Development and evaluation of a SYBR green-based real time RT-PCR assay for detection of the emerging avian influenza A (H7N9) virus

PLoS One. 2013 Nov 20;8(11):e80028. doi: 10.1371/journal.pone.0080028. eCollection 2013.

Abstract

Most recently a novel avian-origin influenza A (H7N9) virus emerged in China and has been associated with lots of human infection and fatal cases. Genetic analysis of the viral genome revealed that this reassortant virus might be better adapted to humans than other avian influenza viruses. Molecular diagnostic methods are thus urgently needed in public health laboratories. In this study, a SYBR green-based one-step real time reverse transcription-PCR (RT-PCR) was developed to detect the novel H7N9 virus. The primer pairs on the basis of the hemagglutinin and neuraminidase gene sequences of H7N9 viruses amplified subtype-specific fragments with Tm values of 80.77±0.06°C for H7 and 81.20±0.17°C for N9 respectively. The standard curves showed a dynamic linear range across 6 log units of RNA copy number (10(6) to 10(1) copies/ µl) with a detection limit of 10 copies per reaction for both H7 and N9 assays by using serial ten-fold diluted in-vitro transcribed viral RNA. In addition, no cross-reactivity was observed with seasonal H1N1, H1N1 pdm09, H3N2, H5N1 and H9N2 viruses as well as other human respiratory viruses. When the assay was further evaluated in H7N9 virus infected clinical samples, positive amplification signals were obtained in all of the specimens with the accordance between H7 and N9 assays. Therefore, the established SYBR green-based real time RT-PCR assay could provide a rapid, sensitive, specific and reliable alternative approach with lower costs for high throughput screening of suspected samples from humans, animals and environments in first line public health laboratories.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Base Sequence
  • Benzothiazoles
  • DNA, Viral / chemistry
  • DNA, Viral / genetics*
  • Diamines
  • Influenza A Virus, H7N9 Subtype / genetics
  • Influenza A Virus, H7N9 Subtype / isolation & purification*
  • Limit of Detection
  • Molecular Sequence Data
  • Organic Chemicals / chemistry*
  • Quinolines
  • RNA, Viral / genetics
  • Real-Time Polymerase Chain Reaction / methods*
  • Sequence Homology, Nucleic Acid
  • Transcription, Genetic

Substances

  • Benzothiazoles
  • DNA, Viral
  • Diamines
  • Organic Chemicals
  • Quinolines
  • RNA, Viral
  • SYBR Green I

Grants and funding

This study was supported in part by the Jiangsu Province Health Development Project with Science and Education (ZX201109), the Jiangsu Province Key Medical Talent Foundation (JKRC2011002, RC2011191), and the Science and Technology Pillar program of Jiangsu Province (BE2011796). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.