Rapid Lab Test Available for Bird Flu Diagnosis

Medical Author: Melissa Conrad Stoppler, MD
Medical Editor: William C. Shiel, Jr, MD, FACP, FACR

Scientists at the U.S. Centers for Disease Control and Prevention (CDC) have developed a rapid diagnostic test for bird flu infection that was approved for use by the U.S. Food and Drug Administration (FDA) on February 3, 2006.

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.

From December 1, 2003, through February 3, 2006, the World Health Organization (WHO) reported 161 confirmed human cases of avian influenza A H5N1 ("bird flu"); of these, 86 (53%) were fatal. While the virus is not readily passed from human to human, the major fear with the avian influenza virus is that it may at some point mutate (change its genetic material) into a form that can easily be spread among humans, resulting in a worldwide influenza epidemic (pandemic).

For more information about the bird flu, please see the following articles:

Reference: Morbidity and Mortality Weekly Report, early release Centers for Disease Control and Prevention, Feb. 3, 2006


Last Editorial Review: 2/9/2006



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