ABSTRACT
Objective To conduct a bibliometric analysis of international scientific literatures on research of avian influenza. Methods We performed a search in the Web of Science (WoS) database and analyzed the relevant records with Thomson Data Analyzer (TDA) and citation trees. Results Due to the rapid growth in publications by the United States and China, the number of publications on research of avian influenza has increased remarkably since 2005. The publication of Japan and Netherlands were of high quality due to support of international research programs. The researches about H5N1 virus mutation by the United States, Japan and Netherlands were the typical achievement of the area but also triggered arguments. Conclusion More international efforts arewarranted on research of H7N9 and other influenza viruses.
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Objective To investigate the evolutionary characteristics and important amino acid sites of the neuraminidase (NA) gene of the novel influenza virus A/H7N9 in 2013 epidemic. Methods The NA gene sequences of influenza virus A N9 subtype of different times and areaswere downloaded from the database of The National Center for Biotechnology Information (NCBI) and The Global Initiative on Sharing All Influenza Data (GISAID). MEGA 5. 05 and BioEdit softwares were used for phylogenetic tree construction and nucleotide/protein sequence analysis. Results The NA gene sequence of the novel influenza virus A/H7N9 in 2013 shared a 96% similarity with that of the H11N9 avian strain found in Czech Republic in 2010. There were 5 amino acid deletions in this novel influenza virus,and one of the new strains had a variation in potential enzymatic active sites. Conclusion The NA gene of this 2013 novel influenza virus might originate from the avian H11N9 strains detected in Czech Republic. The deletion of amino acid might result in human infection and high fatality rate.
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Objective To investigate the evolution and variations in coding amino acids of hemagglutinin (HA) gene of the novel avian influenza virus H7N9 in 2013 epidemic. Methods The HA gene sequences of influenza virus H7N9, H7N2, H7N3 and H7N7 subtypeswere downloaded from the database of The National Center for Biotechnology Information (NCBI) and The Global Initiative on Sharing All Influenza Data (GISAID). MEGA 5. 05 software was used for sequence analysis and N- J method was used for constructing the phylogenetic trees. The amino acid sequences at the receptor binding sites, glycosylation sites, and cleavage siteswas aligned and analyzed. Results The HA genes this novel A/H7N9 virus in 2013 shared a 95. 3%- 95. 6% similarity with JQ906573. 1| Zhejiang (H7N3 virus) isolated in 2011. The most important variation in this novel H7N9 isolates was found at the receptor binding site: Q226L. The 5 glycosylation sites were highly conservative. One basic amino acid (R) at the HA cleavage sites, located between aa339 and aa340, was also found in this novel isolate. Conclusion The HA gene of this novel H7N9 isolate might originate from H7 subtypes carried by birds in China. Thebinding site change caused by Q226L variation might be responsible for human infection of this novel H7N9 isolate.
ABSTRACT
H7N9 virus is a novel avian-origin virus. The hemagglutinin (HA) and neuraminidase (NA) of the virus play key roles in the interspecies transmission, viral replication and pathogenicity. One of significant characters of H7N9 is that it has no noticeable pathogenicity among poultry, but is highly pathogenic for human being and is associated with high mortality. H7 subtype avian virus can be compatible with different NA subtypes, and has caused many infection events in human being. It can be predicted that the influence ofH7 subtype avian influenza A virus will persist and lead to serious public health problem, and therefore deserves more attention. Establishment of prevetion and control network can help to reduce the threat of H7N9 virus to human health.
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A novel avian influenza was discovered in Mainland China in March 2013, and the virus was identified as avian influenza A (H7N9)-anew virus that has not been reported previously before. Further research showed that the virus was probably a combination of three different subtypes of influenza A virus. By May 31, a total of 131 confirmed cases have been reported in China, including 39 deaths. Shanghai reported 33 confirmed cases, with the onset of 29 cases found before closing the live poultry markets by the municipal government on April 6. The onsets of the rest 4 cases were all found during the first incubation period after the closure. We found that 66. 7% (22/33) of the confirmed cases in Shanghai were above 60 years of age, and of the 15 deaths, 80% (12/15) were aged above 60 years old. It was also noted that 90. 9% (30/33) of the confirmed cases had an exposure history to susceptible animals orenvironmental circumstances. The cases appeared to be sporadic; although there were two family clusters, no evidence of human-to-human transmission has been found so far. Shanghai municipal government activated the Flu Pandemic Preparedness and Response Plan (Level IH ) onApril 2, 2013, timely after the first few cases was identified. The rapid responses of public health emergencies included citywide suspending of live poultry markets, health education, and risk communication; the epidemic was controlled effectively and timely. In this paper we analyzed the pros and cons of our prevention and control strategies, hoping to provide reference for future epidemics.
ABSTRACT
In March 2013, death caused by infection with the novel H7N9 avian influenza virus was firstly reported in China. In addition to the viral evolution factors such as gene recombination and variation in key amino acid sites, social factors also contribute to human infection of the deadly virus. By now China still needs a standardized poultry breeding process, an orderly poultry trade market, a strong health awareness among poultry-related workers, and a strong sel--protection awareness among all citizens. Social factors may increase the chance of influenza virus transmission from birds to humans via increasing close contact. Therefore, a close joint effort of related government departments, including the agriculture, forestry, and medication, is needed for effective control and surveillance of H7N9 epidemic. The health protection and risk awareness should be upgraded among the citizens through health education. Meanwhile, research and development of influenza vaccine should be accelerated based on the surveillance data of the influenza virus evolution. Public health prophylaxis based on social influencing factors should be important in reducing the incidence of avian flu infection in human.