Adolescent ; Adult ; Aged ; Aged, 80 and over ; Animals ; Birds ; virology ; Child ; Child, Preschool ; Global Warming ; Humans ; Infant ; Influenza A virus ; Influenza, Human ; epidemiology ; Middle Aged ; Orthomyxoviridae Infections ; epidemiology ; Temperature ; Young Adult

To investigate the susceptibility of Chukars to duck avian influenza virus H9N2 and explore their role in interspecies transmission of influenza viruses. Chukars were inoculated with duck avian influenza viruses H9N2. The present study demonstrated that inflammatory lesions and virus antigen were present in the trachea, bronchus, and parabronchus, and the viruses could be isolated from throat swabs and lung tissue homogenate supernatants. At 14 d post virus inoculation, anti-H9 influenza virus antibody in the serum was detected. The results indicated that Chukars are susceptible to duck avian influenza virus and serve as an intermediate host, thereby facilitating viral gene evolution and supporting the need for continued surveillance of epidemiology and evolution of the influenza virus in Chukars.
Animals ; Galliformes ; Influenza A Virus, H9N2 Subtype ; pathogenicity ; physiology ; Influenza in Birds ; virology ; Respiratory System ; pathology ; virology ; Virus Replication ; physiology

Objective: To study the willingness and influence factors related to "centralized slaughtering, fresh poultry listing and marketing" strategy, among the household chefs, and provide reference for government to adjust and optimize the strategy on avian influenza prevention. Methods: According to the geographical characteristics and regional functions, 6 'monitoring stations' were selected from 12 residential districts of Guangzhou, respectively. Another 21 meat markets which selling live poultry, were selected in each station and 5 household chefs of each market were invited to attend a face to face interview. Basic information, personal cognitive, willingness and influencing factors to the policy were under study. Univariate and multivariate logistic regression methods were used. Results: A total of 664 household chefs underwent the survey and results showed that the rate of support to the "centralized slaughtering, fresh poultry listing and marketing" strategy was 44.6% (296/664). Results from the multi-factor logistic regression showed that those household chefs who were males (OR=1.618, 95% CI: 1.156-2.264, P=0.005), having received higher education (OR=1.814, 95% CI: 1.296-2.539, P=0.001), or believing that the existence of live poultry stalls was related to the transmission of avian influenza (OR=1.918, 95% CI: 1.341-2.743, P<0.001) were factors at higher risk. These household chefs also intended to avoid the use of live poultry stalls (OR=1.666, 95%CI: 1.203-2.309, P=0.002) and accept the "centralized slaughtering, fresh poultry listing and marketing" strategy. Conclusion: Detailed study on this subject and, setting up pilot project in some areas as well as prioritizing the education programs for household chefs seemed helpful to the implementation of the 'freezing-fresh poultry' policy.
Animals ; Attitude to Health ; China ; Humans ; Influenza A Virus, H7N9 Subtype ; Influenza in Birds ; Influenza, Human/prevention & control* ; Male ; Marketing ; Meat-Packing Industry ; Multivariate Analysis ; Pilot Projects ; Poultry/virology* ; Surveys and Questionnaires

Objective: To investigate the infection pattern and etiological characteristics of a case of human infection with highly pathogenic avian influenza A (H7N9) virus and provide evidence for the prevention and control of human infection with highly pathogenic avian influenza virus. Methods: Epidemiological investigation was conducted to explore the case's exposure history, infection route and disease progression. Samples collected from the patient, environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (RT-PCR). Virus isolation, genome sequencing and phylogenetic analysis were conducted for positive samples. Results: The case had no live poultry contact history, but had a history of pulled chicken processing without taking protection measure in an unventilated kitchen before the onset. Samples collected from the patient's lower respiratory tract, the remaining frozen chicken meat and the live poultry market were all influenza A (H7N9) virus positive. The isolated viruses from these positive samples were highly homogenous. An insertion which lead to the addition of multiple basic amino acid residues (PEVPKRKRTAR/GL) was found at the HA cleavage site, suggesting that this virus might be highly pathogenic. Conclusions: Live poultry processing without protection measure is an important infection mode of "poultry to human" transmission of avian influenza viruses. Due to the limitation of protection measures in live poultry markets in Guangzhou, it is necessary to promote the standardized large scale poultry farming, the complete restriction of live poultry sales and centralized poultry slaughtering as well as ice fresh sale.
Animals ; Chickens ; China ; Commerce ; Humans ; Influenza A Virus, H7N9 Subtype/pathogenicity* ; Influenza in Birds/virology* ; Influenza, Human/virology* ; Phylogeny ; Poultry/virology* ; Real-Time Polymerase Chain Reaction ; Zoonoses

