Hello Everyone:
Helen Engle posted this to Tahoma Audubon's listserv today. I had read
parts of this article in the Sunday, Dec 30 Seattle Times-PI, but a large
portion of the original article had been removed in the newspaper. In this
full article, there is some additional surprising information about
transmission of the virus. Read on for startling information and statistics
that are just now being understood by scientists. This is not just about a
few Crows.
Carol Schulz
DesMoines, WA
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>From Helen:
Dear Friends:
Here's a good Write-up!
Jerry Bertrand, NAS Board of Directors Science Committee Chair, sent this
out today. (Thanks Jerry, keep us all in the loop!)

Helen Engle
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WEST NILE?S WIDENING TOLL IMPACT ON NORTH AMERICAN WILDLIFE
FAR WORSE THAN ON HUMANS
By Rick Weiss, Washington Post Staff Writer, December 28, 2002

First there was the silence of the crows.
Then the horses fell ill - - more than 14,000 this past summer alone - along
with squirrels, chipmunks and mountain goats. Even mighty raptors - eagles,
hawks and great horned owls - dropped from the sky.
Now scientists are beginning to taking stock of West Nile virus?s North
American invasion, and they are taken aback by the scale and sweep of its
ecological impact. While the human toll dominated the nation?s attention
this year - the virus killed at least 241 people and infected many thousands
more - - the effects on wildlife were far worse.
The virus swept westward with alarming rapidity this year, appearing in
almost every state in the nation - an astonishing expansion for a bug that
had never been seen in the Western Hemisphere until three years ago.
Equally unexpected, nearly 200 species of birds, reptiles and mammals fell
ill from West Nile this year, including rabbits and reindeer, pelicans and
bats, even a few dogs and cats. The virus also slammed dozens of exotic
species in about 100 U.S. zoos, killing cockatiels, emus, seals, flamingos
and penguins. Florida alligator farms lost more than 200 of the reptiles.
?In my years of working, I?ve never seen a mosquito-borne virus spread so
quickly,? said Robert G. McLean with the Agriculture Department?s National
Wildlife Research Center in Fort Collins, Colo.
Indeed, the epidemic has so resembled a bioterrorism attack that the
nation?s zoos - which spearheaded an effort to track West Nile?s march and
mount emergency vaccinations - could end up with potentially important roles
in the emerging arena of homeland security. Just last month, in a hastily
organized effort reminiscent of President Bush?s smallpox plan, officials at
two California zoos inoculated their endangered California condors with an
experimental vaccine that may be the animals? only hope for survival.
West Nile is not fatal in all animals, and over time some species are
expected to adapt. But even partial dropoffs in key populations could have
serious consequences. Rodent populations could blossom in areas where
raptors are dying, and pest birds such as house sparrows may be increasing
where crows are absent.
The worst is still ahead, scientists say. Come spring, West Nile is expected
to complete its push to the West Coast, home to endangered whooping cranes
and economically important flocks of domestic geese. The virus is also
poised to leap to the subtropics, where rare birds and other vulnerable
creatures already face formidable threats to their survival.
?Once it gets to the tropics, where you?ve got species already stressed by
habitat destruction and you have the potential for year-round mosquito
transmission, some of those populations are not going to make it,? said
Peter Marra, an animal ecologist and West Nile specialist at the Smithsonian
Environmental Research Center in Edgewater, Md. ?I?m concerned about parrots
and hummingbird populations. There?s not that many of them left.?
NORTH AMERICAN DEBUT
West Nile made its North American debut in the fall of 1999, discovered in a
dead New York crow. Scientists don?t know how the virus reached U.S. shores
- perhaps it hid inside a single infected bird imported from the Middle
East. But one thing is certain, said Stephen Ostroff of the Centers for
Disease Control and Prevention (CDC) in Atlanta: ?There?s no way that West
Nile is going to go away.?
The virus appears no more virulent in Americans than in other people around
the world, and scientists suspect that the population will gradually gain
immunity through low-level exposures. That is the situation today in
countries where the virus has been active for many years. Most people in
those countries have antibodies to the virus from early childhood, and
serious complications or death from West Nile are rare.
