Prevailing I292V #PB2 #mutation in #avian #influenza #H9N2 virus increases viral #polymerase function and attenuates IFN-β induction in human cells (J Gen Virol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

J Gen Virol. 2019 Jul 15. doi: 10.1099/jgv.0.001294. [Epub ahead of print]

Prevailing I292V PB2 mutation in avian influenza H9N2 virus increases viral polymerase function and attenuates IFN-β induction in human cells.

Gao W1, Zu Z1, Liu J1, Song J1, Wang X1, Wang C1, Liu L1, Tong Q1, Wang M1, Sun H1, Sun Y1, Liu J1, Chang KC2, Pu J1.

Author information: 1 Key Laboratory of Animal Epidemiology, Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, PR China. 2 School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Loughborough, UK.



Adaptation of PB2 protein is important for the establishment of avian influenza viruses in mammalian hosts. Here, we identify I292V as the prevalent mutation in PB2 of circulating avian H9N2 and pandemic H1N1 viruses. The same dominant PB2 mutation is also found in most human isolates of emergent avian H7N9 and H10N8 viruses. In human cells, PB2-292V in H9N2 virus has the combined ability of conferring higher viral polymerase activity and stronger attenuation of IFN-β induction than that of its predecessor PB2-292I. IFN-β attenuation is accompanied by higher binding affinity of PB2-292V for host mitochondrial antiviral signalling protein, an important intermediary protein in the induction of IFN-β. In the mouse in vivo model, PB2-292V mutation increases H9N2 virus replication with ensuing increase in disease severity. Collectively, PB2-292V is a new mammalian adaptive marker that promotes H9N2 virus replication in mammalian hosts with the potential to improve transmission from birds to humans.

PMID: 31305236 DOI: 10.1099/jgv.0.001294

Keywords: Avian Influenza; H9N2; Viral pathogenesis.



#Respiratory disease due to mixed viral #infections in #poultry flocks in #Egypt between 2017 and 2018: #Upsurge of highly pathogenic #avian #influenza virus subtype #H5N8 since 2018 (Transbound Emerg Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Transbound Emerg Dis. 2019 Jul 11. doi: 10.1111/tbed.13281. [Epub ahead of print]

Respiratory disease due to mixed viral infections in poultry flocks in Egypt between 2017 and 2018: Upsurge of highly pathogenic avian influenza virus subtype H5N8 since 2018.

Hassan KE1,2, El-Kady MF2, El-Sawah AAA2, Luttermann C3, Parvin R1,4, Shany S2, Beer M1, Harder T1.

Author information: 1 Institute of Diagnostic Virology, Friedrich-Loeffler-Institute, Greifswald-Riems, Germany. 2 Department of Poultry Diseases, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt. 3 Institute of Immunology Virology, Friedrich-Loeffler-Institute, Greifswald-Riems, Germany. 4 Department of Pathology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, Bangladesh.



For several years, poultry production in Egypt has been suffering from co-circulation of multiple respiratory viruses including highly pathogenic avian influenza virus (HPAIV) H5N1 (clade and low pathogenic H9N2 (clade G1-B). Incursion of HPAIV H5N8 (clade to Egypt in November 2016 via wild birds followed by spread into commercial poultry flocks further complicated the situation. Current analyses focussed on 39 poultry farms suffering from respiratory manifestation and high mortality in six Egyptian governorates during 2017-2018. Real-time RT-PCR (RT-qPCR) substantiated the co-presence of at least two respiratory virus species in more than 80% of the investigated flocks. The percentage of HPAIV H5N1-positive holdings was fairly stable in 2017 (12.8%) and 2018 (10.2%), while the percentage of HPAIV H5N8-positive holdings increased from 23% in 2017 to 66.6% during 2018. The proportion of H9N2-positive samples was constantly high (2017:100% and 2018:63%), and H9N2 co-circulated with HPAIV H5N8 in 22 out of 39 (56.8%) flocks. Analyses of 26 H5, 18 H9 and 4 N2 new sequences confirmed continuous genetic diversification. In silico analysis revealed numerous amino acid substitutions in the HA and NA proteins suggestive of increased adaptation to mammalian hosts and putative antigenic variation. For sensitive detection of H9N2 viruses by RT-qPCR, an update of primers and probe sequences was crucial. Reasons for the relative increase of HPAIV H5N8 infections versus H5N1 remained unclear, but lack of suitable vaccines against clade cannot be excluded. A reconsideration of surveillance and control measures should include updating of diagnostic tools and vaccination strategies.

© 2019 Blackwell Verlag GmbH.

