DNA test might be able to save state's fowl
bioterror attacks may help stem Newcastle disease
By Ian Hoffman, STAFF
With an exotic virus crippling state poultry exports to Europe and
23 countries, animal-health authorities are pinning new hope
of stemming Newcastle disease on a DNA testing method originally pioneered for
detecting bioterror attacks.
For weeks, Southern California
poultry ranchers and backyard bird-raisers have watched as state and federal
authorities in white suits destroyed 3.1 million birds suspected of carrying the
highly lethal virus.
Exotic Newcastle disease poses no threat to humans
and poultry products and hasn't yet passed the Tehachapi mountains into Northern
California. But it threatens to outrun efforts at containment and, according to
U.S. Agriculture Secretary Ann Veneman, "constitutes a real danger to the
In the six to 12 days
needed for a typical lab test to identify infected birds for eradication, the
virus has drifted farm to farm, yard to yard, hitching a ride on the wind,
trucks, shoes and perhaps even the gear of vaccination workers.
scientists at UC Davis, Lawrence Livermore Lab and the U.S. Department of
Agriculture have devised a faster, more precise test based on
DNA-finger- printing methods that Livermore perfected for sniffing out plague,
anthrax and other dangerous human pathogens. Results are available overnight.
"As far as I can tell, it is
a very good and accurate test. It has high specificity and high sensitivity,"
said Dr. Greg Cutler, a Southern California veterinarian who credits the
new test with saving a ranch flock from eradication.
Animal Health and Food Safety Laboratory at UC Davis is running up to 200 of the
new tests a day as state and federal experts check more flocks. They are moving
into Stanislaus and Fresno counties, where growers for poultry giants Tyson
Foods and Holly Farms raise broilers and egg-laying chickens.
faster we can detect and move into control, the less economic impact this
disease is going to have," said Sharon Hietala, a professor of clinical
immunology at the Davis lab and co-developer of the test. "If we can respond
more rapidly to the infection, the California Department of Food and Agriculture
can make decisions to contain, quarantine or destroy the flock in days instead
The test relies on polymerase chain reaction or PCR, a common
method of multiplying and analyzing DNA in great detail. Livermore scientists
use powerful computers to compare the DNA sequences of pathogens with those of
close genetic kin. Further experiments nail down the DNA regions or "signatures"
that are unique to the pathogen. Scientists then draw up an assay or recipe that
includes fluorescent probes that light up to signal the segments' presence.
Livermore assays are the underpinning of the Bush administration's new
Bio-Watch system, a network of biodetectors being installed on air-pollution
monitors in 20 major U.S. cities.
The task was a little different with
exotic Newcastle disease, because its chromosome is made of RNA rather than DNA
and because close cousins of the virus were hard to find.
very interesting creatures," said Paula McCready, head of Livermore's DNA
signature team. "They mutate very quickly so it's very difficult to find those
regions that are unique to the virus."
With a PCR test, McCready said,
"We can find out whether the organisms are gone and can certify when we have a
The test spared 170,000 layer hens in Riverside
County that USDA officials had slated for "depopulation" or euthanasia. The
standard test, in which lab workers inject tissue of potentially infected birds
into eggs and wait for the virus to multiply inside, showed the birds had a
virus in the same family as exotic Newcastle.
"Everyone was all upset,
saying, 'Hey, we've got Newcastle here,'" recalled Cutler, the rancher's vet.
"They had already quarantined the place and they were looking toward
depopulating. I said, 'Hey, wait, let's look at the real-time PCR.'"
Tissue samples were flown to Davis and tested in Hietala's lab. The
results showed the presence of a nonvirulent vaccine strain, as Cutler
suspected, not exotic Newcastle disease.
"Within four hours we knew it
wasn't exotic Newcastle disease," Cutler said.
The test itself costs
about $7.50 to perform. Cutler figures it saved the federal government about
$850,000 in payment to the rancher for his birds.
Contact Ian Hoffman at
Contra Costa Times, Contra Costa County
Posted on Fri, Mar. 14,
Test finds bird virus quicker
By Taunya English
LIVERMORE - A rapid-read test developed by scientists from Lawrence
Livermore Laboratory and UC Davis is one of the newest tools in the fight to
curtail the spread of an infectious bird virus that has caused poultry
quarantines in Southern California and Nevada.
Exotic Newcastle disease
is highly contagious and nearly always fatal to birds but does not threaten
human health, according to the California Department of Food and
The "no movement" quarantine is pinching California's $1.4
billion poultry industry and has affected 17 production facilities. Scientists
hope the tests can be used to routinely screen unaffected poultry flocks once
Newcastle disease has been fully checked.
"The industry is huge in
California and we are a food supplier nationally and internationally," said
Livermore lab geneticist Paula McCready. To get back in business, "you have to
prove your area and animals are disease-free."
Since exotic Newcastle
struck Southern California in October, nearly 3 million commercial egg-producing
chickens have been euthanized statewide. By February the disease containment
effort reached $35 million, the agriculture department reports.
