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The test uses technology known as
Reverse Transcription--Polymerase Chain Reaction (RT-PCR)
to amplify and detect
genetic material from the
influenza A/H5 from the Asian lineage, the same virus that has been associated
with bird flu outbreaks in animals and humans in east Asia, Turkey, and Iraq. No
infections with this virus have been reported in animals or human in North
America, although the doctors at the CDC have recommended an “enhanced
surveillance” for possible cases of bird flu in the U.S since February 2004.
This means that people who develop respiratory illnesses who have had contact
with infected poultry in a country with known avian influenza outbreaks should
be tested to determine whether they have been infected with the bird flu virus.
The new test is carried out on a
sample of a respiratory secretion (either through a swab or
aspiration) taken at a
clinic, emergency room or doctor's office. The sample would then be sent to one
of about 140 laboratories in the CDC’s network, which should be able to perform
the test and generate results in two to four hours. Older tests to identify the
bird flu virus took a minimum of two to three days for results to be available.
The definitive diagnosis of
influenza A/H5 (Asian lineage) may require additional laboratory testing, and
the results of the new test may need to be assessed in consultation with
influenza surveillance experts. Also, a negative test result does not absolutely
rule out the possibility
of infection. Still, the test will have value in the rapid identification of
bird flu virus infection in persons who are ill who may have been exposed to the
avian influenza virus. Experts note that the test is not intended as a screening
test for infection in the general public.
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