• Korean Journal of Veterinary Service
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• v.26 no.3
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• pp.215-219
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• 2003

This study was conducted to investigate the similarity between hemagglutination inhibition (HI) test and enzyme-linked immunosorbent assay(ELISA) titers and sample to positive ratio (S/P ratio) of Newcastle disease(ND) virus. To perform this study, the 372 sera of broiler chicks and 120 sera of layers and breed chicks were collected from slaughter house and farms, respectively. As a result of HI test out of different chicks, the positive percentage of ND antibody titer of broiler, layer and breeder, when a standard positive HI titer were '2', was 84.4%, 100% and 100%, respectively. The positive percentage of ND antibody titer by ELISA was shown 38.4%, 100% and 100% and S/P ratio were also shown 81.5%, 98.2% and 99.2%, respectively. The results of comparative survey with same sera by two experimental methods were as follows; In low HI titer, ELISA titer was not similar to HI titer, but S/P ratio was similar to it. In high HI titer, ELISA titer was not similar to HI titer. Therefore, HI titer was more similar to S/P ratio than ELISA titer.

• Journal of Veterinary Science
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• v.23 no.4
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• pp.25.1-25.14
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• 2022

Background: The commercially available Newcastle disease (ND) vaccines were developed based on Newcastle disease virus (NDV) isolates genetically divergent from field strains that can only prevent clinical disease, not shedding of virulent heterologous virus, highlighting the need to develop genotype-matched vaccines Objectives: This study examined the efficacy of the NDV genotype-matched vaccine, mIBS025 strain formulated in standard vaccine stabilizer, and in carboxymethyl sago starch-acid hydrogel (CMSS-AH) following vaccination via an eye drop (ED) and drinking water (DW). Methods: A challenge virus was prepared from a recent NDV isolated from ND vaccinated flock. Groups of specific-pathogen-free chickens were vaccinated with mIBS025 vaccine strain prepared in a standard vaccine stabilizer and CMSS-AH via ED and DW and then challenged with the UPM/NDV/IBS362/2016 strain. Results: Chickens vaccinated with CMSS-AH mIBS025 ED (group 2) developed the earliest and highest Hemagglutination Inhibition (HI) NDV antibody titer (8log₂) followed by standard mIBS025 ED (group 3) (7log₂) both conferred complete protection and drastically reduced virus shedding. By contrast, chickens vaccinated with standard mIBS025 DW (group 5) and CMSS-AH mIBS025 DW (group 4) developed low HI NDV antibody titers of 4log₂ and 3log₂, respectively, which correspondingly conferred only 50% and 60% protection and continuously shed the virulent virus via the oropharyngeal and cloacal routes until the end of the study at 14 dpc. Conclusions: The efficacy of mIBS025 vaccines prepared in a standard vaccine stabilizer or CMSS-AH was affected by the vaccination routes. The groups vaccinated via ED had better protective immunity than those vaccinated via DW.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.3
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• pp.366-370
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• 2004

One hundred and sixty day-old Hainan chicks were randomly allotted into eight pens to investigate the effect of different dietary concentrations of chromium (Cr) in the form of chromium chloride, and different dosages of florfenicol on humoral immune responses by determining antibody titers to Newcastle disease (ND) vaccines using the hemagglutination inhibition test. The results indicated that ND antibody titers were significantly higher in chicks receiving Cr at low (5 mg/kg feed) and middle (10 mg/kg feed) dose compared with the control (p<0.01). However, ND antibody titers were significantly decreased in chicks receiving Cr at a high dosage of 500 mg/kg feed (p<0.01), though the ND antibody titers of the early days (d 21 and d 28 of age) were higher than that of the control group. It is suggested that excessive Cr intake has detrimental effects on ND antibody production in chicks. No significantly lower response was measured in chicks that received florfenicol at a low dosage of 50 mg/kg feed (p>0.05), but the ND antibody titers were significantly decreased in chicks receiving 200 and 400 mg/kg feed of the drug (p<0.01). The ND antibody titers of group receiving 200 mg/kg feed of florfenicol plus 10 mg/kg Cr were slightly higher than that of the group receiving single florfenicol of 200 mg/kg although, no significant differences were observed between these two treatments. It is suggested that the humoral immune response impaired by florfenicol (200 mg/kg feed) could not be significantly reversed by Cr (10 mg/kg feed).

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.539-549
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• 2004

Mean death time of inoculated embryonated egg is one of the methods to determine the virulence of the Newcastle disease viruses (NDV). Evaluation of tissue tropism of NDV in the host has been proposed as an another way to determine the pathogenicity of NDV based on the principal site of viral replication. To evaluate the tissue tropism among NDV, an immunohistochemistry(IHC) technique using monoclonal antibody was applied in one-day-old SPF chickens inoculated with different ND vaccine strains such as Ulster 2C, VG/GA and B1 viruses by eye drop instillation. The tissues used for this comparison were trachea, intestine, Harderian gland and cecal tonsil, which were collected at 0.5, 1, 2, 3, 5, 8, 10, 14 days post inoculation. Among test groups, chickens inoculated with B1 viurs, which is known to replicate in the respiratory system, have IHC positive staining mainly in the trachea and those inoculated with Ulster 2C have IHC positive staining mainly in the intestine. However, chickens inoculated with VG/GA strain have IHC positive staining in both the trachea and intestine. Therefore, a differences in tissue tropism among ND vaccine strains has been proved by the IHC technique. Based on this results, the IHC staining technique could be used to classify the NDV or to study the pathogenesis of NDV in chickens.

