Human infection with an avian H9N2 influenza A virus in Hong Kong in 2003

Abstract

Avian H9N2 influenza A virus has caused repeated human infections in Asia since 1998. Here we report that an H9N2 influenza virus infected a 5-year-old child in Hong Kong in 2003. To identify the possible source of the infection, the human isolate and other H9N2 influenza viruses isolated from Hong Kong poultry markets from January to October 2003 were genetically and antigenically characterized. The findings of this study show that the human H9N2 influenza virus, A/Hong Kong/2108/03, is of purely avian origin and is closely related to some viruses circulating in poultry in the markets of Hong Kong. The continued presence of H9N2 influenza viruses in poultry markets in southern China increases the likelihood of avian-to-human interspecies transmission.

FIG.1.

Phylogenetic relationships of the influenza A virus genes HA, nucleotide positions 55 to 1042 (A); NA, nucleotide positions 1 to 1372 (B); M (matrix), nucleotide positions 1 to 972 (C); NP (nucleoprotein), nucleotide positions 49 to 1009 (D); NS (nonstructural), nucleotide positions 23 to 823 (E); PA (polymerase acidic), nucleotide positions 1423 to 2144 (F); PB1 (polymerase basic 1), nucleotide positions 1 to 1218 (G); and PB2 (polymerase basic 2), nucleotide positions 1101 to 2220 (H). Trees were generated with MEGA2 by using a Tamura-Nei (gamma) neighbor-joining analysis. The HA phylogenetic tree is rooted to A/turkey/Wisconsin/66; the NA tree is rooted to A/Leningrad/134/57; and the PA and PB1 trees are rooted to A/Ann Arbor/6/60 and B/Lee/40, respectively. The M, NP, NS, and PB2 trees are rooted to A/equine/Prague/1/56. Scale bars, 0.05 (HA, NS, PB1) and 0.02 (NA, M, NP, PA, PB2) nucleotide changes per nucleotide. The numbers at the nodes indicate bootstrap values from 500 bootstrap replicates. All viruses sequenced in the present study are underlined, and the remaining sequences can be found in GenBank. Abbreviations: Bei, Beijing; Cu, chukar; Ck, chicken; Dk, duck; GD, Guangdong; Gf, Guinea fowl; Gs, goose; GZ, Guangzhou; HK, Hong Kong; Kor, Korea; Pg, pigeon; Ph, pheasant; Qa, quail; SCk, silky chicken; ST, Shantou; Sw, swine; Ty, turkey; WDk, wild duck.

FIG.1.

Phylogenetic relationships of the influenza A virus genes HA, nucleotide positions 55 to 1042 (A); NA, nucleotide positions 1 to 1372 (B); M (matrix), nucleotide positions 1 to 972 (C); NP (nucleoprotein), nucleotide positions 49 to 1009 (D); NS (nonstructural), nucleotide positions 23 to 823 (E); PA (polymerase acidic), nucleotide positions 1423 to 2144 (F); PB1 (polymerase basic 1), nucleotide positions 1 to 1218 (G); and PB2 (polymerase basic 2), nucleotide positions 1101 to 2220 (H). Trees were generated with MEGA2 by using a Tamura-Nei (gamma) neighbor-joining analysis. The HA phylogenetic tree is rooted to A/turkey/Wisconsin/66; the NA tree is rooted to A/Leningrad/134/57; and the PA and PB1 trees are rooted to A/Ann Arbor/6/60 and B/Lee/40, respectively. The M, NP, NS, and PB2 trees are rooted to A/equine/Prague/1/56. Scale bars, 0.05 (HA, NS, PB1) and 0.02 (NA, M, NP, PA, PB2) nucleotide changes per nucleotide. The numbers at the nodes indicate bootstrap values from 500 bootstrap replicates. All viruses sequenced in the present study are underlined, and the remaining sequences can be found in GenBank. Abbreviations: Bei, Beijing; Cu, chukar; Ck, chicken; Dk, duck; GD, Guangdong; Gf, Guinea fowl; Gs, goose; GZ, Guangzhou; HK, Hong Kong; Kor, Korea; Pg, pigeon; Ph, pheasant; Qa, quail; SCk, silky chicken; ST, Shantou; Sw, swine; Ty, turkey; WDk, wild duck.

