ABSTRACT
This research presents an innovative reflective fiber optic probe structure, mutinously designed to detect H7N9 avian influenza virus gene precisely. This innovative structure skillfully combines multimode fiber (MMF) with a thin-diameter seven-core photonic crystal fiber (SCF-PCF), forming a semi-open Fabry-Pérot (FPI) cavity. This structure has demonstrated exceptional sensitivity in light intensity-refractive index (RI) response through rigorous theoretical and experimental validation. The development of a quasi-distributed parallel sensor array, which provides temperature compensation during measurements, has achieved a remarkable RI response sensitivity of up to 532.7 dB/RIU. The probe-type fiber optic sensitive unit, expertly functionalized with streptavidin, offers high specificity in detecting H7N9 avian influenza virus gene, with an impressively low detection limit of 10-2 pM. The development of this biosensor marks a significant development in biological detection, offering a practical engineering solution for achieving high sensitivity and specificity in light-intensity-modulated biosensing. Its potential for wide-ranging applications in various fields is now well-established.
Subject(s)
Biosensing Techniques , Influenza A Virus, H7N9 Subtype , Temperature , Biosensing Techniques/methods , Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/isolation & purification , Optical Fibers , Limit of Detection , Fiber Optic Technology/methods , Animals , Genes, ViralABSTRACT
Although molecular imprinting technology has been widely used in the construction of virus sensors, it is still a great challenge to identify subtypes viruses specifically because of their high similarity in morphology, size and structure. Here, a monoclonal molecular imprinted polymers (MIPs) sensor for recognition of H5N1 is constructed to permit the accurate distinguishing of H5N1 from other influenza A virus (IAV) subtypes. Firstly, H5N1 are immobilized on magnetic microspheres to produce H5N1-MagNPs, then the high affinity nanogel H5N1-MIPs is prepared by solid phase imprinting technique. When H5N1-MIPs is combined with MagNP-H5N1, different concentrations of H5N1 are added for competitive substitution. The quantitative detection of H5N1 is realized by the change of fluorescence intensity of supernatant. As expected, the constructed sensor shows satisfactory selectivity, and can identify the target virus from highly similar IAV subtypes, such as H1N1, H7N9 and H9N2. The sensor was highly sensitive, with a detection limit of 0.58 fM, and a selectivity factor that is comparable to that of other small MIPs sensors is achieved. In addition, the proposed sensor is cheap, with a cost of only RMB 0.08 yuan. The proposed monoclonal sensor provides a new method for the specific recognition of designated virus subtype, which is expected to be used for large-scale screening and accurate treatment of infected people.
Subject(s)
Influenza A Virus, H5N1 Subtype , Molecular Imprinting , Influenza A Virus, H5N1 Subtype/isolation & purification , Molecularly Imprinted Polymers/chemistry , Influenza A Virus, H1N1 Subtype/isolation & purification , Limit of Detection , Biosensing Techniques/methods , Influenza A Virus, H9N2 Subtype/isolation & purification , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza A virus/isolation & purification , HumansABSTRACT
Multiplex detection can enhance diagnostic precision and improve diagnostic efficiency, providing important assistance for epidemiological investigation and epidemic prevention. There is a great need for multi-detection sensing platforms to accurately diagnose diseases. Herein, we reported a µPAD-based chemiluminescence (CL) assay for ultrasensitive multiplex detection of AIV biomarkers, based on three DNAzyme/Lum/PEI/CaCO3. Three time-resolved CL signals were sequentially generated with detection limits of 0.32, 0.34, and 0.29 pM for H1N1, H7N9, and H5N1, respectively, and with excellent selectivity against interfering DNA. The recovery test in human serum displayed satisfactory analysis capabilities for complex biological samples. The µPAD-based CL assay achieved multiplex detection within 70 s, with a high time resolution of 20 s. The proposed strategy has the advantages of low cost, high sensitivity, good selectivity, and wide time resolution, the µPAD-based CL assay has shown great potential in the early and accurate diagnosis of diseases.