The annual seasonal epidemic of influenza caused serious disease burden around the world, and serious social panic and economic losses. Due to the high variability and uncertainty of influenza virus, prevention and control of influenza faces many challenges. Surveillance is a key strategy to prevent and control influenza, and influenza is the first infectious disease to be monitored globally. More than 60 years, influenza surveillance programs in China has made great contributions to the prevention and control of influenza in China and the world. Especially in the past 10 years, the influenza surveillance network has developed rapidly, the scale has been expanded significantly, the monitoring content and scope have been continuously improved, and the monitoring quality has been rapidly improved. The China Influenza Surveillance Network is one of the early detection systems for emerging infectious diseases in China and the world. It helps to improve the capacity of public health system in prevention and control and early warning of emerging infectious diseases.
Animals ; Birds ; China ; Communicable Diseases, Emerging/virology* ; Disease Outbreaks ; Global Health ; Humans ; Influenza in Birds/virology* ; Influenza, Human/virology* ; Population Surveillance/methods* ; Public Health ; Public Policy

Objective: To understand the molecular characteristics of hemagglutinin (HA) and neuraminidase (NA) as well as the disease risk of influenza virus A H7N9 in Guizhou province. Methods: RNAs were extracted and sequenced from HA and NA genes of H7N9 virus strains obtained from 18 cases of human infection with H7N9 virus and 6 environmental swabs in Guizhou province during 2014-2017. Then the variation and the genetic evolution of the virus were analyzed by using a series of bioinformatics software package. Results: Homology analysis of HA and NA genes revealed that 2 strains detected during 2014-2015 shared 98.8%-99.2% and 99.2% similarities with vaccine strains A/Shanghai/2/2013 and A/Anhui/1/2013 recommended by WHO, respectively. Two strains detected in 2016 and 14 strains detected in 2017 shared 98.2%-99.3% and 97.6%-98.8% similarities with vaccine strain A/Hunan/02650/2016, respectively. Other 6 stains detected in 2017 shared 99.1%-99.4% and 98.9%-99.3% similarities with strain A/Guangdong/17SF003/2016, respectively. Phylogenetic analysis showed that all the strains were directly evolved in the Yangtze River Delta evolution branch, but they were derived from different small branch. PEVPKRKRTAR↓GLF was found in 6 of 24 strains cleavage site sequences of HA protein, indicating the characteristic of highly pathogenic avian influenza virus. Mutations A134V, G186V and Q226L at the receptor binding sites were found in the HA. All the strains had a stalk deletion of 5 amino acid residue "QISNT" in NA protein, and drug resistance mutation R294K occurred in strain A/Guizhou-Danzhai/18980/2017. In addition, potential glycosylation motifs mutations NCS42NCT were found in the NA of 9 of 24 strains. Conclusions: HA and NA genes of avian influenza A (H7N9) virus showed genetic divergence in Guizhou province during 2014-2017. The mutations of key sites might enhance the virulence of the virus, human beings are more susceptible to it. Hence, the risk of infection is increasing.
Animals ; Base Sequence ; Birds ; China/epidemiology* ; Genome, Viral ; Hemagglutinin Glycoproteins, Influenza Virus/immunology* ; Hemagglutinins/genetics* ; Humans ; Influenza A Virus, H7N9 Subtype/isolation & purification* ; Influenza in Birds ; Influenza, Human/virology* ; Neuraminidase/genetics* ; Phylogeny ; RNA, Viral/genetics* ; Sequence Analysis, DNA

