Another potential advantage is that the MChip would, for the
first time, create a way to simultaneously screen large numbers
of flu samples to learn both the type and subtype of virus present.
Current real-time tests provide information about the type of virus
(type A or B) in a sample, but additional tests must be run to determine
the virus subtype (for example, H5N1 subtype.)
Working in biosafety-level-3-enhanced labs in Atlanta, CDC scientists,
including Catherine B. Smith, M.S., extracted H5N1 genetic material
from virus samples derived from human, feline and multiple avian
hosts, including geese, chickens and ducks. The samples represented
infections that had occurred between 2003 and 2006 over a vast geographic
area, including Vietnam, Nigeria, Indonesia and Kazakhstan. Six
of the human viral isolates were taken from an Indonesian family
in which human-to-human H5N1 virus transmission was suspected. The
virus diversity in the samples is important, explains Dr. Rowlen,
because any diagnostic tool designed for eventual use on a rapidly
changing virus, such as H5N1, must be able to detect as many variants
as possible.
Dr. Rowlen and her colleagues tested the ability of the MChip to
correctly identify 24 different H5N1 viral isolates, and distinguish
those from seven non-H5N1 isolates. The MChip accurately identified
and gave complete subtype information (identifying the samples as
H5N1) for the 21 out of 24 strains of H5N1. Importantly, notes Dr.
Rowlen, the test gave no false positives, meaning that the chip
never indicated the presence of H5N1 when none was present.
Following exposure to a viral isolate, the MChip displays results
as a pattern of fluorescent spots. To automate the process of interpreting
this pattern--thus eliminating the possibility of human error--the
researchers developed an artificial neural network trained to recognize
the distinctive pattern indicative of H5N1. Automating the interpretation
of MChip results could allow it to be used more readily by health
workers at the site of possible flu outbreaks, notes Dr. Rowlen.
"This new technology, once manufactured and distributed, could have
the potential to revolutionize the way laboratories test for influenza,"
says Nancy J. Cox, Ph.D., director of the CDC's influenza division.
"The MChip could enable more scientists and physicians, possibly
even those working in remote places, to more quickly test for H5N1
and to accurately identify the specific strain and its features.
This would greatly increase our ability to learn more about the
viruses causing illness and take the best steps to respond."
The raw materials for the MChip cost less than 10 dollars, Dr. Rowlen
says, and discussions are under way to commercialize its manufacture.
###
For more information on influenza see http://www3.niaid.nih.gov/news/focuson/flu. Also visit http://www.pandemicflu.gov/
for one-stop access to U.S. Government information on avian and
pandemic flu.
NIAID is a component of the National Institutes of Health. NIAID
supports basic and applied research to prevent, diagnose and treat
infectious diseases such as HIV/AIDS and other sexually transmitted
infections, influenza, tuberculosis, malaria and illness from potential
agents of bioterrorism. NIAID also supports research on basic immunology,
transplantation and immune-related disorders, including autoimmune
diseases, asthma and allergies.
The National Institutes of Health (NIH)--The Nation's Medical Research
Agency--includes 27 Institutes and Centers and is a component of
the U. S. Department of Health and Human Services. It is the primary
federal agency for conducting and supporting basic, clinical and
translational medical research, and it investigates the causes,
treatments and cures for both common and rare diseases. For more
information about NIH and its programs, visit http://www.nih.gov/.
Since it was founded in 1946 to help control malaria, CDC has remained
at the forefront of public health efforts to prevent and control
infectious and chronic diseases, injuries, workplace hazards, disabilities,
and environmental health threats. Today, CDC is globally recognized
for conducting research and investigations and for its action oriented
approach. For more information on CDC and its programs, visit http://www.cdc.gov/. References: ED Dawson et al. Identification
of A/H5N1 influenza viruses using a single gene diagnostic microarrray.
Analytical Chemistry. DOI: 10.1021/ac061920o (2006).
ED Dawson et al. MChip: A new tool for influenza surveillance. Analytical
Chemistry. DOI: 10.1021/ac061739f (2006).
"Quick Diagnosis of Flu Strains Possible with New Microchip Test
(FluChip)" HHS News Release Aug. 25 2006. http://www3.niaid.nih.gov/news/newsreleases/2006/fluchip.htm.
Contact: NIAID News Office
NIH/National Institute of Allergy and Infectious Diseases
Rapid Flu Test Helps Target Avian Flu
Main Category: Bird Flu / Avian Flu News
Article Date: 14 Nov 2005 - 0:00 PST
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A rapid test for the detection of influenza type A and B viruses
is now available from Oxoid Limited. The Xpect? Flu A & B test
not only detects infuenza A and B viruses from clinical samples
within 15 minutes, but it also distinguishes between these two virus
types.
Distinguishing between influenza types A and B helps virologists
to target investigations for the H5N1 strain (a type A virus), which
is responsible for the avian flu epidemic that is currently sweeping
through poultry and wild bird populations in many Asian countries1,2.
Although H5N1 is principally an avian virus, cases of human infection
have been reported in Hong Kong, Thailand, Vietnam and Cambodia
1,3,4. Most cases are due to contact with infected poultry or contaminated
surfaces, however a few cases of human to human transmission may
have occurred3. Because of this, and the ability of influenza viruses
to change (drift and shift), many experts believe that we are on
the verge of a serious flu pandemic1,2,3.
Virologists and health officials around the world are working to
ensure that countries are as prepared as they can be for the possibility
of widespread human infection. According to a UN spokesman, the
size and impact of a flu pandemic will depend on how quickly it
is detected2.
Xpect? Flu A & B detects and distinguishes the type A influenza
virus from type B in just 15 minutes, and with 100% specificity5,
directly from nose or throat swabs. This simple lateral flow test
is extremely easy to perform and interpret, giving virologists quick
and valuable information with which to target further investigations
and patient care. For samples that may require transportation, a
wide variety of transport media are suitable. Furthermore, samples
can be refrigerated and tested within 72 hours or frozen at -20?C
or below and tested within 6 months.
Xpect? Flu A & B is included in a wide range of products for
virologists available from Oxoid, please check with your local Oxoid
representative for availability, or for further information, please
telephone +44 (0) 1256 841144, email val.kane@oxoid.com or visit
http://www.oxoid.com
-ends- References
1 WHO (2004), Avian influenza. WHO Fact Sheet.
2 BBC News (2005), Bird flu 'could kill 150m people'. 30 September
2005.
3 CDC (2005), Avian Influenza Infection in Humans, CDC report, 24
May 2005.
4 CDC (2005), Key facts about Avian Influenza (Bird Flu) and Avian
Influenza A (H5N1) Virus, CDC report, 24 may 2005.
Oxoid Limited Wade Road Basingstoke Hampshire RG24 8PW United Kingdom
Tel: +44 (0) 1256 841144 Fax: +44 (0) 1256 463388 oxoid@oxoid.com
http://www.oxoid.com
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