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

OBJECTIVETo elucidate the variation in characterizations and genetic evolution of the matrix protein 2 or ion channel protein(M2) genes of avian influenza subtype H5N1 viruses in the boundary region of Yunnan province from 2008 to 2012.

METHODSA total of swab samples were collected from foreign poultry such as the junction between Yunnan and Vietnam, Laos,myanmar and wild birds in boundary region of Yunnan province from 2008 to 2012 and screened by H5N1 subtype-specific multiplex RT-PCR. The M genes of H5N1 virus from the positive samples were amplified by RT-PCR and cloned into pMD18-T vectors for sequencing. The alignment and phylogenetic analysis of M2 genes were performed with sequences of the known reference strains.

RESULTSA total of 71 positive samples were found out of 1240 samples and the positive rate was 5.72%. A total of 14 different M2 sequences were obtained from 30 positive samples and were divided into 3 distinct clades or sub-clades(1.2.1, 1.2.2 and 2) by phylogenetic analysis, 5, 7 and 2, respectively. The M2 genes and Hemagglutinin(HA) genes of H5N1 viruses from the boundary region of Yunnan province had showed different relationship of genetic evolution. The substitution or mutation of key amino acids sites had been found among the domains of epitope, adamantane-resistance, and poultry or human original viral strains.

CONCLUSIONThe M2 genes of H5N1 subtype viruses in boundary region of Yunnan province from 2008 to 2012 showed genetic divergence and the virus of clade 1.2.2 had become dominant epidemic strain in this region.

Animals ; Birds ; virology ; Chickens ; virology ; China ; Evolution, Molecular ; Influenza A Virus, H5N1 Subtype ; classification ; genetics ; Influenza in Birds ; virology ; Phylogeny ; Poultry ; virology ; Viral Matrix Proteins ; genetics

OBJECTIVETo understand the infection status and epidemic rule of new bunia virus in the livestock and poultry which are closely related with humans such as sheep, cattle, dogs, pigs and chicken in the hilly area of Jiaodong peninsula in Shandong province.

METHODSPenglai and Laizhou in the hilly area of Jiaodong peninsula in Shandong province where severe fever with thrombocytopenia syndrome cases occurred in 2010 were selected as experimental sites. During April to November in 2011, serum specimens of the sheep, cattle, dogs, pigs and chicken with ticks in endemic area were randomly collected by random number table.5 ml venous blood was collected in each livestocks or poultries and there were total 3576 samples.New bunia virus antibody in different species of livestocks or poultries serum was continuously detected using double antigen sandwich enzyme-linked immunosorbent assay, and the infection rates of new bunia virus between different species of livestocks or poultries and between Penglai and Laizhou were analyzed using chi-square test.

RESULTSTest results in 3576 samples of livestocks or poultries serum specimen showed that the infection rate was as high as 63% (636/1013) in sheep, 53% (444/841)in cattle, 46% (242/530) in chicken, 29% (104/362)in the dogs, and 1% (12/830) in pigs. There were significant differences of new bunia virus infection among different species (χ(2) = 815.26, P < 0.05).In Penglai, the infection rate was as high as 71% (400/563) in sheep, 57% (232/409)in cattle, 35% (93/266) in chicken, 44% (796/1819)in total, while in Laizhou, the infection rate was 53% (236/450)in sheep, 49% (212/432)in cattle, 56% (149/264)in chicken, 36% (642/1757)in total, their difference was statistically significant(χ(2) values were 37.04, 4.93, 24.63, 19.38, all P values were < 0.05).Infection rates of dogs and pigs showed no obvious fluctuation.However, there were two peaks of infection in sheep in summer and autumn, the infection rate was as high as 62% (68/110) in June and 86% (204/236) in November;There were two peaks of infection in cattle in spring and autumn, the infection rate was as high as 56% (53/94) in April and 73% (116/159) in November; there was only one peak of infection in chicken, the infection rate was as high as 65% (55/85) in September.

CONCLUSIONThe infection rate is higher in sheep, cattle, chickens and dogs in the hilly area of Jiaodong peninsula. The peak season is spring, summer and autumn.

Animals ; Bunyaviridae ; isolation & purification ; Bunyaviridae Infections ; epidemiology ; veterinary ; Cattle ; Chickens ; China ; epidemiology ; Dogs ; Livestock ; virology ; Poultry ; virology ; Sheep

