Efficacy of live B1 or Ulster 2C Newcastle disease vaccines simultaneously vaccinated with inactivated oil adjuvant vaccine for protection of Newcastle disease virus in broiler chickens.
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Two hundred, one-day-old broiler chicks were divided into groups 1, 2 and 3 containing 60, 70 and 70 chicks, respectively. The groups were divided into subgroups of 10 chicks that were vaccinated according to the following scheme: group 1 unvaccinated control, group 2 vaccinated subcutaneously at 1 day old with inactivated oil adjuvant vaccine (IOAV) in combination with live B1 vaccine. Group 3 was vaccinated in the same mode as group 2 with IOAV and live Ulster 2C vaccine. All birds were challenged when they were 28 days old. Mortality rate, body weight gain and feed conversion ratio (FCR) were monitored before and after challenge. All the chickens in group 1 died, indicating that there was no disease resistance of this unvaccinated control group of chickens. Conversely, the monitored disease resistance of chickens in groups 2 and 3 was 68.57% +/- 18.64 and 88.57% +/- 9.00, respectively (P < 0.05). The morbidity of chickens in groups 2 and 3 was 37.89% +/- 14.36 and 14.76% +/- 12.40, respectively (P < 0.05). The body weight gain, feed intake and FCR of group 3 were significantly better than those of group 2 (P < 0.05) during 1-42 days old. The simultaneous vaccination with B1 or Ulster 2C and IOAV of 1-day-old chicks gave some protection of 28-day-old broilers without a booster vaccination. (+info)
Experimental pathogenesis for chickens, turkeys, and pigeons of exotic Newcastle disease virus from an outbreak in California during 2002-2003.
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Exotic Newcastle disease virus (NDV) isolated from chickens during the 2002-2003 California outbreak (CA exotic Newcastle disease [END] virus) was inoculated into 4-week-old specific-pathogen-free (SPF) White Leghorn chickens, 3-week-old SPF Beltsville White turkeys, 6-week-old commercial Broad Breasted White turkeys, and 10- to 20-week-old racing pigeons, and the clinicopathologic features of disease were compared. Birds were monitored clinically and euthanized sequentially with collection of tissues. Tissues were examined by histopathology, by immunohistochemistry to detect viral nucleoprotein, and by in situ hybridization to detect viral mRNA. Clinically, infected chickens and SPF turkeys showed severe depression, and all died or were euthanized because of severe clinical signs by day 5 postinoculation. In these birds, histologic lesions were widespread and virus was detected in multiple organs. All infected commercial turkeys showed mild depression, and incoordination was observed in some birds. Histologic lesions were mild, and viral distribution was limited. In pigeons, only 1 bird showed overt clinical disease, and histologic lesions and viral distribution were present in limited organs. Consequently, susceptibility to highly virulent NDV was shown to vary among chickens, SPF turkeys, commercial turkeys, and pigeons. Additionally, we have evidence of CA END virus subclinical infections that suggest pigeons could be subclinical carriers of other virulent NDV. (+info)
Effect of probe-site mismatches on detection of virulent Newcastle disease viruses using a fusion-gene real-time reverse transcription polymerase chain reaction test.
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Virulent forms of Newcastle disease virus (NDV) are a major concern for poultry producers around the world and the rapid diagnosis of an outbreak is crucial to any control program. A validated real-time reverse transcription-PCR test (fusion test) directed at the fusion-cleavage site of NDV was developed to differentiate virulent Newcastle disease virus strains from those of low virulence, however one virulent isolate, Dove/Italy/2736/2000, escaped detection during the initial evaluation of the test. The objectives of this study were to determine how this isolate differed from other detectable isolates, to identify other isolates that may fail detection, and to characterize the effect of specific probe-site mutations on the fusion test at a range of annealing temperatures. Using a virulent NDV isolate (Game fowl/US(CA)/2002) as a backbone that has 100% identity to the fusion-test probe, specific changes were made to the fusion-test probe-site to reflect the unique mismatches found in Dove/Italy/2736/2000 and other selected regions of the probe. Mutated clones with mismatches unique to Dove/Italy/2736/2000 at positions 6, 13, and 14 were not detected until annealing temperatures were lowered to 50 degrees C. Those detected at 58 degrees C contained 1-2 mismatches (position 1 and 6, 13 and 14, or 14 only) although increased cycle threshold values compared to the parent clone indicated decreased sensitivity. Data from this study predicts that the fusion test may fail to detect some viruses among lineage 4b and potential solutions to identify this subset of viruses include lowering the annealing temperature or modifying the probe. (+info)
Characterization of class I Newcastle disease virus isolates from Hong Kong live bird markets and detection using real-time reverse transcription-PCR.
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Newcastle disease viruses isolated from Hong Kong live bird markets (LBMs) were not detected by a USDA-validated matrix gene real-time reverse transcription-PCR (RT-PCR) assay. Based upon phylogenetic analysis of the fusion gene, these viruses were related to lentogenic class I viruses found in U.S. LBMs and wild waterfowl. An alternative real-time RT-PCR assay which complements the matrix gene assay was developed to efficiently detect class I viruses. (+info)
Detection of Newcastle disease virus RNA by reverse transcription-polymerase chain reaction using formalin-fixed, paraffin-embedded tissue and comparison with immunohistochemistry and in situ hybridization.
