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Zhang Q, Mei X, Zhang C, Li J, Chang N, Aji D, Shi W, Bi Y, Ma Z. Novel reassortant 2.3.4.4B H5N6 highly pathogenic avian influenza viruses circulating among wild, domestic birds in Xinjiang, Northwest China. J Vet Sci 2021; 22:e43. [PMID: 34170087 PMCID: PMC8318794 DOI: 10.4142/jvs.2021.22.e43] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 04/18/2021] [Accepted: 04/28/2021] [Indexed: 12/27/2022] Open
Abstract
Background The H5 avian influenza viruses (AIVs) of clade 2.3.4.4 circulate in wild and domestic birds worldwide. In 2017, nine strains of H5N6 AIVs were isolated from aquatic poultry in Xinjiang, Northwest China. Objectives This study aimed to analyze the origin, reassortment, and mutations of the AIV isolates. Methods AIVs were isolated from oropharyngeal and cloacal swabs of poultry. Identification was accomplished by inoculating isolates into embryonated chicken eggs and performing hemagglutination tests and reverse transcription polymerase chain reaction (RT-PCR). The viral genomes were amplified with RT-PCR and then sequenced. The sequence alignment, phylogenetic, and molecular characteristic analyses were performed by using bioinformatic software. Results Nine isolates originated from the same ancestor. The viral HA gene belonged to clade 2.3.4.4B, while the NA gene had a close phylogenetic relationship with the 2.3.4.4C H5N6 highly pathogenic avian influenza viruses (HPAIVs) isolated from shoveler ducks in Ningxia in 2015. The NP gene was grouped into an independent subcluster within the 2.3.4.4B H5N8 AIVs, and the remaining six genes all had close phylogenetic relationships with the 2.3.4.4B H5N8 HPAIVs isolated from the wild birds in China, Egypt, Uganda, Cameroon, and India in 2016–2017, Multiple basic amino acid residues associated with HPAIVs were located adjacent to the cleavage site of the HA protein. The nine isolates comprised reassortant 2.3.4.4B HPAIVs originating from 2.3.4.4B H5N8 and 2.3.4.4C H5N6 viruses in wild birds. Conclusions These results suggest that the Northern Tianshan Mountain wetlands in Xinjiang may have a key role in AIVs disseminating from Central China to the Eurasian continent and East African.
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Affiliation(s)
- Qian Zhang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Xindi Mei
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Cheng Zhang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China.,CAS Key Laboratory of Pathogenic Microbiology and Immunology, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, Institute of Microbiology, Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Science, Beijing 100101, China
| | - Juan Li
- Key Laboratory of Etiology and Emerging infections Disease in Shandong First Medical University, Taian 271016, China
| | - Nana Chang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Dilihuma Aji
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China
| | - Weifeng Shi
- Key Laboratory of Etiology and Emerging infections Disease in Shandong First Medical University, Taian 271016, China
| | - Yuhai Bi
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China.,CAS Key Laboratory of Pathogenic Microbiology and Immunology, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, Institute of Microbiology, Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Science, Beijing 100101, China.
| | - Zhenghai Ma
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi 830046, China.
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2
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Zhang T, Fan K, Zhang X, Xu Y, Xu J, Xu B, Li R. Diversity of avian influenza A(H5N6) viruses in wild birds in southern China. J Gen Virol 2020; 101:902-909. [PMID: 32519938 PMCID: PMC7654745 DOI: 10.1099/jgv.0.001449] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 05/22/2020] [Indexed: 11/18/2022] Open
Abstract
The predominance of H5N6 in ducks and continuous human cases have heightened its potential threat to public health in China. Therefore, the detection of emerging variants of H5N6 avian influenza viruses has become a priority for pandemic preparedness. Questions remain as to its origin and circulation within the wild bird reservoir and interactions at the wild-domestic interface. Samples were collected from migratory birds in Poyang Lake, Jiangxi Province, PR China during the routine bird ring survey in 2014-16. Phylogenetic and coalescent analyses were conducted to uncover the evolutionary relationship among viruses circulating in wild birds. Here, we report the potential origin and phylogenetic diversity of H5N6 viruses isolated from wild birds in Poyang Lake. Sequence analyses indicated that Jiangxi H5N6 viruses most likely evolved from Eurasian-derived H5Nx and H6N6 viruses through multiple reassortment events. Crucially, the diversity of the HA gene implies that these Jiangxi H5N6 viruses have diverged into two primary clades - clade 2.3.4.4 and clade 2.3.2.1 c. Phylogenetic analysis revealed two independent pathways of reassortment during 2014-16 that might have facilitated the generation of emerging variants within wild bird populations as well as inter-species infections. Our findings contribute to our understanding of the genetic diversification of H5N6 viruses in the wild bird population. These results highlight the necessity of large-scale surveillance of wild birds in the Poyang Lake area to address the threat of regional epizootic epidemics and attendant pandemics.
