The technique, which is based on molecular biological methods, swiftly identifies from patient swab samples, the Influenza A virus, designated H1N1 that caused the 2009 pandemic.

Scientists at the RIKEN Omics Science Center (OSC; Yokohama, Japan) combined both reverse transcriptase (RT) and isothermal DNA amplification reactions in one step for the assay, which does away with the need for ribonucleic acid (RNA) extraction and polymerase chain reaction (PCR). They adapted the real-time smart-amplification process (RT-SmartAmp) technique using a fluorescent primer to specifically detect the 2009 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 studies 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 pandemic 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 pandemic influenza virus within 24 hours of fever onset.

The human-to-human transmission of new, highly pathogenic strains of influenza virus poses today a major threat to human health and to the security of global society. With its rapid global spread, the 2009 pandemic 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. The scientists concluded that their results set a new standard for infection diagnosis speed, providing a highly effective tool for rapidly detecting subtypes of the H5N1 virus and drug-resistant influenza viruses and promising support in the battle to prevent global pandemic infection.

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RIKEN Omics Science Center