ABSTRACT
In 2017, an H7N8 avian influenza virus (AIV) was isolated from a domestic duck from a farm in Central China. Sequences analysis showed that this strain received its genes from H7, H1, H2, H3, H5, and H6 AIVs of domestic poultry and wild birds in Asia. It exhibited low pathogenicity in chickens and mild pathogenicity in mice. These results suggest the importance of continued surveillance of the H7N8 virus to better understand the ecology and evolution of the AIVs in poultry and wild birds and the potential threat to human health.
Subject(s)
Ducks/virology , Influenza A virus/genetics , Influenza in Birds/virology , Influenza, Human/virology , Poultry Diseases/virology , Animals , Animals, Domestic/virology , Animals, Wild , Chickens/virology , China , Humans , Influenza A virus/pathogenicity , Influenza in Birds/transmission , Influenza, Human/transmission , Mice , Phylogeny , Poultry/virology , Poultry Diseases/transmissionSubject(s)
Antigenic Variation , Epidemiological Monitoring/veterinary , Hemagglutinins/genetics , Hemagglutinins/immunology , Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/pathogenicity , Animals , China , Ducks/virology , Humans , Influenza A Virus, H7N9 Subtype/chemistry , Influenza Vaccines/administration & dosage , Influenza Vaccines/immunology , Influenza in Birds/immunology , Influenza in Birds/prevention & control , Influenza in Birds/virology , Poultry/virology , Virulence , Virus SheddingABSTRACT
The H5 subtype of highly pathogenic avian influenza (HPAI) viruses pose a serious challenge to public health and the poultry industry in China. In this study, we generated a chimeric QH/KJ recombinant virus expressing the entire haemagglutinin (HA)-1 region of the HPAI virus A/chicken/China/QH/2017(H5N6) (clade 2.3.4.4) and the HA2 region of the HPAI virus A/chicken/China/KJ/2017(H5N1) (clade 2.3.2.1). The resulting chimeric PR8-QH/KJ virus exhibited similar in vitro growth kinetics as the parental PR8-QH and PR8-KJ viruses. The chimeric PR8-QH/KJ virus induced specific, cross-reactive haemagglutination-inhibition and serum-neutralizing antibodies against both QH and KJ viruses, although PR8-QH and PR8-KJ exhibited no cross-reactivity with each other. Furthermore, the chimeric PR8-QH/KJ vaccine significantly reduced virus shedding and completely protected chickens from challenge with HPAI H5N6 and H5N1 viruses. However, the Re-8 vaccine against clade 2.3.4.4 viruses provided specific-pathogen-free chickens only partial protection when challenged with QH virus. Our results suggest that the antigenic variation of these epidemic viruses occurred and they can escape the current vaccine immunization. The Re-8 vaccine needs an update. The chimeric PR8-QH/KJ vaccine is effective against H5 HPAI virus clades 2.3.4.4 and 2.3.2.1 in chickens.
Subject(s)
Antibodies, Viral/blood , Hemagglutinin Glycoproteins, Influenza Virus/immunology , Influenza Vaccines/immunology , Influenza in Birds/prevention & control , Animals , Antibodies, Neutralizing/blood , Chickens , China , Cross Reactions , Hemagglutination Inhibition Tests , Hemagglutinin Glycoproteins, Influenza Virus/genetics , Influenza A virus/genetics , Influenza A virus/immunology , Influenza Vaccines/administration & dosage , Influenza in Birds/virology , Neutralization Tests , Survival Analysis , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/immunologyABSTRACT
The highly pathogenic avian influenza (HPAI) H5 and H7N9 viruses pose a serious challenge to public health and the poultry industry in China. In this study, we generated a chimeric H7/H5 recombinant virus that expressed the entire HA1 region of the HPAI A/chicken/Guangdong/RZ/2017(H7N9) virus and the HA2 region of the HPAI A/chicken/Fujian/5/2016(H5N6) viruses. The resulting chimeric PR8-H7/H5 virus exhibited similar growth kinetics as the parental PR8-H5 and PR8-H7 viruses in vitro. The inactivated chimeric PR8-H7/H5 vaccine induced specific, cross-reactive hemagglutination inhibition antibodies against the H7 virus only but induced serum-neutralizing antibodies against both H7 and H5 viruses. Furthermore, the inactivated chimeric PR8-H7/H5 vaccine significantly reduced virus shedding and protected chickens from challenge with the HPAI H5N6 and H7N9 viruses. Our results suggested that the inactivated chimeric PR8-H7/H5 vaccine was effective against HPAI H5 and H7N9 viruses in chickens.
Subject(s)
Antibodies, Viral/immunology , Chickens/immunology , Hemagglutinins, Viral/immunology , Influenza A virus/immunology , Influenza Vaccines/immunology , Influenza in Birds/prevention & control , Animals , Antibodies, Neutralizing/immunology , Chickens/virology , Cross Reactions , HEK293 Cells , Hemagglutination Inhibition Tests/veterinary , Hemagglutinins, Viral/genetics , Humans , Influenza A Virus, H7N9 Subtype/genetics , Influenza A Virus, H7N9 Subtype/immunology , Influenza A Virus, H7N9 Subtype/pathogenicity , Influenza A virus/genetics , Influenza A virus/pathogenicity , Influenza in Birds/virology , Poultry , Vaccines, Inactivated/immunology , Vaccines, Synthetic/immunologyABSTRACT
To investigate the prevalence and evolution of the H6 subtype avian influenza viruses (AIVs) circulating in poultry in China from 2011 to 2016, 11 molecular epidemiological surveys was performed in this study. In total, 893 H6 subtype viral strains were isolated from 67,639 swab samples and 360 environmental samples. From these strains, 35 representative strains were selected and their whole genomic sequences determined. According to a phylogenetic analysis and molecular characterization, all 35 viral strains belonged to the Eurasian avian lineage. All of them were categorized as 'low pathogenic' and a few strains had some bioinformatical mutations. This epidemiological survey shows that the prevalence of H6 subtype AIVs increased from 2012 to 2016 in China, and suggests that infections by H6 subtype AIVs in China has increased in recent years.