• Korean Journal of Poultry Science
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• v.37 no.1
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• pp.89-99
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• 2010

Newcastle disease (ND), caused by Newcastle disease virus (NDV), has caused periodic epidemics in Korea at an interval of 3 to 5 years until the early 2000s. At least five distinct genotypes of NDV have been responsible for epizootic episodes in Korea; genotype III virus (before the 1970s), genotype V (the mid-1980s), genotype VI (the late 1980s to early 1990s), genotype VIIa (the mid-1990s), and genotype VIId viruses (the late 1990s to present). Recent epidemic strains of NDV (VIId viruses) shared geographical features with neighboring countries such as China and Japan. These VIId viruses as well as genotypes III and V viruses were viscerotropic and highly virulent for chickens. Antigenic variation occurred between VIId field viruses and LaSota vaccine strain, as found in other epidemic strains in past in Korea. Nevertheless the commercial vaccine was considered to effectively protect vaccinated birds from mortality against VIId viruses as well as other viruses belonging to genotypes III and V.

• Korean Journal of Poultry Science
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• v.11 no.1
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• pp.49-64
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• 1984

During the 1978-79 Newcastle disease (ND) epizootic period, a detailed survey was conducted on the five representative farms which had been following one of the recommended vaccination programs. When the disease broke out during laying period, clinical symptoms were mild to moderate respiratory distress and greenish diarrhea. Affected flocks experienced weekly mortality from less than 1% to 17%. Egg production returned to normal 18 to 36 days after the initial signs appeared although some flocks never returned to normal. On postmortem examination,, most affected chickens showed severe hemorrhagic lesions in the duodenum, hematoma on ova, and heavy fat accmulation on various visceral organs. Most of the NO affected flocks had geometric mean hemagglutination inhibition antibody(HIA) titers of 7 log$_2$ or higher two to three weeks after the appearance of clinical signs. These HIA titers were at least 16-fold higher than those before infection. Flock mean HIA titers before infection were usually lower than 3 log$_2$. Severity of clinical signs and anamnestic antibody response were maximum in the flocks whose vaccination immunity was insufficient or waned considerably. Observations showed that even young birds, if properly vaccinated, could get effective protection from field ND exposure.

• Korean Journal of Veterinary Service
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• v.34 no.1
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• pp.19-29
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• 2011

Prevalence of major legal communicable diseases in chickens and ducks, which had occurred in Jeonbuk province from year 2004 to 2008. Total 283 farms 1,419,244 chickens and ducks have been affected by avian diseases. Specifically, fowl typhoid (FT) occurred in 92 farms 416,600 chickens, Marek's disease (MD) in 45 farms 145,563, duck virus hepatitis (DVH) in 31 farms 199,200, infectious bursal disease (IBD) in 27 farms 113,220, infectious bronchitis (IB) in 27 farms 280,300, low pathogenic avian influenza (LPAI) in 26 farms 78,495, avian mycoplasmosis in 16 farms 103,774, Newcastle disease (ND) occurred in 11 farms 61,052, avian encephalomyelitis (AE) in 7 farms 21,000, Pullorum disease (PD) occurred in 1 farm 40. According to total analysis about major legal communicable diseases, 1 species of first-class legal communicable diseases have occurred, 3 species of second-class and 6 species of third-class all adding up to 10 species. In the first-class diseases, Newcastle disease have occurred. Pullorum and fowl typhoid, duck virus hepatitis in the second-class have occurred and as third-class diseases, Marek's disease, Infectious bursal disease, Infectious bronchitis, avian mycoplasmosis, avian encephalomyelitis, low pathogenic avian influenza have occurred.

• Korean Journal of Veterinary Service
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• v.24 no.1
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• pp.21-29
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• 2001

To compare of serum antibody titers using ELISA and HI, serum samples were collected from 100 breeders and their progeny 550 broilers. The breeders and broilers were vaccinated with infectious bronchitis(IB)- and Newcastle disease(ND)-viruses according to general vaccination program. The antibodies in serum samples against IB and ND viruses were detected by enzyme-linked immunosorbent assay(ELISA) using commercial ELISA kit and hemagglutination inhibition(HI) test. Geometric mean titer(GMT) of ELISA and In titers were monitored from 1-day-old to 35-day-old broilers and compared to those of breeder chickens. The antibody titers of breeders vaccinated with ]B virus showed 47,800, ELISA and 7.2, HI, respectively. Progeny chicks, 1-day-old, vaccinated with IBV showed high antibody titers than those of breed chickens. Those chicks were maintained protective antibody levels until 11-day-old. From 14-day-old, the antibody level decreased below protective levels. In ND, breeders serum antibody titers ELISA and Eiu were 30,200 GMT and 8.7 HI titer, respectively. On 1-day-old chicks, antibody levels was decreased to half in ELISA(16,270) compared with those of breeders, but In titers was 7.4. Progeny broilers, protective antibody level was maintained until 14- day-old by ELISA, but at 11-day-old by HI titers. After then, ND antibody titer was continuously decreased underdefense level. These result indicated that the ELISA method be more sensitive than HI titration to detect serum antibody level for IBV and NDV.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.4
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• pp.543-547
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• 2004

Newcastle disease vaccine (NDV)-loaded chitosan microspheres (NDV-CM) were prepared. Stimulatory effects of these NDV-CM on antibody response compared to free NDV were examined in vitro and in vivo. In vitro stimulation of macrophages with virus vaccine resulted in higher number of cells compared to saline-treated control. Both NDV and NDV-CM induced secretion of interleukin-1 (IL-1) in dose dependent manner and the secretion of IL-1 by NDV-CM was delayed compared to free NDV. Irrespective of vaccine formulation, NDV subunit antigen was not effective in preventing mortality of the birds after challenge. However, CM loaded with NDV made of whole viron had antibody responses and protection similar to those shown by ND-K, a commercial inactivated oilemulsion vaccine.