Zhuanqiang Yan

Isolation and phylogenetic analysis of hemagglutinin gene of H9N2 influenza viruses from chickens in South China from 2012 to 2013.

As part of our ongoing influenza surveillance program in South China, 19 field strains of H9N2 subtype avian influenza viruses (AIVs) were isolated from dead or diseased chicken flocks in Guangdong province, South China, between 2012 and 2013. Hemagglutinin (HA) genes of these strains were sequenced and analyzed and phylogenic analysis showed that 12 of the 19 isolates belonged to the lineage h9.4.2.5, while the other seven belonged to h9.4.2.6. Specifically, we found that all of the viruses isolated in 2013 belonged to lineage h9.4.2.5. The lineage h9.4.2.5 viruses contained a PSRSSR↓GLF motif at HA cleavage site, while the lineage h9.4.2.6 viruses contained a PARSSR↓GLF at the same position. Most of the isolates in lineage h9.4.2.5 lost one potential glycosylation site at residues 200-202, and had an additional one at residues 295-297 in HA1. Notably, 19 isolates had an amino acid exchange (Q226L) in the receptor binding site, which indicated that the viruses had potential affinity of binding to human like receptor. The present study shows the importance of continuing surveillance of new H9N2 strains to better prepare for the next epidemic or pandemic outbreak of H9N2 AIV infections in chicken flocks.

Complete Genome Sequence of a Recombinant Nephropathogenic Infectious Bronchitis Virus Strain in China

ABSTRACT Recently, nephropathogenic infectious bronchitis virus (IBV) outbreaks have occurred in commercial broiler flocks and have been associated with a high incidence and morbidity in China. The CK/CH/Zhejiang/06/10 strain (IBV-YX10) was isolated from a 12-day-old broiler chicken in a flock of chickens with swollen speckled kidneys and distended ureters filled with uric acid in China in 2010. Here we reported the complete genomic sequence of the IBV-YX10 which was a natural recombinant nephropathogenic infectious bronchitis virus strain. These findings will contribute additional insights into the molecular characteristics of evolving IBV genomes and the need for effective control of IBV in China.

Complete Genome Sequence Analysis of a Natural Reassortant Infectious Bursal Disease Virus in China

ABSTRACT A novel isolate of infectious bursal disease virus (IBDV) was designated GX-NN-L. The GX-NN-L IBDV was a very virulent infectious bursal disease virus (vvIBDV) isolated from broiler flocks in Guangxi province, China, in 2011. The GX-NN-L IBDV caused high mortality, immunosuppression, low weight gain, and bursal atrophy in commercial broilers. Here, we report the complete genome sequence of the GX-NN-L IBDV, a reassortment strain with segments A and B derived from very virulent strains and attenuated IBDV, respectively. These findings from this study provide additional insights into the genetic exchange between attenuated and very virulent strains of IBDV and continuous monitoring of the spread of the virus in chicken.

Complete Genome Sequence of a Novel H9N2 Subtype Influenza Virus FJG9 Strain in China Reveals a Natural Reassortant Event

ABSTRACT A/chicken/FJ/G9/09 (FJ/G9) is an H9N2 subtype avian influenza virus (H9N2 AIV) strain causing high morbidity that was isolated from broilers in Fujian Province of China in 2009. FJ/G9 has been used as the vaccine strain against H9N2 AIV infection in Fujian Province of China. Here, we report the complete genome sequence of FJ/G9 with natural six-way reassortment, which is the most complex genotype strain in China and even in the world so far. The present findings will aid in understanding the complexity and diversity of H9N2 subtype avian influenza virus.

Complete Genome Sequence of a Newcastle Disease Virus Strain Isolated from Broiler Breeder Flocks in China

ABSTRACT In 2010 and 2011, several devastating Newcastle disease (ND) outbreaks occurred in China, affecting broilers, layers, and breeders. The CK-JSX1-201005 virus was isolated from broiler breeder flocks vaccinated with the classical ND virus (NDV) vaccine program, but laying rate decreased from 80% to 30 to 40% in the clinic. Here, we report the complete genome sequence and molecular characteristic of the CK-JSX1-201005 NDV. These findings provide additional insights into the genetic variation of NDV circulating in China and are useful for vaccine development for NDV.

Pathogenicity and genetic characterization of a duck Tembusu virus associated with egg-dropping in Muscovy ducks.

Duck Tembusu virus (DTMUV) has spread to the major duck-farming region in China, causing acute egg-production drop in Chinese duck population. In this study, we characterized a DTMUV strain (named GD2014) isolated from an egg-production drop duck farm in Guangdong province, South China. The virus was pathogenic to Muscovy duck embryos and caused severe egg production drop for laying Muscovy ducks. The genome sequence of GD2014 shared 97-99% homologies with other waterfowl-origin Tembusu viruses, and shared 89% identities with MM1775 strain isolated from mosquito. Phylogenetic analysis of entire open reading frame (ORF), E gene and NS5 gene indicated that GD2014 belonged to Ntaya group. These results have implications for understanding the orgin, emergence and pathogenicity of DTMUV as well as for the development of vaccines and diagnostics based on epidemiological data.