But in North American wildlife, the virus has proven to be unusually
aggressive and capable of infecting a surprisingly diverse array of animals.
?Most viruses tend to be rather host-specific, but that?s not the case with
what we were seeing,? said Tracey McNamara, chief of pathology for the
Wildlife Conservation Society, which has its headquarters at the Bronx Zoo,
where the first infected crow was found.
It is still unclear how many of the 200 or so species struck by West Nile
infection have suffered significant population declines. But a consensus is
emerging that among birds, in particular, far more species are being hurt
than scientists had predicted - not just thecrows, ravens and jays that were
known to be especially vulnerable.
?There?s been a huge die-off of raptors,? said McLean of the agriculture
department?s Fort Collins lab.
The experience of the University of Minnesota?s Raptor Center, which
rehabilitates sick and injured raptors, was typical. ?In mid-August, we had
our first case: a great horned owl,? said spokeswoman Sue Kirchoff. ?In
September and October, we were just inundated.?
The center took in 70 ailing birds of prey, including great horned owls,
eagles and red-tailed hawks. Officials there presume that if that many were
found and brought to the center, countless others died in the wild, with
potentially far-ranging repercussions.
?From a biological standpoint, raptors take longer to mature and have fewer
offspring? than smaller birds, said Patti Bright of the American Bird
Conservancy. ?Whether they?ll be able to rebound, well, we just don?t know.?
It will take a while longer, Bright and others said, before it is known
whether rodent populations are taking advantage of West Nile?s impact on
birds of prey.
The evidence for declines in songbirds and other small avian species is less
direct, in part because they are so much less visible. ?We?re simply not
going to know for a while with the smaller birds, because we?re not going to
find the bodies,? said David S. Wilcove, a professor of ecology at Princeton
University who has been studying West Nile.
Still, researchers this year found more than 140 bird species sickened or
dead with West Nile, including chickadees, doves, grackles, gulls, herons,
kingfishers, pelicans, sparrows, swans, turkeys, warblers, woodpeckers and
wrens. And while most of those species will probably pull through as
resistant individuals mate and pass their antiviral vigor to their
offspring, ornithologists expect that others will not be so lucky.
They point to the experience in Hawaii, where the arrival of avian pox virus
in the 1890s and avian malaria in the 1930s drove dozens of species to
extinction or close to it. ?Those viruses just hammered Hawaiian forest
birds,? Wilcove said. ?That illustrates the potential for harm when a
disease organism encounters a na?ve population.?

BIRD-TO-BIRD INFECTION
Several unexpected aspects of the epidemic have fed Wilcove?s and others?
pessimism.
One surprise is that the virus can be transmitted directly from bird to
bird, not only via mosquitoes. Raptors can acquire the virus by eating
infected prey, and some birds can apparently spread the virus in their
droppings. There?s also evidence that some birds can pass the virus directly
to their chicks while they?re still inside the egg.
Another surprise is that West Nile virus can be transmitted directly from
adult mosquitoes to their eggs, so that newly hatched aquatic larvae are
born infected. That could make insecticides, which typically kill only
adults, less effective.
Scientists have also been surprised to learn that the virus can persevere
through the winter, even in many Northern states. Researchers are not sure
which animals are serving as the virus?s winter host, but the phenomenon is
allowing the disease to spread year round and is giving the summer viral
eruption an earlier start each year.
Yet another surprise is the number of mosquito species - 36 at last count -
that carry the virus. ?This is a virus that?s never seen a mosquito it
doesn?t like,? said Ostroff of the CDC. ?That?s not typical for most
pathogenic viruses.?
If that weren?t enough, some researchers suspect that West Nile might be
capable of mixing its genetic material with that of a closely related virus,
such as the one that causes St. Louis encephalitis, if both viruses were to
infect a single animal. Other viruses have periodically produced such
hybrids, creating in the process an entirely new and dangerous bug.
