scholarly journals Reassortment with dominant chicken H9N2 influenza virus contributed to the fifth H7N9 virus human epidemic

2021 ◽  
Author(s):  
Juan Pu ◽  
Yanbo Yin ◽  
Jiyu Liu ◽  
Xinyu Wang ◽  
Yong Zhou ◽  
...  
Keyword(s):  
Public Health ◽  
Influenza Virus ◽  
Influenza Viruses ◽  
H9n2 Virus ◽  
Close Monitoring ◽  
H7n9 Virus ◽  
Virus Genotype ◽  
H9n2 Influenza Virus ◽  
Adaptive Mutations ◽  
Viral Genes

H9N2 Avian influenza virus (AIV) is regarded as a principal donor of viral genes through reassortment to co-circulating influenza viruses that can result in zoonotic reassortants. Whether H9N2 virus can maintain sustained evolutionary impact on such reassortants is unclear. Since 2013, avian H7N9 virus had caused five sequential human epidemics in China; the fifth wave in 2016-2017 was by far the largest but the mechanistic explanation behind the scale of infection is not clear. Here, we found that, just prior to the fifth H7N9 virus epidemic, H9N2 viruses had phylogenetically mutated into new sub-clades, changed antigenicity and increased its prevalence in chickens vaccinated with existing H9N2 vaccines. In turn, the new H9N2 virus sub-clades of PB2 and PA genes, housing mammalian adaptive mutations, were reassorted into co-circulating H7N9 virus to create a novel dominant H7N9 virus genotype that was responsible for the fifth H7N9 virus epidemic. H9N2-derived PB2 and PA genes in H7N9 virus conferred enhanced polymerase activity in human cells at 33°C and 37°C, and increased viral replication in the upper and lower respiratory tracts of infected mice which could account for the sharp increase in human cases of H7N9 virus infection in the 2016-2017 epidemic. The role of H9N2 virus in the continual mutation of H7N9 virus highlights the public health significance of H9N2 virus in the generation of variant reassortants of increasing zoonotic potential. IMPORTANCE Avian H9N2 influenza virus, although primarily restricted to chicken populations, is a major threat to human public health by acting as a donor of variant viral genes through reassortment to co-circulating influenza viruses. We established that the high prevalence of evolving H9N2 virus in vaccinated flocks played a key role, as donor of new sub-clade PB2 and PA genes in the generation of a dominant H7N9 virus genotype (G72) with enhanced infectivity in humans during the 2016-2017 N7N9 virus epidemic. Our findings emphasize that the ongoing evolution of prevalent H9N2 virus in chickens is an important source, via reassortment, of mammalian adaptive genes for other influenza virus subtypes. Thus, close monitoring of prevalence and variants of H9N2 virus in chicken flocks is necessary in the detection of zoonotic mutations.

scholarly journals A PB1-K577E Mutation in H9N2 Influenza Virus Increases Polymerase Activity and Pathogenicity in Mice

Viruses ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 653 ◽  
Author(s):  
Haruhiko Kamiki ◽  
Hiromichi Matsugo ◽  
Tomoya Kobayashi ◽  
Hiroho Ishida ◽  
Akiko Takenaka-Uema ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Novel Mutation ◽  
Polymerase Activity ◽  
Influenza Viruses ◽  
H9n2 Virus ◽  
Wild Type Virus ◽  
H9n2 Influenza Virus ◽  
Pathogenicity Determinant ◽  
Lower Temperature ◽  
Human Infections

H9N2 avian influenza viruses are present in poultry worldwide. These viruses are considered to have pandemic potential, because recent isolates can recognize human-type receptor and several sporadic human infections have been reported. In this study, we aimed to identify mutations related to mammalian adaptation of H9N2 influenza virus. We found that mouse-adapted viruses had several mutations in hemagglutinin (HA), PB2, PA, and PB1. Among the detected mutations, PB1-K577E was a novel mutation that had not been previously reported to involve mammalian adaptation. A recombinant H9N2 virus bearing only the PB1-K577E mutation showed enhanced pathogenicity in mice, with increased virus titers in nasal turbinates compared to that in mice infected with the wild-type virus. In addition, the PB1-K577E mutation increased virus polymerase activity in human cell culture at a lower temperature. These data suggest that the PB1-K577E mutation is a novel pathogenicity determinant of H9N2 virus in mice and could be a signature for mammalian adaptation.

