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ORIGINAL RESEARCH article

Front. Microbiol.

Sec. Infectious Agents and Disease

This article is part of the Research TopicEpidemiology and Control of Emerging/Re-emerging Poultry and Waterfowl DiseasesView all 5 articles

Genome analysis screening virulence genes for the altered pathogenicity of Riemerella anatipestifer in hens

Provisionally accepted
Junfeng  LvJunfeng Lv1Hui  ChenHui Chen2Xiuli  MaXiuli Ma1Yang  CongYang Cong1Xiaofei  SongXiaofei Song2Yufeng  LiYufeng Li1Yuehua  GaoYuehua Gao1Zhuomin  QinZhuomin Qin1*
  • 1Poultry Institute, Shandong Academy of Agricultural Sciences, Jinan, China
  • 2Qilu Animal Health Products Co, Jinan, China

The final, formatted version of the article will be published soon.

Background: In recent years, Riemerella anatipestifer infection in chickens has markedly increased, resulting in substantial economic losses to the poultry industry. The present study was designed to assess the pathogenicity of R. anatipestifer in laying hens and to elucidate the molecular mechanisms underlying its altered virulence. Methods: R. anatipestifer strains were isolated from laying hens presenting with oviduct obstruction and diminished egg production. Animal challenge experiments were conducted to evaluate the pathogenic potential of these hen-isolated strains. Genomic DNA sequences were subjected to comparative analysis to identify virulence genes differential between newly hen-derived and previous strains. Results: Three serotypes, 1, 5, and 10, were identified using PCR and agglutination assays. Animal challenge experiments demonstrated that all three strains could induce oviduct obstruction in 30-, 60-, and 90-day-old hens. Genomic sequencing analysis revealed 18 mutated virulence genes associated with diverse virulence determinants, including type IV secretion systems (T4SSs), hemolysin, yersiniabactin (Ybt), lipooligosaccharide (LOS), lipopolysaccharide (LPS), BrkA, capsule biosynthesis, flagella, caseinolytic protease C (ClpC), FeoAB, and Vi antigens, all of which have been established as critical factors in bacterial pathogenicity. Conclusion: The findings of this study confirm an association between R. anatipestifer infection and reduced egg production in hens, and provide a foundation for elucidating the specific roles of virulence genes in the altered pathogenicity of R. anatipestifer in chickens.

Keywords: Riemerella anatipestifer, laying hens, genome analysis, virulence genes, pathogenicity alteration

Received: 15 Sep 2025; Accepted: 24 Nov 2025.

Copyright: © 2025 Lv, Chen, Ma, Cong, Song, Li, Gao and Qin. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Zhuomin Qin

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