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Avian Influenza

Avian influenza (AI) is a virus-caused disease found in birds. It can infect chickens, turkeys, pheasants, quail, ducks, geese and other birds. Each year there is a flu season for birds just as there is for humans. There are many strains of AI viruses. After determining which proteins are found on the surface of the virus, the strains are labeled with an "H" number (H1-H16) and an "N" number (1-9). Additionally, they are classified as either having low or high pathogenicity. The highly pathogenic H5N1 avian influenza is the strain of most concern.

AI is primarily spread by direct contact between healthy and infected birds through respiratory secretions and feces. It can be spread from birds to people as a result of extensive direct contact with infected birds. There are concerns that the virus could mutate, or change into a type that could be spread from human to human.

Surveillance

As birds from Alaska and Canada begin their migration south through the continental United States during the summer, federal and state biologists will begin capturing and sampling the birds in every state as part of the interagency strategic plan for the early detection of highly pathogenic H5N1 avian influenza in wild birds.

Disease biologists and field specialists with the USDA are teaming up with state biologists to collect approximately 50,000 to 75,000 bird samples and 50,000 environmental samples throughout the lower 48 states and Hawaii. This effort is in addition to the sampling currently taking place in Alaska.

Because Alaska is at the crossroads of bird migration flyways, scientists believe the highly pathogenic H5N1 subtype would most likely arrive there if it spread to North America via migratory birds. Thus, the interagency strategic plan recommends a prioritized sampling system with emphasis in Alaska, elsewhere in the Pacific Flyway and the Pacific islands, followed by the Central, Mississippi and Atlantic Flyways.

The wild bird monitoring plan is part of the President's National Strategy for Pandemic Influenza Preparedness. President Bush allocated $29 million in his avian influenza supplemental funding package for implementation of the wild bird monitoring plan. Seventeen million of that was allocated to the USDA and $12 million to the Department of the Interior. The USDA in turn formed collaborative agreements with state fish and game agencies to assist with the wild bird sampling in every state.

The ability to effectively prevent the spread of highly pathogenic H5N1 into domestic poultry operations is greatly enhanced by being able to rapidly detect the pathogen if it is introduced into wild migratory birds in the United States. The interagency plan outlines 5 specific strategies for early detection of the virus in wild migratory birds:

• Investigation of disease-outbreak events in wild birds
• Expanded monitoring of live wild birds
• Monitoring of hunter-killed birds
• Use of sentinel animals, such as backyard poultry flocks
• Environmental sampling of bird feces

Migratory waterbirds, such as ducks, geese and shorebirds, are natural reservoirs for 144 subtypes of avian influenza that are generally low pathogenic strains that rarely cause signs of illness in the birds or humans. However, the particularly potent subtype of H5N1 avian influenza that emerged in Asia and has now been found in domestic and wild birds in Europe and Africa has caused mortality in more than 80 species of wild birds.

Additional information about avian flu and security relating to domestic poultry, wild bird monitoring and research, as well as pandemic planning nationwide is available at the U.S. government's comprehensive website for pandemic preparedness at http://www.avianflu.gov or http://www.usda.gov/birdflu. The National Agricultural Library has information resources available from http://www.nal.usda.gov/awic/aflu/Avian%20Influenza.htm.

Summary above taken from:

USDA information releases