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Abolnik C. Spillover of an endemic avian Influenza H6N2 chicken lineage to ostriches and reassortment with clade 2.3.4.4b H5N1 high pathogenicity viruses in chickens. Vet Res Commun 2024; 48:1233-1237. [PMID: 37966679 PMCID: PMC10998810 DOI: 10.1007/s11259-023-10258-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/07/2023] [Indexed: 11/16/2023]
Abstract
Prior to 2017, chicken production in South Africa had only ever been affected by an endemic strain of H6N2 low pathogenic avian influenza (LPAI), but since 2017, an outbreak of Goose/Guangdong clade 2.3.4.4b H5N8 high pathogenicity avian influenza (HPAI) introduced by wild birds, followed by clade 2.3.4.4b H5N1 HPAI (2021-present), affected the country. In the present study, the viruses from seven cases of H6N2 LPAI from commercial poultry between October 2019 and August 2020 were genome-sequenced along with an H5N2 HPAI virus, and phylogenetic analysis was performed. The H5N2 HPAI virus caused localized outbreaks in a small-scale chicken farm and a large commercial layer farm in the KwaZulu-Natal province between late October and early December 2022. The phylogenetic results confirmed the first incidence of the chicken-adapted H6N2 lineage in commercial ostriches in the Western Cape province, with a likely epidemiological origin in chickens from the KwaZulu Natal province. The results also showed that the H5N2 HPAI virus was a novel reassortant of PB2, PB1, PA, NP and NA genome segments derived from a parental H6N2 virus that circulated in region, whereas the HA, M and NS genome segments were derived from sub-genotype SA10 H5N1 HPAI parental virus that had circulated in the local wild bird reservoir since July 2021.
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Affiliation(s)
- Celia Abolnik
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa.
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Yan Z, Li Y, Huang S, Wen F. Global distribution, receptor binding, and cross-species transmission of H6 influenza viruses: risks and implications for humans. J Virol 2023; 97:e0137023. [PMID: 37877722 PMCID: PMC10688349 DOI: 10.1128/jvi.01370-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023] Open
Abstract
The H6 subtype of avian influenza virus (AIV) is a pervasive subtype that is ubiquitously found in both wild bird and poultry populations across the globe. Recent investigations have unveiled its capacity to infect mammals, thereby expanding its host range beyond that of other subtypes and potentially facilitating its global transmission. This heightened breadth also endows H6 AIVs with the potential to serve as a genetic reservoir for the emergence of highly pathogenic avian influenza strains through genetic reassortment and adaptive mutations. Furthermore, alterations in key amino acid loci within the H6 AIV genome foster the evolution of viral infection mechanisms, which may enable the virus to surmount interspecies barriers and infect mammals, including humans, thus posing a potential threat to human well-being. In this review, we summarize the origins, dissemination patterns, geographical distribution, cross-species transmission dynamics, and genetic attributes of H6 influenza viruses. This study holds implications for the timely detection and surveillance of H6 AIVs.
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Affiliation(s)
- Zhanfei Yan
- College of Life Science and Engineering, Foshan University, Foshan, Guangdong, China
| | - You Li
- College of Life Science and Engineering, Foshan University, Foshan, Guangdong, China
| | - Shujian Huang
- College of Life Science and Engineering, Foshan University, Foshan, Guangdong, China
| | - Feng Wen
- College of Life Science and Engineering, Foshan University, Foshan, Guangdong, China
- Guangdong Provincial Key Laboratory of Animal Molecular Design and Precise Breeding, College of Life Science and Engineering, Foshan University, Foshan, China
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Dong MY, Guo ZW, Li YX, Lv JD, Xiang XL, Cui M, Han XF, Cao SJ, Huang Y, Xia J. Research Note: A recombinant duck-derived H6N2 subtype avian influenza virus can replicate and shed in young chickens and cause disease. Poult Sci 2023; 102:103012. [PMID: 37611454 PMCID: PMC10466914 DOI: 10.1016/j.psj.2023.103012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 08/02/2023] [Accepted: 08/04/2023] [Indexed: 08/25/2023] Open
Abstract
The H6N2 subtype avian influenza virus (AIV) is commonly detected in the migratory waterfowl reservoirs. Previously, H6N2 AIV was believed to be nonpathogenic to young chickens and could not infect or shed in their respiratory tract under experimental conditions. However, in present study, a highly recombinant strain of duck-derived H6N2 AIV was discovered and isolated for pathogenicity tests. The results revealed that H6N2 could induce seroconversion in chickens and high morbidity of over 86.7%, along with evident upper respiratory tract hemorrhage. Moreover, 5 substitutions were detected in the upper respiratory tract shedding reisolated virus, with a high viral load in the target organs of infected chickens. In contrast, ducks failed to exhibit any symptoms, pathological lesions, or viral shedding, while demonstrated seroconversion and high viral load in the livers. These findings indicate that H6N2 AIV could also show pathogenicity to chickens under experimental conditions, thereby effectively replicating and shedding in chickens. Therefore, the study provides further elucidations on the pathogenicity of H6N2 AIV.