?This virus is amazing,? said CDC virologist Robert S. Lanciotti. ?I?ve been
in this field almost 20 years, and I?ve never seen anything like it.?
Neither has the state of California, but it is about to, experts say.
?It?s going to spread to the West Coast big time by next year, no question,?
USDA?s McLean said. ?Each habitat is different, but California seems to be
an area that has all the factors you need for a major spread. I think
they?re going to be facing major problems in humans, horses, birds and other
animals. I just don?t see any barriers.?
Such predictions have a particularly ominous ring for researchers on the
California Condor Recovery Team, who have been struggling to bring the
ungainly bird back from the brink of extinction. They knew that this
summer?s experimental inoculations of zoo birds with the horse vaccine - the
only West Nile vaccine approved for marketing in this country - had been
disappointing, with many birds failing to develop protective antibodies. So
in November, veterinarians at the Los Angeles and San Diego zoos injected
into the thighs of their condors an experimental vaccine to try to confer
immunity before the spring egg-laying season.
?We had absolutely zero negative effects,? said Cynthia
Stringfield,veterinarian of the Los Angeles Zoo, and preliminary blood tests
suggested that the birds ?had a fantastic immune response.? If further
tests show that the vaccine works, the team will try to vaccinate all 128
captive California condors and the approximately 70 birds now living in the
wild.
WHAT ZOOS DO
Zoos may take the lead in the fight against West Nile in more ways than
that. More than 100 U.S. zoos and wildlife parks have joined a newly created
information-sharing network, which has its headquarters at Chicago?s Lincoln
Park Zoo, to track West Nile and other emerging infections in exotic
animals.
Some scientists suspect the network may even prove useful in the cause of
homeland security, by providing a sensitive, nationwide ?sentinel system?
for detecting the first hints of a bioterrorism attack. After all, zoo
officials noted, New York crows were dying in droves in the fall of 1999,
but no one figured out that West Nile was the culprit - or that the deaths
were related to a spate of unusual human illnesses - until a crow died on
the grounds of the Bronx Zoo.
Zoos, it turns out, take every death seriously - even those of non-zoo
animals on zoo grounds - because any death can mark the start of a
devastating epidemic. ?Every dead animal is picked up and immediately
necropsied,? said McNamara, the Bronx Zoo pathologist. ?That?s not true in
Central Park.?
When the Bronx crow was found to be teeming with West Nile, it was the first
evidence that the Old World virus had leaped the Atlantic - and the
beginning of the recognition that an epidemic was already underway in
humans. With a system in place, McNamara said, a zoo vet could be the first
to know if terrorists have released a human or animal pathogen. The
consortium is seeking federal funding.
Still, some scientists fear that the nation may soon become less able to
prevent outbreaks such as that of West Nile - whether accidental or
intentional. They said the U.S. system for screening incoming animal, plant
and microbial life - a patchwork of more than 20 agencies - has long been
undervalued and underfunded. Now the largest component, the Agriculture
Department?s Animal and Plant Health Inspection Service, is to become part
of the new Homeland Security Department. That?s leading many ecologists to
fear that it will narrow its focus to classical bioterrorism pathogens such
as anthrax, leaving the nation more vulnerable to civilian bugs such as West
Nile.
?I have a feeling that beetles in imported wood packaging are not going to
be at the top of the list,? said Faith T. Campbell, director of the invasive
species program at the American Lands Alliance in Washington. Yet the recent
U.S. invasion by Asian longhorned beetles, which arrived in wood packaging
from China, is expected to cost the nation as much as $669 billion in
insect-destroyed trees in urban areas alone in coming decades, Campbell
said.
Whether West Nile ends up decimating many animal populations or settling in
as a mere high- grade ecological disturbance, the epidemic should be a
wake-up call to beef up the nation?s surveillance and quarantine network,
said Princeton?s Wilcove.
?We may be lucky this time and get by with minimal losses of human life and
minimal losses of wildlife, but this is not going to be the last disease to
get into this country,? he said. ?One of these days we?re going to draw the
short straw.?
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? 2002 The Washington Post Company