• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.563-573
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• 2000

Periodic outbreaks of Newcastle disease (ND) caused by velogenic viscerotropic ND virus (vvNDV) has become a major concern in Korea nowadays. Throughout last epidemic, the winter season in 2000, most chicken flocks infected early, under 2-4 weeks of age, showed high mortality up to 50-100%. Serum samples collected from 201 breeder, 284 layer and 112 broiler chicken flocks were examined to evaluate the efficacy of various vaccination methods and programs routinely used for mass vaccination in the field poultry farms. Despite repeated live vaccination, most poultry flocks vaccinated by drinking water route using nipple water supply system failed to produce solid active immune response to NDV during the growing time. In the present study, we applied the spray vaccination technique using Ulvavac or Desvac sprayer to the experimental poultry flocks and examined the efficacy of live vaccination effects induced by it under field condition. Measurable antibody to NDV as well as early protection against vvNDV challenge were found in poultry flocks vaccinated by spray route. Further, we did not found significant post vaccination reactions caused by spray vaccination if properly administered. These data indicate that the spray vaccination will be safe and reliable mass vaccination method for the prevention of ND.

• Korean Journal of Veterinary Research
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• v.52 no.4
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• pp.213-221
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• 2012

A total of 18 Newcastle disease virus (NDV) isolates that were recovered from 1949 through 1997 were characterized and pathotyped. All viruses were highly virulent as determined by intracerebral pathogenicity indices ${\geq}1.81$ in day-old. These pathotypes are typical for viscerotropic velogenic NDV (VVNDV) pathotype viruses. Some differences were observed for the chicken red blood cell elution rate and thermostability of the hemagglutinin at $56^{\circ}C$. Three antigenic groups were identified by a hemagglutination-inhibition assay using NDV monoclonal antibodies. And the predominant gross lesions were as follows: discharge from the nasal cavity, tracheal mucus, petechial hemorrhage in the heart fat, kidney urates and hemorrhage with or without necrosis in the gastrointestinal tract. Severe hemorrhagic or necrotic lesions were also noted in the lymphoid organs and were localized primarily in the spleen and cecal tonsil. However, differences in the occurrence and frequency of the gross lesions were observed between the virus strains. Among them, NDV strains that induced neurological symptoms belonged only to genotype VI. This strain had spread throughout Korea during the late 1980s to the 1990s, which suggests that specific VVNDVs genotypes might result in neurological symptoms.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.565-573
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• 1998

To study the specific tools for the diagnosis of Newcastle disease virus (NDV) in chicken, polymerase chain reaction (PCR) and its presumable conditions were evaluated for the detection of hemagglutinin-neuraminidase (HN) gene of NDV RNA. For these purposes, Kyojeongwon strain of the NDV was propagated in allantoic cavity of SPF embryonating chicken eggs, and viral RNA was extracted from fractionated virus after the allantoic fluids were ultracentrifuged with sucrose gradient. The first-strand cDNA was then made for the HN gene of NDV RNA by reverse transcription at $42^{\circ}C$ for 1 hour using specific primer complementary to the HN gene. The single-stranded cDNA was used as template in the PCR of the HN-DNA, and various conditions of the PCR were evaluated to set up method for the specific detection of the HN-DNA. The PCR conditions promising for the detection of HN gene consist of preheating at $94^{\circ}C$, 5 min, 30 cycles of denaturation at $94^{\circ}C$, 1 min, annealing at $55^{\circ}C$, 1 min and polymerization at $72^{\circ}C$, 2 min, and a cycle of extension at $72^{\circ}C$, 5 min. when NDVs of allantoic fluids without fractionation were applied to the above PCR condition, the HN genes were detected effectively not only from Kyojeongwon but from other velogenic strains such as Herts and a field isolate.

• Journal of Microbiology and Biotechnology
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• v.21 no.3
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• pp.263-266
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• 2011

Methylelaiophylin isolated from Streptomyces melanosporofaciens was selected as an ${\alpha}$-glucosidase inhibitor with an $IC_{50}$ value of 10 ${\mu}M$. It showed mixed-type inhibition of ${\alpha}$-glucosidase with a $K_i$ value of 5.94 ${\mu}M$. In addition, methylelaiophylin inhibited the intracellular trafficking of hemagglutinin-neuramidase (HN), a glycoprotein of Newcastle disease virus (NDV), in baby hamster kidney (BHK) cells. Methylelaiophylin inhibited the cell surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.