Newcastle first struck, the standard screening method required that a specimen
from a bird be inoculated in eggs for days before it could be analyzed. The new
Livermore lab and UC Davis technique can recognize the virus from the barest
essentials of a specimen and cuts the detection time to just four
Exotic Newcastle spreads rapidly through bird droppings, breath
and eggs and can decimate a flock. Chickens are especially susceptible to the
disease and the respiratory problems and lethargy that accompany the
Before 2002, the disease had not been found in the United States
Sharon Hietala, a professor with the California Animal Health
and Food Safety Laboratory at the UC Davis School of Veterinary Medicine, calls
exotic Newcastle the "foot-and-mouth disease of the poultry
Detection delays equate to lags in isolating infected animals
and controlling the disease. Delays also result in more reimbursements to
farmers whose animals or eggs are destroyed.
UC Davis and Livermore lab
have a long-standing relationship, but in this case the lab harnessed its human
genome and homeland-security bioterrorism expertise to focus on the problem of
finding a quicker detection method for the bird virus.
McCready said her
team looked for genetic markers unique to the exotic Newcastle virus but
different from other Newcastle viruses endemic to the United States. The
accuracy of the rapid, genomic-approach test was also verified through
sequencing, or identifying particular pieces of DNA.
Hundreds of bird
specimens are tested with the new technique each day, Hietala said. And those
rapid tests are being validated with the older inoculation methodology, she
said. With each identical result, the evidence mounts that the scientists have
developed a dependable, low-cost and speedy detection test.
October, two rapid tests have been developed; one of them to pinpoint the highly
pathogenic Newcastle virus.Authorities
recently quarantined a flock of Southern California birds that officials
suspected were infected with Newcastle. But before
the birds were killed, the rapid test uncovered the vaccine strain and avoided a
near $1 million indemnity for the flock.
"You can imagine
the relief that farmer felt," she said.
Reach Taunya English at
925-743-2216 or firstname.lastname@example.org.
The Signal, CA
Birds Euthanized Due to Outbreak
Franks [Signal Staff Writer]
A 1-kilometer area around William S. Hart
Park in Newhall is under quarantine for the exotic Newcastle disease, after an
outbreak forced the destruction of the park's captive birds, officials
said.On Wednesday and Thursday, all birds in the
park's barnyard area were destroyed because some tested positive for the
Many more birds may have to be killed; over the next several
days, federal officials plan to go door-to-door in the area surrounding the park
to determine if additional birds must be destroyed.
Superintendent Norm Phillips said he and his staff are mourning the loss of the
park?s 37 birds, which had been quarantined from the public since December. The
park?s birds included 19 chickens, seven ducks, seven geese, three turkeys and a
pheasant. A wild bird that was being housed at the park as confiscated evidence
was also destroyed.
"It is very disheartening," Phillips said. "We try
not to get attached to the birds, but when you feed them every day, you can't
help but get attached"
Phillips said members of the park's staff called
the U.S. Department of Agriculture on Sunday after they noticed that Birdzilla,
a turkey who had been at the park for nearly 20 years, was displaying possible
symptoms of the disease. He said the USDA then came to the park and tested three
of its hens, all of which tested positive.
"On Wednesday the USDA came
out. We knew what they were going to do, so we got ourselves ready," Phillips
said. "We didn't want the public to see, so we put (the birds) behind the barn.
I asked for the test results. They were positive. I couldn't watch."
On Thursday, after receiving permission from the Department of Fish and
Game, the confiscated wild bird was destroyed.
Phillips said the barnyard
portion of the park will be closed to the public until the USDA sanitizes the
"I advise anyone who owns birds not to come to the park
until the quarantine is lifted,"Phillips said.
Larry Cooper, spokesman
for the California Department of Food and Agriculture, said that over the next
several days federal officials will go door-to-door to residences in the
quarantined area, looking for other infected birds that may need to be
"A veterinarian will appraise the bird and the probability
that it was exposed to the disease," Cooper said. "If the veterinarian
classifies it as a dangerous contact bird, it has to be euthanized unless the
homeowner requests an appeal.
"People have the right of appeal, but if it
is deemed to be infected, those birds are going to die anyway."
Compensation is available for bird owners who have their birds
destroyed by the USDA.
Newcastle disease, which does not affect humans,
is a contagious and fatal viral disease that affects the respiratory, nervous
and digestive systems of most species of birds. The death rate is nearly 100
percent in unvaccinated birds, and the disease can still infect and kill birds
even if they are vaccinated.
Cooper said Newcastle is not a public health
threat and does not affect the safety of poultry or eggs, but the disease can be
unintentionally transmitted from one bird to another by humans and other
He said owners of any species of bird inside the quarantined
area are prohibited from moving their birds or poultry products out of the area
without a permit from the USDA. Violators of the quarantine may be subject to
fines of up to $25,000.
The discovery at Hart Park was the second known
occurrence of the disease in the Santa Clarita Valley. In December the USDA
destroyed all of the poultry at the Canyon Country Feed Bin after some of the
birds were found to be infected. The owners were compensated, but nonetheless
said the incident forced them to shut down permanently on Jan. 31 after nearly
50 years in business.
