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ABSTRACT: Newcastle Disease Virus (NDV) has been considered to only infect avian species. However, one paramyxovirus named as Xiny10 was isolated from swine. The differences of Xiny10, another previous swine NDV (JL01) and vaccine strain La Sota were compared on the basis of sequences of the whole-lengthen Fusion (F) gene and biological characteristics.
Through serologic tests and sequence alignment, Xiny10 was proved as NDV. It has great differences with JL01 in virulence, biological characteristics, genotype and amino acid homology of F gene. The sequence alignment showed Xiny10 and La Sota both belonged to genotype II. It shared 97.3% to 98.7% identities with genotype II NDVs, which was higher than these strains from the other genotypes.
These above data suggested that the swine virus was NDV and it might be generated from La Sota.
Virology Journal 07/2012; 9:129. · 2.34 Impact Factor
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ABSTRACT: From April 2010 to January 2011, a severe new viral disease had devastated most duck-farming regions in China. This disease affected not only laying ducks but also meat ducks, causing huge economic losses for the poultry industry. The objective of this study is to develop a one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the detection of the new virus related to Tembusu-related Flavivirus.
The RT-LAMP assay is very simple and rapid, and the amplification can be completed within 50 min under isothermal conditions at 63°C by a set of 6 primers targeting the E gene based on the sequences analysis of the newly isolated viruses and other closely related Flavivirus.The monitoring of gene amplification can also be visualized by using SYBR green I fluorescent dye. In addition, the RT-LAMP assay for newly isolated Tembusu-related Flavivirus showed higher sensitivity with an RNA detection-limit of 2 copies/μL compared with 190 copies/μL of the conventional RT-PCR method. The specificity was identified without cross reaction to other common avian pathogens. By screening a panel of clinical samples this method was more feasible in clinical settings and there was higher positive coincidence rate than conventional RT-PCR and virus isolation.
The RT-LAMP assay for newly isolated Tembusu-related Flavivirus is a valuable tool for the rapid and real-time detection not only in well-equipped laboratories but also in general conditions.
Virology Journal 12/2011; 8:553. · 2.34 Impact Factor
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Yuhai Bi,
Lu Lu,
Jing Li,
Yanbo Yin,
Yi Zhang,
Huijie Gao, Zhuoming Qin,
Basit Zeshan,
Jinhua Liu,
Lei Sun,
Wenjun Liu
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ABSTRACT: H9N2 influenza A viruses have undergone extensive reassortments in different host species, and could lead to the epidemics or pandemics with the potential emergence of novel viruses.
To understand the genetic and pathogenic features of early and current circulating H9N2 viruses, 15 representative H9N2 viruses isolated from diseased chickens in northern China between 1998 and 2010 were characterized and compared with all Chinese H9N2 viruses available in the NCBI database. Then, the representative viruses of different genotypes were selected to study the pathogenicity in mice with the aim to investigate the adaptation and the potential pathogenicity of the novel H9N2 reassortants to mammals.
Our results demonstrated that most of the 15 isolates were reassortants and generated four novel genotypes (B62-B65), which incorporated the gene segments from Eurasian H9N2 lineage, North American H9N2 branch, and H5N1 viruses. It was noteworthy that the newly identified genotype B65 has been prevalent in China since 2007, and more importantly, different H9N2 influenza viruses displayed a diverse pathogenicity to mice. The isolates of the 2008-2010 epidemic (genotypes B55 and B65) were lowly infectious, while two representative viruses of genotypes B0 and G2 isolated from the late 1990s were highly pathogenic to mice. In addition, Ck/SD/LY-1/08 (genotype 63, containing H5N1-like NP and PA genes) was able to replicate well in mouse lungs with high virus titers but caused mild clinical signs.
Several lines of evidence indicated that the H9N2 influenza viruses constantly change their genetics and pathogenicity. Thus, the genetic evolution of H9N2 viruses and their pathogenicity to mammals should be closely monitored to prevent the emergence of novel pandemic viruses.
