United States prepares for highly pathogenic H5N1 avian influenza in wild birds      

[MARCH 23, 2006]  WASHINGTON -- Avian influenza is a disease caused by a virus that infects domestic poultry and wild birds, including geese, ducks and shorebirds. Each year there is a bird flu season just as there is for humans, and, as with people, some forms of the flu are worse than others.

The highly pathogenic H5N1 strain of bird flu has been found in an increasing number of countries in Europe, Asia and Africa. Currently, H5N1 avian influenza is not present in the United States. It is likely the highly pathogenic H5N1 strain will spread to this country, and the U.S. government is taking steps to prepare for and minimize the potential impact of bird flu.

There are a number of ways that highly pathogenic H5N1 could potentially reach the United States -- wild bird migration, illegal smuggling of birds or poultry products, and travel by infected people or people traveling with virus-contaminated articles from regions where H5N1 already exists.

Historically, highly pathogenic strains of avian influenza have been detected in domestic poultry populations three times in the United States: in 1924, 1983 and 2004. There have been no occurrences of highly pathogenic avian influenza in wild birds in the United States, and no significant human illness resulted from any of these outbreaks.

• The 1924 H7 outbreak was contained and eradicated in East Coast live bird markets.

• The 1983-84 H5N2 outbreak resulted in the destruction of approximately 17 million chickens, turkeys and guinea fowl in the northeastern U.S. to contain and eradicate the disease.

• In 2004, the U.S. Department of Agriculture confirmed an H5N2 outbreak in chickens in the southern United States. The disease was quickly eradicated, thanks to close coordination and cooperation between USDA, state, local and industry leaders. Because of the quick response, which included quarantine and culling of birds, the disease was limited to one flock.

Monitoring bird health in the U.S.

The U.S. Department of the Interior and U.S. Department of Agriculture have proactive interagency efforts under way to monitor wild migratory birds in the United States and to test statistically significant samples of populations of various migratory bird species for avian influenza.

Agencies of the Department of Agriculture and the Department of the Interior, including the U.S. Geological Survey and the U.S. Fish and Wildlife Service, have been working for the past several months with state of Alaska biologists to strategically sample live birds, hunter-taken birds, sentinel flocks and the environment used by these targeted populations for highly pathogenic H5N1 bird flu in the Pacific Flyway. An interagency plan for monitoring of wild birds, which expands and intensifies the program in 2006, focuses on this Alaska area because it is a flyway crossroads for migratory birds that annually return from their winter migration in Asia and come in contact with other North American migratory birds that return to Alaska in the spring from wintering areas in the southern United States and Central America. 

Testing also is being carried out in other migratory bird flyways in cooperation with state and local agencies. This enhanced monitoring program will provide an early warning to the agriculture, public health and wildlife communities should migratory birds be found to carry the highly pathogenic H5N1 virus.

Since 1998, USDA and the University of Alaska have tested more than 12,000 wild migratory birds in Alaska, and since 2000 USDA and the University of Georgia have tested more than 4,000 wild birds in the Atlantic Flyway. All birds tested negative for highly pathogenic H5N1. As part of this enhanced monitoring, in 2006 USDA, the Department of the Interior and its cooperators plan to test between 75,000 to 100,000 samples from live and dead birds. Eleven thousand of the live bird samples will be initially screened by the U.S. Geological Survey at its National Wildlife Health Center in Madison, Wis. The remaining samples will be initially tested at labs certified by USDA in the National Animal Health Laboratory Network. Suspected findings of highly pathogenic avian influenza will be further tested and diagnosed by the USDA National Veterinary Services Laboratory lab in Ames, Iowa.

USDA's Animal Plant Health Inspection Service and Interior's Fish and Wildlife Service also work with the U.S. Department of Homeland Security's U.S. Customs and Border Protection at major U.S. air and seaports to inspect, examine and regulate the importation of live poultry, commercial birds, pet birds and "hatching eggs."

Interior land management agencies -- including the National Park Service, Fish and Wildlife Service, Bureau of Land Management, Bureau of Indian Affairs, and Bureau of Reclamation -- are educating their employees, working with stakeholder and support groups, and preparing protocols to protect visitors and employees on public lands. Many of these lands provide nesting, migration and wintering habitat for waterfowl and other migratory birds; and more than 450 million people visit Department of the Interior lands annually. Interior also has developed a departmental pandemic influenza plan to assure continuity of operations.

In addition, USDA monitors U.S. domestic and wild bird populations. Monitoring is conducted in four key areas: live bird markets, commercial flocks, backyard flocks and migratory bird populations. Frequent testing occurs in live bird markets and commercial flocks. Additionally, birds are tested that show signs of illness. To help backyard and smaller poultry producers, the USDA "Biosecurity for the Birds" program provides important information about reducing the chances of birds becoming infected with avian influenza. Biosecurity refers to the application of practical, common-sense management practices to keep avian influenza and other poultry diseases out of our commercial and backyard flocks.

In the event of a highly pathogenic avian flu outbreak in the United States, USDA maintains a bank of bird vaccines to protect healthy birds outside a quarantine area, if necessary. The vaccine would be used to create a firewall around a quarantine to prevent spread. Currently, USDA has 40 million available bird vaccine doses, which have been proven effective against the highly pathogenic H5N1 virus. Another 70 million doses are in development. USDA works closely with its federal, state and tribal partners, as well as industry stakeholders, to ensure that effective and coordinated emergency response plans are ready should an outbreak of highly pathogenic avian influenza occur. In addition, USDA researchers are developing faster diagnostic tests, enhanced vaccines for birds and new information about how avian influenza spreads so that the United States is better prepared for avian influenza outbreaks.

Bird import restrictions

As a primary safeguard, USDA maintains trade restrictions on the importation of poultry and poultry products from countries where the highly pathogenic H5N1 avian influenza strain has been detected in commercial or traditionally raised poultry, not in wild or migratory birds. Additionally, USDA has increased its monitoring of domestic commercial markets for illegally smuggled poultry and poultry products. All imported live birds must be quarantined for 30 days at a USDA quarantine facility and tested for the avian influenza virus before entering the country. Home quarantine and testing for avian influenza also is required for returning U.S.-origin pet birds. The U.S. Fish and Wildlife Service works with USDA to communicate these trade restrictions to the pet bird trade community and incorporates them into decisions on permits it issues for wild bird trade.

[U.S. Department of Agriculture news release]