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Chen F.,South China Agricultural University | Yan Z.-Q.,South China Agricultural University | Liu J.,Guangdong Wens Foodstuffs Group Co. | Ji J.,South China Agricultural University | And 6 more authors.
Virus Genes | Year: 2012

Avian influenza virus (H9N2) infection is a major problem of product performance in poultry worldwide. Vaccination is used to limit spread, but more knowledge is needed on the epidemiology of virus subtypes to improve vaccine design. In this study, 40 H9N2 subtype avian influenza viruses (AIVs) were isolated from vaccinated poultry flocks in China from 2010 to 2011. Hemagglutinin (HA) from different virus strains was sequenced and analyzed. We found that the HA genes of these strains shared nucleotide and deduced amino acid homologies that ranged from 90.1 to 92.9 and 91.4 to 95.0 %, respectively, when compared with vaccine strains. Phylogenetic analysis showed that the strains tested could be divided into two major groups. Group I consisted of 24 strains isolated mainly from Eastern and Central China. Group II consisted of 20 strains isolated from Southern China. The cleavage site within the HA protein contained two basic motifs, PSRSSR;GLF for group I, and PARSSR;GLF for group II. Additional potential glycosylation sites were found at amino acid position 295 in the HA1 of the isolates in group I, compared with isolates in group II and the vaccine strains. Furthermore, 38 out of the 40 isolates had a leucine residue at position 216 (aa 226 in H3), which was characteristic of human influenza virus-like receptor specificity. In the present study we found that geographical factors play a significant role in virus evolution, and emphasize the importance of continuing surveillance of H9N2 AIVs in chickens in China. © Springer Science+Business Media, LLC 2012.

Liu Y.,South China Agricultural University | Ji J.,South China Agricultural University | Xie Q.,South China Agricultural University | Wang J.,South China Agricultural University | And 8 more authors.
Virology Journal | Year: 2011

Background. The swine influenza (SI) is an infectious disease of swine and human. The novel swine-origin influenza A (H1N1) that emerged from April 2009 in Mexico spread rapidly and caused a human pandemic globally. To determine whether the tremendous virus had existed in or transmitted to pigs in southern China, eight H1N1 influenza strains were identified from pigs of Guangdong province during 2008-2009. Results. Based on the homology and phylogenetic analyses of the nucleotide sequences of each gene segments, the isolates were confirmed to belong to the classical SI group, with HA, NP and NS most similar to 2009 human-like H1N1 influenza virus lineages. All of the eight strains were low pathogenic influenza viruses, had the same host range, and not sensitive to class of antiviral drugs. Conclusions. This study provides the evidence that there is no 2009 H1N1-like virus emerged in southern China, but the importance of swine influenza virus surveillance in China should be given a high priority. © 2011 Liu et al; licensee BioMed Central Ltd.

Huang P.,South China Agricultural University | Lin P.,South China Agricultural University | Yan S.,South China Agricultural University | Yan S.,Guangdong Wens Foodstuffs Group Co. | Xiao M.,South China Agricultural University
International Review on Computers and Software | Year: 2012

For the modern poultry breeding companies, it is worthwhile to predict the poultry growth performance based on the massive historical data gradually cumulated in production. However, because of the complexity and uncertainty brought by the influence of environmental and physiological factors, extracting valuable knowledge from poultry raising dataset is a challenge. As a way to uncover the seasonal growth rule hidden among the broiler data, which is regulated by both the natural law of seasons and the biological law of poultry upgrowth, we suggest developing decision support system (DSS) using statistical methods and data mining technology based on the collected meteorological factors. This paper focuses on the building process of a model-driven DSS for seasonal broiler growth performance prediction. Systematic approach is deployed including data preprocessing, candidate predictor variables selection, and modeling. Prediction models including multiple linear regression and neural network are adopted for both linear and nonlinear fitting. Finally, case study of the broiler growth dataset of the most famous poultry raising company in China is used to evaluate the developed DSS and the results show the effectiveness of our approach. © 2012 Praise Worthy Prize S.r.l. -All rights reserved.- All rights reserved.

Liu Y.,South China Agricultural University | Liu Y.,Guangdong Wens Foodstuffs Group Co. | Wang J.,South China Agricultural University | Wang J.,Guangdong Wens Foodstuffs Group Co. | And 6 more authors.
Virology Journal | Year: 2012

Background: After the occurrence of 2009 pandemic H1N1, close attention has been paid to the H1N1 subtype swine influenza viruses (H1N1 SIV) by scientific communities in many countries. A large-scale sequence analysis of the NCBI Influenza Virus Resource Database on H1N1 SIVs submitted primarily by scientists in China during 1992 to 2011 was performed. The aims of this study were to elucidate the genetic and evolutionary characteristics of H1N1 SIVs, to identify and unify the lineages and genetic characteristics of the H1N1 SIVs isolated in mainland China. Results: Most of the strains were isolated during the period of 2008 to 2010 from Guangdong and Shandong provinces, China. Based on the phylogenetic and genotypic analyses, all of the H1N1 SIV strains can be classified into 8 lineages and 10 genotypes. All strains were of the characteristics of low pathogenic influenza viruses. The viruses of different lineage are characterized with different amino acid residues at the receptor-binding sites. Viruses containing PB2 genes of the classical swine, early seasonal human and recent seasonal human lineage might be more infectious to human. Some genotypes were directly related with human influenza viruses, which include strains that harbored genes derived from human influenza viruses. Conclusions: Phylogenetic diversity and complexity existed in H1N1 SIVs isolated in mainland China. These H1N1 SIV strains were closely related to other subtype influenza viruses, especially to human influenza viruses. Moreover, it was shown that, novel lineages and genotypes of H1N1 SIVs emerged recently in mainland China. These findings provided new and essential information for further understanding of the genetic and evolutionary characteristics and monitoring the H1N1 SIVs in mainland China. © 2012 Liu et al; licensee BioMed Central Ltd.

Xie Q.,South China Agricultural University | Ji J.,South China Agricultural University | Xie J.,South China Agricultural University | Xie J.,Guangdong Wens Foodstuffs Group Co. | And 7 more authors.
Virology Journal | Year: 2011

Background: In last three years, 96 suspected poultry farms from different provinces in China were diagnosed for avian infectious bronchitis (IB) survey. Finally, 221 IBV strains were confirmed by dwarf embryo test and RT-PCR assay. By virus recovery trials, 187 of the isolates caused the birds died or distressed from nephritis, which was accordant with the clinical record. Results: Based on epidemiology analysis of recent field isolates of nephropathogenic IB in vaccinated farms in China, YL6 strain were used for vaccination and evaluated by antibody titer and challenge tests. The immunoprotection test indicated that the practical application of vaccine based on the recent field strains could finely facilitate controlling the nephropathogenic IB. Conclusions: Our study was aim at setting a guide for safeguard against nephropathogenic IBV-caused disease in China. © 2011Xie et al; licensee BioMed Central Ltd.

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