Infectious bursal disease virus (IBDV) is an important member of the Birnaviridae family. IBUV mainly targets the bursa of Fabricius, the central immune organ of chicken, resulting in chicken infectious bursal disease (IBD). IBD represents one of the great challenges for ongoing development of the poultry industry. Reverse genetics for IBDV emerged over twenty years ago. Since then, the technologies behind virus rescue have continually improved leading to a deep understanding of IBDV gene function and tailored vaccine development. Our lab has also been instrumental in the field of IBDV research. Here we review studies on the pathogenic mechanism and the effective prevention and control of IBD.
Animals ; Birnaviridae Infections ; virology ; Chickens ; Infectious bursal disease virus ; genetics ; physiology ; Poultry Products ; virology ; Reverse Genetics

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

Objective: To understand the antimicrobial resistance and genome characteristics of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces in China in 2020. Methods: In 2020, 265 Campylobacter strains including 244 Campylobacter jejuni and 21 Campylobacter coli collected from retailed poultry meat samples in China were tested for antimicrobial resistance to 9 antimicrobial compounds by using the agar dilution method. Forty-two selected isolates were sent for whole genome sequencing and 38 high-quality genomes were analyzed for their antimicrobial resistance genes, virulence genes, sequence types and genetic diversity. Results: The resistance rates of Campylobacter isolates from poultry meats to tetracycline, nalidixic acid and ciprofloxacin were the highest (84%-100%), with 53.2% of the isolates showing multidrug resistance in this study. The resistance rates of C. coli to erythromycin, azithromycin, telithromycin, gentamicin and clindamycin were significantly higher than those of C. jejuni (P<0.05). The resistance genes conferring resistance to β-lactams (100%, 38/38), quinolones (94.7%, 36/38), tetracycline (81.6%, 31/38) and aminoglycosides (50%, 19/38) were the most frequently detected among 38 Campylobacter genomes. C. jejuni carried more virulence genes than C. coli. In total, 19 and 17 sequence types (ST) were obtained from 20 sequenced C. jejuni and 18 C. coli isolates, respectively, including 5 novel STs. The isolates showed a high genetic diversity based on their sequence types. Conclusion: The phenomenon of antimicrobial resistance in Campylobacter from poultry meat sources in China is relatively serious, and resistance and virulence genes are widely distributed in Campylobacter. There is genetic diversity in Campylobacter.
Humans ; Animals ; Anti-Bacterial Agents/pharmacology* ; Campylobacter/genetics* ; Poultry ; Drug Resistance, Bacterial/genetics* ; Genomics ; China ; Tetracycline

Objective: To understand the antimicrobial resistance and genome characteristics of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces in China in 2020. Methods: In 2020, 265 Campylobacter strains including 244 Campylobacter jejuni and 21 Campylobacter coli collected from retailed poultry meat samples in China were tested for antimicrobial resistance to 9 antimicrobial compounds by using the agar dilution method. Forty-two selected isolates were sent for whole genome sequencing and 38 high-quality genomes were analyzed for their antimicrobial resistance genes, virulence genes, sequence types and genetic diversity. Results: The resistance rates of Campylobacter isolates from poultry meats to tetracycline, nalidixic acid and ciprofloxacin were the highest (84%-100%), with 53.2% of the isolates showing multidrug resistance in this study. The resistance rates of C. coli to erythromycin, azithromycin, telithromycin, gentamicin and clindamycin were significantly higher than those of C. jejuni (P<0.05). The resistance genes conferring resistance to β-lactams (100%, 38/38), quinolones (94.7%, 36/38), tetracycline (81.6%, 31/38) and aminoglycosides (50%, 19/38) were the most frequently detected among 38 Campylobacter genomes. C. jejuni carried more virulence genes than C. coli. In total, 19 and 17 sequence types (ST) were obtained from 20 sequenced C. jejuni and 18 C. coli isolates, respectively, including 5 novel STs. The isolates showed a high genetic diversity based on their sequence types. Conclusion: The phenomenon of antimicrobial resistance in Campylobacter from poultry meat sources in China is relatively serious, and resistance and virulence genes are widely distributed in Campylobacter. There is genetic diversity in Campylobacter.
Humans ; Animals ; Anti-Bacterial Agents/pharmacology* ; Campylobacter/genetics* ; Poultry ; Drug Resistance, Bacterial/genetics* ; Genomics ; China ; Tetracycline

