LAMP real-time turbidity detection for fowl adenovirus.

Background: Fowl adenovirus (FAdV) is an infectious agent that can cause jaundice, severe anaemia, dyspnoea and reproductive disorders in fowls. Since 2015, FAdV disease has been rapidly spreading among broiler chickens in China, where it has caused significant economic losses. In this study, a loop-mediated isothermal amplification (LAMP) real-time turbidity method with strong specificity to FAdV was established.

[Genetic evolution and substitution frequency of avian influenza virus HA gene in chicken H9N2 subtype in China in the last 20 years].

Objective: Low pathogenic avian influenza (LPAI) H9N2 subtype virus has been prevalent in domestic poultry in China over two decades. This study was to determine the genetic evolution trend of H9N2 avian influenza virus (AIV) under immune pressure of vaccine.

Methods: H9 HA sequences of 40 isolates from the present study and 136 pandemic strains and 7 classical strains from China downloaded from GenBank, were genetically analyzed to determine evolution, molecular characteristic, and mutation frequency.

H9N2 avian influenza virus-derived natural reassortant H5N2 virus in swan containing the hemagglutinin segment from Eurasian H5 avian influenza virus with an in-frame deletion of four basic residues in the polybasic hemagglutinin cleavage site.

We isolated a novel H5N2 avian influenza virus from swans in China. The virus was derived from a widespread H9N2 avian influenza virus but acquired the hemagglutinin gene from Eurasian H5 subtype with a naturally occurring in-frame deletion of four basic residues in the polybasic hemagglutinin cleavage site.

Genomic and phylogenetic characterization of novel, recombinant H5N2 avian influenza virus strains isolated from vaccinated chickens with clinical symptoms in China.

Infection of poultry with diverse lineages of H5N2 avian influenza viruses has been documented for over three decades in different parts of the world, with limited outbreaks caused by this highly pathogenic avian influenza virus. In the present study, three avian H5N2 influenza viruses, A/chicken/Shijiazhuang/1209/2013, A/chicken/Chiping/0321/2014, and A/chicken/Laiwu/0313/2014, were isolated from chickens with clinical symptoms of avian influenza. Complete genomic and phylogenetic analyses demonstrated that all three isolates are novel recombinant viruses with hemagglutinin (HA) and matrix (M) genes derived from H5N1, and remaining genes derived from H9N2-like viruses.

[Evolution of non-coding nucleotide sequences in Newcastle disease virus genomes ].

[OBJECTIVE] Although much is done in the coding genes of Newcastle disease virus (NDV) , limited papers can be found with non-coding sequences. In this paper, the evolution tendency of non-coding sequences was studied. [METHODS] NDV strain LC12 isolated from duck with egg drop syndrome in 2012, and others 35 strains genome cDNA of different NDV genotype were sought and obtained from GenBank.

Surveillance and molecular characterization of Newcastle disease virus in seafowl from coastal areas of China in 2011.

Four Newcastle disease virus (NDV) isolates were obtained from 997 fecal and tissue samples were collected in 2011 from seafowl that included seagull, sea duck, and swan from the coastal areas of Guangdong, Jiangsu, and Shandong in China. These isolates (SD1, SD2, GD1, and JS1) were characterized for their pathogenicity according to their mean death time, intracerebral pathogenicity index and intravenous pathogenicity index. Full-length fusion protein genes containing the cleavage site were sequenced, and amino-acid sequences around the cleavage site were deduced.

Genetic and biological characterizations of a Newcastle disease virus from swine in China.

Background: 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.

Rapid detection of newly isolated Tembusu-related Flavivirus by reverse-transcription loop-mediated isothermal amplification assay.

Background: 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.

Recombinant chicken interferon-α inhibits H9N2 avian influenza virus replication in vivo by oral administration.

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.

[Correlation of the neutralization index in chicken embryo with the homologies of F and HN gene of different Newcastle-disease isolates].

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.

Pathotypical characterization and molecular epidemiology of Newcastle disease virus isolates from different hosts in China from 1996 to 2005.

Thirty Newcastle disease virus (NDV) strains isolated from outbreaks in China during 1996 to 2005 were characterized pathotypically and genotypically. All strains except one were velogenic. An analysis of the variable region (nucleotides 47 to 420) of the F gene indicated that 6 isolates belonged to genotype II, 3 to genotype III, 1 (isolated from a pigeon) to genotype VI, and 20 to genotype VII.

Molecular characterization of three new virulent Newcastle disease virus variants isolated in China.

Three cases of Newcastle disease virus (NDV) found in nature had the lentogenic motif (112)G-R-Q-G-R-L(117) in their fusion protein cleavage sites. However, both intracerebral pathogenicity and intravenous pathogenicity indexes showed that these NDV isolates were virulent. In comparison with the LaSota live virus vaccine, these viruses had significant genetic variations in the hemagglutinin-neuraminidase gene.

[Study on immune efficacy of Newcastle disease chitosan microsphere vaccine].

Newcastle disease is an acute and highly contagious disease caused by Newcastle disease virus (NDV), one of which does great harms to the poultry industry. The most basic measure of controlling New Castle disease is to alid vaccine, now we usually use La Sota live vaccine and inactivated NDV vaccine, but these two vaccines both have more or less limitation. It can produce higher mucosal immunity titers by taking vaccine orally, meanwhile it can induce humoral and cell-mediated immune response and mucosal immunity strongly.

[Genetic characterization and correlation among fragments of HN gene of the field Newcastle disease viruses].

Twenty-four isolates of Newcastle disease virus (NDV) prevailing during 1997 -- 2005 in China were collected. These isolates were purified by CEF plaque assay and replicated in SPF chicken embryos. The hemagglutinin-neuraminidase (HN) genes of these viruses were cloned and sequenced.

[Molecular characterization of a genotype II virulent Newcastle disease virus isolate from chicken].

Newcastle disease virus (NDV) field strain SQZ04 was isolated from a broiler flock with typical symptoms and lesions, and cloned by plaque-purification three times. NDV SQZ04 was determined as a virulent strain with MDT of 50.5h and 51.