KEYWORDS: Egypt; Highly pathogenic avian influenza; co-infection; control; diagnostic tools; reassortant viruses

PMID: 31297991 DOI: 10.1111/tbed.13281

Keywords: Avian Influenza; H5N1; H5N8; H9N2; Poultry; Egypt.


#PB2 #mutations arising during #H9N2 #influenza #evolution in the Middle East confer enhanced #replication and growth in #mammals (PLoS Pathog., abstract)

[Source: PLoS Pathogens, full page: (LINK). Abstract, edited.]


PB2 mutations arising during H9N2 influenza evolution in the Middle East confer enhanced replication and growth in mammals

Yasuha Arai, Norihito Kawashita, Madiha Salah Ibrahim, Emad Mohamed Elgendy, Tomo Daidoji, Takao Ono, Tatsuya Takagi, Takaaki Nakaya, Kazuhiko Matsumoto, Yohei Watanabe

Published: July 2, 2019 / DOI: / This is an uncorrected proof.



Avian influenza virus H9N2 has been endemic in birds in the Middle East, in particular in Egypt with multiple cases of human infections since 1998. Despite concerns about the pandemic threat posed by H9N2, little is known about the biological properties of H9N2 in this epicentre of infection. Here, we investigated the evolutionary dynamics of H9N2 in the Middle East and identified phylogeny-associated PB2 mutations that acted cooperatively to increase H9N2 replication/transcription in human cells. The accumulation of PB2 mutations also correlated with an increase in H9N2 virus growth in the upper and lower airways of mice and in virulence. These mutations clustered on a solvent-exposed region in the PB2-627 domain in proximity to potential interfaces with host factors. These PB2 mutations have been found at high prevalence during evolution of H9N2 in the field, indicating that they have provided a selective advantage for viral adaptation to infect poultry. Therefore, continuous prevalence of H9N2 virus in the Middle East has generated a far more fit or optimized replication phenotype, leading to an expanded viral host range, including to mammals, which may pose public health risks beyond the current outbreaks.


Author summary

The G1-like clade of H9N2 influenza viruses can undergo genetic reassortment with other influenza virus subtypes to produce novel zoonotic viruses, such as the Gs/GD lineage H5N1, H7N9, H10N8, and H5N8 viruses. Since 1998, the G1-like subclade of H9N2 influenza virus has been widely circulating in birds in Central Asia and the Middle East and a number of human cases have been reported. However, little is known about the biological properties of H9N2 viruses in this epicentre of infection. Our data showed that, during about two decades of evolution in nature, G1-like subclade strains evolved to produce strains with appreciably higher replication phenotypes in Central Asia and the Middle East, which led to their expanded host range, including to humans. Therefore, G1-like subclade strains in these areas may accumulate mutations to produce novel viruses and the large gene pool in these areas would enable reassortment with other influenza viruses. This study indicated the need for studies of H9N2 viruses in such areas to monitor their evolutionary dynamics and possible genetic changes.


Citation: Arai Y, Kawashita N, Ibrahim MS, Elgendy EM, Daidoji T, Ono T, et al. (2019) PB2 mutations arising during H9N2 influenza evolution in the Middle East confer enhanced replication and growth in mammals. PLoS Pathog 15(7): e1007919.

Editor: Adam S. Lauring, University of Michigan, UNITED STATES

Received: March 11, 2019; Accepted: June 14, 2019; Published: July 2, 2019

Copyright: © 2019 Arai et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript and its Supporting Information files.

Funding: This work was supported by CREST (to KM) from Japan Science and Technology Agency (; Grant Number JPMJCR15F4), partly by a Grant-in-Aid for Scientific Research B (to YW), Young Scientists B (to YA) and Scientific Research on Innovative Areas (to YW) from Japan Society for the Promotion of Science (; Grant Numbers 15H05295, 18K15171 and 19H04841, respectively), and partly by grants from the Takeda Science Foundation (; [to YW]), the Heiwa Nakajima Foundation (; [to YW]), and a Sasakawa Scientific Research Grant from The Japan Science Society (; [to YA]), and partly by the JSPS Core-to-Core Program (; [to TN]). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Avian Influenza, H9N2.


#Pathogenicity and Full #Genome Sequencing of the #Avian #Influenza #H9N2 #Moroccan Isolate 2016 (Avian Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Avian Dis. 2018 Nov 16;63(1):24-30. doi: 10.1637/11941-080418-Reg.1.

Pathogenicity and Full Genome Sequencing of the Avian Influenza H9N2 Moroccan Isolate 2016.

Boumart Z1, Bamouh Z2, Jazouli M2, Zecchin B3, Fusaro A3, Salviato A3, Monne I3, Tadlaoui KO2, Harrak ME2.

