• Journal of Veterinary Clinics
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• v.18 no.2
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• pp.152-155
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• 2001

A two-year-old male peacock (Pavo cristatus) showed acute watery green diarrhea, followed by neurological signs including torticollis and muscular tremor. By the hemagglutination inhibition test for detecting the antibody against the Newcastle disease virus (NDV), the peacock serum inhibited the agglutination of chicken red blood cells. Grossly distinctive hemorrhagic lesions were found in the mucosa of proventiculus and intestine and lung. The spleen revealed multiple variable sized necrotic foci. Histologically, the mucosa of gastrointestinal track had hemorrhagic lesions and some of them underwent ulceration. The spleen exhibited multiple variable sized necrotic foci in which fibrin exudation was marked. Central nervous system had mild non-suppulative menin-goencephalitis consisting of vasculitis, perivascular hemorrhage, gliosis and meningitis. The cells particularly in the cerebellum were degenerative to necrotic. Some of these nerve cells revealed characteristic peripheral chromatolysis. From the present serological and pathological findings, it is suggested that NDV causing death of peacock was velogenic viscerotropic strain. This is the first report of the occurrence of velogenic viscerotropic NDV in an adult peacock in Korea.

• 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.46 no.3
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• pp.185-196
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• 2006

Newcastle disease (ND) is a highly contagious disease of poultry that can cause severe economic losses throughout the world. Vaccination has been used for a long time and proved as one of the most effective method to reduce the economic loss due to ND virus infection, The measurement of antibody titer such as hamagglutination-inhibition (Hl) test with sera has been used as a useful method to evaluate the immunity leve of host. However, Hl test is gradually being replaced by the enzyme linked-immunosorbent assay (ELISA), To evaluate the efficacy of ELISA in the chickens vaccinated with different procedure, present study has been performed. After SPF chicks and commercial broilers were vaccinated with different kinds of live vaccines such as V4, VG/GA and/or Bl at various time, the antibody level has been measured using both HI test and ELISA. Challenge test with velogenic viscerotropic NDV was also performed to measure the protective level of antibody. In the SPF chickens, the mean ELISA titer after vaccination and survival rate after challenge was increased and correlated with days post inoculation. More than 80% of chickens with higher than 1,000 ELISA titer after vaccination were survived after challenge with velogenic ND virus and had good correlation between survival rate and antibody titier. In commercial broiler chickens, most of them at market age had low level of ELISA titer regardless of the number of vaccination, and had a low correlation between survival rate and ELISA titer. However, the ELISA titer of remaining birds after challenge was increased. This result indicated that ELISA titer had good response against velogenic NOV infection compared to Hl titer.

• Korean Journal of Poultry Science
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• v.28 no.2
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• pp.99-106
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• 2001

Pathologic changes and distribution of viral antigen as determined by immunohistochemistry were compared among 4-wk-old specific-pathogen free (SPF) chickens inoculated intratracheally with velogenic vis-cerotropic Newcastle disease virus isolated in Korea. Although the pattern of organ involvement and severity of lesion was different among chickens infected with different velogenic viscerotropic Newcastle disease (VVND) viruses, the pathological types of lesion was similar among the chickens. Severe lymphocytic necrosis and depletion were main histologic lesions in the immune related organs such as thymus, Fabricius bursa and spleen. The frequency of IP positive staining was variable depends on the types of tissues but not types of the kinds of VVND viruses infected. Brain, Fabricius bursa, thymus, cecal tonsil and trachea were IP positive with fairly high frequency and spleen, lung, proventriculus, intestine, pancreas, liver, kidney, heart and Harderian gland were with relatively low frequency. These results suggest that histologic evaluation and viral antigen specific immunohistochemical staining methods to determine virus distribution will be useful for pathogenic study of velogenic viscerotropic Newcastle disease virus infection in chicken.

