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
. 2021 May 7;13(5):856.
doi: 10.3390/v13050856.

Genetic Characterization and Pathogenesis of Avian Influenza Virus H7N3 Isolated from Spot-Billed Ducks in South Korea, Early 2019

Thuy-Tien Thi Trinh  1 , Indira Tiwari  1 , Kaliannan Durairaj  1 , Bao Tuan Duong  1 , Anh Thi Viet Nguyen  1 , Hien Thi Tuong  1 , Vui Thi Hoang  1 , Duong Duc Than  1 , SunJeong Nam  2 , Seon-Ju Yeo  3 , Hyun Park  1
Affiliations

Genetic Characterization and Pathogenesis of Avian Influenza Virus H7N3 Isolated from Spot-Billed Ducks in South Korea, Early 2019

Thuy-Tien Thi Trinh et al. Viruses. .

Abstract

Low-pathogenicity avian influenza viruses (LPAIV) introduced by migratory birds circulate in wild birds and can be transmitted to poultry. These viruses can mutate to become highly pathogenic avian influenza viruses causing severe disease and death in poultry. In March 2019, an H7N3 avian influenza virus-A/Spot-billed duck/South Korea/WKU2019-1/2019 (H7N3)-was isolated from spot-billed ducks in South Korea. This study aimed to evaluate the phylogenetic and mutational analysis of this isolate. Molecular analysis revealed that the genes for HA (hemagglutinin) and NA (neuraminidase) of this strain belonged to the Central Asian lineage, whereas genes for other internal proteins such as polymerase basic protein 1 (PB1), PB2, nucleoprotein, polymerase acidic protein, matrix protein, and non-structural protein belonged to that of the Korean lineage. In addition, a monobasic amino acid (PQIEPR/GLF) at the HA cleavage site, and the non-deletion of the stalk region in the NA gene indicated that this isolate was a typical LPAIV. Nucleotide sequence similarity analysis of HA revealed that the highest homology (99.51%) of this isolate is to that of A/common teal/Shanghai/CM1216/2017 (H7N7), and amino acid sequence of NA (99.48%) was closely related to that of A/teal/Egypt/MB-D-487OP/2016 (H7N3). An in vitro propagation of the A/Spot-billed duck/South Korea/WKU2019-1/2019 (H7N3) virus showed highest (7.38 Log10 TCID50/mL) virus titer at 60 h post-infection, and in experimental mouse lungs, the virus was detected at six days' post-infection. Our study characterizes genetic mutations, as well as pathogenesis in both in vitro and in vivo model of a new Korea H7N3 viruses in 2019, carrying multiple potential mutations to become highly pathogenic and develop an ability to infect humans; thus, emphasizing the need for routine surveillance of avian influenza viruses in wild birds.

