Biological Characteristics and Pathogenicity Analysis of a Low Virulence G2a Porcine Epidemic Diarrhea Virus

Kechen Yu; Xueting Liu; Ying Lu; Meijing Long; Jiaguo Bai; Qiuying Qin; Xueli Su; Guifu He; Xue Mi; Chunjie Yang; Ruomu Wang; Hejie Wang; Ying Chen; Zuzhang Wei; Weijian Huang; Kang Ouyang

doi:10.1128/spectrum.04535-22

Microbiology Spectrum (Jun 2023)

Biological Characteristics and Pathogenicity Analysis of a Low Virulence G2a Porcine Epidemic Diarrhea Virus

Kechen Yu,
Xueting Liu,
Ying Lu,
Meijing Long,
Jiaguo Bai,
Qiuying Qin,
Xueli Su,
Guifu He,
Xue Mi,
Chunjie Yang,
Ruomu Wang,
Hejie Wang,
Ying Chen,
Zuzhang Wei,
Weijian Huang,
Kang Ouyang

Affiliations

Kechen Yu: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Xueting Liu: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Ying Lu: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Meijing Long: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Jiaguo Bai: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Qiuying Qin: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Xueli Su: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Guifu He: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Xue Mi: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Chunjie Yang: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Ruomu Wang: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Hejie Wang: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Ying Chen: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Zuzhang Wei: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Weijian Huang: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China
Kang Ouyang: Guangxi Colleges and Universities Key Laboratory of Prevention and Control for Animal Disease, College of Animal Science and Technology, Guangxi University, Nanning, China

DOI: https://doi.org/10.1128/spectrum.04535-22
Journal volume & issue: Vol. 11, no. 3

Abstract

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ABSTRACT Since the outbreak caused by a porcine epidemic diarrhea virus (PEDV) variant in 2010, the current epidemic of PEDV genotype 2 (G2) has caused huge economic losses to the pig industry in China. In order to better understand the biological characteristics and pathogenicity of the current PEDV field strains, 12 PEDV isolates were collected and plaque purified during 2017 to 2018 in Guangxi, China. The neutralizing epitopes of the spike proteins and the ORF3 proteins were analyzed to evaluate genetic variations, and they were compared with the reported G2a and G2b strains. Phylogenetic analysis of the S protein showed that the 12 isolates were clustered into the G2 subgroup (with 5 and 7 strains in G2a and G2b, respectively) and that they shared 97.4 to 99.9% amino acid identities. Among them, one of the G2a strains, CH/GXNN-1/2018, which had a titer of 106.15 PFU/mL, was selected for pathogenicity analysis. Although piglets infected with the CH/GXNN-1/2018 strain exhibited severe clinical signs and the highest level of virus shedding within 24 h postinfection (hpi), recovery and decreased virus shedding were seen after 48 hpi, and no piglets died during the whole process. Thus, the CH/GXNN-1/2018 strain had low virulence in suckling piglets. Virus neutralizing antibody analysis showed that the CH/GXNN-1/2018 strain induced cross-protection against both homologous G2a and heterologous G2b PEDV strains as early as 72 hpi. These results are of great significance for understanding PEDV in Guangxi, China, and they provide a promising naturally occurring low-virulent vaccine candidate for further study. IMPORTANCE The current epidemic of porcine epidemic diarrhea virus (PEDV) G2 has caused huge economic losses to the pig industry. Evaluation for low virulence of the PEDV strains of subgroup G2a would be useful for the future development of effective vaccines. In this study, 12 field strains of PEDV were obtained successfully, and they were characterized from Guangxi, China. The neutralizing epitopes of the spike proteins and the ORF3 proteins were analyzed to evaluate antigenic variations. One of the G2a strains, CH/GXNN-1/2018, was selected for pathogenicity analysis, and it showed that the CH/GXNN-1/2018 strain had low virulence in suckling piglets. These results provide a promising naturally occurring low-virulent vaccine candidate for further study.

Published in Microbiology Spectrum

ISSN: 2165-0497 (Online)
Publisher: American Society for Microbiology
Country of publisher: United States
LCC subjects: Science: Microbiology
Website: https://journals.asm.org/journal/spectrum

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