scholarly journals Cross-Reactive, Cell-Mediated Immunity and Protection of Chickens from Lethal H5N1 Influenza Virus Infection in Hong Kong Poultry Markets

2001 ◽  
Vol 75 (6) ◽  
pp. 2516-2525 ◽  
Author(s):  
Sang Heui Seo ◽  
Robert G. Webster
Keyword(s):  
T Cells ◽  
Influenza Virus ◽  
Hong Kong ◽  
Virus Infection ◽  
Cellular Immunity ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
H5n1 Influenza Virus ◽  
H9n2 Influenza Virus ◽  
H5n1 Influenza

ABSTRACT In 1997, avian H5N1 influenza virus transmitted from chickens to humans resulted in 18 confirmed infections. Despite harboring lethal H5N1 influenza viruses, most chickens in the Hong Kong poultry markets showed no disease signs. At this time, H9N2 influenza viruses were cocirculating in the markets. We investigated the role of H9N2 influenza viruses in protecting chickens from lethal H5N1 influenza virus infections. Sera from chickens infected with an H9N2 influenza virus did not cross-react with an H5N1 influenza virus in neutralization or hemagglutination inhibition assays. Most chickens primed with an H9N2 influenza virus 3 to 70 days earlier survived the lethal challenge of an H5N1 influenza virus, but infected birds shed H5N1 influenza virus in their feces. Adoptive transfer of T lymphocytes or CD8+ T cells from inbred chickens (B2/B2) infected with an H9N2 influenza virus to naive inbred chickens (B2/B2) protected them from lethal H5N1 influenza virus. In vitro cytotoxicity assays showed that T lymphocytes or CD8+ T cells from chickens infected with an H9N2 influenza virus recognized target cells infected with either an H5N1 or H9N2 influenza virus in a dose-dependent manner. Our findings indicate that cross-reactive cellular immunity induced by H9N2 influenza viruses protected chickens from lethal infection with H5N1 influenza viruses in the Hong Kong markets in 1997 but permitted virus shedding in the feces. Our findings are the first to suggest that cross-reactive cellular immunity can change the outcome of avian influenza virus infection in birds in live markets and create a situation for the perpetuation of H5N1 influenza viruses.

scholarly journals Emergence of H7N9 Influenza A Virus Resistant to Neuraminidase Inhibitors in Nonhuman Primates

2015 ◽  
Vol 59 (8) ◽  
pp. 4962-4973 ◽  
Author(s):  
Yasushi Itoh ◽  
Shintaro Shichinohe ◽  
Misako Nakayama ◽  
Manabu Igarashi ◽  
Akihiro Ishii ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Cynomolgus Macaque ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
H7n9 Virus ◽  
Macaque Model ◽  
H7n9 Influenza Virus ◽  
Number Of Patients ◽  
H7n9 Influenza

ABSTRACTThe number of patients infected with H7N9 influenza virus has been increasing since 2013. We examined the efficacy of neuraminidase (NA) inhibitors and the efficacy of a vaccine against an H7N9 influenza virus, A/Anhui/1/2013 (H7N9), isolated from a patient in a cynomolgus macaque model. NA inhibitors (oseltamivir and peramivir) barely reduced the total virus amount because of the emergence of resistant variants with R289K or I219T in NA [residues 289 and 219 in N9 of A/Anhui/1/2013 (H7N9) correspond to 292 and 222 in N2, respectively] in three of the six treated macaques, whereas subcutaneous immunization of an inactivated vaccine derived from A/duck/Mongolia/119/2008 (H7N9) prevented propagation of A/Anhui/1/2013 (H7N9) in all vaccinated macaques. The percentage of macaques in which variant H7N9 viruses with low sensitivity to the NA inhibitors were detected was much higher than that of macaques in which variant H5N1 highly pathogenic influenza virus was detected after treatment with one of the NA inhibitors in our previous study. The virus with R289K in NA was reported in samples from human patients, whereas that with I219T in NA was identified for the first time in this study using macaques, though no variant H7N9 virus was reported in previous studies using mice. Therefore, the macaque model enables prediction of the frequency of emerging H7N9 virus resistant to NA inhibitorsin vivo. Since H7N9 strains resistant to NA inhibitors might easily emerge compared to other influenza viruses, monitoring of the emergence of variants is required during treatment of H7N9 influenza virus infection with NA inhibitors.

