Rapid diagnosis of H5N1 avian influenza virus infection by newly developed influenza H5 hemagglutinin gene-specific loop-mediated isothermal amplification method

J Virol Methods. 2007 May;141(2):173-80. doi: 10.1016/j.jviromet.2006.12.004. Epub 2007 Jan 10.


Reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) is a unique gene amplification method that can be completed within 35 min at 62.5 degrees C. In the present study, RT-LAMP was used to develop a rapid and sensitive laboratory diagnostic system for the H5N1 highly pathogenic avian influenza (HPAI). The sensitivity of the system was 0.1-0.01 plaque-forming units per reaction for HPAI-H5N1 viruses belonging to the genetically and antigenically distinct clade 1, represented by A/Vietnam/JP1203/2004, and clade 2, represented by A/Indonesia/JP283/2006. This RT-LAMP sensitivity is 10-fold higher than the sensitivity of standard one-step RT-PCR. By using viral RNAs extracted from avian influenza viruses of H1-H15 hemagglutinin (HA) subtypes and human pathogenic respiratory viruses, it was confirmed that the RT-LAMP system amplifies specifically RNA of the H5 subtype virus. The system detected H5-HA genes in throat swabs collected from humans as well as from wild birds. These results suggest that the present RT-LAMP system is a useful diagnostic tool for surveillance of recent outbreaks of the HPAI-H5N1 virus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Animals
  • Antigens, Viral / genetics
  • Base Sequence
  • Child
  • Child, Preschool
  • Crows
  • DNA Primers / genetics
  • Genes, Viral
  • Hemagglutinin Glycoproteins, Influenza Virus / genetics
  • Humans
  • Influenza A Virus, H5N1 Subtype / genetics
  • Influenza A Virus, H5N1 Subtype / isolation & purification*
  • Influenza A virus / genetics
  • Influenza A virus / isolation & purification*
  • Influenza in Birds / diagnosis*
  • Influenza in Birds / virology
  • Influenza, Human / diagnosis*
  • Influenza, Human / virology
  • Middle Aged
  • Molecular Sequence Data
  • Reverse Transcriptase Polymerase Chain Reaction / methods*
  • Sensitivity and Specificity
  • Species Specificity


  • Antigens, Viral
  • DNA Primers
  • Hemagglutinin Glycoproteins, Influenza Virus
  • hemagglutinin, avian influenza A virus