Emergence and Characterization of Three Pseudorabies Variants with Moderate Pathogenicity in Growing Pigs

Pseudorabies virus (PRV) remains a critical threat for the global swine industry, with heightened attention due to the emergence of variant strains since late 2011 in China. Emergent viral variants generally undergo three to four years of adaptation to present new phenotypes. However, limited invest...

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Main Authors: Zhendong Zhang, Cong Wang, Chengyue Wu, Qingteng Wei, Zhengqin Ye, Wenqiang Wang, Zhe Sun, Kegong Tian, Xiangdong Li
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Microorganisms
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Online Access:https://www.mdpi.com/2076-2607/13/4/851
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author Zhendong Zhang
Cong Wang
Chengyue Wu
Qingteng Wei
Zhengqin Ye
Wenqiang Wang
Zhe Sun
Kegong Tian
Xiangdong Li
author_facet Zhendong Zhang
Cong Wang
Chengyue Wu
Qingteng Wei
Zhengqin Ye
Wenqiang Wang
Zhe Sun
Kegong Tian
Xiangdong Li
author_sort Zhendong Zhang
collection DOAJ
description Pseudorabies virus (PRV) remains a critical threat for the global swine industry, with heightened attention due to the emergence of variant strains since late 2011 in China. Emergent viral variants generally undergo three to four years of adaptation to present new phenotypes. However, limited investigations have been performed on the evolution and pathogenicity of variant PRV strains in growing pigs after 2015. In this study, three PRV field strains, named SD1501, SD1701, and SD1801, were isolated and their genetic characteristics and pathogenicity on 9-week-old pigs were analyzed. Nucleotide identity and phylogenetic analyses based on the complete genome sequence, as well as major immunogenic and virulence-related genes revealed that all three isolates clustered closely with genotype II variant strains prevalent in China. The pathogenicity analysis demonstrated that the three isolates exhibited moderate pathogenicity in growing pigs with a TCID<sub>50</sub> of 10<sup>7</sup>. Infected pigs displayed transient fever and reduced appetite, with only one pig in each challenge group showing typical neurological symptoms and succumbing within 6 days post infection. These findings enrich the epidemiological data of PRV and provide direct evidence for the phenotypic variations caused by PRV infection, which enhances our understanding of PRV evolution in China and contributes to PRV control in the field.
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spelling doaj-art-854867747d7c4517886c26cdcf444ffa2025-08-20T02:18:00ZengMDPI AGMicroorganisms2076-26072025-04-0113485110.3390/microorganisms13040851Emergence and Characterization of Three Pseudorabies Variants with Moderate Pathogenicity in Growing PigsZhendong Zhang0Cong Wang1Chengyue Wu2Qingteng Wei3Zhengqin Ye4Wenqiang Wang5Zhe Sun6Kegong Tian7Xiangdong Li8Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, ChinaChina Animal Husbandry Industry Co., Ltd., Beijing 100070, ChinaCollege of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, ChinaNational Research Center for Veterinary Medicine, Luoyang 471003, ChinaNational Research Center for Veterinary Medicine, Luoyang 471003, ChinaJiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, ChinaPseudorabies virus (PRV) remains a critical threat for the global swine industry, with heightened attention due to the emergence of variant strains since late 2011 in China. Emergent viral variants generally undergo three to four years of adaptation to present new phenotypes. However, limited investigations have been performed on the evolution and pathogenicity of variant PRV strains in growing pigs after 2015. In this study, three PRV field strains, named SD1501, SD1701, and SD1801, were isolated and their genetic characteristics and pathogenicity on 9-week-old pigs were analyzed. Nucleotide identity and phylogenetic analyses based on the complete genome sequence, as well as major immunogenic and virulence-related genes revealed that all three isolates clustered closely with genotype II variant strains prevalent in China. The pathogenicity analysis demonstrated that the three isolates exhibited moderate pathogenicity in growing pigs with a TCID<sub>50</sub> of 10<sup>7</sup>. Infected pigs displayed transient fever and reduced appetite, with only one pig in each challenge group showing typical neurological symptoms and succumbing within 6 days post infection. These findings enrich the epidemiological data of PRV and provide direct evidence for the phenotypic variations caused by PRV infection, which enhances our understanding of PRV evolution in China and contributes to PRV control in the field.https://www.mdpi.com/2076-2607/13/4/851pseudorabies viruscomplete genomegenetic characterizationevolutionpathogenicity
spellingShingle Zhendong Zhang
Cong Wang
Chengyue Wu
Qingteng Wei
Zhengqin Ye
Wenqiang Wang
Zhe Sun
Kegong Tian
Xiangdong Li
Emergence and Characterization of Three Pseudorabies Variants with Moderate Pathogenicity in Growing Pigs
Microorganisms
pseudorabies virus
complete genome
genetic characterization
evolution
pathogenicity
title Emergence and Characterization of Three Pseudorabies Variants with Moderate Pathogenicity in Growing Pigs
title_full Emergence and Characterization of Three Pseudorabies Variants with Moderate Pathogenicity in Growing Pigs
title_fullStr Emergence and Characterization of Three Pseudorabies Variants with Moderate Pathogenicity in Growing Pigs
title_full_unstemmed Emergence and Characterization of Three Pseudorabies Variants with Moderate Pathogenicity in Growing Pigs
title_short Emergence and Characterization of Three Pseudorabies Variants with Moderate Pathogenicity in Growing Pigs
title_sort emergence and characterization of three pseudorabies variants with moderate pathogenicity in growing pigs
topic pseudorabies virus
complete genome
genetic characterization
evolution
pathogenicity
url https://www.mdpi.com/2076-2607/13/4/851
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