Volume 28, Number 8—August 2022
Zoonotic Threat of G4 Genotype Eurasian Avian-Like Swine Influenza A(H1N1) Viruses, China, 2020
|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‡
|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.