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Affiliation(s)
- Tao Zhang
- Ministry of Education Key Laboratory for Earth System Modelling, Department of Earth System Science, Tsinghua University, Beijing, PR China
- Centre for Healthy Cities, Institute for China Sustainable Urbanization, Tsinghua University, Beijing, PR China
| | - Kai Fan
- College of Veterinary Medicine, China Agricultural University, Beijing, PR China
| | - Xue Zhang
- College of Veterinary Medicine, China Agricultural University, Beijing, PR China
| | - Yujuan Xu
- College of Veterinary Medicine, China Agricultural University, Beijing, PR China
| | - Jian Xu
- School of Geography and Environmental Science, Ministry of Education’s Key Laboratory of Poyang Lake Wetland and Watershed Research, Jiangxi Normal University, Nanchang, Jiangxi, PR China
| | - Bing Xu
- Ministry of Education Key Laboratory for Earth System Modelling, Department of Earth System Science, Tsinghua University, Beijing, PR China
- Centre for Healthy Cities, Institute for China Sustainable Urbanization, Tsinghua University, Beijing, PR China
| | - Ruiyun Li
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Faculty of Medicine, Imperial College London, London, UK
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3
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Sun J, Zhao L, Li X, Meng W, Chu D, Yang X, Peng P, Zhi M, Qin S, Fu T, Li J, Lu S, Wang W, He X, Yu M, Lv X, Ma W, Liao M, Liu Z, Zhang G, Wang Y, Li Y, Chai H, Lu J, Hua Y. Novel H5N6 avian influenza virus reassortants with European H5N8 isolated in migratory birds, China. Transbound Emerg Dis 2019; 67:648-660. [PMID: 31580519 DOI: 10.1111/tbed.13380] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 09/15/2019] [Accepted: 09/16/2019] [Indexed: 12/21/2022]
Abstract
Five novel H5N6 influenza viruses, including four highly pathogenic avian influenza viruses and one low pathogenic avian influenza virus, were isolated from migratory birds in Ningxia, China, in November 2017. To understand the genetic origination of the novel H5N6 virus, and the infectivity and pathogenicity of the four highly pathogenic avian influenza viruses in mammals, phylogeographic analyses and infection studies in mice were performed. The phylogenetic and phylogeographic analyses showed that the H5N6 isolates, which are closely related to the viruses from Korea, Japan and the Netherlands, originated from reassortant virus between H5N8 and HxN6 viruses from western Russia. The animal study revealed that the SBD-87 isolate presented moderate virulence in mice, suggesting a potential public risk to humans and a potential threat to public health.
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Affiliation(s)
- Jing Sun
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Lu Zhao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Harbin, China
| | - Xiang Li
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Weiyue Meng
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
| | - Dong Chu
- General Station for Surveillance of Wildlife Disease & Wildlife Borne Diseases, National Forestry and Grassland Administration, Shenyang, China
| | - Xiaoyu Yang
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Peng Peng
- General Station for Surveillance of Wildlife Disease & Wildlife Borne Diseases, National Forestry and Grassland Administration, Shenyang, China
| | - Min Zhi
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Siyuan Qin
- General Station for Surveillance of Wildlife Disease & Wildlife Borne Diseases, National Forestry and Grassland Administration, Shenyang, China
| | - Tian Fu
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Jinghao Li
- General Station for Surveillance of Wildlife Disease & Wildlife Borne Diseases, National Forestry and Grassland Administration, Shenyang, China
| | - Shaoxia Lu
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Weidong Wang
- Monitoring Center for Terrestrial Wildlife Epidemic Diseases, Yinchuan, China
| | - Xin He
- Monitoring Center for Terrestrial Wildlife Epidemic Diseases, Yinchuan, China
| | - Mengqi Yu
- Monitoring Center for Terrestrial Wildlife Epidemic Diseases, Yinchuan, China
| | - Xinru Lv
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Wenge Ma
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Mengying Liao
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Zhensheng Liu
