Advances in the molecular based techniques for the diagnosis and characterization of avian influenza virus infections.
There have been remarkable advances in the molecular diagnosis and characterization of avian influenza virus infections in domestic poultry and free-living birds in the past two decades. Rapid pathotyping became possible with the recognition that the amino acid sequence of the connecting peptide of the haemagglutinin precursor, HA(0), is a major virulence determinant for H5 and H7 subtype viruses. This in turn resulted in nucleic acid sequencing as a relatively routine method for identifying highly pathogenic avian influenza virus isolates. Subsequent development of diagnostic methods based on reverse transcription-polymerase chain reaction (RT-PCR), real-time RT-PCR, nucleic acid sequence-based amplification and loop-mediated isothermal amplification has made the rapid detection of group A influenza and H5 and H7 subtype viruses possible. Further development of these assay platforms has enabled the specific detection of H5N1 Eurasian subtype viruses and the inference of their HA(0) cleavage sites. Identification of additional virulence determinants of influenza A viruses for birds and mammals will allow the emerging area of microarray technology to further extend our understanding of their ecology, epidemiology and pathogenesis.
Pasick
J
J
Canadian Food Inspection Agency, National Centre for Foreign Animal Disease, Winnipeg, MB, Canada. jpasick@inspection.gc.ca
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001717:Birds; D005838:Genotype; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics*; D006801:Humans; D009980:Influenza A virus / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D005585:Influenza in Birds / Q000175:diagnosis* / Q000821:virology; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques / Q000379:methods; D011200:Poultry; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D012367:RNA, Viral