Keywords: H7N3; South Korea; avian influenza virus; spot-billed duck.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
(A–H) Phylogenetic analysis of H7N3 (WKU2019-1) for eight gene segments. (A) PB2, (B) PB2, (C) PA, (D) HA, (E) NP, (F) NA, (G) M, (H) NS. (PB—polymerase basic protein; NP—nucleoprotein; HA—hemagglutinin; PA—polymerase acidic protein; NA—neuraminidase; M—matrix protein; NS—non-structural protein).
Figure 1
Figure 1
(A–H) Phylogenetic analysis of H7N3 (WKU2019-1) for eight gene segments. (A) PB2, (B) PB2, (C) PA, (D) HA, (E) NP, (F) NA, (G) M, (H) NS. (PB—polymerase basic protein; NP—nucleoprotein; HA—hemagglutinin; PA—polymerase acidic protein; NA—neuraminidase; M—matrix protein; NS—non-structural protein).
Figure 1
Figure 1
(A–H) Phylogenetic analysis of H7N3 (WKU2019-1) for eight gene segments. (A) PB2, (B) PB2, (C) PA, (D) HA, (E) NP, (F) NA, (G) M, (H) NS. (PB—polymerase basic protein; NP—nucleoprotein; HA—hemagglutinin; PA—polymerase acidic protein; NA—neuraminidase; M—matrix protein; NS—non-structural protein).
Figure 1
Figure 1
(A–H) Phylogenetic analysis of H7N3 (WKU2019-1) for eight gene segments. (A) PB2, (B) PB2, (C) PA, (D) HA, (E) NP, (F) NA, (G) M, (H) NS. (PB—polymerase basic protein; NP—nucleoprotein; HA—hemagglutinin; PA—polymerase acidic protein; NA—neuraminidase; M—matrix protein; NS—non-structural protein).
Figure 2
Figure 2
Locations of the putative origin of genomic compositions of the H7N3 (WKU2019-1).
Figure 3
Figure 3
Original reassortment events of the novel avian influenza isolate H7N3 (WKU2019-1).
Figure 4
Figure 4
The virus growth kinetics of H7N3 (WKU2019-1) isolate in MDCK cells. MDCK cells were infected at an MOI of 0.01. The cell culture supernatant was harvested at different time-points (12, 24, 36, 48, 60, 72, and 84 h) after infection. The virus titer in cell culture supernatant was determined by an enzyme-linked immunosorbent assay (ELISA) using anti-influenza nucleoprotein to detect infected cells, and TCID50 was determined in MDCK cells. The data are represented as mean ± SD and calculated from three repeats, *** p < 0.001.
Figure 5
Figure 5
Pathogenicity of the H7N3 (WKU2019-1) isolate in vivo. For each virus strain, BALB/c mice were intranasally infected with 105 EID50/mouse concentrations of the virus. (A) Mean body weight (n = 5), (B) the survival rates (n = 5), (C) virus titers in the lung (n = 3), (D) lung weight (n = 3) were noted.
Figure 6
Figure 6
Histology of lung inflammation determined by hematoxylin and eosin (H&E) staining. For each isolate, BALB/c mice were intranasally infected with EID50 concentrations of the virus at 105 EID50/mouse. The uninfected control (normal); H7N3 (WKU2019-1)-; H1N1 (CA/04/09)-; and H7N7-infected mouse lungs were collected and stained with H&E at days 3, 6, and 15 post-infection (dpi) (scale bar, 100 µm; original magnification × 100). Discussion.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Shi Y., Cui H., Wang J., Chi Q., Li X., Teng Q., Chen H., Yang J., Liu Q., Li Z. Characterizations of H4 avian influenza viruses isolated from ducks in live poultry markets and farm in Shanghai. Sci. Rep. 2016;6:37843. doi: 10.1038/srep37843. - DOI - PMC - PubMed
    1. Naguib M.M., Verhagen J.H., Mostafa A., Wille M., Li R., Graaf A., Järhult J.D., Ellström P., Zohari S., Lundkvist Å., et al. Global patterns of avian influenza A (H7): Virus evolution and zoonotic threats. FEMS Microbiol. Rev. 2019;43:608–621. doi: 10.1093/femsre/fuz019. - DOI - PMC - PubMed
    1. Jang J.W., Ko S.-Y., Byoun M.S., Sung H.W., Lim C.S., Byun M.S. GENEDIA Multi Influenza Ag Rapid Test for detection and H1, H3, and H5 subtyping of influenza viruses. J. Clin. Virol. 2015;73:42–46. doi: 10.1016/j.jcv.2015.10.014. - DOI - PubMed
    1. Lupiani B., Reddy S.M. The history of avian influenza. Comp. Immunol. Microbiol. Infect. Dis. 2009;32:311–323. doi: 10.1016/j.cimid.2008.01.004. - DOI - PubMed
    1. Zanin M., Koçer Z.A., Poulson R.L., Gabbard J.D., Howerth E.W., Jones C.A., Friedman K., Seiler J., Danner A., Kercher L., et al. Potential for Low-Pathogenic Avian H7 Influenza A Viruses to Replicate and Cause Disease in a Mammalian Model. J. Virol. 2016;91 doi: 10.1128/JVI.01934-16. - DOI - PMC - PubMed

Publication types

MeSH terms

-