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Frequently Asked Questions
Avian Influenza

What is avian influenza?
Avian influenza, or bird flu, is a group of viruses that affect wild and domestic birds. These viruses are only found in a small number of birds in the wild, usually waterfowl and shorebirds, and rarely cause disease in these birds. The viruses are transmitted in fecal droppings, saliva, and nasal discharges. In birds, most strains of the virus (identified with letters and numbers—e.g. H7N3) are low pathogenic avian influenza and cause mild symptoms. The virus currently of global concern is a strain of H5N1. This highly pathogenic avian influenza H5N1 virus has resulted in severe illness and death in poultry. To date, this highly pathogenic avian influenza H5N1 avian influenza has not been detected in wild birds, domestic poultry, or humans in North America.
What signs do birds with avian influenza demonstrate?
Low pathogenic avian influenza signs in poultry are typically mild. Decreased food consumption, respiratory signs (coughing and sneezing) and a decrease in egg production might demonstrate the presence of the disease. Domestic birds that are affected with highly pathogenic avian influenza are sicker than those with low pathogenic avian influenza and could exhibit one or more of the following clinical signs: sudden death, lack of energy and appetite, decreased egg production, soft-shelled or misshapen eggs, nasal discharge, coughing, sneezing, lack of coordination, and diarrhea. Signs of avian influenza in wild birds are not well described, because wild birds generally do not get sick from the common strains of this virus.
What should I do if I see a group of dead birds?
Do not pick up sick or found dead wild animals without gloves. Whenever you touch an animal, wash hands immediately after the contact occurs. Call the WI Dead Bird Hotline (1-800-433-1610) to report a bird dead from unknown causes. If an unusual bird mortality is observed (such as a large number of dead birds) you can also contact your local DNR service center or the DNR Wildlife Health program at 608-221-5375.

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How is avian influenza diagnosed in wild birds?
Currently, the most common sampling approach involves collection of fecal samples. Samples are usually taken by swabbing the bird’s lower digestive tract opening. These samples are placed in a special media that supports the avian influenza virus and are taken to approved laboratories. The initial test is a polymerase chain reaction (PCR) test. A PCR test is a rapid method of identifying the virus, typically producing results within 3 hours. If a sample tests positive for H5N1 on a rapid test, a virus isolation confirmatory test is performed. This test involves growing the sample in embryonated chicken eggs, which then provides the material to allow detailed identification of the strain of virus and whether it is highly pathogenic avian influenza or low pathogenic avian influenza. This test can take 3-5 days to produce results.
Which species of wild birds are the primary carriers of avian influenza?
Most avian influenza viruses have been isolated from wild waterfowl, shorebirds, and wading birds. With rare exceptions, the thousands of AI isolates found in wild birds have been low pathogenic avian influenza and have rarely caused signs of illness. The occurrence of avian influenza in wild ducks in North America reaches its height in late summer and early fall. At most times of the year, infection rates are usually less than 1 percent. In studied shorebirds, infection rates are highest during the spring migration, although in comparison with waterfowl, their infection rates are much lower.
Has H5N1 affected migratory birds differently than other avian influenza viruses in the past?
Yes. In May 2005, a wild-bird die-off was associated with highly pathogenic avian influenza H5N1 in Qinghai, China, where Bar-headed Geese died. This was the first time since 1961 in which large numbers of wild birds were documented to have died from avian influenza. However, most of the wild birds confirmed as having highly pathogenic avian influenza H5N1 have been sick, dying, or dead when tested.

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Are migratory birds carrying the virus from one country to another?
The role of migratory birds in the transfer of the H5N1 strain is not clear. The pattern and timing of several outbreaks of H5N1 in Asia, Africa, and Europe have not coincided with periods of major migratory movements or migratory routes. However, there are also reports of wild bird mortality that are associated with outbreaks of highly pathogenic avian influenza H5N1 in poultry. It is not known if wild birds were the source of the virus or if wild birds acquired the virus from poultry. Once infected, wild birds can be a source of infection for domestic poultry that are kept outside and not physically separated from wild birds.
What is WDNR doing to monitor Wisconsin for avian influenza among wild birds?
The WDNR has had a surveillance program to investigate wild bird deaths and screen selected wild birds for evidence of avian influenza for decades. In 2007, Wisconsin is screening approximately 1,500 samples from live and dead birds for evidence of H5N1 throughout the state as part of a nationwide effort. Working in partnership with the USDA-APHIS-Wildlife Services, WDNR is collecting samples from dead birds reported by the public, from captured live birds, and from waterfowl harvested in the fall by hunters. Samples from hunter harvested birds are being collected from areas of high waterfowl concentration, such as Horicon and Grand River Marshes. While dead birds of any species are being sampled, priority is given to water birds.
Do avian influenza viruses spread from birds to humans?
There is only one case documented where H5N1 is thought to have been transmitted directly from wild birds to people. However, there are approximately 200 human cases where poultry to human transmission of the virus is suspected. These human cases are a relatively small number compared with the huge number of poultry affected and the numerous associated opportunities for human exposure, especially in areas of Asia where backyard flocks are common. Please visit the Centers for Disease Control website (Exit DNR) for further information on avian influenza infection in humans.