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China.,Key Laboratory of Conservation Biology, National Forestry and Grassland Administration, Harbin, China
| | - Guogang Zhang
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
| | - Yulong Wang
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - Yanbing Li
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Harbin, China
| | - Hongliang Chai
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China.,Key Laboratory of Conservation Biology, National Forestry and Grassland Administration, Harbin, China
| | - Jun Lu
- Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China
| | - Yuping Hua
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
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4
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Kim YI, Si YJ, Kwon HI, Kim EH, Park SJ, Robles NJ, Nguyen HD, Yu MA, Yu KM, Lee YJ, Lee MH, Choi YK. Pathogenicity and genetic characterisation of a novel reassortant, highly pathogenic avian influenza (HPAI) H5N6 virus isolated in Korea, 2017. ACTA ACUST UNITED AC 2019; 23. [PMID: 29463346 PMCID: PMC5824127 DOI: 10.2807/1560-7917.es.2018.23.7.18-00045] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We investigated influenza A(H5N6) viruses from migratory birds in Chungnam and Gyeonggi Provinces, South Korea following a reported die-off of poultry in nearby provinces in November 2017. Genetic analysis and virulence studies in chickens and ducks identified our isolate from December 2017 as a novel highly pathogenic avian influenza virus. It resulted from reassortment between the highly virulent H5N8 strain from Korea with the N6 gene from a low-pathogenic H3N6 virus from the Netherlands.
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Affiliation(s)
- Young-Il Kim
- These authors contributed equally to this article.,College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Young-Jae Si
- These authors contributed equally to this article.,College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Hyeok-Il Kwon
- College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Eun-Ha Kim
- College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Su-Jin Park
- College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Norbert John Robles
- College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Hiep Dinh Nguyen
- College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Min-Ah Yu
- College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Kwang-Min Yu
- College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
| | - Youn-Jeong Lee
- Avian Influenza Research and Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, South Korea
| | - Myoung-Heon Lee
- Avian Influenza Research and Diagnostic Division, Animal and Plant Quarantine Agency, Gimcheon-si, Gyeongsangbuk-do, South Korea
| | - Young Ki Choi
- These authors contributed equally to this article.,College of Medicine and Medical Research Institute, Chungbuk National University, Seowon-gu, Cheongju, South Korea
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5
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Han L, Chen C, Han X, Lin S, Ao X, Han X, Wang J, Ye H. Structural Insights for Anti-Influenza Vaccine Design. Comput Struct Biotechnol J 2019; 17:475-483. [PMID: 31007873 PMCID: PMC6458449 DOI: 10.1016/j.csbj.2019.03.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/17/2019] [Accepted: 03/21/2019] [Indexed: 01/29/2023] Open
Abstract
Influenza A virus are a persistent and significant threat to human health, and current vaccines do not provide sufficient protection due to antigenic drift, which allows influenza viruses to easily escape immune surveillance and antiviral drug activity. Influenza hemagglutinin (HA) is a glycoprotein needed for the entry of enveloped influenza viruses into host cells and is a potential target for anti-influenza humoral immune responses. In recent years, a number of broadly neutralizing antibodies (bnAbs) have been isolated, and their relative structural information obtained from the crystallization of influenza antigens in complex with bnAbs has provided some new insights into future influenza vaccine research. Here, we review the current knowledge of the HA-targeted bnAbs and the structure-based mechanisms contributing to neutralization. We also discuss the potential for this structure-based approach to overcome the challenge of obtaining a highly desired "universal" influenza vaccine, especially on small proteins and peptides.
