field.
A limited number of possible human-to-human transmissions have been reported. However, there is no evidence for sustained human-to-human spread of the highly pathogenic Asian strain of H5N1 avian flu. World health authorities thoroughly investigate every suspected case of human-to-human transmission and continue to conclude that the virus has not evolved into a form that will allow it to become a pandemic disease that could affect large numbers of people.
The risk is greater for humans who are handling infected domestic birds and possibly infected wild birds in affected countries. While it is not presently an issue for the avian flu virus in North America, DU encourages people to follow the standard precautions offered by the National Wildlife Health Center for protecting themselves against all diseases when handling hunter killed animals. If the disease were to ever become an issue here, these habits would add an extra layer of protection for people, even though it remains highly unlikely for the disease to be transmitted directly from birds to people.
How do people get the high pathogenic Asian H5N1 strain of the avian flu virus?
To date, transmission from domestic poultry, through contact with infected birds, contaminated surfaces or feces, is the most prevalent way this Asian H5N1 strain of avian flu virus has caused human infection. One single incident of wild bird to human transmission has been recorded as described in the above.
Do migratory waterfowl disperse the high pathogenic Asian H5N1 strain of avian flu virus?
The available evidence supports the contention that migrating birds are responsible for part of the spread of the highly pathogenic Asian H5N1 strain of avian flu. However, the illegal movement and trade of poultry has also been implicated in the dispersal of the virus and seen by most authorities as the most serious threat to spread the disease.
Tens of thousands of wild birds have been sampled in North America, and officials haven't found any infected with the highly pathogenic Asian H5N1 strain of avian flu virus. While the high pathogenic Asian H5N1 strain kills some waterfowl species, most survive and may become carriers of the disease without showing any outward symptoms. Intensive monitoring of wild birds is continuing worldwide in order to follow the spread of the high pathogenic Asian H5N1 strain of avian flu in Europe, Asia, Australia and Africa. Researchers continue to confirm the occurrence of HPAI H5N1 in wild birds in several countries of Asia and Europe.
Where has the high pathogenic Asian H5N1 strain of avian flu virus been detected?
To date (10/01/07), the high pathogenic Asian H5N1 strain of avian flu has not been detected in North America. An extensive government surveillance system has been established to detect its arrival should it occur.
The World Organization for Animal Health and The World Health Organization maintain Web pages devoted to reporting all laboratory confirmed cases of the H5 strains of avian flu in humans and animals based on location.
What is being done to monitor the high pathogenic Asian H5N1 strain of avian flu in North America ?
Because some waterfowl and shorebird species migrate between Alaska and Asia and across the Atlantic from Europe, authorities in the wildlife conservation, hunting and medical professions are taking steps to monitor the situation closely and take action if necessary.
The probability of the arrival of high pathogenic Asian H5N1 avian flu in North American waterfowl cannot be predicted. The U.S. Fish and Wildlife Service, U.S. Geological Survey National Wildlife Health Center and others are diligently monitoring migratory birds in all 50 states, and a similar program is underway in Canada. Tens of thousands of waterfowl and shorebird samples have been collected, and the high pathogenic Asian H5N1 virus has not been found. You can check on the latest information about wild bird sampling for early detection of highly pathogenic avian influenza in the U.S. at http://wildlifedisease.nbii.gov/ai/
In the United States, the federal government has established a Web site at www.pandemicflu.gov. Managed by the U.S. Department of Health and Human Services, the Web site provides one-stop access to U.S. government avian and pandemic flu information.
Why has the high pathogenic Asian H5N1 strain of the avian flu virus received so much attention from the medical community and the media?
A much greater concern than the negligible risk of widespread high pathogenic Asian H5N1 transmission from wild birds directly to the human population is the risk that the virus could change and acquire the ability to efficiently jump from human to human. Experts are concerned that under these conditions, the virus could spread rapidly among humans resulting in a global pandemic (in other words, infection occurring over a wide geographic area and affecting a high proportion of the population). This has not occurred during the nine years since high pathogenic Asian H5N1 has emerged but it remains a possibility, and health officials must prepare for the worst-case scenario. This fact is the basis for the widespread concern and publicity that has been reported throughout the world during the last year. World health authorities are intensively monitoring the possible occurrence of a new pandemic strain emerging.
Are North American waterfowl hunters at risk of contracting the high pathogenic Asian H5N1 strain of avian flu while waterfowl hunting?
There is no evidence that the high pathogenic Asian H5N1 strain of avian flu is present in North America, so there presently is no risk to hunters on this continent. Therefore, there is no risk of contracting the virus from birds in North America. In fact, the risk of contracting the virus from birds in areas where the virus is presently found is low and has been, so far, highest in individuals who had close contact with infected domestic poultry or fowl.
What kind of precautions should I take if handling wild birds?
While the high pathogenic Asian H5N1 strain of avian flu is presently not a threat to the U.S. public, DU encourages people to follow the standard precautions offered for protecting themselves against wildlife related diseases when handling harvested animals.
According to the National Wildlife Health Center, “Persons handling wild birds should follow routine hand washing and safe food preparation practices. These include disinfecting surfaces, being careful to avoid cross contamination with other food products, keeping raw meat away from other food utensils, and thoroughly cooking all wild birds prior to eating. Following these steps is good practice to minimize risks associated with the handling and preparation of wild fowl.”
Ducks Unlimited encourages waterfowl hunters to follow these practices while handling dead waterfowl. There are other diseases besides avian flu that can be spread to humans. We believe hunters should think of making these standard habits, as they will add an additional layer of protection against avian flu and any other disease.
Is it OK to eat ducks, geese and other wild birds?
Yes. The standard recommendation for ensuring that any wild game is safely cooked is to cook all types of meat thoroughly to at least 155-165 degrees Fahrenheit to kill disease organisms, parasites and viruses such as avian flu.
What should I do if I find an unusual number of dead ducks or geese while hunting or visiting a wetland?
It's not uncommon to see dead ducks or geese while in the field. Do not assume that any form of bird flu killed the ducks or geese, because these birds can die from many other causes.
However, if you should notice an unusual number of dead waterfowl, you should call the nearest office of your state wildlife agency, and report what you have seen.
Where can I obtain more information about avian flu?
The federal government has established a Web site for avian flu that provides a central source of information on management of the virus. The site confirms the involvement of the federal agencies in the monitoring of and response to emerging information and offers links to relevant avian flu information.
Avian flu antibodies have shown up in some duck hunters and state wildlife agency employees in Iowa. What does that mean? Is it a cause for concern?
It means that at some time in the past these people came in contact with a different form of avian flu than the Asian variety that has caused all the recent concern, and that their immune system reacted by producing antibodies that eliminated the virus. This is one of the ways our bodies normally react to low pathogenic viruses and other antigens.
Of the 107 people sampled who had closely handled wild birds for an average of 20 years, only three showed the antibody reaction. This is an extremely low rate of antibody response considering that 10–50 percent of wild waterfowl typically are infected with some form of avian influenza in the fall preceding migration. It is almost certain that the viruses were simply incapable of infecting those who were exposed in most cases. There may have been only three cases in which the virus was strong enough to elicit an antibody response. This is similar to what health authorities would expect and is not seen as a cause for concern. It provides little guidance as to how the human body might react to the H5N1 virus. However, research continues to see if more sensitive assays will detect additional cases with antibodies.