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What are the potential routes for a pathogenic strain of avian influenza to arrive in North America?
Bird migration is only one possible route of introduction of highly pathogenic avian influenza H5N1 into North America. Illegal smuggling of birds and poultry products and travel by infected people or people traveling with virus-contaminated articles are possible means of introducing the new strain of highly pathogenic avian influenza H5N1 virus into the United States.
Should hunters be concerned about avian influenza?
There are no known cases where H5N1 has been transmitted from wild birds to hunters. However, even apparently healthy wild birds can be infected with other infectious organisms that can move between wildlife and people. Therefore, it is always good practice to wear some basic protection, such as gloves, and keep tools and work surfaces clean when preparing game animals. Viruses like H5N1 are shed from birds in saliva, nasal discharges, and fecal droppings, so avoiding contact with these materials while plucking and cleaning birds is good practice. Avian influenza viruses generally do not persist very long after they have left their host and can be killed with heat, drying, and disinfectants. Concerned hunters should take the precautions suggested below and keep current with new information on highly pathogenic avian influenza H5N1.
How can I protect myself from avian influenza and other diseases while hunting?
Do not pick up sick or found dead wild animals without gloves. Whenever you touch an animal, wash hands immediately after the contact occurs.
  • Call the WI Dead Bird Hotline (1-800-433-1610) to report a bird dead from unknown causes. If an unusual bird mortality is observed (such as a large number of dead birds) contact your local DNR service center or call the DNR Bureau of Wildlife Management at 608-266-8204.
  • Keep harvested birds cool and dry after harvest.
  • Do not eat, drink, or smoke while cleaning birds.
  • Consider wearing disposable or rubber gloves when cleaning game and wash your hands after any contact.
  • Clean all tools and surfaces used to clean the bird immediately afterward, using hot soapy water, disinfect with a 10% chlorine bleach solution.
  • Cook game meat thoroughly; temperatures of 155-165°F will kill most disease organisms, including avian influenza viruses.

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Can avian influenza be contracted from eating wild game birds?
To date, there is no evidence that anyone has become infected with AI after consuming properly cooked foods. Cooking game meat thoroughly at temperatures of 155-165°F will kill most disease organisms, including avian influenza viruses.
Are hunting dogs at risk of getting avian influenza?
Dogs used in wild game bird hunting are not considered at risk of acquiring avian influenza, since there have been no documented cases of the H5N1 virus infecting dogs. Dog owners should consult their veterinarian or visit the American Veterinary Medical Association website (Exit DNR) for more information about other strains of influenza that occur occasionally in pets.
Can I become infected with avian influenza virus by cleaning a bird feeder?
There is no evidence of highly pathogenic H5N1 yet in birds or people in the United States. Generally, perching birds (Passeriformes) are the predominate type of birds at feeders. While there are documented cases of H5N1 causing death in some Passeriformes (e.g., House Sparrow, Eurasian Tree-Sparrow, House Finch) in Asia/Europe, most of the wild birds that are traditionally associated with avian influenza viruses are waterfowl and shorebirds.
While highly pathogenic H5N1 has not been detected in North America, it is good practice to clean birdbaths and bird feeders regularly to minimize exposure to other potential avian diseases. Clean birdbaths and feeders using a 10% bleach solution as a disinfectant before the final rinse. Keep fresh, dry food in a feeder and maintain the ground underneath free of discarded hulls and droppings. Change the water in a birdbath every 2-3 days.

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Can domestic cats be infected with avian influenza viruses?
While domestic cats are not usually susceptible to avian influenza, it is known that they can become infected and die with H5N1 viruses. Unlike the case in domestic and wild birds, there is no evidence that domestic cats are a reservoir of the virus. All available evidence indicates that cat infections occur in association with H5N1 outbreaks in domestic or wild birds and are thought to have occurred by the cat eating raw infected birds. Cat owners should consult their veterinarian or visit the American Veterinary Medical Association website (Exit DNR) for more information about other strains of influenza that occur occasionally in pets.
Is there a domestic poultry risk associated with H5N1 from wild birds in the United States?
In the United States, there are no documented cases of highly pathogenic avian influenza transmission (e.g. H5N1) from a wild bird to domestic birds, and it is believed that most highly pathogenic avian influenza viruses evolve after avian influenza virus becomes established in domestic bird populations. Please visit the United States Department of Agriculture website (Exit DNR) for further information on the risk of H5N1 in domestic poultry.
Are my children or I at risk from goose, duck and other bird feces found in parks and playgrounds?
There is no evidence of H5N1 yet in birds or people in the United States. However, there are several specific precautions park/playground visitors can take to prevent disease exposure from a variety of infections wild birds carry:
  • Do not feed birds
  • Avoid sick and dead birds
  • Avoid picking up feathers
  • Avoid picnicking near the birds
  • Wash hands thoroughly before eating, drinking, or smoking
  • Wash hands, clothes, and shoes soiled with bird feces

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    Additional Avian Influenza Web Resources

    Questions on this topic, please contact Wildlife Health

    Questions for Wildlife Management

    Last Revised: Wednesday October 17 2007