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Genetic diversity of the 2013-14 human isolates of influenza H7N9 in China.

Farooqui A, Leon AJ, Huang L, Wu S, Cai Y, Lin P, Chen W, Fang X, Zeng T, Liu Y, Zhang L, Su T, Chen W, Ghedin E, Zhu H, Guan Y, Kelvin DJ - BMC Infect. Dis. (2015)

Bottom Line: The sequences of the isolates from Shantou have closer evolutionary proximity to the predominant Eastern H7N9 cluster (similar to A/Shanghai/1/2013 (H7N9)) than to the Southern H7N9 cluster (similar to A/Guangdong/1/2013 (H7N9)).The Eastern cluster, which includes the four isolates from Shantou, presents a wide geographic distribution and overlaps with the more restricted area of circulation of the Southern cluster.Continued monitoring of the avian disease is of critical importance to better understand and predict the epidemiological behaviour of the human cases.

View Article: PubMed Central - PubMed

Affiliation: Division of Immunology, International Institute of Infection and Immunity, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong, 515041, China. amberfarooqui@hotmail.com.

ABSTRACT

Background: Influenza H7N9 has become an endemic pathogen in China where circulating virus is found extensively in wild birds and domestic poultry. Two epidemic waves of Human H7N9 infections have taken place in Eastern and South Central China during the years of 2013 and 2014. In this study, we report on the first four human cases of influenza H7N9 in Shantou, Guangdong province, which occurred during the second H7N9 wave, and the subsequent analysis of the viral isolates.

Methods: Viral genomes were subjected to multisegment amplification and sequenced in an Illumina MiSeq. Later, phylogenetic analyses of influenza H7N9 viruses were performed to establish the evolutionary context of the disease in humans.

Results: The sequences of the isolates from Shantou have closer evolutionary proximity to the predominant Eastern H7N9 cluster (similar to A/Shanghai/1/2013 (H7N9)) than to the Southern H7N9 cluster (similar to A/Guangdong/1/2013 (H7N9)).

Conclusions: Two distinct phylogenetic groups of influenza H7N9 circulate currently in China and cause infections in humans as a consequence of cross-species spillover from the avian disease. The Eastern cluster, which includes the four isolates from Shantou, presents a wide geographic distribution and overlaps with the more restricted area of circulation of the Southern cluster. Continued monitoring of the avian disease is of critical importance to better understand and predict the epidemiological behaviour of the human cases.

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Related in: MedlinePlus

Mapping of aminoacid substitutions found in the hemagglutinin A) and neuraminidase B) proteins that are present in the four Shantou isolates. Ribbon diagrams were generated with Pymol (1.7.1.13) (http://www.pymol.org) and the 3D protein structures with RCSB’s Protein Workshop (http://www.rcsb.org) using PDB accessions 4KOL (HA) and 4MWL (NA).
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Fig4: Mapping of aminoacid substitutions found in the hemagglutinin A) and neuraminidase B) proteins that are present in the four Shantou isolates. Ribbon diagrams were generated with Pymol (1.7.1.13) (http://www.pymol.org) and the 3D protein structures with RCSB’s Protein Workshop (http://www.rcsb.org) using PDB accessions 4KOL (HA) and 4MWL (NA).

Mentions: At the aminoacid level, several novel substitutions were present in all four Shantou strains (Additional file 2: Table S2): PA (P271S and N321C), HA (E409G [H3 numbering]), M2 (V27I), NA (S78N and R220Q [both in N2 numbering]) and NS1 (S48I and A82P). Mapping the aminoacid substitutions to the 3D structures of the HA and NA genes (PDB accessions 4KOL and 4MWL, respectively) showed that HA-E409G belongs to the stalk domain of the HA2 protein, NA-S78N belongs to the stalk domain of the NA protein, and NA-R220Q is situated in an area of the NA protein surface not related to the active site (Figure 4).Figure 4


Genetic diversity of the 2013-14 human isolates of influenza H7N9 in China.

