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Those ducks at the park could turn deadly

By LISA GREENE

STAFF WRITER

As a wary world waits to see if the notorious bird flu virus will explode in a deadly pandemic, scientists are keeping their eyes on the skies.

Why?

Migrating birds.

With their ability to fly thousands of miles, they often come into contact with other birds from countries that might have been touched by the deadly flu virus. And that has scientists scrambling to keep a close watch on the wild bird population. Consider these ongoing efforts:

• In Alaska, testing is going on for thousands of birds who will have passed through the state, which is a magnet for ducks, geese, sandpipers and other species that gorge on its insects. In fact, the state is the crossroads of three of the world's great migratory flyways. Birds from Asia and North America mingle here, winging across continents to find the perfect bird nursery.

“The opportunity for movement of the virus is probably stronger here than anywhere else in North America,” said Kevin Winker, an associate professor and curator of birds at the University of Alaska Museum in Fairbanks. Winker has been testing birds for bird flu since 1998, drawn here by the chance to study more than 450 different bird species.

But in the past, Winker and his colleagues have tested about 1,500 to 3,000 birds a year. This year's tally was expected to reach 20,000.

• Over on the other side of the country, in Maine, hundreds of Canada geese and other migratory birds were being captured and tested by Maine state biologists for avian flu. Canada geese are a favored choice of birds for testing because they often mingle with other species of migrating birds, said Michael Schummer, a game bird specialist.
  
  The deadly strain of bird flu, known as H5N1, first appeared in Hong Kong in 1997. A campaign to kill infected birds stopped the virus then, but it re-emerged in Asia in 2003 and the number of cases — and deaths — there started growing steadily.

After being contained in Asia for the next couple of years, it has since made a much faster march westward:

• The first human deaths from H5N1 outside Asia, in January 2006 in Turkey, heightened concern about the spread of the disease, but the World Health Organization pointed out that the deaths were among people who had been in close contact with infected birds, and were not passed from human to human.
• The first outbreaks in the European Union were recorded in January 2006 when cases were confirmed in wild swans in Italy, Greece, Germany and Austria.
• Within weeks, cases were confirmed in Slovenia, Slovakia, Hungary and France, where mass vaccination of ducks and geese on farms was carried out.
• At the end of February, the first case involving a cat in Europe was discovered on a German island where a number of wild birds had died from the disease earlier.
• The virus also reached Nigeria in February 2006
• In mid-March, human deaths were con-firmed in Azerbaijan, where what is believed to be the first canine case was also diagnosed, in a stray dog.
• The first case in the UK was confirmed on April 6, in a swan found dead on the eastern coast of Scotland.
• And in Spain, a great crested grebe was determined to have the disease in early July.

The infection rate in humans is increasing after more than 48 countries across three continents reported initial outbreaks in birds this year. In 10 countries, H5N1 has killed at least 131 of the 229 people known to have been infected since late 2003, according to the World Health Organization.

In addition, U.N. officials tracking the flu say that the virus has led to the deaths of 200 million birds. As the sick birds have multiplied, so too has the alarm. Even the famous ravens who live in the Tower of London have been moved inside.

The spread of the virus among migrating birds still doesn't pose the same public health threat as the potential spread among people. Most flu experts agree that the greatest chance for bird flu to threaten U.S. residents will occur if the virus gains the ability to jump from person to person.

So far, that hasn't happened. Those who have fallen ill have had direct contact with birds. Scientists don't know when—or if—the virus will ever gain that ability. If it does, that would set the stage for a global epidemic, or pan-demic, and it most likely would start in Asia.

But U.S. scientists believe the spread of bird flu among wild birds poses a danger.

”Many of the other diseases that pop up in public concern are sort of flavor-of-the-month club that don't kill a lot of people—Ebola, SARS, monkeypox,“ Winker said.

A true flu pandemic could kill anywhere from 2 million to 100 million people world-wide, scientists estimate. If scientists and doctors sound alarmist, it's because they look to history: The 1918 Spanish flu epidemic killed more than 40 million people worldwide.

“The 1918 pandemic was wholesale destruction, and yet the mortality rate was only 2 percent,” said Dr. Greg Poland, director of the Mayo Clinic Vaccine Research Group and a member of the advisory committee on vaccines for the federal Centers of Disease Control and Prevention.

“(With this flu) the mortality rate is 50 percent. That's what's suddenly grabbed people's attention,” he said.

As a way of contrasting what's going on, consider this. Influenza viruses circulate each year and kill thousands—an average of 36,000 in the United States alone. But they are kept in check by vaccines and the immunity that people have from being exposed before. In the case of bird flu, vaccine has not yet been manufactured and people have no immunity. What‘s more, it appears to be especially lethal.

What makes this particular strain of flu so deadly, say doctors, is its ability to settle deeper into cells in the lungs. So in addition to the regular symptoms of flu (fever, cough, sore throat and muscle aches), those infected are more likely to experience pneumonia and acute respiratory distress. They literally drown in the liquid filling their lungs.

To help ease the public's fears about the disease, the U.S. government has launched several Web sites to help spread information about the virus, including one called pandemicflu.gov and avianflu.gov.

The government also recently released a 227-page report detailing — as well as it could — plans for dealing with a pandemic. The report emphasizes that businesses and state and local governments should prepare for a flu pandemic just as they would for a terrorist attack or natural disaster, and not rely on the federal government to do everything.

Officials have painted dire scenarios about the chaos that would spread in a pandemic, including closed businesses, schools and offices, interrupted food supplies and a shortage of hospital beds for the sick.

Once the virus enters the United States in a few wild birds, it likely will spread to others. Wild animals could be threatened. So could commercial poultry and farm animals, although experts stress the risk of that is low.

Wild birds spread the disease easily among themselves because they carry the virus in their digestive tract. Water becomes contaminated, and then other birds get infected by eating and drinking there.

If U.S. wild birds are infected, federal officials fear the virus could spread to commercial poultry. But they stress that the U.S. poultry industry, with its cooped chickens and separate farms, is far different from Asia's family flocks. U.S. chickens have less contact with both wild birds and people.

But still there is concern that the mere threat of bird flu here could cause a crippling fear in the food industry, even though cooking kills the virus. Still, there is such nervousness already that the KFC chain has begun pasting a sticker on its containers assuring customers of its safety.

Sources: KRT; Los Angeles Times; CDC, pandemic.gov, Time magazine, BBC.com

FIND OUT MORE: Check these sites for more in-depth reporting on bird flu: NPR.org • BBC.com • WHO.int • cdc.gov• nytimes.com

CALL: Centers for Disease Control, 800-CDC-INFO