Five H9N2 avian influenza virus strains were isolated from the environmental samples in live poultry market in Qinghai Lake region from July to September, 2012. To evaluate the phylogenetic characteristics of these H9N2 isolates, the eight gene segments were amplified by RT-PCR and sequenced. The phylogenetic and molecular characteristics of the five strains were analyzed. The results showed that the HA genes of five strains shared 93. 2%-99. 1% nucleotide identities with each other, and the NA genes shared 94. 5%-99. 8% nucleotide identities. The HA cleavage site sequence of the A/environment/qinghai/ 017/2012 isolate was PSKSSRGLF, and the HA cleavage site sequences of the other four strains were all PSRSSRGLF. The HA receptor-binding site had the Q226L mutation. The M1 gene segment had the N30D and T215A mutations. The phylogenetic analysis showed that the five strains were similar to the virus A/chicken/Hunan/5260/2005 (H9N2) isolated in Hunan Province, China and were reassortant genotype viruses; the HA, NA, and NS genes belonged to the Y280-like lineage; the MP gene belonged to the G1-like lineage; the NP, PB1, PB2, and PA genes belonged to the F98-like lineage.
Animals ; China ; Genome, Viral ; Genotype ; Influenza A Virus, H9N2 Subtype ; classification ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Molecular Sequence Data ; Phylogeny ; Poultry ; Poultry Diseases ; virology ; Viral Proteins ; genetics

Abstract: To investigate the distribution of avian influenza virus in environmental samples from live poultry markets (LPM) in China, samples were collected and tested by nucleic acid during 2009-2013 season. Each sample was tested by real-time RT PCR using flu A specific primers. If any real-time PCR was positive, the sample was inoculated into specific-pathogen-free (SPF) embryonated chicken eggs for viral isolation. The results indicated that the positive rate of nucleic acid in enviromental samples exhibited seasonality. The positive rate of nucleic acid was significantly higher in Winter and Spring. The positive rate of nucleic acid in LPM located in the south of China was higher than in northern China. Samples of Sewage for cleaning poultry and chopping board showed that higher positive rate of nucleic acid than other samples. The Subtype identification showed that H5 and H9 were main subtypes in the enviromental samples. Viral isolation indicated H5 subtypes was more than H9 subtypes between 2009 and 2013 while H9 subtypes increased in 2013. Our findings suggested the significance of public health based on LPM surveillance and provided the basis of prevention and early warning for avian flu infection human.
Animals ; China ; Feces ; virology ; Fresh Water ; virology ; Influenza A virus ; classification ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Poultry ; Poultry Diseases ; virology ; Public Health ; Seasons ; Sewage ; virology

Recent advances in reverse genetics techniques make it possible to manipulate the genome of RNA viruses such as Newcastle disease virus (NDV). Several NDV vaccine strains have been used as vaccine vectors in poultry, mammals, and humans to express antigens of different pathogens. The safety, immunogenicity, and protective efficacy of these NDV-vectored vaccines have been evaluated in pre-clinical and clinical studies. The vaccines are safe in mammals, humans, and poultry. Bivalent NDV-vectored vaccines against pathogens of economic importance to the poultry industry have been developed. These bivalent vaccines confer solid protective immunity against NDV and other foreign antigens. In most cases, NDV-vectored vaccines induce strong local and systemic immune responses against the target foreign antigen. This review summarizes the development of NDV-vectored vaccines and their potential use as a base for designing other effective vaccines for veterinary and human use.
Animals ; Genome ; Humans ; Mammals ; Newcastle disease virus* ; Newcastle Disease* ; Poultry ; Reverse Genetics ; RNA Viruses ; Vaccines*

