Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014 Aug;88(15):8297-306.
doi: 10.1128/JVI.00630-14. Epub 2014 May 14.

Continuing reassortment leads to the genetic diversity of influenza virus H7N9 in Guangdong, China

Jing Lu  1 , Jie Wu  2 , Xianqiao Zeng  2 , Dawei Guan  2 , Lirong Zou  2 , Lina Yi  1 , Lijun Liang  2 , Hanzhong Ni  2 , Min Kang  2 , Xin Zhang  2 , Haojie Zhong  2 , Xiang He  1 , Corina Monagin  3 , Jinyan Lin  2 , Changwen Ke  4
Affiliations

Continuing reassortment leads to the genetic diversity of influenza virus H7N9 in Guangdong, China

Jing Lu et al. J Virol. 2014 Aug.

Abstract

On 30 March 2013, a novel avian influenza A H7N9 virus causing severe human respiratory infections was identified in China. Preliminary sequence analyses have shown that the virus is a reassortant of H7N9 and H9N2 avian influenza viruses. In this study, we conducted enhanced surveillance for H7N9 virus in Guangdong, China, from April to August 2013. We isolated two H7N9 viral strains from environmental samples associated with poultry markets and one from a clinical patient. Sequence analyses showed that the Guangdong H7N9 virus isolated from April to May shared high sequence similarity with other strains from eastern China. The A/Guangdong/1/2013 (H7N9) virus isolated from the Guangdong patient on 10 August 2013 was divergent from previously sequenced H7N9 viruses and more closely related to local circulating H9N2 viruses in the NS and NP genes. Phylogenetic analyses revealed that four internal genes of the A/Guangdong/1/2013 (H7N9) virus-the NS, NP, PB1, and PB2 genes-were in clusters different from those for H7N9 viruses identified previously in other provinces of China. The discovery presented here suggests that continuing reassortment led to the emergence of the A/Guangdong/1/2013 (H7N9) virus as a novel H7N9 virus in Guangdong, China, and that viral adaptation to avian and human hosts must be assessed.

Importance: In this study, we isolated and characterized the avian influenza A H7N9 virus in Guangdong, China, from April to August 2013. We show that the viruses isolated from Guangdong environmental samples and chickens from April to May 2013 were highly similar to other H7N9 strains found in eastern China. The H7N9 virus isolated from the clinical patient in Guangdong in August 2013 was divergent from previously identified H7N9 viruses, with the NS and NP genes originating from recent H9N2 viruses circulating in the province. This study provides direct evidence that continuing reassortment occurred and led to the emergence of a novel H7N9 influenza virus in Guangdong, China. These results also shed light on how the H7N9 virus evolved, which is critically important for future monitoring and tracing of viral transmission.

