Characterization of an Avian Influenza A (H5N1) Virus Isolated from a Child with a Fatal Respiratory Illness

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Science  16 Jan 1998:
Vol. 279, Issue 5349, pp. 393-396
DOI: 10.1126/science.279.5349.393


  • Figure 1

    Alignment and comparison of complete HA coding sequence for the A/Hong Kong/156/97 virus isolate. Dashes under the sequence adjacent to the cleavage site indicate the positions of the insertions relative to the reference strain A/Turkey/England/91. The boxed amino acids indicate potential glycosylation sites. Underlined, bold peptides describe the location of the receptor binding site (12). The nucleotide sequence has been deposited in GenBank (accession number AF036356).

  • Figure 2

    Phylogenetic relationship of the HA1 domain of the hemagglutinin gene of representative avian H5 viruses and the H5 virus isolated from a human (A/Hong Kong/156/97, boxed). The tree is rooted in A/Chick/Scotland/59 (H5N1) as an outgroup. This is a neighbor-joining analysis determined by PHYLIP.

  • Figure 3

    Amplification of influenza HA gene from RNA extracted directly from the tracheal aspirate obtained from the patient. Lanes 1 and 14 contain a DNA ladder, with fragment sizes indicated along the left edge of the gel. RNA was extracted by means of the Qiagen (Valencia, California) RNeasy kit from the clinical material (lanes labeled HK/156/97: 4, 7, 10, 13), from known H1 (lane 2), H3 (lane 5), and H5 (lane 8) influenza A viruses, influenza B virus (lane 11), and water controls (lanes labeled −: 3, 6, 9, 12); reverse transcriptase reactions were carried out using 5 μl of RNA and 25 units of avian myeloblastosis virus reverse transcriptase in a 25-μl reaction. PCR was carried out using H1 (lanes 2 to 4), H3 (lanes 5 to 7), H5 (lanes 8 to 10), and B (lanes 11 to 13) HA-specific primers (PP, primer pairs); the expected product sizes are 1104, 785, 1110, and 1104 base pairs, respectively. PCR cycling conditions included denaturation at 94°C for 7 min, annealing for 2 min at 50°C, and extension for 3 min at 72°C, followed by 29 cycles of denaturation at 94°C for 1 min, annealing for 2 min at 50°C, extension for 3 min at 72°C, and an additional extension of 7 min at 72°C.

  • Figure 4

    Immunofluorescence staining of cells from the tracheal aspirate obtained from the patient. Acetone-fixed cells were incubated with influenza virus–specific monoclonal antibodies followed by fluorescein isothiocyanate–conjugated goat antibodies to mouse immunoglobulin G. The influenza virus–specific monoclonal antibodies used were (A) a pool of two antibodies raised against the H5 HA of A/chicken/Pennsylvania/1370/83, (B) an antibody that is broadly cross-reactive with the HA of human H3N2 viruses, (C) a pool of two antibodies specific for the NP of influenza A viruses, and (D) antibody specific for influenza B viruses.


  • Table 1

    Molecular analysis of the gene segments of the A/Hong Kong/156/97 virus. Nucleotide sequences were compared, and identity was determined by FASTA (Wisconsin Package, version 9.0) searches of GenBank and European Molecular Biology Laboratory (EMBL) databases as of August and June 1997, respectively. The nucleotide sequences have been deposited in GenBank (accession numbers AF036356 throughAF036363).

    Gene segmentRegion amplifiedRegion sequencedViruses with greatest degrees of identityIdentity (%)
    PB28–233761–2310A/Budgerigar/Hokkaido/1/77 (H4N6)90.1
    PB110–234032–2291A/Singapore/1/57 (H2N2)90.6
    PA1–220031–1754 and 1974–2179A/Duck/Hokkaido/8/80 (H3N8)91.0
    HA1–177321–1743A/Turkey/England/91 (H5N1)93.5
    NP7–156121–1542A/Mallard/Astrakhan/244/82 (H14N6)93.6
    NA1–140029–1391A/Parrot/Ulster/73 (H7N1)91.1
    M775–1027796–1001A/Turkey/Minnesota/833/80 (H1N1)98.5
    NS1–89027–860A/Duck/Hong Kong/717/79 (H1N3)93.7

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