Subject(s)
Biomarkers , Luminescent Measurements , Luminescent Measurements/methods , Humans , Biomarkers/blood , Biomarkers/analysis , Paper , Influenza A Virus, H1N1 Subtype/isolation & purification , Influenza A Virus, H5N1 Subtype/isolation & purification , Influenza A Virus, H5N1 Subtype/genetics , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza A Virus, H7N9 Subtype/genetics , Animals , Influenza in Birds/diagnosis , Influenza in Birds/virology , DNA, Catalytic/chemistry , DNA, Catalytic/metabolism , Birds/virology , Limit of Detection , Influenza, Human/diagnosis , Influenza, Human/virology , Microfluidic Analytical Techniques/methods , Microfluidic Analytical Techniques/instrumentationABSTRACT
The H7 subtype avian influenza viruses are circulating widely worldwide, causing significant economic losses to the poultry industry and posing a serious threat to human health. In 2019, H7N2 and H7N9 co-circulated in Chinese poultry, yet the risk of H7N2 remained unclear. We isolated and sequenced four H7N2 viruses from chickens, revealing them as novel reassortants with H7N9-derived HA, M, NS genes and H9N2-derived PB2, PB1, PA,NP, NA genes. To further explore the key segment of pathogenicity, H7N2-H7N9NA and H7N2-H9N2HA single-substitution were constructed. Pathogenicity study showed H7N2 isolates to be highly pathogenic in chickens, with H7N2-H7N9NA slightly weaker than H7N2-Wild type. Transcriptomic analysis suggested that H7N9-derived HA genes primarily drove the high pathogenicity of H7N2 isolates, eliciting a strong inflammatory response. These findings underscored the increased threat posed by reassorted H7N2 viruses to chickens, emphasizing the necessity of long-term monitoring of H7 subtype avian influenza viruses.
Subject(s)
Chickens , Influenza A Virus, H7N2 Subtype , Influenza A Virus, H7N9 Subtype , Influenza in Birds , Reassortant Viruses , Animals , Chickens/virology , Influenza in Birds/virology , Influenza in Birds/transmission , Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/pathogenicity , Influenza A Virus, H7N9 Subtype/isolation & purification , Reassortant Viruses/pathogenicity , Reassortant Viruses/genetics , Influenza A Virus, H7N2 Subtype/pathogenicity , Influenza A Virus, H7N2 Subtype/genetics , Poultry Diseases/virology , Poultry Diseases/transmission , Virulence , Phylogeny , Influenza A Virus, H9N2 Subtype/genetics , Influenza A Virus, H9N2 Subtype/pathogenicity , Influenza A Virus, H9N2 Subtype/physiology , ChinaABSTRACT
Current methods used for diagnosis of acute infection of pathogens rely on detection of nucleic acids, antigens, or certain classes of antibodies such as IgM. Here we report a virus enzyme assay as an alternative to these methods for detection of acute viral infection. In this method, we used a luciferin derivative as the substrate for detection of the enzyme activity of influenza viral neuraminidase as a means for diagnosis of influenza. The resulting commercial test, the qFLU Dx Test, uses a different supply chain that does not compete with those for the current tests. The assay reagents were formulated as a master mix that accommodated both the neuraminidase and luciferase reactions, thereby enabling rapid and prolonged production of stable light signal in the presence of influenza virus in the sample. The assay was evaluated using depository throat swab specimens. As expected, the assay exhibited similar detection rates for all influenza types and subtypes except for A(H7N9), which exhibited lower detection rate due to lower viral titer in the specimens. When throat swab specimens were diluted with the sample buffer of the test kit and tested with the qFLU Dx Test. The sensitivity and specificity were 82.41% (95% confidence interval: 79.66-85.84%) and 95.39% (95% confidence interval: 94.32-96.46%), respectively, for these diluted specimens in comparison to a real-time polymerase chain reaction assay. The uniqueness of the qFLU Dx Test as an enzymatic assay makes it highly complementary with currently available methods.