Objective: To analyze the characteristics of low pathogenic H3, H4 and H6 subtypes of avian influenza viruses in environment related avian influenza viruses in China from 2014 to 2021. Methods: Surveillance sites were located in 31 provinces, autonomous region and municipalities to collect environmental samples related to avian influenza, detect the nucleic acid detection of influenza A virus, isolate virus, deeply sequence, analyze pathogenicity related molecular sites, and determine the distribution and variation characteristics of common H3, H4 and H6 subtypes of avian influenza virus in different regions, places and sample types. Results: A total of 388 645 samples were collected. The positive rate of low pathogenic H3 (0.56‰) and H6 (0.53‰) was higher than that of H4 (0.09‰). The positive rate of H4 subtype virus in live poultry market was higher than that in other places, and the difference was statistically significant. The positive rate of H3 and H6 subtypes in sewage samples was higher than that in other samples, and the difference was statistically significant. The positive rate of H3, H4 and H6 viruses in the south was higher than that in the north, and the difference was statistically significant. December was the most active time for virus. The analysis of pathogenicity related molecular sites showed that H3, H4 and H6 subtypes of viruses combined with avian influenza virus receptors, and some gene sites related to increased pathogenicity had mutations. Conclusion: The H3, H4 and H6 subtypes of low pathogenic avian influenza viruses have a high isolation positive rate in the live poultry market and sewage. The distribution of the three subtypes of viruses has obvious regional and seasonal characteristics, and the genetic characteristics still show the feature of low pathogenic avian influenza.
Humans ; Animals ; Influenza in Birds/epidemiology* ; Sewage ; Phylogeny ; Influenza A virus/genetics* ; Poultry ; China/epidemiology*

OBJECTIVETo study the distribution of Yersinia enterocolitica and its virulence factors in Nantong, Jiangsu.

METHODSYersinia strains were isolated from livestock and poultry. Conventional PCR was used to detect the virulence factors of all strains and strain 0:8 was analyzed by pulsed-field gel electrophoresis(PFGE).

RESULTSThe combined isolation rate of Yersinia enterocolitica from livestock and poultry was 31.06% and the gene distribution characters were: 39.57% of them were ail-, ystA- , ystB-, yadA- , virF-; 60.43% were ail- , ystA- , ystB + , yadA- , virF- respectively. The two reference strains from America and Denmark showed similar electrophoresis patterns but were significantly different with O:8 strains isolated from China while the serotypes of Yersinia enterocolitica O:3 and O:9 which were the main epidemic strains in China, were not found in this area.

CONCLUSIONThe pathogenic Yersinia enterocolitis O:3 and O:9 were not found in Nantong,Jiangsu province.

Animals ; Animals, Domestic ; microbiology ; China ; Electrophoresis ; Poultry ; microbiology ; Virulence Factors ; genetics ; metabolism ; Yersinia enterocolitica ; genetics ; isolation & purification ; pathogenicity

A/Puerto Rico/8/34 (PR8)-derived recombinant viruses have been used for seasonal flu vaccines; however, they are insufficient for vaccines against some human-fatal H5N1 highly pathogenic avian influenza (HPAI) viruses (HPAIV) due to low productivity. Additionally, the polymerase basic 2 (PB2) protein, an important mammalian-pathogenicity determinant, of PR8 possesses several mammalian-pathogenic mutations. We previously reported two avian PB2 genes (01310 and 0028) related to efficient replication in embryonated chicken eggs (ECEs) and nonpathogenicity in BALB/c mice. In this study, we generated PR8-derived H5N1 recombinant viruses harboring hemagglutinin (attenuated) and neuraminidase genes of a clade 2.3.2.1c H5N1 HPAIV (K10-483), as well as the 01310 or 0028 PB2 genes, and investigated their replication and immunogenicity. Compared with a control virus harboring six internal PR8 genes (rK10-483), the recombinant viruses possessing the 01310 and 0028 PB2 genes showed significantly higher replication efficiency in ECEs and higher antibody titers in chickens. In contrast to rK10-483, none of the viruses replicated in BALB/c mice, and all showed low titers in Madin-Darby canine kidney cells. Additionally, the recombinant viruses did not induce a neutralization antibody but elicited decreased protective immune responses against K10-483 in mice. Thus, the highly replicative and mammalian nonpathogenic recombinant H5N1 strains might be promising vaccine candidates against HPAI in poultry.
Animals ; Chickens ; Efficiency ; Eggs ; Hemagglutinins ; Influenza in Birds* ; Influenza Vaccines ; Kidney ; Mice ; Neuraminidase ; Ovum ; Poultry ; Reverse Genetics ; Seasons ; Vaccines ; Virulence