Farooqui A, Leon AJ, Huang L, Wu S, Cai Y, Lin P, Chen W, Fang X, Zeng T, Liu Y, Zhang L, Su T, Chen W, Ghedin E, Zhu H, Guan Y, Kelvin DJ - BMC Infect. Dis. (2015)

Mapping of aminoacid substitutions found in the hemagglutinin A) and neuraminidase B) proteins that are present in the four Shantou isolates. Ribbon diagrams were generated with Pymol (1.7.1.13) (http://www.pymol.org) and the 3D protein structures with RCSB’s Protein Workshop (http://www.rcsb.org) using PDB accessions 4KOL (HA) and 4MWL (NA).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4352237&req=5

Fig4: Mapping of aminoacid substitutions found in the hemagglutinin A) and neuraminidase B) proteins that are present in the four Shantou isolates. Ribbon diagrams were generated with Pymol (1.7.1.13) (http://www.pymol.org) and the 3D protein structures with RCSB’s Protein Workshop (http://www.rcsb.org) using PDB accessions 4KOL (HA) and 4MWL (NA).
Mentions: At the aminoacid level, several novel substitutions were present in all four Shantou strains (Additional file 2: Table S2): PA (P271S and N321C), HA (E409G [H3 numbering]), M2 (V27I), NA (S78N and R220Q [both in N2 numbering]) and NS1 (S48I and A82P). Mapping the aminoacid substitutions to the 3D structures of the HA and NA genes (PDB accessions 4KOL and 4MWL, respectively) showed that HA-E409G belongs to the stalk domain of the HA2 protein, NA-S78N belongs to the stalk domain of the NA protein, and NA-R220Q is situated in an area of the NA protein surface not related to the active site (Figure 4).Figure 4

Bottom Line: The sequences of the isolates from Shantou have closer evolutionary proximity to the predominant Eastern H7N9 cluster (similar to A/Shanghai/1/2013 (H7N9)) than to the Southern H7N9 cluster (similar to A/Guangdong/1/2013 (H7N9)).The Eastern cluster, which includes the four isolates from Shantou, presents a wide geographic distribution and overlaps with the more restricted area of circulation of the Southern cluster.Continued monitoring of the avian disease is of critical importance to better understand and predict the epidemiological behaviour of the human cases.

View Article: PubMed Central - PubMed

Affiliation: Division of Immunology, International Institute of Infection and Immunity, Shantou University Medical College, 22 Xinling Road, Shantou, Guangdong, 515041, China. amberfarooqui@hotmail.com.

ABSTRACT

Background: Influenza H7N9 has become an endemic pathogen in China where circulating virus is found extensively in wild birds and domestic poultry. Two epidemic waves of Human H7N9 infections have taken place in Eastern and South Central China during the years of 2013 and 2014. In this study, we report on the first four human cases of influenza H7N9 in Shantou, Guangdong province, which occurred during the second H7N9 wave, and the subsequent analysis of the viral isolates.

Methods: Viral genomes were subjected to multisegment amplification and sequenced in an Illumina MiSeq. Later, phylogenetic analyses of influenza H7N9 viruses were performed to establish the evolutionary context of the disease in humans.

Results: The sequences of the isolates from Shantou have closer evolutionary proximity to the predominant Eastern H7N9 cluster (similar to A/Shanghai/1/2013 (H7N9)) than to the Southern H7N9 cluster (similar to A/Guangdong/1/2013 (H7N9)).

Conclusions: Two distinct phylogenetic groups of influenza H7N9 circulate currently in China and cause infections in humans as a consequence of cross-species spillover from the avian disease. The Eastern cluster, which includes the four isolates from Shantou, presents a wide geographic distribution and overlaps with the more restricted area of circulation of the Southern cluster. Continued monitoring of the avian disease is of critical importance to better understand and predict the epidemiological behaviour of the human cases.

Show MeSH
Related in: MedlinePlus