• Korean Journal of Veterinary Research
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• v.42 no.3
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• pp.351-362
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• 2002

Newcastle disease (ND) is a highly contagious infection of poultry, Two pathology-based techniques, in situ RT-PCR and in situ hybridization (ISH) were applied to formalin-fixed, paraffin-embedded tissues from chickens naturally infected with velogenic ND virus (VNDV). Two pairs of primers and a probe for ISH and in situ RT-PCR, respectively, were selected from highly conserved region of matrix gene of NDV. The ISH experiment was carried out using MicroProbe$^{TM}$ capillary action system within 2 hours. In situ RT-PCR was performed using MicroProbe$^{TM}$ capillary action system and GeneAmp In Situ PCR system. With ISH and in situ RT-PCR, viral nucleic acid was detected in the central nervous system of chickens from infected with neurotropic velogenic Newcastle disease virus (NVNDV), whereas viral nucleic acid was detected in various organs or tissues of chickens from infected with viscerotropic velogenic Newcastle disease virus (VVNDV). In the NVND group, positive signals were characteristically defined in the cytoplasm of neuron, vascular endothelial cells, and perivascular mononuclear macrophages in the central nervous system. One of NVND group, chicken from one farm exhibited positive signals in the bronchial epithelium. The VVND group chickens showed positive reaction in the macrophages, vascular endothelium, and bronchiolar epithelium. Markedly, viral nucleic acid was detected in the macrophages of morphologically normal tissues which were peripheral or located in distant areas from lesions. The central nervous system of chickens infected with VVND virus had positive signals in the vascular endothelial cell, perivascular mononuclear macrophages and some neuron. The number and intensity of the positive cells by in situ RT-PCR were more and stronger, respectively, in comparison with those by ISH. Particularly, positive reaction was detected in macrophages infiltrating in cardiac muscle by in situ RT-PCR, but not obtained by ISH. Therefore, these results demonstrated that ISH is a rapid diagnostic method for detection of NDV and in situ RT-PCR can be used as an efficient method for detection of low viral load infection or subclinical viral infection of NDV.

• Korean Journal of Veterinary Service
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• v.24 no.2
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• pp.147-159
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• 2001

This Study was conducted to determine vaccination programs for the control of Newcastle Disease(ND) in chickens and investigate protective effect against Newcastle disease virus (NDV) after live ND vaccination. Maternal HI antibody titer level of chickens according to day(age) 1, 7, 14, 21, 28 and 35 were decreased gradually as 7.10$\pm$0.74, 6.57$\pm$0.74, 3.71$\pm$1.25, 2.20$\pm$1.03, 1.20$\pm$1.23 and 0.50$\pm$0.71. As a result of HI test and ELISA, both chickens vaccinated with VG/GA strain live vaccine at 1-day-old and chickens not vaccinated do not have antibody titer for protection against NDV at 14-day-old. Except for LaSota strain vaccine, in case of vaccination with VG/GA spray and VG/GA, B1 and LaSota strain drinking water at 14-day-old, the protective effect was 100% in chickens inoculated NDV($10^{7.2}$ $EID_{50}$/50${\mu}\ell$, eye drop) at 21-day-old, but not 10～50% at 28-day-old. These data suggest that live NDV vaccination should be given at 10-day-old 20-25day-old for protect against NDV at periodic outbreaks of ND caused by velogenic viscerotropic NDV in the environment of a farm.

• 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.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2005.11a
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• pp.44-52
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• 2005

The study, using sequence analysis and phylogenetic relationship of the fusion protein gene, divided the Korean epizootic isolates of Newcastle disease virus (NDV) into several lineages to determine the molecular epidemiology of the virus. A 695 base pair fragment was amplified by polymerase chain reaction between matrix protein gene and fusion protein gene of 30 Korean NDV isolates, which were isolated from field outbreaks of Newcastle disease between 1949 and 2002. All isolates showed the amino acid sequence 112 R-R-Q/R-K-R116 at the C-terminus of the F2 protein and phenylalanine (F) at the N-terminus of the F1 protein, residue 117. These amino acid sequences were identical to a known virulent motif. The region of the F gene between nucleotides 47 and 435 was compared by phylogenetic analysis. Based on nucleotide sequence, the Korean NDV isolates belonged to genotype III, V, VI and VII corresponding to isolates in 1949, 1982 to 1984, 1988 to 1997, and 1995 to 2002, respectively. These data showed that genotypes of five Korean Newcastle disease epizootics had replaced each other serially (III, V, VI and VII) in chronological order. Further, the five Korean Newcastle disease epizootics were closely related with the Necastle disease panzootics or Newcastle disease epizootics in other countries. Present study showed that the Korean genotype V isolated before 1984 was related with European Newcastle disease epizootics in the 1970s, whereas the Korean genotype VI and VII isolated after 1988 were more closely related with Far East Newcastle disease epizootics, especially Newcastle disease3 epizootics in Japan, Taiwan and China. Since 1988, the genotype VI and VII of Far East origin were dominant in South Korea. That might be due to the increased trade of agricultural products including poultry among Far East Asian countries.