Subject(s)
Diagnostic Tests, Routine/methods , Influenza A Virus, H7N9 Subtype/enzymology , Influenza, Human/diagnosis , Neuraminidase/analysis , Viral Proteins/analysis , Diagnostic Tests, Routine/instrumentation , Humans , Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza, Human/virology , Neuraminidase/genetics , Neuraminidase/metabolism , Pharynx/virology , Reagent Kits, Diagnostic , Sensitivity and Specificity , Viral Proteins/genetics , Viral Proteins/metabolismABSTRACT
Zoonotic infection with avian influenza viruses (AIVs) of subtype H7, such as H7N9 and H7N4, has raised concerns worldwide. During the winter of 2020-2021, five novel H7 low pathogenic AIVs (LPAIVs) containing different neuraminidase (NA) subtypes, including two H7N3, an H7N8, and two H7N9, were detected in wild bird feces in South Korea. Complete genome sequencing and phylogenetic analysis showed that the novel H7Nx AIVs were reassortants containing two gene segments (hemagglutinin (HA) and matrix) that were related to the zoonotic Jiangsu-Cambodian H7 viruses causing zoonotic infection and six gene segments originating from LPAIVs circulating in migratory birds in Eurasia. A genomic constellation analysis demonstrated that all H7 isolates contained a mix of gene segments from different viruses, indicating that multiple reassortment occurred. The well-known mammalian adaptive substitution (E627K and D701N) in PB2 was not detected in any of these isolates. The detection of multiple reassortant H7Nx AIVs in wild birds highlights the need for intensive surveillance in both wild birds and poultry in Eurasia.
Subject(s)
Influenza A Virus, H7N3 Subtype/genetics , Influenza A Virus, H7N9 Subtype/genetics , Influenza in Birds/virology , Animals , Animals, Wild/virology , Birds/genetics , Birds/virology , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Influenza A Virus, H7N3 Subtype/isolation & purification , Influenza A Virus, H7N3 Subtype/pathogenicity , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza A Virus, H7N9 Subtype/pathogenicity , Influenza in Birds/epidemiology , Phylogeny , Republic of Korea/epidemiologyABSTRACT
H7 low pathogenic avian influenza viruses (LPAIVs) can mutate into highly pathogenic avian influenza viruses (HPAIVs). In addition to avian species, H7 avian influenza viruses (AIVs) also infect humans. In this study, two AIVs, H7N9 (20X-20) and H7N7 (34X-2), isolated from the feces of wild birds in South Korea in 2021, were genetically analyzed. The HA cleavage site of the two H7 Korean viruses was confirmed to be ELPKGR/GLF, indicating they are LPAIVs. There were no amino acid substitutions at the receptor-binding site of the HA gene of two H7 Korean viruses compared to that of A/Anhui/1/2013 (H7N9), which prefer human receptors. In the phylogenetic tree analysis, the HA gene of the two H7 Korean viruses shared the highest nucleotide similarity with the Korean H7 subtype AIVs. In addition, the HA gene of the two H7 Korean viruses showed high nucleotide similarity to that of the A/Jiangsu/1/2018(H7N4) virus, which is a human influenza virus originating from avian influenza virus. Most internal genes (PB2, PB1, PA, NP, NA, M, and NS) of the two H7 Korean viruses belonged to the Eurasian lineage, except for the M gene of 34X-2. This result suggests that active reassortment occurred among AIVs. In pathogenicity studies of mice, the two H7 Korean viruses replicated in the lungs of mice. In addition, the body weight of mice infected with 34X-2 decreased 7 days post-infection (dpi) and inflammation was observed in the peribronchiolar and perivascular regions of the lungs of mice. These results suggest that mammals can be infected with the two H7 Korean AIVs. Our data showed that even low pathogenic H7 AIVs may infect mammals, including humans, as confirmed by the A/Jiangsu/1/2018(H7N4) virus. Therefore, continuous monitoring and pathogenicity assessment of AIVs, even of LPAIVs, are required.
