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Volume 28, Number 8—August 2022
Dispatch

Zoonotic Threat of G4 Genotype Eurasian Avian-Like Swine Influenza A(H1N1) Viruses, China, 2020

Min Gu1, Kaibiao Chen1, Zhichuang Ge, Jun Jiao, Tianyu Cai, Suhan Liu, Xiaoquan Wang, Xinan Jiao, Daxin Peng, and Xiufan LiuComments to Author 
Author affiliations: Yangzhou University, Yangzhou, China (M. Gu, K. Chen, Z. Ge, J. Jiao, T. Cai, S. Liu, X. Wang, X. Jiao, D. Peng, X. Liu); Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou (M. Gu, X. Wang, X. Jiao, D. Peng, X. Liu)

Main Article

Table 2

Virus replication of 2 G4 Eurasian avian-like H1N1 swine isolates from pigs in China in vitro and in vivo*

Virus strain log10 EID50/0.1 mL log10 TCID50/0.1 mL Virus growth in MDCK cells, mean titer ±SD, log10 TCID50/0.1 mL†
 Virus replication in infected mice,
mean titer +SD, log10 copies/μL‡
3 dpi
 5 dpi
12 hpi 24 hpi 36 hpi 48 hpi 60 hpi Lung Turb Brain Lung Turb Brain
HD11 9.5 7.5 3.872§ +0.645 5.041 +0.219 7.000¶ +0.441 5.556# +0.096 5.667** +0.000 5.679# +0.355 4.295** +0.181 2.495 +0.318 3.828 +1.484 2.385 +0.219 2.703 +0.661
HD21 9.375 5.769 3.055 +0.481 4.389 +0.096 4.556 +0.096 4.556 +0.096 4.444 +0.096 3.894 +0.195 2.008 +0.988 1.667 +0.537 4.550 +0.53 2.334 +0.221 2.692 +0.132

*We conducted 2-way analysis of variance in Prism software version 8 (GraphPad, https://www.graphpad.com) for virus titer comparison between HD11 and HD21 groups in each time point in cells or each tissue of the same sampling day in mice. dpi, days postinfection; EID50, 50% egg infectious dose; HD11, A/swine/Jiangsu/HD11/2020(H1N1); HD21, A/swine/Anhui/HD21/2020(H1N1); hpi, hours postinfection; TCID50, 50% tissue culture infectious dose (determined in MDCK cells); turb, turbinate. †MDCK monolayers were infected with HD11 and HD21 at a multiplicity of infection (MOI) of 0.1. The virus titers of cell supernatants collected at different time points of 12, 24, 36, 48, and 60 h postinfection were determined via the TCID50 assay in MDCK cells. ‡Three 6-week-old BALB/c mice per group challenged with 106.0 EID50 virus in 50 μL volume were euthanized to collect tissue samples including the lung, turbinate, and brain for virus titration on 3 and 5 d postinoculation. The viral load expressed with virus copies in tissue homogenates was measured through the real-time quantitative reverse transcription PCR method as described (12). §p<0.05. ¶p<0.0001. #p<0.01. **p<0.001.

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1These authors contributed equally to this article.

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