scholarly journals Mutation and Epistasis in Influenza Virus Evolution

Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 407 ◽  
Author(s):  
Daniel Lyons ◽  
Adam Lauring
Keyword(s):  
Public Health ◽  
Influenza Virus ◽  
Vaccine Efficacy ◽  
Rapid Evolution ◽  
Evolutionary Process ◽  
Virus Evolution ◽  
Influenza Viruses ◽  
Antiviral Resistance ◽  
Epistatic Interactions ◽  
Public Health Challenge

Influenza remains a persistent public health challenge, because the rapid evolution of influenza viruses has led to marginal vaccine efficacy, antiviral resistance, and the annual emergence of novel strains. This evolvability is driven, in part, by the virus’s capacity to generate diversity through mutation and reassortment. Because many new traits require multiple mutations and mutations are frequently combined by reassortment, epistatic interactions between mutations play an important role in influenza virus evolution. While mutation and epistasis are fundamental to the adaptability of influenza viruses, they also constrain the evolutionary process in important ways. Here, we review recent work on mutational effects and epistasis in influenza viruses.

scholarly journals Face masks to prevent transmission of influenza virus: a systematic review

2010 ◽  
Vol 138 (4) ◽  
pp. 449-456 ◽  
Author(s):  
B. J. COWLING ◽  
Y. ZHOU ◽  
D. K. M. IP ◽  
G. M. LEUNG ◽  
A. E. AIELLO
Keyword(s):  
Public Health ◽  
Influenza Virus ◽  
Influenza A ◽  
English Language ◽  
Virus Transmission ◽  
International Health ◽  
Influenza Viruses ◽  
Community Settings ◽  
Influenza A H1n1 ◽  
Health Agencies

SUMMARYInfluenza viruses circulate around the world every year. From time to time new strains emerge and cause global pandemics. Many national and international health agencies recommended the use of face masks during the 2009 influenza A (H1N1) pandemic. We reviewed the English-language literature on this subject to inform public health preparedness. There is some evidence to support the wearing of masks or respirators during illness to protect others, and public health emphasis on mask wearing during illness may help to reduce influenza virus transmission. There are fewer data to support the use of masks or respirators to prevent becoming infected. Further studies in controlled settings and studies of natural infections in healthcare and community settings are required to better define the effectiveness of face masks and respirators in preventing influenza virus transmission.

scholarly journals Sialic Acid-Binding ProteinSp2CBMTD Protects Mice against Lethal Challenge with Emerging Influenza A (H7N9) Virus

2014 ◽  
Vol 59 (3) ◽  
pp. 1495-1504 ◽  
Author(s):  
Elena A. Govorkova ◽  
Tatiana Baranovich ◽  
Bindumadhav M. Marathe ◽  
Lei Yang ◽  
Margaret A. Taylor ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Sialic Acid ◽  
Influenza A ◽  
Adaptive Immune Response ◽  
Genetically Engineered ◽  
Influenza Viruses ◽  
H7n9 Virus ◽  
Lethal Challenge ◽  
Proinflammatory Mediators