Subject(s)
Influenza A Virus, H7N7 Subtype/genetics , Influenza A Virus, H7N9 Subtype/genetics , Influenza in Birds/epidemiology , Animals , Animals, Wild/virology , Birds/genetics , Birds/virology , Feces/virology , Female , Influenza A Virus, H7N7 Subtype/isolation & purification , Influenza A Virus, H7N7 Subtype/pathogenicity , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza A Virus, H7N9 Subtype/pathogenicity , Mice , Mice, Inbred BALB C , Phylogeny , Republic of Korea/epidemiology , VirulenceABSTRACT
The H7N9 avian influenza virus (AIV) that emerged in China have caused five waves of human infection. Further human cases have been successfully prevented since September 2017 through the use of an H7N9 vaccine in poultry. However, the H7N9 AIV has not been eradicated from poultry in China, and its evolution remains largely unexplored. In this study, we isolated 19 H7N9 AIVs during surveillance and diagnosis from February 2018 to December 2019, and genetic analysis showed that these viruses have formed two different genotypes. Animal studies indicated that the H7N9 viruses are highly lethal to chicken, cause mild infection in ducks, but have distinct pathotypes in mice. The viruses bound to avian-type receptors with high affinity, but gradually lost their ability to bind to human-type receptors. Importantly, we found that H7N9 AIVs isolated in 2019 were antigenically different from the H7N9 vaccine strain that was used for H7N9 influenza control in poultry, and that replication of these viruses cannot, therefore, be completely prevented in vaccinated chickens. We further revealed that two amino acid mutations at positions 135 and 160 in the HA protein added two glycosylation sites and facilitated the escape of the H7N9 viruses from the vaccine-induced immunity. Our study provides important insights into H7N9 virus evolution and control.
Subject(s)
Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza Vaccines/therapeutic use , Influenza in Birds/prevention & control , Poultry Diseases/virology , Animals , Animals, Zoo/virology , Chickens/virology , China/epidemiology , Ducks/virology , Infection Control/methods , Influenza A Virus, H7N9 Subtype/classification , Influenza A Virus, H7N9 Subtype/physiology , Influenza in Birds/epidemiology , Influenza in Birds/virology , Mice , Phylogeny , Population Surveillance , Poultry , Poultry Diseases/epidemiology , Poultry Diseases/prevention & controlABSTRACT
BACKGROUND: H7N9 avian influenza virus (AIV) including highly and low pathogenic viruses have been detected in China since 2013. H7N9 AIV has a high mortality rate after infection in humans, and most human cases have close contacted with poultry in the live poultry market. Therefore, it is necessary to develop a rapid point-of-care testing (POCT) technique for H7N9 AIV detection. METHODS: The H7N9 AIV was inactivated and purified, and was used as the antigen to immunize BALB/c. Twelve H7-HA specific monoclonal antibodies (McAbs) were produced through the hybridoma technique. The McAb 10A8 was conjugated with colloid gold as detecting antibody; McAb 9B6 was dispensed on the nitrocellulose membran as the capture test line and the Goat-anti mouse IgG antibody was dispensed as control line respectively. The immunochromatographic strip was prepared. RESULTS: The analysis of ELISA and virus neutralization test showed that the obtained McAbs specifically recognized H7 HA. Based on the prepared strip, the detection of H7 AIV was achieved within 10 min. No cross-reaction occurred between H7 AIVs and other tested viruses. The detection limit of the strip for H7 was 2.4 log10EID50/0.1 mL for chicken swab samples. CONCLUSION: The McAbs were specific for H7 and the immunochromatographic strip developed in this study was convenient, rapid and reliable for the detection of H7 AIV. The strip could provide an effective method for the rapid and early detection of H7 AIV.