PubMed Disclaimer

Figures

FIG 1
FIG 1
Distribution (A) and timeline of identification (B) of influenza A H7N9 and H9N2 viruses from LPM and clinical patients in Guangdong Province, China, in 2013. The 10 provinces and/or cities that reported H7N9 virus cases between March and May 2013 are marked in red (A).
FIG 2
FIG 2
Maximum-likelihood phylogenetic trees for the HA, NA, M, PA, NS, NP, PB1, and PB2 genes of H7N9 isolates. The viruses isolated in this study are marked as in Fig. 1. The separated clusters of major circulating H7N9 viruses and the A/Guangdong/1/2013 (H7N9) virus are highlighted in blue and red, respectively. Supporting bootstrap values greater than 70 are shown.
FIG 2
FIG 2
Maximum-likelihood phylogenetic trees for the HA, NA, M, PA, NS, NP, PB1, and PB2 genes of H7N9 isolates. The viruses isolated in this study are marked as in Fig. 1. The separated clusters of major circulating H7N9 viruses and the A/Guangdong/1/2013 (H7N9) virus are highlighted in blue and red, respectively. Supporting bootstrap values greater than 70 are shown.
FIG 2
FIG 2
Maximum-likelihood phylogenetic trees for the HA, NA, M, PA, NS, NP, PB1, and PB2 genes of H7N9 isolates. The viruses isolated in this study are marked as in Fig. 1. The separated clusters of major circulating H7N9 viruses and the A/Guangdong/1/2013 (H7N9) virus are highlighted in blue and red, respectively. Supporting bootstrap values greater than 70 are shown.
FIG 2
FIG 2
Maximum-likelihood phylogenetic trees for the HA, NA, M, PA, NS, NP, PB1, and PB2 genes of H7N9 isolates. The viruses isolated in this study are marked as in Fig. 1. The separated clusters of major circulating H7N9 viruses and the A/Guangdong/1/2013 (H7N9) virus are highlighted in blue and red, respectively. Supporting bootstrap values greater than 70 are shown.
FIG 2
FIG 2
Maximum-likelihood phylogenetic trees for the HA, NA, M, PA, NS, NP, PB1, and PB2 genes of H7N9 isolates. The viruses isolated in this study are marked as in Fig. 1. The separated clusters of major circulating H7N9 viruses and the A/Guangdong/1/2013 (H7N9) virus are highlighted in blue and red, respectively. Supporting bootstrap values greater than 70 are shown.
FIG 2
FIG 2
Maximum-likelihood phylogenetic trees for the HA, NA, M, PA, NS, NP, PB1, and PB2 genes of H7N9 isolates. The viruses isolated in this study are marked as in Fig. 1. The separated clusters of major circulating H7N9 viruses and the A/Guangdong/1/2013 (H7N9) virus are highlighted in blue and red, respectively. Supporting bootstrap values greater than 70 are shown.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Chen Y, Liang W, Yang S, Wu N, Gao H, Sheng J, Yao H, Wo J, Fang Q, Cui D, Li Y, Yao X, Zhang Y, Wu H, Zheng S, Diao H, Xia S, Chan KH, Tsoi HW, Teng JL, Song W, Wang P, Lau SY, Zheng M, Chan JF, To KK, Chen H, Li L, Yuen KY. 2013. Human infections with the emerging avian influenza A H7N9 virus from wet market poultry: clinical analysis and characterisation of viral genome. Lancet 381:1916–1925. 10.1016/S0140-6736(13)60903-4 - DOI - PMC - PubMed
    1. Gao R, Cao B, Hu Y, Feng Z, Wang D, Hu W, Chen J, Jie Z, Qiu H, Xu K, Xu X, Lu H, Zhu W, Gao Z, Xiang N, Shen Y, He Z, Gu Y, Zhang Z, Yang Y, Zhao X, Zhou L, Li X, Zou S, Zhang Y, Yang L, Guo J, Dong J, Li Q, Dong L, Zhu Y, Bai T, Wang S, Hao P, Yang W, Han J, Yu H, Li D, Gao GF, Wu G, Wang Y, Yuan Z, Shu Y. 2013. Human infection with a novel avian-origin influenza A (H7N9) virus. N. Engl. J. Med. 368:1888–1897. 10.1056/NEJMoa1304459 - DOI - PubMed
    1. Liu W, Yang K, Qi X, Xu K, Ji H, Ai J, Ge A, Wu Y, Li Y, Dai Q, Liang Q, Bao C, Bergquist R, Tang F, Zhu Y. 2013. Spatial and temporal analysis of human infection with avian influenza A(H7N9) virus in China, 2013. Euro Surveill. 18(47):pii=20640 http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20640 - PubMed
    1. Wu A, Su C, Wang D, Peng Y, Liu M, Hua S, Li T, Gao GF, Tang H, Chen J, Liu X, Shu Y, Peng D, Jiang T. 2013. Sequential reassortments underlie diverse influenza H7N9 genotypes in China. Cell Host Microbe 14:446–452. 10.1016/j.chom.2013.09.001 - DOI - PubMed
    1. Lam TT, Wang J, Shen Y, Zhou B, Duan L, Cheung CL, Ma C, Lycett SJ, Leung CY, Chen X, Li L, Hong W, Chai Y, Zhou L, Liang H, Ou Z, Liu Y, Farooqui A, Kelvin DJ, Poon LL, Smith DK, Pybus OG, Leung GM, Shu Y, Webster RG, Webby RJ, Peiris JS, Rambaut A, Zhu H, Guan Y. 2013. The genesis and source of the H7N9 influenza viruses causing human infections in China. Nature 502:241–244. 10.1038/nature12515 - DOI - PMC - PubMed

Publication types

MeSH terms

LinkOut - more resources