There has been much in the news lately about avian flu and the dangers of a flu pandemic. Recently, the focus has been on Asia and Europe. Since many species that breed in Alaska during the summer migrate from the Far East, there has been some concern that avian flu may come to Alaska with these migratory birds. The following is an overview of avian flu and how it may affect Alaska.

Influenza (the flu) is a viral infection of the lungs. There are three types of influenza: A, B, and C. Types B and C are of little consequence to humans. Type A is another matter altogether.

Avian flu was first identified over 100 years ago. It is caused by a Type A influenza virus. The Type A influenza virus can be further differentiated into 15 different subtypes. (Much like dividing dogs into husky, beagle, terrier, etc.). These subtypes are determined by certain proteins (antigens) on the surface of the virus. Most of the subtypes infect only a limited number of species. The virus is generally specific to its host. Humans are infected by 3 of the 15 subtypes. Birds, on the other hand, can be infected all 15. The subtype of concern is H5N1. Wild birds, predominantly waterfowl, carry the flu virus naturally with usually no effect to their own health. They spread the virus through the air and through nasal secretions, saliva, and feces. If domesticated birds come in contact with the virus through contaminated food, water, or surfaces, the consequences are deadly. Domesticated birds have not developed a natural immunity to avian flu. Avian flu outbreaks are monitored very carefully in the poultry industry with sometimes millions of birds slaughtered to halt the spread of the flu. These outbreaks have occurred in the U.S., Canada, Europe, and Asia.

How can a bird flu infect humans? The Type A influenza virus is elegantly simple. It is genetically adaptable and mutates easily. If two subtypes are present in a host at the same time, during viral reproduction the genetic material can essentially mix and match to produce a new subtype. This is generally does not have consequences except when a new subtype is produced that has 1) a new set of surface proteins that the human immune system does not recognize and 2) the ability to spread easily from human to human. The result would be a very high mortality rate because the virus has not been intercepted by the immune system. Each of the recent flu pandemics (1918, 1958, 1968) were caused by a mutation of an avian flu virus. The virus that is responsible for all the human deaths from avian flu (61 deaths out of 100 confirmed cases) within the last year does not have the ability spread from human to human. All of these people were in contact with domesticated birds, not wild migratory birds. The early spread of the disease closely tracks commercial poultry movements in Asia.      

There have been no reported cases of H5N1 in North America. Current research by Dr. Jon Runstadler of the University of Alaska Fairbanks is monitoring the presence of H5N1 in Alaskan waterfowl, shorebirds, and passerines. In fall of 2005, personnel from the Runstadler lab collected approximately 1,000 fecal swabs from birds banded at ABO’s Creamer’s Field Migration Station. As expected, samples have revealed the presence of avian flu strains, but not H5N1.

In addition, the American Bird Conservancy states that there is no evidence that feeding of wild birds plays a role in the spread of the disease, but people should clean bird feeders regularly to limit the spread of other diseases.

For further information, start with the Center for Disease Control Avian Flu website.

Other useful web sites, handouts, and articles:

USGS National Wildlife Health Center Avian Influenza website (updated several time/week)
http://www.nwhc.usgs.gov/disease_information/avian_influenza/index.jsp

U.S. Fish & Wildlife has a page:
http://alaska.fws.gov/media/avian_influenza/index.htm

State of Alaska Avian Flu website
http://www.avianflu.alaska.gov and http://www.adfg.state.ak.us/special/avianflu/avianflu.php

Some Questions and Answers About "Bird Flu" pdf
http://www.avianflu.alaska.gov/PDFs/q-and-a_3-20-06.pdf

A Few Facts About Avian Influenza in Alaska pdf
http://www.avianflu.alaska.gov/PDFs/factsheet_3-23-06.pdf

What Hunters Should Know About Avian Influenza pdf
http://www.avianflu.alaska.gov/PDFs/Avianflu_hunter_notice.pdf

Questions and Answers about Avian Influenza for Subsistence Hunters in Alaska pdf
http://www.avianflu.alaska.gov/PDFs/subsistence%20bird%20flu%20handout.pdf

Are Migratory Birds to Blame? Check out this New York Times article.

Do you raise poultry or have other domestic birds? Here are PDFs of two USDA articles that may help you:

USDAAKBackyard_Flock_Biosecurity.pdf
USDAbackyardbiosec6steps.pdf