Subject(s)
Immunoassay , Influenza A Virus, H7N9 Subtype , Influenza in Birds , Animals , Antibodies, Monoclonal , Chromatography, Affinity , Enzyme-Linked Immunosorbent Assay , Gold Colloid , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza in Birds/diagnosis , Mice, Inbred BALB C , Point-of-Care Testing , PoultryABSTRACT
The genome composition of a given avian influenza virus is the primary determinant of its potential for cross-species transmission from birds to humans. Here, we introduce a viral genome-based computational tool that can be used to evaluate the human infectivity of avian isolates of influenza A H7N9 viruses, which can enable prediction of the potential risk of these isolates infecting humans. This tool, which is based on a novel class weight-biased logistic regression (CWBLR) algorithm, uses the sequences of the eight genome segments of an H7N9 strain as the input and gives the probability of this strain infecting humans (reflecting its human infectivity). We examined the replication efficiency and the pathogenicity of several H7N9 avian isolates that were predicted to have very low or high human infectivity by the CWBLR model in cell culture and in mice, and found that the strains with high predicted human infectivity replicated more efficiently in mammalian cells and were more infective in mice than those that were predicted to have low human infectivity. These results demonstrate that our CWBLR model can serve as a powerful tool for predicting the human infectivity and cross-species transmission risks of H7N9 avian strains.
Subject(s)
Influenza A Virus, H7N9 Subtype/pathogenicity , Influenza in Birds/virology , Influenza, Human/virology , Animals , Birds , Genome, Viral , Humans , Influenza A Virus, H7N9 Subtype/isolation & purification , ZoonosesABSTRACT
We have surveyed avian influenza virus (AIV) genomes from live poultry markets within China since 2014. Here we present a total of 16,091 samples that were collected from May 2016 to February 2019 in 23 provinces and municipalities in China. We identify 2048 AIV-positive samples and perform next generation sequencing. AIV-positive rates (12.73%) from samples had decreased substantially since 2016, compared to that during 2014-2016 (26.90%). Additionally, H9N2 has replaced H5N6 and H7N9 as the dominant AIV subtype in both chickens and ducks. Notably, novel reassortants and variants continually emerged and disseminated in avian populations, including H7N3, H9N9, H9N6 and H5N6 variants. Importantly, almost all of the H9 AIVs and many H7N9 and H6N2 strains prefer human-type receptors, posing an increased risk for human infections. In summary, our nation-wide surveillance highlights substantial changes in the circulation of AIVs since 2016, which greatly impacts the prevention and control of AIVs in China and worldwide.
Subject(s)
Influenza A virus , Influenza in Birds/virology , Poultry/virology , Animals , Birds , Chickens/virology , China/epidemiology , Ducks/virology , Genome, Viral , Humans , Influenza A Virus, H7N3 Subtype/genetics , Influenza A Virus, H7N3 Subtype/isolation & purification , Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza A Virus, H9N2 Subtype/genetics , Influenza A Virus, H9N2 Subtype/isolation & purification , Influenza A virus/genetics , Influenza A virus/isolation & purification , Influenza in Birds/epidemiology , Influenza in Birds/prevention & control , Influenza, Human/virology , Phylogeny , Reassortant Viruses/genetics , Reassortant Viruses/isolation & purificationABSTRACT
The influenza A (H7N9) subtype remains a public health problem in China affecting individuals in contact with live poultry, particularly at live bird markets. Despite enhanced surveillance and biosecurity at LBMs H7N9 viruses are now more widespread in China. This study aims to quantify the temporal relationship between poultry surveillance results and the onset of human H7N9 infections during 2013-2017 and to estimate risk factors associated with geographical risk of H7N9 human infections in counties in Southeast China. Our results suggest that poultry surveillance data can potentially be used as early warning indicators for human H7N9 notifications. Furthermore, we found that human H7N9 incidence at county-level was significantly associated with the presence of wholesale LBMs, the density of retail LBMs, the presence of poultry virological positives, poultry movements from high-risk areas, as well as chicken population density and human population density. The results of this study can influence the current AI H7N9 control program by supporting the integration of poultry surveillance data with human H7N9 notifications as an early warning of the timing and areas at risk for human infection. The findings also highlight areas in China where monitoring of poultry movement and poultry infections could be prioritized.
