Genetic characterization and pathogenicity of a Eurasian avian-like H1N1 swine influenza reassortant virus

Hechao Zhu; Xiangmin Li; Huanchun Chen; Ping Qian

doi:10.1186/s12985-022-01936-6

Genetic characterization and pathogenicity of a Eurasian avian-like H1N1 swine influenza reassortant virus

Virol J. 2022 Dec 2;19(1):205. doi: 10.1186/s12985-022-01936-6.

Authors

Hechao Zhu^{1

2}, Xiangmin Li^{1

3

2}, Huanchun Chen^{1

3

2}, Ping Qian^{4

5

6}

Affiliations

¹ State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
² Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China.
³ College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
⁴ State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. qianp@mail.hzau.edu.cn.
⁵ College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. qianp@mail.hzau.edu.cn.
⁶ Key Laboratory of Preventive Veterinary Medicine in Hubei Province, The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, 430070, Hubei, China. qianp@mail.hzau.edu.cn.

Abstract

Background: Swine influenza viruses (SIV), considered the "mixing vessels" of influenza viruses, posed a significant threat to global health systems and are dangerous pathogens. Eurasian avian-like H1N1(EA-H1N1) viruses have become predominant in swine populations in China since 2016.

Methods: Lung tissue samples were obtained from pregnant sows with miscarriage and respiratory disease in Heilongjiang province, and pathogens were detected by Next-generation sequencing (NGS) and PCR. The nucleic acid of isolates was extracted to detect SIV by RT-PCR. Then, SIV-positive samples were inoculated into embryonated chicken eggs. After successive generations, the isolates were identified by RT-PCR, IFA, WB and TEM. The genetic evolution and pathogenicity to mice of A/swine/Heilongjiang/GN/2020 were analyzed.

Results: The major pathogens were influenza virus (31%), Simbu orthobunyavirus (15%) and Jingmen tick virus (8%) by NGS, while the pathogen that can cause miscarriage and respiratory disease was influenza virus. The SIV(A/swine/Heilongjiang/GN/2020) with hemagglutination activity was isolated from lung samples and was successfully identified by RT-PCR, IFA, WB and TEM. Homology and phylogenetic analysis showed that A/swine/Heilongjiang/GN/2020 is most closely related to A/swine/Henan/SN/10/2018 and belonged to EA-H1N1. Pathogenicity in mice showed that the EA-H1N1 could cause lethal or exhibit extrapulmonary virus spread and cause severe damage to respiratory tracts effectively proliferating in lung and trachea.

Conclusion: A/swine/Heilongjiang/GN/2020 (EA-H1N1) virus was isolated from pregnant sows with miscarriage and respiratory disease in Heilongjiang province, China. Clinical signs associated with influenza infection were observed during 14 days with A/swine/Heilongjiang/GN/2020 infected mice. These data suggest that A/swine/Heilongjiang/GN/2020 (EA-H1N1) had high pathogenicity and could be systemic spread in mice.

Keywords: Eurasian avian-like H1N1 virus; Next-generation sequencing (NGS); Pathogenicity; Phylogenetic analysis; Swine influenza.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Abortion, Spontaneous*
Animals
Chickens
Female
Humans
Influenza A Virus, H1N1 Subtype* / genetics
Influenza A virus*
Influenza, Human*
Mice
Orthomyxoviridae Infections* / veterinary
Phylogeny
Pregnancy
Reassortant Viruses
Swine
Virulence