Influenza virus diagnosed in record time with new genetic test
2 February 2012
Wako, Japan. A new genetic analysis technique developed by
researchers at the RIKEN Omics Science Center (OSC) in Japan has
succeeded in detecting influenza virus infection in only 40 minutes and
with one hundred times the sensitivity of conventional methods.
Clinical research conducted in 2009 and 2010 confirmed the
new technique accurately identified the 2009 pandemic (pdm)
influenza virus in Japanese patients less than 24 hours after fever
onset, much faster than standard diagnostic tests.
The human-to-human transmission of new, highly pathogenic strains
of influenza virus poses a major threat to human health and to the
security of global society. With its rapid global spread, the 2009
pandemic (pdm) influenza virus reminded the world of this threat,
resulting in an estimated 18,000 deaths worldwide. In Japan,
infected patients over the winter season of 2009 accounted for a
staggering 16% of the total population of 127 million.
Tackling the challenge of such global pandemics requires new
technology for rapid clinical diagnosis. To answer this need,
Toshihisa Ishikawa and colleagues at the RIKEN OSC developed the RT-SmartAmp
assay, a technique to rapidly detect the 2009 pdm influenza A(H1N1)
virus from patient swab samples.
By combining both reverse transcriptase (RT) and isothermal DNA
amplification reactions in one step, the RT-SmartAmp assay does away
with the need for RNA extraction and PCR reaction. The researchers
adapted the RT-SmartAmp technique using a fluorescent primer to
specifically detect the 2009 pdm influenza A(H1N1) virus within 40
minutes, without cross-reacting with the seasonal A(H1N1), A(H3N2),
or B-type (Victoria) viruses.
The effectiveness of the RT-SmartAmp method was confirmed in
clinical research carried out at Japanese hospitals during the
period of October 2009 to January 2010, where it outperformed
standard diagnosis tests in both speed and sensitivity. Of a total
255 clinical samples, 140 (54.9%) were identified as 2009 pdm
A(H1N1)-positive by RT-SmartAmp, compared to only 110 (43.1%)
detected by standard diagnostic tests. In 72.8% of all 140
infection-positive cases, the RT-SmartAmp assay detected the
presence of the pdm influenza virus within 24 hours of fever onset.
Taken together, these results set a new standard for infection
diagnosis speed, providing a highly-effective tool for rapidly
detecting sub-types of the H5N1 virus and oseltamivir-resistant
influenza viruses and promising support in the battle to prevent
global pandemic infection.
Kawai et al. One-step detection of the 2009 pandemic influenza
A(H1N1) virus by the RT-SmartAmp assay and its clinical validation”.
PLoS ONE, 2012, doi:10.1371/journal.pone.0030236