A New, Rapid
Laboratory Test for Avian Influenza in the Live Bird Market
By Sharon Durham
February 18, 2003
A strain of avian influenza that
has been endemic in live bird markets can now be detected quickly using a new
laboratory test developed by an Agricultural
Research Service scientist.
ARS veterinary medical officer David Suarez developed the test to quickly
identify birds infected with the avian influenza strain H7N2, which has been
found among birds in northeastern U.S. markets since 1994. Live bird markets in
New York City and other areas sell a broad variety of poultry.
The laboratory test, called the real-time reverse transcriptase-polymerase
chain reaction test (RT-PCR), uses a fluorescent probe and produces results in
less than 3 hours.
For poultry, influenza infections can range from mild to severe, causing
production losses or, in severe cases, sickness and death. The deadly form is
called highly pathogenic avian influenza (HPAI). The mild form is hard to
differentiate from other, more common health characteristics in a flock.
Suarez's test uses the virus's genetic code to identify it.
In Virginia recently, a mild form of avian influenza infected 197 flocks,
forcing authorities to humanely euthanize 4.5 million birds as a precaution.
The virus remained as a mild strain, but had the potential to mutate and
decimate flocks in as little as a week.
Live bird markets in Florida and the northeastern United States serve as
central mixing areas for avian influenza viruses. The markets can harbor
viruses and act as virus "reservoirs" from which the disease
organisms can spread to larger commercial facilities.
The mild form H7N2 virus has been found in commercial poultry operations at
least three times in the last five years, causing disease and serious economic
losses for the industry. A 1983 outbreak cost $63 million in federal funds and
$350 million in increased consumer costs. This new test may aid in identifying
the viruses earlier and with more accuracy, therefore helping to control the
disease and reduce such economic losses.
Read more about this research in the
February issue of
Agricultural Research magazine.
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.