Identification of virulence-related amino acid mutations of avian encephalomyelitis virus associated with vaccination methods

Avian encephalomyelitis virus (AEV), a picornavirus, primarily infects the central nervous system of 1 to 2-week-old young chickens but not pullets. When wild-type AEV undergoes serial passaging in chicken embryos, it becomes to be embryo-adapted and can cause avian encephalomyelitis in chickens of...

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Main Authors: Zheng Xu, Pengcheng Fan, Chengcheng Zhang, Mengjiao Guo, Zongyi Bo, Yantao Wu, Xiaorong Zhang
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-03-01
Series:Frontiers in Veterinary Science
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Online Access:https://www.frontiersin.org/articles/10.3389/fvets.2025.1548515/full
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author Zheng Xu
Pengcheng Fan
Chengcheng Zhang
Mengjiao Guo
Zongyi Bo
Zongyi Bo
Yantao Wu
Yantao Wu
Xiaorong Zhang
author_facet Zheng Xu
Pengcheng Fan
Chengcheng Zhang
Mengjiao Guo
Zongyi Bo
Zongyi Bo
Yantao Wu
Yantao Wu
Xiaorong Zhang
author_sort Zheng Xu
collection DOAJ
description Avian encephalomyelitis virus (AEV), a picornavirus, primarily infects the central nervous system of 1 to 2-week-old young chickens but not pullets. When wild-type AEV undergoes serial passaging in chicken embryos, it becomes to be embryo-adapted and can cause avian encephalomyelitis in chickens of all ages following intracutaneous infection through parenteral routes. This study was conducted to explore whether an outbreak of AEV in 95-day-old chickens was linked to inadvertent embryo adaptation of the AEV vaccine and its association with vaccination method. In this study, an AEV strain AEV/JS202201 was isolated from the flocks of chickens that had been shortly after vaccinated with the AEV vaccine combined with the avian pox vaccine by the wing-web method. Whole-genome sequencing was performed on the isolated AEV/JS202201 and the immunized VACCINE X strain. The results showed that the length of AEV/JS202201 and VACCINE X strain was determined to be 7,032 bp and 7,034 bp, respectively (both excluding the poly A tail). Compared with VACCINE X strain, one mutation, T24A, were found at the VP4 in the isolated AEV/JS202201 strain. Multiple sequence alignment revealed that no other AEV strains exhibited this mutation. Animal regression experiment confirmed that AEV/JS202201 could infect layer pullets and caused typical pathological changes in brain tissue, with a higher morbidity rate (4/10) and more severe clinical symptoms in chickens immunized via the wing-web method compared to those immunized orally (2/10). In summary, this study found a potential virulence-related mutation in the VP4 protein of AEV and emphasized that the oral vaccine method is safer than the wing-web method.
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spelling doaj-art-b9dbd9105fa9466483f86c6390fa60102025-08-20T02:02:50ZengFrontiers Media S.A.Frontiers in Veterinary Science2297-17692025-03-011210.3389/fvets.2025.15485151548515Identification of virulence-related amino acid mutations of avian encephalomyelitis virus associated with vaccination methodsZheng Xu0Pengcheng Fan1Chengcheng Zhang2Mengjiao Guo3Zongyi Bo4Zongyi Bo5Yantao Wu6Yantao Wu7Xiaorong Zhang8Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, ChinaJiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, ChinaJiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, ChinaJiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, ChinaJiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, ChinaJiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, ChinaJoint International Research Laboratory of Agriculture and Agri-Product Safety, The Ministry of Education of China, Yangzhou University, Yangzhou, ChinaJiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, ChinaAvian encephalomyelitis virus (AEV), a picornavirus, primarily infects the central nervous system of 1 to 2-week-old young chickens but not pullets. When wild-type AEV undergoes serial passaging in chicken embryos, it becomes to be embryo-adapted and can cause avian encephalomyelitis in chickens of all ages following intracutaneous infection through parenteral routes. This study was conducted to explore whether an outbreak of AEV in 95-day-old chickens was linked to inadvertent embryo adaptation of the AEV vaccine and its association with vaccination method. In this study, an AEV strain AEV/JS202201 was isolated from the flocks of chickens that had been shortly after vaccinated with the AEV vaccine combined with the avian pox vaccine by the wing-web method. Whole-genome sequencing was performed on the isolated AEV/JS202201 and the immunized VACCINE X strain. The results showed that the length of AEV/JS202201 and VACCINE X strain was determined to be 7,032 bp and 7,034 bp, respectively (both excluding the poly A tail). Compared with VACCINE X strain, one mutation, T24A, were found at the VP4 in the isolated AEV/JS202201 strain. Multiple sequence alignment revealed that no other AEV strains exhibited this mutation. Animal regression experiment confirmed that AEV/JS202201 could infect layer pullets and caused typical pathological changes in brain tissue, with a higher morbidity rate (4/10) and more severe clinical symptoms in chickens immunized via the wing-web method compared to those immunized orally (2/10). In summary, this study found a potential virulence-related mutation in the VP4 protein of AEV and emphasized that the oral vaccine method is safer than the wing-web method.https://www.frontiersin.org/articles/10.3389/fvets.2025.1548515/fullavian encephalomyelitis virusembryo-adapted strainmutationsvaccination methodwhole-genome sequencingphylogenetic analysis
spellingShingle Zheng Xu
Pengcheng Fan
Chengcheng Zhang
Mengjiao Guo
Zongyi Bo
Zongyi Bo
Yantao Wu
Yantao Wu
Xiaorong Zhang
Identification of virulence-related amino acid mutations of avian encephalomyelitis virus associated with vaccination methods
Frontiers in Veterinary Science
avian encephalomyelitis virus
embryo-adapted strain
mutations
vaccination method
whole-genome sequencing
phylogenetic analysis
title Identification of virulence-related amino acid mutations of avian encephalomyelitis virus associated with vaccination methods
title_full Identification of virulence-related amino acid mutations of avian encephalomyelitis virus associated with vaccination methods
title_fullStr Identification of virulence-related amino acid mutations of avian encephalomyelitis virus associated with vaccination methods
title_full_unstemmed Identification of virulence-related amino acid mutations of avian encephalomyelitis virus associated with vaccination methods
title_short Identification of virulence-related amino acid mutations of avian encephalomyelitis virus associated with vaccination methods
title_sort identification of virulence related amino acid mutations of avian encephalomyelitis virus associated with vaccination methods
topic avian encephalomyelitis virus
embryo-adapted strain
mutations
vaccination method
whole-genome sequencing
phylogenetic analysis
url https://www.frontiersin.org/articles/10.3389/fvets.2025.1548515/full
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