Bird Flu in the US

WASHINGTON (AP) -- Scientists have discovered possible bird flu in two wild
swans on the shore of Lake Erie -- but it does not appear to be the
much-feared Asian strain that has ravaged poultry and killed at least 138
people elsewhere in the world.

It will take up to two weeks to confirm whether the seemingly healthy wild
mute swans in Michigan really harbored the H5N1 virus or not.

On Monday, the Agriculture Department declared that initial testing had
ruled out the so-called highly pathogenic version of H5N1 -- but that they
could have a relatively harmless, low-grade H5N1 strain instead.

That's the suspicion, making Monday's announcement almost a practice run for
the day the more worrisome Asian strain actually arrives.

"This is not the highly pathogenic avian influenza virus that has spread
through much of other parts of the world," said Ron DeHaven, administrator
of USDA's Animal and Plant Health Inspection Service, adding, "We do not
believe this virus represents a risk to human health."

Monday's announcement was the first reported hit from a massive new program
to test up to 100,000 wild birds in an effort to catch the deadly Asian H5N1
virus if it does wing its way to North America, something the government
thinks could happen this year.

Were the highly pathogenic H5N1 to be found in any wild birds here, that
could trigger additional security steps to prevent infection of commercial
poultry flocks, and even more intensive monitoring.

Wild birds, especially waterfowl, are flu's natural reservoir -- they carry
a multitude of influenza viruses. Sometimes, those strains jump species, and
if it's a flu virus very different from one people have experienced before,
a worldwide epidemic could result.

That's why scientists have closely tracked the virulent H5N1 strain since it
began its global march in late 2003. It is blamed for the death or
destruction of millions of birds overseas. Virtually all the people who have
caught it did so from close contact with infected birds or their droppings.
But scientists worry that the virus eventually could mutate to become easily
spread from person to person.

Last week, the government expanded the bird-testing program to encompass the
entire nation, after initial sampling mostly in Alaska. Twenty mute swans
from a Monroe County, Michigan, game area were among the first new batches
of tests -- because, coincidentally, they were part of a state program to
lower overcrowding of the nonnative species. That testing found the
possibility of H5N1 in two of the swans.

Initial genetic testing ruled out the deadly Asian strain. In fact, USDA
said the virus' genes suggest that it is similar to a low-grade North
American version of H5N1, a virus found here in wild ducks in 1975 and 1986
and on a Michigan turkey farm in 2003. Another similar version was detected
last year in Canada, and scientists have thought it probably common in wild
birds -- but didn't have the testing to prove it.

"This is no surprise," DeHaven stressed.

Plus, all the swans appeared healthy, a good signal, he added. The virulent
form of H5N1 usually rapidly sickens birds.

So why Monday's announcement? To be open about all this testing, DeHaven
said. And even low-pathogenic H5N1 requires monitoring, because it has the
potential to mutate into the more virulent form, he added.

More important, "It was a real good test run of the system," Dr. Willie
Reed, director of the Michigan State University laboratory where the initial
testing was done, told The Associated Press.

Flu strains are named for two proteins that stud the virus' surface. There
are 16 known hemagglutinin versions, the "H," and nine neuramindases, the
"N."

Michigan State's initial screening tests searched for the presence of H5 or
H7, two variants that can signal signs of concern in birds. On Friday,
Reed's lab alerted USDA's confirmatory laboratory in Ames, Iowa, that it had
found H5 in the two swans.

Over the weekend, more testing at Ames found the N1 protein. That doesn't
necessarily mean the swans harbored the H5N1 strain; they could have carried
two different flu strains at once, say an H5N2 and an H6N1.

That's a lot of science-speak to say stay tuned: It will take up to two
weeks to sort out exactly what the swans had, and to make sure it was a
low-pathogen version -- by injecting baby chicks with the swans' virus to
see if they die.


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