A quail-origin subtype of the influenza virus was isolated from a human-infecting H7N9 subtype of the avian influenza virus found in a live poultry market and was given the name A/Quail/Hangzhou/1/ 2013 (H9N2). We analyzed the whole genome of this virus and its biologic characteristics. Sequence analyses suggested that the: HA and NS genes belonged to a CK/BJ/1/94-like lineage; NA, NP, PA and PB1 genes belonged to a SH/F/98-like lineage; M and PB2 genes belonged to a G1-like lineage. Analyses of key amino acids showed that the cleavage site in HA protein was PSRSSR ↓ GL, and that the HA protein had a human receptor-binding site with Leu226. Deletion of amino acids 69 - 73 was detected in the stalk of NA protein, the M2 protein had an Asn31 mutation, and the NS1 protein had two mutations at Ser42, Ala149. The intravenous pathogenicity of this virus was 0.36. A study in chickens suggested that all inoculated birds shed the virus from the trachea and cloaca on the third day post-infection (p. i. ) until 11 days. All chickens that had direct contact shed the virus on the second day p. i. until 8 days. Results of virus reisolation suggested that lung and tracheal tissues could shed the virus in 5 days, whereas the other organs could shed the virus in 3 days. These results suggest that this virus strain is H9N2 subtype LPAIV, whose lineage is prevalent in mainland China. This research provides evidence on how to monitor and prevent the H9N2 subtype of the avian influenza virus.
Animals ; Chick Embryo ; Chickens ; China ; Genotype ; Influenza A Virus, H9N2 Subtype ; classification ; genetics ; isolation & purification ; Influenza in Birds ; virology ; Phylogeny ; Quail ; virology

Elution time of velogenic, mesogenic and lentogenic strains of Newcastle disease virus was determined. The differences in their elution time were also calculated. Four samples, each of a velogenic strain (VGF2), a mesogenic strain (Komarov) and a lentogenic strain (LaSota) were used for hemagglutination test with 0.6% chicken red blood cells. The time it took for wells of the end hemagglutination points (highest dilution that gave agglutination) to elute was recorded as elution time for each sample. The mean elution time of the three strains of Newcastle disease virus differed significantly (p < 0.05). The velogenic strain gave the highest mean elution time of 118 min, followed by the mesogenic strain with 59 min and the lentogenic strain with 25 min. Based on this result it appears that elution time could form a basis for rough characterization of isolates of Newcastle disease virus into the three major strains.
Animals ; Chickens/blood ; Erythrocytes/*virology ; Hemagglutination Tests ; *Hemagglutination, Viral ; Newcastle disease virus/isolation&purification/*pathogenicity

Avian leukosis virus subgroup J (ALV-J) is an avian retrovirus that can induce myelocytomas. A high-frequency mutation in gene envelope endows ALV-J with the potential for cross-species transmission. We wished to ascertain if the ALV-J can spread across species under selection pressure in susceptible and resistant hosts. First, we inoculated (in turn) two susceptible host birds (specific pathogen-free (SPF) chickens and turkeys). Then, we inoculated three resistant hosts (pheasants, quails and ducks) to detect the viral shedding, pathologic changes, and genetic evolution of different isolates. We found that pheasants and quails were infected under the selective pressure that accumulates stepwise in different hosts, and that ducks were not infected. Infection rates for SPF chickens and turkeys were 100% (16/16), whereas those for pheasants and quails were 37.5% (6/16) and 11.1% (3/27). Infected hosts showed immune tolerance, and inflammation and tissue damage could be seen in the liver, spleen, kidneys and cardiovascular system. Non-synonymous mutation and synonymous ratio (NS/S) analyses revealed the NS/S in hypervariable region (hr) 2 of pheasants and quails was 2.5. That finding suggested that mutation of isolates in pheasants and quails was induced by selective pressure from the resistant host, and that the hr2 region is a critical domain in cross-species transmission of ALV-J. Sequencing showed that ALV-J isolates from turkeys, pheasants and quails had moved away from the original virus, and were closer to the ALV-J prototype strain HPRS-103. However, the HPRS-103 strain cannot infect pheasants and quails, so further studies are needed.
Amino Acid Sequence ; Animals ; Avian Leukosis ; transmission ; virology ; Avian Leukosis Virus ; classification ; genetics ; physiology ; Chickens ; Ducks ; virology ; Galliformes ; virology ; Host Specificity ; Molecular Sequence Data ; Poultry Diseases ; transmission ; virology ; Quail ; virology ; Sequence Alignment ; Turkeys ; virology ; Viral Envelope Proteins ; chemistry ; genetics ; metabolism

Fowl adenovirus serotype 4 (FAdV-4) strain SD1511 was isolated from chickens with severe inclusion body hepatitis and hydropericardium syndrome in Shandong Province, China. The isolate was cultured in primary chicken embryo kidney cells. A study of pathogenicity indicated that SD1511 readily infected 7-35-d-old chickens by intramuscular injection and intranasal and oral routes, causing 50%-100% mortality. The 35-d-old chickens suffered more severe infection than 7- and 21-d-old chickens with mortality highest in the intramuscular injection group. The serum from surviving chickens showed potent viral neutralizing capability. The complete genome of SD1511 was sequenced and analyzed. The strain was found to belong to the FAdV-4 cluster with more than 99% identity with the virulent FAdV-4 strains isolated in China in recent years except for some distinct variations, including deletions of open reading frame 27 (ORF27), ORF48, and part of ORF19. Our findings suggest that SD1511 might be used as a prototype strain for the study of pathogenesis and vaccine development.
Animals ; Antibodies, Neutralizing ; Aviadenovirus/pathogenicity* ; Cell Line ; Chick Embryo/virology* ; Chickens/virology* ; China ; Gene Deletion ; Genetic Variation ; Genome ; Genome, Viral ; Genomics ; Kidney/virology* ; Liver/virology* ; Open Reading Frames ; Poultry Diseases/virology* ; Serogroup ; Viral Load ; Virulence ; Virus Diseases/virology*