The last major outbreak of the Newcastle disease
was in 1971, when 1,341 infected flocks were found and nearly 12 million birds
were destroyed in California. There was also a small outbreak of the disease in
Then on Oct. 1, the disease was confirmed in the state again.
California was then placed under a federal quarantine to restrict the movement
of birds to try to stop the spread of the disease.
Since then, 13,207
premises have been quarantined in California, Nevada and Arizona. More than
2,000 of those premises in California contained infected birds and more than 3
million birds have been destroyed. Of those 2,000 sites, 395 were in Los Angeles
Cooper said as of February the USDA and the CDFA have spent more
than $35 million on an intensive eradication program throughout the
He said the state's quarantine and eradication program will
continue until the disease is destroyed.
For more information or to
report an outbreak of the Newcastle disease, call the California Department of
Food and Agriculture at (800) 491-1899 or go online to http://www.cdfa.ca.gov
Public release date: 13-Mar-2003
University of California - Berkeley
LIVERMORE-- Newly developed rapid diagnostic assays
to detect exotic Newcastle disease developed by a partnership of researchers
at Lawrence Livermore National Laboratory and other institutions have
"significantly aided" containment of the poultry disease. That's the view of
professor Alex Ardans, director of the California Animal Health and Food
Safety Laboratory based at the UC Davis School of Veterinary
Design and development of the assays have been done by a team
from the Laboratory, the California Animal Health and Food Safety Laboratory
(or CAHFS) at UC Davis and the U.S. Department of Agriculture.
time of the outbreak of exotic Newcastle disease last October in California,
available assays to identify the disease required 6 to 12 days, according to
A key signature that allows identification of the virus within
four hours of receiving the sample was facilitated by a genomic-approach
developed by an eight-member LLNL team, led by Paula McCready.
ongoing collaboration between LLNL and UC Davis doesn't only benefit the state
of California, but also the nation," Ardans said. "The Livermore approach to
developing assays for microbial diseases is being embraced
The rapid tests are being used to assist state and federal
exotic Newcastle disease task force personnel in disease detection and control
During the past five months, almost 3 million commercial
egg-producing chickens have been euthanized in California because of exotic
Newcastle disease. Additionally, more than 100,000 game birds and backyard
poultry also have been euthanized.
Currently, seven counties, all in
Southern California, are under quarantine, with a prohibition on moving
poultry such as chickens, turkeys, geese, partridges and other
Ardans believes federal and state agriculture officials are
making headway in the fight against exotic Newcastle disease. During the past
two weeks, the number of new cases of infected "backyard birds" seems to be
decreasing in some areas, he noted.
A highly lethal viral ailment,
exotic Newcastle disease affects poultry, causing respiratory problems and
lethargy. Chickens are particularly susceptible to the disease and usually die
within a few days.
"With the faster detection method, we can rapidly
identify the affected animals and isolate them before the disease spreads
further," said McCready.
"If an outbreak is not quickly contained, it
spreads rapidly, affecting the state's poultry industry and its ability to
trade with other states and countries."
Laboratory researchers were
contacted by CAHFS on Oct. 13, and within days had generated possible target
signatures for development of a rapid assay.
LLNL biomedical scientist
Evan Skowronski worked with CAHFS staff at UC Davis over the next two months
to optimize performance of the assays and pioneer ways to rapidly process
hundreds of samples per day. Skowronski was instrumental in sequencing the
first viruses isolated from commercial flocks to confirm the accuracy of the
In addition to disease identification in affected birds, the
rapid test is now being used routinely in surveillance efforts in unaffected
commercial flocks to assure their disease-free status.
involving nearly 600 different poultry houses will continue after the outbreak
is contained as a disease surveillance program to demonstrate that the state
is free of the disease.
"We were able to make a rapid response to an
outbreak of an emerging disease," said McCready, who is associate program
leader for biology in the Chemical and Biological National Security
The team's computations group, led by Tom Slezak, used unique
software developed by Laboratory researchers to identify a target sequence to
distinguish the highly virulent forms of the virus from other
This has been extremely useful in the rapid differentiation of
exotic Newcastle disease virus from closely related Newcastle disease viruses
used in vaccines or those causing less severe disease.
"To the best of
our knowledge, this is the first working rapid assay for Newcastle disease to
be adapted for routine diagnostic and surveillance use," McCready
The development of this exotic Newcastle disease signature and
the additional work required to ready it for use was paid for with Laboratory
Directed Research and Development money, a Laboratory fund for cutting-edge
In addition to McCready, Skowronski and Slezak, other members
of the Laboratory assay development team include bioinfomatics scientists Beth
Vitalis, Tom Kuczmarski and Shea Gardner, along with biomedical scientists
Shanavaz Nasarabadi and Jason Olivas. Funded in 1952, Lawrence Livermore
National Laboratory is a national security laboratory, with a mission to
ensure national security and apply science and technology to the important
issues of our time. Lawrence Livermore National Laboratory is managed by the
University of California for the U.S. Department of Energy's National Nuclear