Author information: 1 Research and Development Department, Multi-Chemical Industry, Lot 157, Z I, Sud-Ouest (ERAC) B. P. 278, Mohammedia 28810, Morocco, 2 Research and Development Department, Multi-Chemical Industry, Lot 157, Z I, Sud-Ouest (ERAC) B. P. 278, Mohammedia 28810, Morocco. 3 Istituto Zooprofilattico Sperimentale delle Venezie, Padua, Italy.

Abstract in English, Spanish

In Morocco in early 2016, a low pathogenic avian influenza virus serotype H9N2 caused large economic losses to the poultry industry, with specific clinical symptoms and high mortality rates on infected farms. Subsequent to the H9N2 outbreak, the causal agent was successfully isolated from chicken flocks with high morbidity and mortality rates, propagated on embryonated eggs, and fully sequenced. The phylogenetic analysis suggested that the Moroccan isolate could have derived from the Middle East isolate A/chicken/Dubai/D2506.A/2015. This study was designed to assess the pathogenicity of the Moroccan isolate H9N2 in experimentally infected broiler and specific-pathogen-free (SPF) chickens. At 22 days of age, one broiler and two SPF chicken groups were inoculated by dropping 0.2 ml of the H9N2 isolate (107.5 EID50/ml) in both nostrils and eyes. Clinically inoculated chickens with H9N2 displayed mild lesions, low mortality rates, and an absence of clinical signs. The H9N2 virus was more pathogenic in broiler chickens and produced more severe tissue lesions compared to SPF chickens. The viral shedding was detected up to 6 days postinoculation (pi) in oropharyngeal and cloacal swabs in infected birds with a maximum shedding in the oropharynges of the broiler group. All experimental chickens seroconverted and registered high hemagglutination inhibition titers as early as day 7 pi. The present study indicates that the H9N2 virus isolated from a natural outbreak was of low pathogenicity under experimental conditions. However, under field conditions infection with other pathogens might have aggravated the disease.

KEYWORDS: H9N2; SPF; broiler; isolate; pathogenicity; serology; shedding

PMID: 31251516 DOI: 10.1637/11941-080418-Reg.1

Keywords: Avian Influenza; H9N2; Poultry; Morocco.


Emergence of #waterfowl-originated #gene cassettes in HPAI #H7N9 viruses caused severe #human #infection in #Fujian, #China (Influenza Other Respir Viruses, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Influenza Other Respir Viruses. 2019 Jun 11. doi: 10.1111/irv.12657. [Epub ahead of print]

Emergence of waterfowl-originated gene cassettes in HPAI H7N9 viruses caused severe human infection in Fujian, China.

Yang L1, Xie J2,3, Zhang Y1, Zhu W1, Li X1, Wei H1, Li Z1, Zhao L2, Bo H1, Liu J1, Dong J1, Chen T1, Shu Y1,4, Weng Y2,3, Wang D1.

Author information: 1 National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China. 2 Fujian center for disease control and prevention, Fuzhou, China. 3 Fujian provincial key laboratory of zoonosis research, Fuzhou, China. 4 School of Public Health Shenzhen, Sun Yat-sen University, Guangdong, China.




Highly pathogenic avian influenza (HPAI) A(H7N9) virus emerged and caused human infections during the 2016-2017 epidemic wave of influenza A(H7N9) viruses in China. We report a human infection with HPAI H7N9 virus and six environmental isolates in Fujian Province, China.


Environmental surveillance was conducted in live poultry markets and poultry farms in Fujian, China. Clinical and epidemiologic data and samples were collected. Real-time RT-PCRs were conducted for each sample, and H7-positive samples were isolated using embryonated chicken eggs. Full genomes of the isolates were obtained by next-generation sequencing. Phylogenetic analysis and antigenic analysis were conducted.


A 59-year-old man who raised about 1000 ducks was identified as HPAI H7N9 infection. Six HPAI H7 viruses were isolated from environmental samples, including five H7N9 viruses and one H7N6 virus. Phylogenetic results showed the human and environmental viruses are highly genetically diverse and containing significantly different gene constellation from that of other HPAI H7N9 previously reported. The internal genes derived from H7N9/H9N2, H5N6, and the Eurasian wild-bird gene pool, indicating waterfowl-originated genotypes, have emerged in HPAI H7N9/N6 viruses and caused human infection.


The new genotypes raise the concern that these HPAI H7 viruses might transmit back into migratory birds and spread to other countries as the HPAI H5Nx viruses. Considering their capability of causing severe infections in both human and poultry, the HPAI H7 viruses in this study pose a risk to public health and the poultry industry and highlight the importance of sustained surveillance of these viruses.