Despite the existence of an active vaccination program, recently emerged strains of nephropathogenic infectious bronchitis virus (IBV) in Korea have caused significant economic losses in the poultry industry. In this study, we assessed the pathogenic and antigenic characteristics of a K-IIb type field strain of IBV that emerged in Korea since 2003, such as Kr/Q43/06. Specific pathogen free 1-week-old chickens exhibited severe respiratory symptoms (dyspnea) and nephropathogenic lesions (swollen kidneys with nephritis and urate deposits) following challenge with the recent IBV field strain. The antigenic relatedness (R value), based on a calculated virus neutralization index, of the K-IIb type field strain and K-IIa type strain KM91 (isolated in 1991) was 30%, which indicated that the recent strain, Kr/Q43/06, is a new variant that is antigenically distinct from strain KM91. This report is the first to document the emergence of a new antigenic variant of nephropathogenic IBV in chicken from Korea.
Animals ; Antigens, Viral ; *Chickens ; Coronavirus Infections/epidemiology/*veterinary/virology ; Infectious bronchitis virus/classification/*pathogenicity ; Korea ; Nephritis/*veterinary/virology ; Poultry Diseases/*virology ; Specific Pathogen-Free Organisms ; Virulence

A GeXP based multiplex PCR assay was developed to simultaneously detect six different chicken respiratory viruses including H5, H7, H9 subtypes of avian influenza virus(AIV), new castle disease virus (NDV), infectious bronchitis virus(IBV) and infectious laryngotracheitis virus(ILTV). According to the conserved sequences of genes of each pathogen, seven pairs of specific primers were designed, and the reaction conditions were optimized. The specificity and accuracy of GeXP were examined using samples of single and mixed infections of virus. The sensitivity was evaluated by performing the assay on serial 10-fold dilutions of cloned plasmids. To further evaluate the reliability, thirty-four clinical samples were detected by GeXP. The corresponding specific fragments of genes were amplified. The detection limit of GeXP was 10(2) copies/microL when all of 7 pre-mixed plasmids containing target genes of six chicken respiratory viruses were present. In the detection of thirty-four clinical samples, the results of GeXP were accorded with the viral isolation completely. In conclusion, this GeXP assay is a rapid, specific, sensitive and high-throughput method for the detection of chicken respiratory virus infections. It can be applied in rapid differential diagnosis for clinical samples, and also provide an effective tool to prevent and control chicken respiratory diseases with similar clinical symptoms.
Animals ; Chickens ; Influenza A virus ; classification ; genetics ; isolation & purification ; physiology ; Influenza in Birds ; diagnosis ; virology ; Multiplex Polymerase Chain Reaction ; methods ; Poultry Diseases ; diagnosis ; virology ; Respiratory Tract Infections ; diagnosis ; veterinary ; virology

In order to clarify Avian leukosis virus (ALV) characteristics from Chinese native chicken breeds, three ALV JS11C1, JS11C2 and JS11C3 were isolated from Chinese native breed "luhua" by inoculation of DF1 cell culture and detection of p27 antigen. Using PCR amplification of env gene, the amplified gp85 genes were analyzed and compared to all six chicken ALV subgroups reported. The gp85 genes of these three viruses were 1 005bp in length and encoded 335 amino acids, and the gp37 genes were 609bp and encoded 203 amino acids. The homology of gp85 among these three isolated strains was 91.9%-97.0%. Comparing to 18 stains of subgroup A, B, C, D, E published in GenBank, the homology was only in the range of 77.7%-84.6%, significantly lower than the gp85 homology observed within the common chicken subgroups A (88.2%-98.5%), B (91.6%-98.8%), and E (97.9%-99.4%). The gp85 homology compared with subgroup J was only 34.2%-36.5%. These results suggested that three isolated strains from Chinese native breed "luhua" belong to a new subgroup different from all six known subgroups from Chickens, and thus designated as subgroup K.
Animals ; Avian Leukosis ; virology ; Avian Leukosis Virus ; classification ; genetics ; isolation & purification ; metabolism ; Breeding ; Chickens ; genetics ; virology ; Molecular Sequence Data ; Phylogeny ; Poultry Diseases ; virology ; Viral Envelope Proteins ; genetics ; metabolism