FIG.1.

Phylogenetic relationships of the influenza A virus genes HA, nucleotide positions 55 to 1042 (A); NA, nucleotide positions 1 to 1372 (B); M (matrix), nucleotide positions 1 to 972 (C); NP (nucleoprotein), nucleotide positions 49 to 1009 (D); NS (nonstructural), nucleotide positions 23 to 823 (E); PA (polymerase acidic), nucleotide positions 1423 to 2144 (F); PB1 (polymerase basic 1), nucleotide positions 1 to 1218 (G); and PB2 (polymerase basic 2), nucleotide positions 1101 to 2220 (H). Trees were generated with MEGA2 by using a Tamura-Nei (gamma) neighbor-joining analysis. The HA phylogenetic tree is rooted to A/turkey/Wisconsin/66; the NA tree is rooted to A/Leningrad/134/57; and the PA and PB1 trees are rooted to A/Ann Arbor/6/60 and B/Lee/40, respectively. The M, NP, NS, and PB2 trees are rooted to A/equine/Prague/1/56. Scale bars, 0.05 (HA, NS, PB1) and 0.02 (NA, M, NP, PA, PB2) nucleotide changes per nucleotide. The numbers at the nodes indicate bootstrap values from 500 bootstrap replicates. All viruses sequenced in the present study are underlined, and the remaining sequences can be found in GenBank. Abbreviations: Bei, Beijing; Cu, chukar; Ck, chicken; Dk, duck; GD, Guangdong; Gf, Guinea fowl; Gs, goose; GZ, Guangzhou; HK, Hong Kong; Kor, Korea; Pg, pigeon; Ph, pheasant; Qa, quail; SCk, silky chicken; ST, Shantou; Sw, swine; Ty, turkey; WDk, wild duck.

FIG.1.

Phylogenetic relationships of the influenza A virus genes HA, nucleotide positions 55 to 1042 (A); NA, nucleotide positions 1 to 1372 (B); M (matrix), nucleotide positions 1 to 972 (C); NP (nucleoprotein), nucleotide positions 49 to 1009 (D); NS (nonstructural), nucleotide positions 23 to 823 (E); PA (polymerase acidic), nucleotide positions 1423 to 2144 (F); PB1 (polymerase basic 1), nucleotide positions 1 to 1218 (G); and PB2 (polymerase basic 2), nucleotide positions 1101 to 2220 (H). Trees were generated with MEGA2 by using a Tamura-Nei (gamma) neighbor-joining analysis. The HA phylogenetic tree is rooted to A/turkey/Wisconsin/66; the NA tree is rooted to A/Leningrad/134/57; and the PA and PB1 trees are rooted to A/Ann Arbor/6/60 and B/Lee/40, respectively. The M, NP, NS, and PB2 trees are rooted to A/equine/Prague/1/56. Scale bars, 0.05 (HA, NS, PB1) and 0.02 (NA, M, NP, PA, PB2) nucleotide changes per nucleotide. The numbers at the nodes indicate bootstrap values from 500 bootstrap replicates. All viruses sequenced in the present study are underlined, and the remaining sequences can be found in GenBank. Abbreviations: Bei, Beijing; Cu, chukar; Ck, chicken; Dk, duck; GD, Guangdong; Gf, Guinea fowl; Gs, goose; GZ, Guangzhou; HK, Hong Kong; Kor, Korea; Pg, pigeon; Ph, pheasant; Qa, quail; SCk, silky chicken; ST, Shantou; Sw, swine; Ty, turkey; WDk, wild duck.