ABSTRACTCompounds that target the cellular factors essential for influenza virus replication represent an innovative approach to antiviral therapy.Sp2CBMTD is a genetically engineered multivalent protein that masks sialic acid-containing cellular receptors on the respiratory epithelium, which are recognized by influenza viruses. Here, we evaluated the antiviral potential ofSp2CBMTD against lethal infection in mice with an emerging A/Anhui/1/2013 (H7N9) influenza virus and addressed the mechanistic basis of its activityin vivo. Sp2CBMTD was administered to mice intranasally as a single or repeated dose (0.1, 1, 10, or 100 μg) before (day −7, −3, and/or −1) or after (6 or 24 h) H7N9 virus inoculation. A singleSp2CBMTD dose (10 or 100 μg) protected 80% to 100% of the mice when administered 7 days before the H7N9 lethal challenge. RepeatedSp2CBMTD administration conferred the highest protection, resulting in 100% survival of the mice even at the lowest dose tested (0.1 μg). When treatment began 24 h after exposure to the H7N9 virus, a single administration of 100 μg ofSp2CBMTD protected 40% of the mice from death. The administration ofSp2CBMTD induced the pulmonary expression of proinflammatory mediators (interleukin-6 [IL-6], IL-1β, RANTES, monocyte chemotactic protein-1 [MCP-1], macrophage inflammatory protein-1α [MIP-1α], and inducible protein [IP-10]) and recruited neutrophils to the respiratory tract before H7N9 virus infection, which resulted in less pronounced inflammation and rapid virus clearance from mouse lungs.Sp2CBMTD administration did not affect the virus-specific adaptive immune response, which was sufficient to protect against reinfection with a higher dose of homologous H7N9 virus or heterologous H5N1 virus. Thus,Sp2CBMTD was effective in preventing H7N9 infections in a lethal mouse model and holds promise as a prophylaxis option against zoonotic influenza viruses.

scholarly journals Wipes Coated with a Singlet-Oxygen-Producing Photosensitizer Are Effective against Human Influenza Virus but Not against Norovirus

2014 ◽  
Vol 80 (14) ◽  
pp. 4391-4397 ◽  
Author(s):  
Katharina Verhaelen ◽  
Martijn Bouwknegt ◽  
Saskia Rutjes ◽  
Ana Maria de Roda Husman ◽  
Erwin Duizer
Keyword(s):  
Public Health ◽  
Influenza Virus ◽  
Health Risk ◽  
Singlet Oxygen ◽  
Human Adenovirus ◽  
Influenza Viruses ◽  
Murine Norovirus ◽  
Human Influenza ◽  
Human Influenza Virus ◽  
Public Health Risk

ABSTRACTTransmission of enteric and respiratory viruses, including human norovirus (hNoV) and human influenza virus, may involve surfaces. In food preparation and health care settings, surfaces are cleaned with wipes; however, wiping may not efficiently reduce contamination or may even spread viruses, increasing a potential public health risk. The virucidal properties of wipes with a singlet-oxygen-generating immobilized photosensitizer (IPS) coating were compared to those of similar but uncoated wipes (non-IPS) and of commonly used viscose wipes. Wipes were spiked with hNoV GI.4 and GII.4, murine norovirus 1 (MNV-1), human adenovirus type 5 (hAdV-5), and influenza virus H1N1 to study viral persistence. We also determined residual and transferred virus proportions on steel carriers after successively wiping a contaminated and an uncontaminated steel carrier. On IPS wipes only, influenza viruses were promptly inactivated with a 5-log10reduction.Dvalues of infectious MNV-1 and hAdV-5 were 8.7 and 7.0 h on IPS wipes, 11.6 and 9.3 h on non-IPS wipes, and 10.2 and 8.2 h on viscose wipes, respectively. Independently of the type of wipe, dry cleaning removed, or drastically reduced, initial spot contamination of hNoV on surfaces. All wipes transferred hNoV to an uncontaminated carrier; however, the risk of continued transmission by reuse of wipes after 6 and 24 h was limited for all viruses. We conclude that cleaning wet spots with dry wipes efficiently reduced spot contamination on surfaces but that cross-contamination with noroviruses by wiping may result in an increased public health risk at high initial virus loads. For influenza virus, IPS wipes present an efficient one-step procedure for cleaning and disinfecting contaminated surfaces.