Virology Journal 11/2011; 8:505. · 2.34 Impact Factor
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ABSTRACT: Since 2003, triple reassortant (TR) swine H3N2 influenza viruses containing gene segments from human, avian, and swine origins have been detected in the U.S. turkey populations. The initial outbreak that occurred involved birds that were vaccinated with the currently available H3 swine- and avian-origin influenza vaccines. Antigenically, all turkey swine-lineage TR H3N2 isolates are closely related to each other but show little or no antigenic cross-reactivity with the avian origin or swine origin influenza vaccine strains that are currently being used in turkey operations. These results call for re-evaluation of currently available influenza vaccines being used in turkey flocks and development of more effective DIVA (differentiation of infected from vaccinated animals) vaccines. In this study, we selected one TR H3N2 strain, A/turkey/OH/313053/04 (H3N2) that showed broad cross reactivity with other recent TR turkey H3N2 isolates, and created NA- and NS-based DIVA vaccines using traditional reassortment as well as reverse genetics methods. Protective efficacy of those vaccines was determined in 2-week-old and 80-week-old breeder turkeys. The reassortant DIVA vaccines significantly reduced the presence of challenge virus in the oviduct of breeder turkeys as well as trachea and cloaca shedding of both young and old breeder turkeys, suggesting that proper vaccination could effectively prevent egg production drop and potential viral contamination of eggs in infected turkeys. Our results demonstrate that the heterologous NA and NS1 DIVA vaccines together with their corresponding serological tests could be useful for the control of TR H3N2 influenza in turkeys.
Vaccine 09/2011; 29(45):7966-74. · 3.77 Impact Factor
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ABSTRACT: European starlings (Sturnus vulgaris) are common, widely distributed birds in North America that frequently come into contact with agricultural operations. However, starlings have been one of the neglected land-based wild bird species for influenza surveillance.
To study the potential role of starlings in the ecology and epidemiology of influenza virus.
We collected 328 digestive and 156 tracheal samples from starlings in Ohio in years 2007 (July) to 2008 (August) and screened for the presence of influenza virus by real-time RT-PCR, standard RT-PCR and virus isolation using embryonated chicken eggs. In addition, we conducted an experimental infection study to evaluate the replication and induction of antibody response by two low pathogenic avian influenza (AI) viruses in starlings.
Although virus isolation was negative, we confirmed 21 influenza positive digestive and tracheal samples by real-time and standard RT-PCR tests. Phylogenetic analysis revealed that five NS genes recovered from Starlings belonged to NS subtype A and were most similar to the NS genes from a wild aquatic bird origin isolate from Ohio. Experimental infection studies using two low pathogenic AI strains showed that starlings could be infected, shed virus, and seroconvert.
This study shows that starlings can carry influenza virus that is genetically similar to wild aquatic bird origin strains and may serve as a carrier of influenza virus to domestic animals.
Influenza and Other Respiratory Viruses 07/2011; 5(4):268-75. · 4.16 Impact Factor
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ABSTRACT: Chicken interferon-alpha (ChIFN-α) has been demonstrated to be an important cytokine in antiviral immunity. However, the preventive or therapeutic effect of ChIFN-α as an oral antiviral agent on avian influenza virus (AIV) infection has not been fully clarified in chickens systemically. In the present study, we investigated the anti-H9N2 AIV effect of ChIFN-α on a cohort of 7- and 33-day-old specific pathogen-free (SPF) chickens by oral administration. Results showed that both the ChIFN-α preventive and therapeutic groups exhibited significantly reduced viral load in trachea when compared with the virus-challenged control group. The therapeutic effect was better than the preventive effect on 7-day-old SPF chickens, which is opposite to 33-day-old SPF chickens. We speculated that T-dependent lymphocyte system of 33-day-old SPF chickens might be easier to be stimulated by ChIFN-α than that of 7-day-old SPF chickens. In addition, there was no side effect on the body weight of chickens treated with ChIFN-α. We also found that IFN-stimulated genes (ISGs) (2',5'-oligoadenylate synthetase and Mx1) were upregulated in groups treated by ChIFN-α and/or virus, indicating that these 2 ISGs not only participated in anti-AIV response in vivo but also could be induced by oral administration of ChIFN-α. The present study suggested that ChIFN-α could be used as a potential preventive and therapeutic antiviral agent against H9N2 AIV infection by oral administration.
