Avian flu testing for flyway birds

State will test birds for avian flu

U.S. effort aimed at early detection

By KAWANZA NEWSON
knewson@journalsentinel.com

Posted: July 14, 2006

Many birds heading south along the Mississippi Flyway this fall may have their flights delayed as they undergo screening for a deadly flu strain.

Wildlife experts will stop hundreds of waterfowl and shorebirds traveling along Lake Superior, Lake Michigan and the Mississippi River to collect fecal samples for detection of the H5N1 virus. In addition, they'll set up check stations for testing of hunter-killed birds and swab carcasses for the virus that has been infecting bird populations around the world.

"We're not doing this because we're really worried this will happen here," said Sarah Shapiro Hurley, deputy administrator of the state Department of Natural Resources' land division. "This is just a part of a national program so that we'll know what's going on with the bird population and be aware of whatever viruses might be circulating."

"Clearly, Alaska and other states have a higher probability of having a wild bird with a highly pathogenic virus move across their area," she said. "There is a very low risk of finding a highly pathogenic bird in Wisconsin."

In March, officials representing three federal agencies announced plans to significantly increase testing of wild birds to allow rapid detection of avian flu if it reaches the United States.

That plan called for collection of about 100,000 samples from live and dead wild birds this year, along with 50,000 samples of water or feces from waterfowl habitats across the U.S. Officials also recommended investigation of any disease outbreaks in wild birds and spot checks of birds killed by hunters, as well as those being sold in live bird markets and being raised by farmers.

Many of the samples will be tested in Madison, which is home to the U.S. Geological Survey's National Wildlife Health Center.

The H5N1 strain has infected a large number of domestic birds in Asia and about 230 people, including 131 who have died since 2003. Most human cases have been linked to contact with sick birds, though the World Health Organization and others have warned that the virus could mutate into a form that spreads easily among humans, possibly triggering a global pandemic.

Research led by University of Wisconsin-Madison flu expert Yoshihiro Kawaoka has shown that it will be extremely difficult to transmit the H5N1 virus between humans because the virus binds only to cells buried deep in the recesses of the human lower respiratory tract. The virus doesn't stick in the upper respiratory tract, where human flus are carried.

Kawaoka will head a $9 million, 20,000-square-foot Institute for Influenza Viral Research being built in existing space at the University Research Park on the far west side of Madison, making the city a national hub for genetic research studies on influenza viruses.

In addition, the Wisconsin State Laboratory of Hygiene was selected by the U.S. Centers for Disease Control and Prevention to become the first state laboratory to test whether flu strains will respond to commonly used anti-viral drugs.

State to test 2,000 samples

As part of the increased migratory bird surveillance, Wisconsin will test at least 2,000 samples from live and dead birds throughout the state.

The DNR received a $100,000 grant from the U.S. Department of Agriculture and is using that money to hire two people who will lead the teams traveling along the shorelines of Lake Michigan and Lake Superior, as well as to buy equipment needed for testing bird samples, said Kent Van Horn, the migratory game bird ecologist who was involved in development of both the Wisconsin plan and the Mississippi Flyway regional plan.

Van Horn said there are six to 10 anticipated monitoring sites throughout the state and that mallard, pintail and green-winged teal ducks will be among the species targeted for testing in Wisconsin.

However, those plans may change, he said.

"The weather and animals will determine where you go and when," he said. "You make these really nice plans, and then the ducks end up somewhere different."

U.S. wildlife experts have been monitoring wild migratory birds since the virus emerged in Asia in 1997. They have tested more than 12,000 birds in Alaska since 1998 and almost 4,000 traveling across the Atlantic since 2000.

Officials have been focusing on Alaska because it is a central hub for bird migration, said Paul Slota, a biologist with the Geological Survey who will be overseeing the testing of samples at the agency's wildlife health center in Madison.

The assumption is that an infected bird would migrate from Asia and come into contact with birds in Alaska, potentially infecting millions. During fall migration, the Alaskan bird could enter the U.S. mainland and likely spread the virus first along the Pacific Flyway. The Pacific Flyway includes Alaska, Arizona, California, Idaho, Nevada, Oregon, Utah, Washington and those portions of Colorado, Montana, New Mexico and Wyoming that are west of the Continental Divide.

Officials have recommended priority testing for birds found in these areas, followed by those obtained along the Central Flyway, Mississippi Flyway and then the Atlantic Flyway, Slota said.

However, it's understood that birds may travel other pathways to reach their destinations, he said.

Flu detection process

Julie Langenberg, a wildlife veterinarian for the DNR, said screening for influenza takes about three days, but additional testing will be conducted if a flu virus is detected.

If that occurs, the sample is kicked into a national reporting loop, where federal officials would learn the sample subtype and then alert Wisconsin officials of the results, she said.

However, it's important to remember that detection of influenza viruses in birds is not uncommon, said Chris Franson, a research wildlife biologist with the wildlife health center in Madison.

The agency has tested more than 4,500 samples in 2006, said Hon Ip, a disease investigations virologist with the Geological Survey.

The samples have come mainly from Alaska but include a variety of other birds from across the country and from as far away as the Pacific islands, he said.

However, to date, no birds have tested positive for H5N1, Ip said.

The birds congregate in late summer and early fall, making it easy to spread the virus between them.

Many birds will show no signs of illness, and common influenza viruses detected in hunter-killed birds can be eliminated with proper washing and cooking, Van Horn said.