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The usefulness of reverse transcription-polymerase chain reaction (RT-PCR) from formalin-fixed, paraffin-embedded (FFPE) tissues was examined and compared to the immunohistochemistry (IHC) and in situ hybridization (ISH) assays for detection of Newcastle disease virus (NDV). Spleen and lung tissues were collected from chickens experimentally infected with either of 2 NDV isolates: a low virulent virus (LaSota) and a virulent virus (from the 2002-2003 California outbreak). The tissues were harvested immediately postmortem and fixed in 10% neutral buffered formalin for approximately 52 hours. Also, just before euthanasia, oral and cloacal swabs were collected for virus isolation. RNA was obtained from the FFPE tissues by digestion with proteinase K and subsequent extraction with phenol, chloroform, and isoamyl alcohol. By seminested RT-PCR with primers for the NDV matrix gene, a 232-base pair (bp) product was generated and visualized by electrophoresis. The results of PCR were compared to those of IHC for viral nucleoprotein and ISH for matrix gene (850 bp) on 3-microm sections and to those of virus isolation from swabs. All samples from infected chickens were positive by RT-PCR, including samples that were negative by both IHC and ISH. The RT-PCR positives included tissue from chickens that were no longer shedding virus detectable by virus isolation. The RT-PCR was an effective and sensitive method to detect NDV in FFPE tissues. To the authors' knowledge, this is the first report of NDV detection in FFPE tissues as a diagnostic approach possibly suitable for archival materials. (+info)
Survival of avirulent thermostable Newcastle disease virus (strain I-2) in raw, baked, oiled, and cooked white rice at ambient temperatures.
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Raw white rice has not been considered a good carrier for oral vaccination, probably because of its antiviral activity. Methods are required to overcome antiviral activity in raw white rice. This study was carried out to determine the effects of various treatments of raw white rice on the survival of strain I-2 of Newcastle disease virus. These included cooking and baking the rice or mixing the rice with vegetable oil prior to coating with vaccine virus. The vaccine-coated rice was then stored for 30 min and 24 h, followed by quantitative recovery of the virus. Thirty min after mixing, uncooked, cooked, and baked rice, and rice mixed with vegetable oil showed titers of 10(6.2), 10(7.2), 10(6.6), and 10(7.0) EID(50)/0.1 ml, respectively. After storage for 24 h at 22-25oC, the titers dropped to 10(5.0), 10(6.5), 10(5.0), and 10(6.0) EID(50)/0.1 ml for uncooked, cooked, baked, and oiled rice, respectively. (+info)
Isolation of avian paramyxovirus 1 from a patient with a lethal case of pneumonia.
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An unknown virus was isolated from a lung biopsy sample and multiple other samples from a patient who developed a lethal case of pneumonia following a peripheral blood stem cell transplant. A random PCR-based molecular screening method was used to identify the infectious agent as avian paramyxovirus 1 (APMV-1; a group encompassing Newcastle disease virus), which is a highly contagious poultry pathogen that has only rarely been found in human infections. Immunohistochemical analysis confirmed the presence of APMV-1 antigen in sloughed alveolar cells in lung tissue from autopsy. Sequence from the human isolate showed that it was most closely related to virulent pigeon strains of APMV-1. This is the most completely documented case of a systemic human infection caused by APMV-1 and is the first report of an association between this virus and a fatal disease in a human. (+info)
Phylogenetic diversity among low-virulence newcastle disease viruses from waterfowl and shorebirds and comparison of genotype distributions to those of poultry-origin isolates.
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Low-virulence Newcastle disease viruses (loNDV) are frequently recovered from wild bird species, but little is known about their distribution, genetic diversity, or potential to cause disease in poultry. NDV isolates recovered from cloacal samples of apparently healthy waterfowl and shorebirds (WS) in the United States during 1986 to 2005 were examined for genomic diversity and their potential for virulence (n = 249). In addition 19 loNDV isolates from U.S. live bird markets (LBMs) were analyzed and found to be genetically distinct from NDV used in live vaccines but related to WS-origin NDV. Phylogenetic analysis of the fusion protein identified nine novel genotypes among the class I NDV, and new genomic subgroups were identified among genotypes I and II of the class II viruses. The WS-origin viruses exhibited broad genetic and antigenic diversity, and some WS genotypes displayed a closer phylogenetic relationship to LBM-origin NDV. All NDV were predicted to be lentogenic based upon sequencing of the fusion cleavage site, intracerebral pathogenicity index, or mean death time in embryo assays. The USDA real-time reverse transcription-PCR assay, which targets the matrix gene, identified nearly all of the class II NDV tested but failed to detect class I viruses from both LBM and WS. The close phylogenetic proximity of some WS and LBM loNDV suggests that viral transmission may occur among wild birds and poultry; however, these events may occur unnoticed due to the broad genetic diversity of loNDV, the lentogenic presentation in birds, and the limitations of current rapid diagnostic tools. (+info)