© 2019 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

KEYWORDS: H7N9 virus; avian influenza; genetic diversity; infection

PMID: 31187583 DOI: 10.1111/irv.12657

Keywords: Avian Influenza; H5N6; H7N6; H7N9; H9N2; Reassortant Strain; Wild birds; Human; Fujian; China.


#Infection of #chicken #H9N2 #influenza viruses in different species of domestic #ducks (Vet Microbiol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Vet Microbiol. 2019 Jun;233:1-4. doi: 10.1016/j.vetmic.2019.04.018. Epub 2019 Apr 12.

Infection of chicken H9N2 influenza viruses in different species of domestic ducks.

Wang C1, Wang Z1, Ren X1, Wang L1, Li C1, Sun Y1, Wang M1, Tong Q1, Sun H2, Pu J3.

Author information: 1 Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China. 2 Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China. Electronic address: 3 Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, and State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing, 100193, China. Electronic address:



Domestic ducks are considered as the interface between wild aquatic birds and terrestrial poultry and play an important role in the transmission and evolution of avian influenza viruses (AIVs). However, the infectivity of H9N2 AIVs in different domestic duck species has not been systematically evaluated. Here we investigated the infectivity of various genotypes of chicken H9N2 AIVs in Pekin duck (Anas Platyrhynchos), Mallard duck (Anas Platyrhynchos) and Muscovy duck (Cairina Moschata) through intranasal inoculation. We found that Pekin ducks and Mallard ducks were generally resistant to chicken H9N2 virus infection, while Muscovy ducks were relatively susceptible to H9N2 AIVs. All the tested viruses were isolated from oropharynx, trachea and lung tissues of Muscovy ducks. Additionally, genotype 57 (G57) H9N2 AIVs, which was predominant in chickens since 2010, showed increased virus replication in this duck species, indicating an improved interspecies transmission ability of recent H9N2 viruses from chickens to ducks. Our results demonstrated the role of Muscovy ducks in the ecology of H9N2 AIVs. More attentions should be paid to this host during viral surveillances. Additionally, inactivated H9N2 vaccine may be unnecessarily used in Pekin and Mallard ducks.

Copyright © 2019 Elsevier B.V. All rights reserved.

KEYWORDS: Avian H9N2 influenza virus; Duck; Replication

PMID: 31176393 DOI: 10.1016/j.vetmic.2019.04.018

Keywords: Avian Influenza; H9N2; Poultry.


A new #reassortant clade #H5N1 highly pathogenic #avian #influenza virus causing recent #outbreaks in #ducks, geese, #chickens and turkeys in #Bangladesh (Transbound Emerg Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Transbound Emerg Dis. 2019 Jun 6. doi: 10.1111/tbed.13264. [Epub ahead of print]

A new reassortant clade H5N1 highly pathogenic avian influenza virus causing recent outbreaks in ducks, geese, chickens and turkeys in Bangladesh.

Nooruzzaman M1, Mumu TT1, Hasnat A1, Akter MN1, Rasel MSU1, Rahman MM1, Parvin R1, Begum JA1, Chowdhury EH1, Islam MR1.

Author information: 1 Department of Pathology, Faculty of Veterinary Science, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh.



A total of 15 dead or sick birds from 13 clinical outbreaks of avian influenza in ducks, geese, chickens and turkeys in 2017 in Bangladesh were examined. The presence of H5N1 influenza A virus in the affected birds was detected by RT-PCR. Phylogenetic analysis based on full length gene sequences of all eight gene segments revealed that these recent outbreaks were caused by a new reassotant of clade H5N1 virus, which had been detected earlier in 2015 during surveillance in live bird markets (LBMs) and wet lands. This reassortant virus acquired PB2, PB1, PA, NP and NS genes from low pathogenic avian influenza viruses mostly of non-H9N2 subtypes but retained HA, NA and M genes of the old clade viruses. Nevertheless, the HA gene of these new viruses was 2.7% divergent from that of the old clade viruses circulated in Bangladesh. Interestingly, similar reassortment events could be traced back in four virus isolates of 2013 from backyard ducks. It suggests that this reassortant virus emerged in 2013, which took two years to be detected at a broader scale (i.e. in LBMs), another two years until it became widely spread in poultry and fully replaced the old viruses. Several mutations were detected in the recent Bangladeshi isolates, which are likely to influence possible phenotypic alterations such as increased mammalian adaptation, reduced susceptibility to antiviral agents and reduced host antiviral response.

This article is protected by copyright. All rights reserved.

KEYWORDS: Bangladesh; H5N1 HPAIV; clade; domestic poultry; new reassortant

PMID: 31168925 DOI: 10.1111/tbed.13264

Keywords: Avian Influenza; H5N1; H9N2; Reassortant Strain; Poultry; Bangladesh.