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Influenzavirus A is a genus of a family of viruses called Orthomyxoviridae
in virus classification. Influenzavirus A has only one species
in it; that species is called "influenza A virus".
Influenza A virus causes "avian influenza" (also known
as bird flu, avian flu, influenzavirus A flu, type A flu, or
genus A flu). It is hosted by birds, but may infect several
species of mammals. All known subtypes are endemic in birds.
It was first identified in Italy in the early 1900s and is now
known to exist worldwide. |
In an effort to keep you informed about bird flu, we are providing
you with the Florida Department of Health’s talking points
and a copy of a recent newspaper article.
Talking Points:
Ø The low-pathogenic H5N1 strain that was detected in Michigan
is NOT the highly-pathogenic strain that we are seeing abroad
that causes illness. This low-path strain has very little in common
with the virulent strain.
Ø Wild birds are known to harbor may influenza viruses,
and the finding of one or more of these viruses during routine
testing is not unusual. The strain found in these swans does NOT
pose a health risk to humans.
Ø Ongoing testing by agencies continues and the fact that
this low-path strain was detected during routine testing proves
that testing procedures are effective.
Ø The public should avoid having direct contact with wild
birds. Dead bird findings should be reported at www.MyFWC.com/bird.
Article
Florida Today, Aug 14, 7:53 PM EDT
White House: Lesser bird flu may be here
By LAURAN NEERGAARD
AP Medical Writer
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, Mich., 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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