The highly pathogenic avian influenza (HPAI) H5N1 virus has caused several outbreaks in domestic poultry. Despite great efforts to control the spread of this virus, it continues to evolve and poses a substantial threat to public health because of a high mortality rate. In this study, we sequenced whole genomes of eight H5N1 avian influenza viruses isolated from domestic poultry in eastern China and compared them with those of typical influenza virus strains. Phylogenetic analyses showed that all eight genomes belonged to clade 2.3.2.1 and clade 7.2, the two main circulating clades in China. Viruses that clustered in clade 2.3.2.1 shared a high degree of homology with H5N1 isolates located in eastern Asian. Isolates that clustered in clade 7.2 were found to circulate throughout China, with an east-to-west density gradient. Pathogenicity studies in mice showed that these isolates replicate in the lungs, and clade 2.3.2.1 viruses exhibit a notably higher degree of virulence compared to clade 7.2 viruses. Our results contribute to the elucidation of the biological characterization and pathogenicity of HPAI H5N1 viruses.
Animals ; China ; Influenza A Virus, H5N1 Subtype ; genetics ; isolation & purification ; pathogenicity ; Influenza in Birds ; virology ; Mice, Inbred BALB C ; Phylogeny ; Poultry

Animals ; China ; Influenza A virus ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Nucleic Acids ; genetics ; Poultry ; virology

A quail-origin subtype of the influenza virus was isolated from a human-infecting H7N9 subtype of the avian influenza virus found in a live poultry market and was given the name A/Quail/Hangzhou/1/ 2013 (H9N2). We analyzed the whole genome of this virus and its biologic characteristics. Sequence analyses suggested that the: HA and NS genes belonged to a CK/BJ/1/94-like lineage; NA, NP, PA and PB1 genes belonged to a SH/F/98-like lineage; M and PB2 genes belonged to a G1-like lineage. Analyses of key amino acids showed that the cleavage site in HA protein was PSRSSR ↓ GL, and that the HA protein had a human receptor-binding site with Leu226. Deletion of amino acids 69 - 73 was detected in the stalk of NA protein, the M2 protein had an Asn31 mutation, and the NS1 protein had two mutations at Ser42, Ala149. The intravenous pathogenicity of this virus was 0.36. A study in chickens suggested that all inoculated birds shed the virus from the trachea and cloaca on the third day post-infection (p. i. ) until 11 days. All chickens that had direct contact shed the virus on the second day p. i. until 8 days. Results of virus reisolation suggested that lung and tracheal tissues could shed the virus in 5 days, whereas the other organs could shed the virus in 3 days. These results suggest that this virus strain is H9N2 subtype LPAIV, whose lineage is prevalent in mainland China. This research provides evidence on how to monitor and prevent the H9N2 subtype of the avian influenza virus.
Animals ; Chick Embryo ; Chickens ; China ; Genotype ; Influenza A Virus, H9N2 Subtype ; classification ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Phylogeny ; Quail ; virology

OBJECTIVETo trace the source of human H7N9 cases in Huai'an and elucidate the genetic characterization of Huai'an strains associated with both humans and birds in live poultry market.

METHODSAn enhanced surveillance was implemented when the first human H7N9 case was confirmed in Huai'an. Clinical specimens, cloacal swabs, and fecal samples were collected and screened by real-time reverse transcription-polymerase chain reaction (RT-PCR) for H7N9 virus. The positive samples were subjected to further RT-PCR and genome sequencing. The phylodynamic patterns of H7N9 virus within and separated from Huai'an and evolutionary dynamics of the virus were analyzed.

RESULTSSix patients with H7N9 infection were previously exposed to live poultry market and presented symptoms such as fever (>38.0 °C) and headaches. Results of this study support the hypothesis that live poultry markets were the source of human H7N9 exposure. Phylogenetic analysis revealed that all novel H7N9 viruses, including Huai'an strains, could be classified into two distinct clades, A and B. Additionally, the diversified H7N9 virus circulated in live poultry markets in Huai'an. Interestingly, the common ancestors of the Huai'an H7N9 virus existed in January 2012. The mean nucleotide substitution rates for each gene segment of the H7N9 virus were (3.09-7.26)×10-3 substitutions/site per year (95% HPD: 1.72×10-3 to 1.16×10-2).

CONCLUSIONOverall, the source of exposure of human H7N9 cases in Huai'an was live poultry market, and our study highlights the presence of divergent genetic lineage of H7N9 virus in both humans and poultry specimens in Huai'an.

Adult ; Aged ; Aged, 80 and over ; Animals ; China ; epidemiology ; Evolution, Molecular ; Female ; Humans ; Influenza A Virus, H7N9 Subtype ; classification ; genetics ; isolation & purification ; Influenza in Birds ; epidemiology ; virology ; Influenza, Human ; epidemiology ; virology ; Male ; Middle Aged ; Molecular Epidemiology ; Phylogeny ; Poultry ; Prevalence