Subject(s)
Chickens/virology , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza in Birds/virology , Influenza, Human/virology , Poultry/virology , Animals , China/epidemiology , Geography , Humans , Influenza in Birds/epidemiology , Influenza in Birds/pathology , Influenza, Human/epidemiology , Influenza, Human/pathology , Public Health , Risk Factors , Social NetworkingABSTRACT
Computer models of hemagglutinins from the H3N2 and H7N9 influenza viruses were developed to study structural organization and dynamic characteristics of the binding site for the conformational rearrangement inhibitors. The metadynamics was used to map the binding site free energy and to define the volume of its most energetically favorable states. It was demonstrated by simulation of the umifenovir (Arbidol) interaction with hemagglutinin that ligand binding requires an increase in the binding site volume and deformation of its most energetically favorable state. We also identified amino acid residues directly involved in the ligand binding that determine the binding efficiency, as well as the dynamic behavior of the binding site. The revealed features of the binding site structural organization of the influenza virus hemagglutinin should be taken into account when searching for new antiviral drugs capable to modulate its functional properties.
Subject(s)
Antiviral Agents/pharmacology , Hemagglutinin Glycoproteins, Influenza Virus/chemistry , Hemagglutinin Glycoproteins, Influenza Virus/metabolism , Influenza A Virus, H3N2 Subtype/isolation & purification , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza, Human/virology , Protein Conformation/drug effects , Binding Sites , Computer Simulation , Humans , Influenza A Virus, H3N2 Subtype/metabolism , Influenza A Virus, H7N9 Subtype/metabolism , Influenza, Human/metabolism , Models, StructuralABSTRACT
OBJECTIVES: To evaluate the prevalence of cardiac injury and its association with mortality in hospitalized patients infected with avian influenza A (H7N9) virus. DESIGN: Retrospective cohort study. SETTING: A total of 133 hospitals in 17 provinces, autonomous regions, and municipalities of mainland China that admitted influenza A (H7N9) virus-infected patients between January 22, 2015, and June 16, 2017. PATIENTS: A total of 321 patients with influenza A (H7N9) virus infection were included in the final analysis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Demographics and clinical characteristics were collected from medical records. Cardiac injury was defined according to cardiac biomarkers, electrocardiography, or echocardiography. Among the 321 patients, 203 (63.2%) showed evidence of cardiac injury. Compared with the uninjured group, the cardiac injury group had lower PaO2/FIO2 (median, 102.0 vs 148.4 mm Hg; p < 0.001), higher Acute Physiology and Chronic Health Evaluation II score (median, 17.0 vs 11.0; p < 0.001), longer stay in the ICU (10.0 vs 9.0 d; p = 0.029), and higher proportion of in-hospital death (64.0% vs 20.3%; p < 0.001). The proportion of virus clearance until discharge or death was lower in the cardiac injury group than in the uninjured group (58.6% vs 86.4%; p < 0.001). Multivariable-adjusted Cox proportional hazards regression analysis showed that cardiac injury was associated with higher mortality (hazards ratio, 2.06; 95% CI, 1.31-3.24) during hospitalization. CONCLUSIONS: Cardiac injury is a frequent condition among hospitalized patients infected with influenza A (H7N9) virus, and it is associated with higher risk of mortality.