Journal of interferon & cytokine research: the official journal of the International Society for Interferon and Cytokine Research 02/2011; 31(7):533-8. · 1.63 Impact Factor
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ABSTRACT: Pigs are capable of generating reassortant influenza viruses of pandemic potential, as both the avian and mammalian influenza viruses can infect pig epithelial cells in the respiratory tract. The source of the current influenza pandemic is H1N1 influenza A virus, possibly of swine origin. This study was conducted to understand better the pathogenesis of H1N1 influenza virus and associated host mucosal immune responses during acute infection in humans. Therefore, we chose a H1N1 swine influenza virus, Sw/OH/24366/07 (SwIV), which has a history of transmission to humans. Clinically, inoculated pigs had nasal discharge and fever and shed virus through nasal secretions. Like pandemic H1N1, SwIV also replicated extensively in both the upper and lower respiratory tracts, and lung lesions were typical of H1N1 infection. We detected innate, proinflammatory, Th1, Th2, and Th3 cytokines, as well as SwIV-specific IgA antibody in lungs of the virus-inoculated pigs. Production of IFN-γ by lymphocytes of the tracheobronchial lymph nodes was also detected. Higher frequencies of cytotoxic T lymphocytes, γδ T cells, dendritic cells, activated T cells, and CD4+ and CD8+ T cells were detected in SwIV-infected pig lungs. Concomitantly, higher frequencies of the immunosuppressive T regulatory cells were also detected in the virus-infected pig lungs. The findings of this study have relevance to pathogenesis of the pandemic H1N1 influenza virus in humans; thus, pigs may serve as a useful animal model to design and test effective mucosal vaccines and therapeutics against influenza virus.
Journal of Virology 11/2010; 84(21):11210-8. · 5.40 Impact Factor
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ABSTRACT: A velogenic Newcastle disease virus (NDV) strain, designated as SRZ03, was isolated from an egg layer flock with NDV vaccine immunization failure in China in 2003. Recombination was found in the F gene of SRZ03. Complete genome sequences analysis indicated that the N-terminal of SRZ03 F gene originated from a genotype II NDV strain, whereas the C-terminal of F gene and the rest of the genes originated from a prevalent velogenic genotype VII NDV strain. It provides us valuable information for understanding the recombination of nonsegmented negative-sense RNA viruses.
Virus Research 03/2008; 131(2):299-303. · 2.94 Impact Factor
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ABSTRACT: Thirteen prevailed Newcastle-disease viruses (NDV) isolated in China during 2001-2004 were purified by chick embryo fibroblast (CEF) plaque assay and characterized pathotypically and genotypically. The biological tests showed that these viruses were highly virulent. Sequence analysis based on the variable region (nucleotide 47-420) of the F gene indicated that of the 13 NDV isolates 2 belonged to genotype II, 2 to genotype IX and 9 to genotype VII. Isolates with genotype VII shared 94.6%-99.3% nucleotide (nt) homology with the F gene, whereas for genotype VII and La Sota was only 82.7%-84.1%. In addition, these NDV isolates all shared 95.2%-100% nt homology with the hemagglutinin-neuraminidase (HN) gene, whereas only 79.1%-84.3% compared these viruses with La Sota. The cross neutralization assays were done using positive serums in specific pathogen free (SPF) chicken embryos respectively. Correlation of the neutralization index in chicken embryo with the homologies of F and HN gene of different NDV isolates were analyzed by SPSS8.0 software. The result showed that the neutralization index was closely correlated with nt sequence (P < 0.01, r = 0.35) or deduced amino acid sequence (P < 0.01, r = 0.34) of the HN gene, whereas weekly correlated (P < 0.05, r = 0.20 or 0.19) with the F gene, and non-correlated with 374 nt segment. This implied that the genetic mutations of HN resulted in antigenic variations of these viruses and the search for new vaccines would be necessary.
ACTA MICROBIOLOGICA SINICA 02/2008; 48(2):226-33.
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Yuhai Bi,
Lu Lu,
Jing Li,
Yanbo Yin,
Yi Zhang,
Huijie Gao, Zhuoming Qin,
Basit Zeshan,
Jinhua Liu,
Lei Sun,
Wenjun Liu
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ABSTRACT: Background: H9N2 influenza A viruses have undergone extensive reassortments in different host species, and could lead to the epidemics or pandemics with the potential emergence of novel viruses.