• Korean Journal of Food Science and Technology
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• v.46 no.2
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• pp.245-248
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• 2014

Trafficking of viral glycoproteins to the cell surface results in syncytium formation in baby hamster kidney (BHK) cells infected with Newcastle disease virus (NDV). An extract from the medicinal Areca catechu L plant inhibited not only syncytium formation, but also trafficking of the hemagglutinin-neuramidase (HN) glycoprotein to the cell-surface. The viral glycoprotein was processed within the endoplasmic reticulum during transit to the cell membrane. Fungal extracts showed inhibitory activities ($IC_{50}10{\mu}g/mL$) against ${\alpha}$-glucosidase. These results suggested that A. catechu L. extracts inhibited the cell-surface expression of NDV-HN glycoprotein without significantly affecting HN glycoprotein synthesis in NDV-infected BHK cells.

• Korean Journal of Poultry Science
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• v.39 no.2
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• pp.113-120
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• 2012

Newcastle disease virus (NDV) Kr005/V strain was generated through 55 serial passages of NDV Kr005 strain in Vero cells. The Kr005/V virus yielded high infective titers of $10^{7.8}$ $TCID_{50}/mL$ in Vero cells and the infected cells showed cytopathic effects such as marked cell rounding, though less frequent syncytia. The Kr005/V virus was heat-stable and classified into the lentogenic type with a Mean Death Time (MDT) of 120h or greater while the Kr005 strain was heat-labile and velogenic (MDT of 49.6 h). Only the single amino acid substitution (T to S) was observed at position 433 of the HN protein of the Kr005/V strain, whereas no amino acid change was found in the F protein. The Kr005/V input virus correlated well (correlation coefficient $r^2$=0.97) with the Kr005 virus when ten field sera were tested by virus neutralization test. The biological properties and usefulness of Vero cell-adapted Kr005/V virus were discussed.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.281-284
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• 2002

Specific pathogen free (SPF) eggs have been used to produce live vaccines. however, their application causes many problems such as cost, space and waste disposal. The substitution of mammalian cells for SPF eggs offers a desirable system of vaccine production. In this study, mammalian cells were tested for the infection of Newcastle disease virus (NDV). As a result, DF-I and MDBK cells showed high virus productivity compared to the other mammalian cells. For the highest productivity of NDV, the optimal multiplicity of infection (M.O.I.) in DF-I or MDBK cells was determined to be 0.2 or 0.5 M.O.I., respectively.

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.99-104
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• 1980

The effects of thyroxine (TX) or propylthiouracil (PPT) administration on the antibody forming activity agains t sheep red blood cell (SRBC) and Newcastle disease virus (NDV) were studied by using of hemagglutination and hemagglutination-inhibition techniques. Antibody titers to both SRBC and NDV increased significantly in the TX-treated group, whereas decreased in the PPT-treated group, compared with control. When TX was administered after antigen inoculatioon, antibody forming activity was significantly enhanced, compared with the TX administration before antigen inoculation.

• Journal of Veterinary Science
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• v.23 no.2
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• pp.21.1-21.7
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• 2022

Newcastle disease (ND), infectious laryngotracheitis (ILT) and avian metapneumovirus (aMPV) can be similar making it critical to quickly differentiate them. Herein, we adapted pre-existing molecular-based diagnostic assays for NDV and ILTV, and developed new assays for aMPV A and B, for use under synchronized thermocycling conditions. All assays performed equivalently with linearity over a 5 log₁₀ dynamic range, a reproducible (R² > 0.99) limit of detection of ≥ 10 target copies, and amplification efficiencies between 86.8%-98.2%. Using biological specimens for NDV and ILTV showed 100% specificity. Identical amplification conditions will simplify procedures for detection in diagnostic laboratories.

• Proceedings of the Korean Society of Veterinary Service Conference
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• 1994.04a
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• pp.144.2-144
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• 1994