Subject(s)
Coronavirus Infections/mortality , Critical Illness/mortality , Heart Injuries/mortality , Influenza, Human/mortality , Adult , Age Factors , China , Coronavirus Infections/virology , Female , Heart Injuries/virology , Humans , Influenza A Virus, H7N9 Subtype/isolation & purification , Male , Middle Aged , Respiratory Distress Syndrome/mortality , Retrospective Studies , Socioeconomic FactorsABSTRACT
BACKGROUND: The emergence of human infection with avian influenza A(H7N9) virus was reported in Wenshan City, southwestern China in 2017. The study describes the epidemiological and virological features of the outbreak and discusses the origin of the infection. METHODS: Poultry exposure and timelines of key events for each patient were collected. Samples derived from the patients, their close contacts, and environments were tested for influenza A(H7N9) virus by real-time reverse transcription polymerase chain reaction. Genetic sequencing and phylogenetic analysis were also conducted. RESULTS: Five patients were reported in the outbreak. An epidemiological investigation showed that all patients had been exposed at live poultry markets. The A(H7N9) isolates from these patients had low pathogenicity in avian species. Both epidemiological investigations of chicken sources and phylogenetic analysis of viral gene sequences indicated that the source of infection was from Guangxi Province, which lies 100 km to the east of Wenshan City. CONCLUSIONS: In the study, a sudden emergence of human cases of H7N9 was documented in urban area of Wenshan City. Chickens were an important carrier in the H7N9 virus spreading from Guangxi to Wenshan. Hygienic management of live poultry markets and virological screening of chickens transported across regions should be reinforced to limit the spread of H7N9 virus.
Subject(s)
Influenza A Virus, H7N9 Subtype/genetics , Influenza in Birds/virology , Influenza, Human/epidemiology , Phylogeny , Adult , Amino Acid Substitution , Animals , Child, Preschool , China/epidemiology , Disease Outbreaks , Female , Humans , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza A Virus, H7N9 Subtype/pathogenicity , Influenza, Human/drug therapy , Influenza, Human/virology , Male , Poultry/virology , Real-Time Polymerase Chain ReactionABSTRACT
We report the use of environmental samples to assess avian influenza virus activity in chickens at live poultry markets in China. Results of environmental and chicken samples correlate moderately well. However, collection of multiple environmental samples from holding, processing, and selling areas is recommended to detect viruses expected to have low prevalence.
Subject(s)
Animal Husbandry , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza in Birds/epidemiology , Animals , Chickens , China/epidemiology , Commerce , Influenza in Birds/virology , Poultry , PrevalenceABSTRACT
Since the first case of novel H7N9 infection was reported, China has experienced five epidemics of H7N9. During the fifth wave, a highly pathogenic H7N9 strain emerged. Meanwhile, the H7N9 virus continues to accumulate mutations, and its affinity for the human respiratory epithelial sialic acid 2-6 receptor has increased. Therefore, a pandemic is still possible. In the past 6 years, we have accumulated rich experience in dealing with H7N9, especially in terms of virus tracing, epidemiological research, key site mutation monitoring, critical disease mechanisms, clinical treatment, and vaccine development. In the research fields above, significant progress has been made to effectively control the spread of the epidemic and reduce the fatality rate. To fully document the research progress concerning H7N9, we reviewed the clinical and epidemiological characteristics of H7N9, the key gene mutations of the virus, and H7N9 vaccine, thus providing a scientific basis for further monitoring and prevention of H7N9 influenza epidemics.
Subject(s)
Epidemics/statistics & numerical data , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza, Human/epidemiology , Animals , China/epidemiology , Humans , Influenza in Birds/transmission , Influenza in Birds/virology , Influenza, Human/virology , Pandemics/prevention & control , Population Surveillance , PoultryABSTRACT
H9N2 viruses can cause great economic losses to the domestic poultry industry when co-infected with other influenza viruses or pathogens. . To better understand the molecular characteristics of H9N2 avian influenza viruses (AIVs) and analyze the genetic evolutionary relationship, we isolated three H9N2 subtypes AIVs from nasopharyngeal swab specimens from the three cases reported in Anhui province since 2015, and systematically reviewed the genome-wide data of 21 poultry--isolated H9N2 viruses during 1998-2017. The six internal genes of three human-isolated viruses and recent poultry-isolated viruses (since 2014) in Anhui province presented high gene homologies with HPAI H7N9, even including H10N8 and H5N6. The three human-isolated H9N2 AIVs and poultry-isolated viruses (since 2008) in Anhui province were highly similar, and classified into genotype S. Seven N-linked potential glycosylation sites in the HA protein were detected in the three human-isolated viruses, which also appeared in poultry-isolated H9N2 AIVs. None of the human-isolated H9N2 AIVs had the I368V mutation in PB1 protein, but all the poultry-isolated H9N2 viruses in 2017 carried this mutation. Multidisciplinary, cross-regional and cross-sectoral approaches are warranted to address complex public health challenges and achieve the goal of 'one health'.