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Affiliation(s)
- Lifen Han
- The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou 350025, China
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Cong Chen
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, China
| | - Xianlin Han
- Department of General Surgery, Peking Union Medical College Hospital, Beijing, China
| | - Shujin Lin
- The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou 350025, China
| | - Xiulan Ao
- The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou 350025, China
| | - Xiao Han
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Jianmin Wang
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, China
| | - Hanhui Ye
- The United Innovation of Mengchao Hepatobiliary Technology Key Laboratory of Fujian Province, Mengchao Hepatobiliary Hospital of Fujian Medical University, Fuzhou 350025, China
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6
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Wang X, Zeng Z, Zhang Z, Zheng Y, Li B, Su G, Li H, Huang L, Qi W, Liao M. The Appropriate Combination of Hemagglutinin and Neuraminidase Prompts the Predominant H5N6 Highly Pathogenic Avian Influenza Virus in Birds. Front Microbiol 2018; 9:1088. [PMID: 29896169 PMCID: PMC5987672 DOI: 10.3389/fmicb.2018.01088] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/07/2018] [Indexed: 11/13/2022] Open
Abstract
Haemagglutinin (HA) and neuraminidase (NA) are two vital surface glycoproteins of influenza virus. The HA of H5N6 highly pathogenic avian influenza virus is divided into Major/H5 and Minor/H5, and its NA consists of short stalk NA and full-length stalk NA. The strain combined with Major/H5 and short stalk NA account for 76.8% of all strains, and the proportion was 23.0% matched by Minor/H5 and full-length stalk NA. Our objective was to investigate the influence of HA-NA matching on the biological characteristics and the effects of the epidemic trend of H5N6 on mice and chickens. Four different strains combined with two HAs and two NAs of the represented H5N6 viruses with the fixed six internal segments were rescued and analyzed. Plaque formation, NA activity of infectious particles, and virus growth curve assays, as well as a saliva acid receptor experiment, with mice and chickens were performed. We found that all the strains can replicate well on Madin-Darby canine kidney (MDCK) cells and chicken embryo fibroblasts (CEF) cells, simultaneously, mice and infection group chickens were complete lethal. However, the strain combined with Major/H5 and short stalk N6 formed smaller plaque on MDCK, showed a moderate replication ability in both MDCK and CEF, and exhibited a higher survival rate among the contact group of chickens. Conversely, strains with opposite biological characters which combined with Minor/H5 and short stalk N6 seldom exist in nature. Hence, we drew the conclusion that the appropriate combination of Major/H5 and short stalk N6 occur widely in nature with appropriate biological characteristics for the proliferation and transmission, whereas other combinations of HA and NA had a low proportion and even have not yet been detected.
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Affiliation(s)
- Xiuhui Wang
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Zhaoyong Zeng
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Zaoyue Zhang
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yi Zheng
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Bo Li
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Guanming Su
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Huanan Li
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Lihong Huang
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Department of Biomedical Sciences, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Wenbao Qi
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou, China
| | - Ming Liao
- National and Regional Joint Engineering Laboratory for Medicament of Zoonoses Prevention and Control, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis, Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province, Guangzhou, China
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7
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Adlhoch C, Brouwer A, Kuiken T, Mulatti P, Smietanka K, Staubach C, Willeberg P, Barrucci F, Verdonck F, Amato L, Baldinelli F. Avian influenza overview November 2017 - February 2018. EFSA J 2018; 16:e05240. [PMID: 32625858 PMCID: PMC7009675 DOI: 10.2903/j.efsa.2018.5240] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Between 16 November 2017 and 15 February 2018, one highly pathogenic avian influenza (HPAI) A(H5N6) and five HPAI A(H5N8) outbreaks in poultry holdings, two HPAI A(H5N6) outbreaks in captive birds and 22 HPAI A(H5N6) wild bird events were reported within Europe. There is a lower incursion of HPAI A(H5N6) in poultry compared to HPAI A(H5N8). There is no evidence to date that HPAI A(H5N6) viruses circulating in Europe are associated with clades infecting humans. Clinical signs in ducks infected with HPAI A(H5N8) seemed to be decreasing, based on reports from Bulgaria. However, HPAI A(H5N8) is still present in Europe and is widespread in neighbouring areas. The majority of mortality events of wild birds from HPAIV A(H5) in this three-month period involved single birds. This indicates that the investigation of events involving single dead birds of target species is important for comprehensive passive surveillance for HPAI A(H5). Moreover, 20 low pathogenic avian influenza (LPAI) outbreaks were reported in three Member States. The risk of zoonotic transmission to the general public in Europe is considered to be very low. The first human case due to avian influenza A(H7N4) was notified in China underlining the threat that newly emerging avian influenza viruses pose for transmission to humans. Close monitoring is required of the situation in Africa and the Middle East with regards to HPAI A(H5N1) and A(H5N8). Uncontrolled spread of virus and subsequent further genetic evolution in regions geographically connected to Europe may increase uncertainty and risk for further dissemination of virus. The risk of HPAI introduction from Third countries via migratory wild birds to Europe is still considered much lower for wild birds crossing the southern borders compared to birds crossing the north-eastern borders, whereas the introduction via trade is still very to extremely unlikely.
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