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Affiliation(s)
- Meng-Yi Dong
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - Zhong-Wei Guo
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - Yong-Xin Li
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - Jia-Dai Lv
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - Xue-Lian Xiang
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - Min Cui
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - Xin-Feng Han
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - San-Jie Cao
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - Yong Huang
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China
| | - Jing Xia
- College of Veterinary Medicine, Sichuan Agricultural University, Chengdu 611130, Sichuan, People's Republic of China.
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Smith T, O'Kennedy MM, Wandrag DB, Adeyemi M, Abolnik C. Efficacy of a plant-produced virus-like particle vaccine in chickens challenged with Influenza A H6N2 virus. Plant Biotechnol J 2020; 18:502-512. [PMID: 31350931 PMCID: PMC6953208 DOI: 10.1111/pbi.13219] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 07/13/2019] [Accepted: 07/23/2019] [Indexed: 05/23/2023]
Abstract
The efficacy, safety, speed, scalability and cost-effectiveness of producing hemagglutinin-based virus-like particle (VLP) vaccines in plants are well-established for human influenza, but untested for the massive poultry influenza vaccine market that remains dominated by traditional egg-grown oil-emulsion whole inactivated virus vaccines. For optimal efficacy, a vaccine should be closely antigenically matched to the field strain, requiring that influenza A vaccines be updated regularly. In this study, an H6 subtype VLP transiently expressed in Nicotiana benthamiana was formulated into a vaccine and evaluated for efficacy in chickens against challenge with a heterologous H6N2 virus. A single dose of the plant-produced H6 VLP vaccine elicited an immune response comparable to two doses of a commercial inactivated H6N2 vaccine, with mean hemagglutination inhibition titres of 9.3 log2 and 8.8 log2 , respectively. Compared to the non-vaccinated control, the H6 VLP vaccine significantly reduced the proportion of shedders and the magnitude of viral shedding by >100-fold in the oropharynx and >6-fold in the cloaca, and shortened oropharyngeal viral shedding by at least a week. Despite its potency, the cost of the antigenic mismatch between the inactivated H6N2 vaccine and challenge strain was evident not only in this vaccine's failure to reduce viral shedding compared to the non-vaccinated group, but its apparent exacerbation of oropharyngeal viral shedding until 21 days post-challenge. We estimate that a kilogram of plant leaf material can produce H6 VLP vaccines sufficient for between 5000 and 30 000 chickens, depending on the effective dose and whether one or two immunizations are administered.
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Affiliation(s)
- Tanja Smith
- Department of Production Animal StudiesFaculty of Veterinary ScienceUniversity of PretoriaPretoriaSouth Africa
- BiosciencesCouncil for Scientific and Industrial ResearchPretoriaSouth Africa
| | - Martha M. O'Kennedy
- Department of Production Animal StudiesFaculty of Veterinary ScienceUniversity of PretoriaPretoriaSouth Africa
- BiosciencesCouncil for Scientific and Industrial ResearchPretoriaSouth Africa
| | - Daniel B.R. Wandrag
- Department of Production Animal StudiesFaculty of Veterinary ScienceUniversity of PretoriaPretoriaSouth Africa
| | - Modupeore Adeyemi
- Department of Production Animal StudiesFaculty of Veterinary ScienceUniversity of PretoriaPretoriaSouth Africa
| | - Celia Abolnik
- Department of Production Animal StudiesFaculty of Veterinary ScienceUniversity of PretoriaPretoriaSouth Africa
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Xin L, Bai T, Zhou JF, Chen YK, Li XD, Zhu WF, Li Y, Tang J, Chen T, Qin K, Shi JH, Gao RB, Wang DY, Chen JM, Shu YL. Seropositivity for Avian Influenza H6 Virus among Humans, China. Emerg Infect Dis 2016; 21:1267-9. [PMID: 26079934 PMCID: PMC4480397 DOI: 10.3201/eid2107.150135] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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