GADD45β, an anti-tumor gene, inhibits avian leukosis virus subgroup J replication in chickens

Avian leukosis virus subgroup J (ALV-J) is a retroviruses that induces neoplasia, hepatomegaly, immunosuppression and poor performance in chickens. The tumorigenic and pathogenic mechanisms of ALV-J remain a hot topic. To explore anti-tumor genes that promote resistance to ALV-J infection in chickens, we bred ALV-J resistant and susceptible chickens (F3 generation). RNA-sequencing (RNA-Seq) of liver tissue from the ALV-J resistant and susceptible chickens identified 216 differentially expressed genes; 88 of those genes were up-regulated in the ALV-J resistant chickens (compared to the susceptible ones). We screened for significantly up-regulated genes (P < 0.01) of interest in the ALV-J resistant chickens, based on their involvement in biological signaling pathways. Functional analyses showed that overexpression of GADD45β inhibited ALV-J replication. GADD45β could enhance defense against ALV-J infection and may be used as a molecular marker to identify ALV-J infections.

Sequence and phylogenetic analysis of surface protein genes of emerging H9N2 influenza viruses isolated from poultry in two geographical regions of China

Subtype H9N2 avian influenza viruses (AIVs) circulating in China have aroused increasing concerns for their impact on poultry and risk to public health. The present study was an attempt to elucidate the phylogenetic relationship of H9N2 AIVs in two geographically distinct regions of China where vaccination is routinely practiced. A total of 18 emerging H9N2 isolates were identified and genetically characterized. Phylogenetic analysis of hemagglutinin (HA) and neuraminidase (NA) genes confirmed that the isolates belonged to the Y280 lineage. Based on the HA genes, the isolates were subdivided into two subgroups. The viruses from Zhejiang Province were clustered together in Group I, while the isolates from Guangdong Province were clustered together in Group II. Antigenic characterization showed that the tested viruses were antigenically different when compared to the current used vaccine strain. It was notable that 14 out of total 18 isolates had an amino acid exchange (Q→L) at position 216 (226 by H3 Numbering) in the receptor-binding site, which indicated that the virus had potential affinity of binding to human like receptor. These results suggest that the emerging viruses have potential risk to public health than previously thought. Therefore, continuous surveillance studies of H9N2 influenza virus are very important to the prognosis and control of future influenza pandemics.

Isolation and Characterization of a Novel Tembusu Virus Circulating in Muscovy Ducks in South China

Duck Tembusu virus (DTMUV) is an infectious pathogen that can cause epidemics in egg-laying ducks. Here, we isolated and characterized a DTMUV, designated GDLH01, thought to be responsible for the noticeable egg drop in Muscovy duck flocks in South China since 2011. The genome sequence of GDLH01 shared 97-99% homology with other avian-origin Tembusu viruses, and 99.5% homology with the mosquito-borne strain SDMS recently reported in China. Phylogenetic analysis based on the nucleotide sequence of the entire open reading frame confirmed that the isolate was of avian origin and closely related to a mosquito-borne strain. Our findings characterize a novel Tembusu virus circulating in Muscovy ducks in South China and emphasize the importance of reinforcing biosecurity measures and developing vaccines to prevent the spread of this viral pathogen.

Sequence and phylogenetic analysis of hemagglutinin genes of H9N2 influenza viruses isolated from chicken in China from 2013 to 2015

Abstract H9N2 avian influenza virus (AIV) infection is a major problem in poultry industry worldwide. In this study, molecular characterizations and phylogenetic relationships of hemagglutinin (HA) gene sequences of H9N2 AIV of 5 Chinese isolates in 2014 recently available in GenBank, 3 widely used vaccine strains, and 52 novel isolates in China from 2013 to 2015 were analyzed. The homology analysis showed that the nucleotide sequences of HA gene of these recent Chinese H9N2 AIV isolates shared homologies from 94.1 to 99.9%. Phylogenetic analysis showed that all isolates belonged to AIV lineage h9.4.2.5. Fifty-six out of the 57 recent Chinese H9N2 AIV isolates had the motifs PSRSSR↓GLF at the cleavage sites within the HA protein, while one isolate PWH01 harbored LSRSSR↓GLF. Remarkably, all of the recent Chinese H9N2 AIV strains had the Q216L substitution in the receptor binding site, which indicated that they had potential to infect humans. Most of recent Chinese H9N2 AIV isolates lost the potential N-linked glycosylation site at residues 200–202 compared with vaccine strains. This present study demonstrated that AIV lineage h9.4.2.5 was more predominant in China than other lineages as it harbored all the H9N2 AIV isolated between 2013 and 2015. Also we showed the importance of continuous surveillance of emerging H9N2 AIV in China and update of vaccine formulation accordingly in order to prevent and control H9N2 AIV.