Gut microbiota modulates type I interferon and antibody-mediated immune responses in chickens infected with influenza virus subtype H9N2

2018 ◽  
Vol 9 (3) ◽  
pp. 417-427 ◽  
Author(s):  
A. Yitbarek ◽  
T. Alkie ◽  
K. Taha-Abdelaziz ◽  
J. Astill ◽  
J.C. Rodriguez-Lecompte ◽  
...  
Keyword(s):  
Immune Response ◽  
Influenza Virus ◽  
Virus Infection ◽  
Gut Microbiota ◽  
Type I Interferon ◽  
Influenza Viruses ◽  
H9n2 Virus ◽  
Type I ◽  
Virus Shedding ◽  
Virus Subtype

Commensal gut microbes play a critical role in shaping host defences against pathogens, including influenza viruses. The current study was conducted to assess the role and mechanisms of action of commensal gut microbiota on the innate and antibody-mediated responses of layer chickens against influenza virus subtype H9N2. A total of 104 one-day-old specific pathogen free chickens were assigned to either of the four treatments, which included two levels of antibiotics treatment (ABX- and ABX+) and two levels of H9N2 virus infection (H9N2- and H9N2+). At day 17 of age, chickens in the H9N2+ group were infected via the oral-nasal route with 400 μl of 107 TCID50/ml (200 μl/each route). Oropharyngeal and cloacal swabs at days 1, 3, 5, 7 and 9 post-infection (p.i.) for virus shedding, tissue samples at 12 h, 24 h and 36 h p.i. for mRNA measurement, and serum samples at days 7 and 14 p.i. for hemagglutination inhibition (HI) assay and IgG antibodies were collected. Virus shedding analysis showed that antibiotic treated (depleted)-H9N2 virus infected chickens showed a significantly higher oropharyngeal virus shedding at all time points, and cloacal shedding at days 3 and 5 p.i. compared to control treated (undepleted)-H9N2 infected chickens. Analysis of mRNA expression showed that infection of depleted chickens with H9N2 virus resulted in significantly down-regulated type I interferon responses both in the respiratory and gastrointestinal tracts compared to undepleted-H9N2 infected chickens. However, antibody-mediated immune response analysis showed a significantly higher HI antibody titre and IgG levels in the serum of chickens depleted with antibiotics and infected with H9N2 virus compared to undepleted-H9N2 infected chickens. In conclusion, findings from the current study suggest that the gut microbiota of chickens plays an important role in the initiation of innate responses against influenza virus infection, while the antibody-mediated immune response remains unaffected.

scholarly journals Epidemiology, Evolution, and Recent Outbreaks of Avian Influenza Virus in China

2015 ◽  
Vol 89 (17) ◽  
pp. 8671-8676 ◽  
Author(s):  
Shuo Su ◽  
Yuhai Bi ◽  
Gary Wong ◽  
Gregory C. Gray ◽  
George F. Gao ◽  
...  
Keyword(s):  
Public Health ◽  
Influenza Virus ◽  
Avian Influenza ◽  
Avian Influenza Virus ◽  
Influenza Viruses ◽  
Warning Signs ◽  
Avian Influenza Viruses ◽  
Recent Increase ◽  
And Control

Novel reassortants of H7N9, H10N8, and H5N6 avian influenza viruses (AIVs) are currently circulating in China's poultry flocks, occasionally infecting humans and other mammals. Combined with the sometimes enzootic H5N1 and H9N2 strains, this cauldron of genetically diverse AIVs pose significant risks to public health. Here, we review the epidemiology, evolution, and recent outbreaks of AIVs in China, discuss reasons behind the recent increase in the emergence of novel AIVs, and identify warning signs which may point to the emergence of a potentially virulent and highly transmissible AIV to humans. This review will be useful to authorities who consider options for the detection and control of AIV transmission in animals and humans, with the goal of preventing future epidemics and pandemics.

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