Subject(s)
Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H9N2 Subtype/genetics , Influenza in Birds/virology , Poultry/virology , Animals , Chickens , China/epidemiology , Genome, Viral , Humans , Incidence , Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza A Virus, H9N2 Subtype/isolation & purification , Influenza in Birds/transmission , Influenza, Human/transmission , Influenza, Human/virology , Phylogeny , Poultry Diseases/transmission , Poultry Diseases/virology , PrevalenceABSTRACT
Avian influenza A (H7N9) is a serve zoonosis with a high mortality rate. Timely and effective diagnosis and early warning is crucial for the clinical treatment of H7N9 patients. The previous studies indicated that thrombocytopenia was associated with the prognosis of influenza cases, but the related evidence of platelet change within the course of the disease remains largely insufficient. A total of 130 laboratory-confirmed H7N9 cases and their corresponding medical records from August 2013 to March 2015 were collected from 23 hospitals of 13 cities in Guangdong, China. The results indicated that there was a significant difference between the outcome of H7N9 cases and their average platelet count (PC) including maximum, minimum, range, admission and discharge/death of the PC value. Furthermore, we built a classification and regression tree (CART) model to predict the fatality rate which varied with average PC. There was a 7% chance for a mortality from H7N9 if PC was over 207.0 × 10^9/L, while there was a 46.3% chance of a mortality from H7N9 when PC was between 123.9 × 10^9/L and 207.0 × 10^9/L, and 81.3% chance of a mortality from H7N9 when PC was less than 123.9 × 10^9/L. This study demonstrates that using platelet count to predict the fatality of H7N9 is significant, and lower platelet counts of H7N9 patients were associated with higher risk of mortality of H7N9 patients, which may need to be taken into consideration when planning clinical treatment.
Subject(s)
Influenza A Virus, H7N9 Subtype/isolation & purification , Influenza, Human/blood , Influenza, Human/mortality , China/epidemiology , Female , Humans , Influenza, Human/virology , Male , Middle Aged , Platelet Count/statistics & numerical data , Retrospective Studies , Survival AnalysisABSTRACT
Avian influenza H7N9 viruses have caused five epidemic waves of human infections since the first human cases were reported in 2013. In 2016, the initial low pathogenic avian influenza (LPAI) H7N9 viruses became highly pathogenic, acquiring multi-basic amino acids at the haemagglutinin cleavage site. These highly pathogenic avian influenza (HPAI) H7N9 viruses have been detected in poultry and humans in China, causing concerns of a serious threat to global public health. In Japan, both HPAI and LPAI H7N9 viruses were isolated from duck meat products carried illegally and relinquished voluntarily at the border by passengers on flights from China to Japan between 2016 and 2017. Some of the LPAI and HPAI H7N9 viruses detected at the border in Japan were characterized previously in chickens and ducks; however, their pathogenicity and replicative ability in mammals remain unknown. In this study, we assessed the biological features of two HPAI H7N9 virus isolates [A/duck/Japan/AQ-HE29-22/2017 (HE29-22) and A/duck/Japan/AQ-HE29-52/2017 (HE29-52); both of these viruses were isolated from duck meat at the border)] and an LPAI H7N9 virus isolate [A/duck/Japan/AQ-HE28-3/2016 (HE28-3)] in mice and ferrets. In mice, HE29-52 was more pathogenic than HE29-22 and HE28-3. In ferrets, the two HPAI virus isolates replicated more efficiently in the lower respiratory tract of the animals than did the LPAI virus isolate. Our results indicate that HPAI H7N9 viruses with the potential to cause severe diseases in mammals have been illegally introduced to Japan.