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Enumeration of cell-infecting particles of Newcastle disease virus by the fluorescent antibody technique.

A procedure has been developed for the determination of the concentration of infective Newcastle disease virus (NDV) based on the enumeration of singly infected and distributed HeLa cells which are visualized by staining with fluorescent antibody. Infective virus assayed by the fluorescent cell-counting procedure is expressed in terms of cell-infecting units (CIU). Adsorption of NDV to HeLa cell monolayers reached a plateau 1 to 1.5 hours after inoculation of coverslip cultures, and 12 per cent of the infective particles inoculated failed to adsorb. The half-life of NDV in protein-free Eagle's medium at 37 degrees C. was 2.1 hours. There was a linear relationship between virus concentration and the number of infected cells. The coefficient of variation of the mean of replicate determinations of infective NDV was 8.2 per cent. The distribution of single infected HeLa cells in the monolayer corresponded to the Poisson distribution. With NDV the cell-infecting unit (CIU) determined in HeLa cells is equivalent to the plaque-forming unit in chick embryo cells and the egg infective dose. In experiments on the mechanism of dissemination of NDV in monolayer cultures of HeLa cells, NDV was found to spread from cell to cell through the extracellular milieu.

Animals↗

The comparative antigenic characterization of Newcastle disease virus strains isolated in Kenya and Kazakhstan.

Twenty six Newcastle disease viruses--12 reference strains and 14 strains isolated in Kenya and Kazakhstan--were characterized by means of a large panel of 38 monoclonal antibodies (MAB) directed against all the three envelope proteins: matrix, hemagglutinin-neuraminidase and fusion. The essential distinctions were revealed between the viruses isolated in Kenya and Kazakhstan while the differences amongst the viruses belonging to the same local group were much smaller. The heterogeneity amongst the viruses isolated in Kenya was more expressed as compared to the Kazakhstanian strains.

Animals↗

Phylogenetic relationships among virulent Newcastle disease virus isolates from the 2002-2003 outbreak in California and other recent outbreaks in North America.

Isolates from the 2002-2003 virulent Newcastle disease virus (v-NDV) outbreak in southern California, Nevada, Arizona, and Texas in the United States were compared to each other along with recent v-NDV isolates from Mexico and Central America and reference avian paramyxovirus type 1 strains. Nucleotide sequencing and phylogenetic analyses were conducted on a 1,195-base genomic segment composing the 3' region of the matrix (M) protein gene and a 5' portion of the fusion (F) protein gene including the M-F intergenic region. This encompasses coding sequences for the nuclear localization signal of the M protein and the F protein cleavage activation site. A dibasic amino acid motif was present at the predicted F protein cleavage activation site in all v-NDVs, including the California 2002-2003, Arizona, Nevada, Texas, Mexico, and Central America isolates. Phylogenetic analyses demonstrated that the California 2002-2003, Arizona, Nevada, and Texas viruses were most closely related to isolates from Mexico and Central America. An isolate from Texas obtained during 2003 appeared to represent a separate introduction of v-NDV into the United States, as this virus was even more closely related to the Mexico 2000 isolates than the California, Arizona, and Nevada viruses. The close phylogenetic relationship between the recent 2002-2003 U.S. v-NDV isolates and those viruses from countries geographically close to the United States warrants continued surveillance of commercial and noncommercial poultry for early detection of highly virulent NDV.

Amino Acid Motifs↗

Newcastle disease outbreaks in fowl in Great Britain during 1984.

During February to July 1984, 23 outbreaks of Newcastle disease were confirmed in chickens in Great Britain. Use of available mouse monoclonal antibodies enabled unequivocal identification of the virus responsible for 22 of the outbreaks as similar to the avian paramyxovirus type 1 (A/PMV-1) virus causing neurotropic disease in pigeons during 1983 and 1984. Epidemiological investigations presented evidence that 19 of these outbreaks occurred either directly or indirectly as a result of spread from diseased pigeons infesting food stores at Liverpool docks. Virus was isolated from carcases of pigeons found among the food and samples of the food itself. The remaining outbreak was shown to involve a virus unrelated to the virus infecting pigeons.

Animals↗

An enzyme-linked immunosorbent assay that measures protective antibody levels to Newcastle disease virus in chickens.

An enzyme-linked immunosorbent assay (ELISA) was developed to measure antibodies to Newcastle disease virus (NDV) in chickens. Chickens 6 to 33 weeks old, with a variety of vaccination histories, were bled before challenge with a velogenic strain of NDV. Fourteen days post-challenge, 63 of the 73 challenged birds had survived. ELISA results of pre-challenge sera corresponded directly with survival rates of birds challenged with NDV.

Animals↗

Continued studies on the adjuvancy effect of natural and synthetic double-stranded RNA preparations with inactivated Newcastle disease vaccines in fowls.

The adjuvant effect of the natural ds-RNA, BRL 5907, with inactivated Newcastle disease vaccines was confirmed using different oil-based formulations and could be given either as single injections or separately at adjacent sites. A minimum dose level of 0-04 mg BRL 5907 per bird was required for a significant enhancement of antibody levels following vaccination. While the synthetic ds-RNA Poly IC gave a similar response to that observed with BRL 5907, no significant effects could be detected with two other natural ds-RNA materials.

Adjuvants, Immunologic↗

[Attempt to design a factorial model of Newcastle disease in poultry in Bulgaria for the period 1970-1979].

Literature data on the statistical methods relating to many objects (informational, factorial, clusteral, regressional, etc.) in the study of epizootic processes have shown that these methods could be employed to raise the quality of the epizootiologic analysis. An attempt has been made to build a factorial model for Newcastle disease in this country. Use has been made of a programme for factorial analysis, substantiated by a computer. The information is presented in the form of a matrix, containing 27 rows (the number of districts) and 15 columns (the number of indices). The latter include parameters of the epizootic processes as well as indices, characterizing the economic status of the individual districts. The factorial model has made it possible to state the correlations of a great number of measurable indices and through these to disclose 4 basic factors that cannot be measured directly which may largely contribute to the elucidation of the epizootic status. The concept has been confirmed that the character of the epizootic process with the Newcastle disease within the size of concrete territorial-and-administrative units (the districts) is determined to a great extent by the economic features of the districts. The programme used in the factorial analysis of Newcastle disease can be applied also to investigate the epizootic process with other infectious diseases of farm animals and birds along with the use of a computer and available information.

Animals↗

Latex immunoassay for rapid detection of Newcastle disease virus.

A rapid test has been developed based on the technique of latex immunoassay for the detection of Newcastle disease virus from suspected tissue suspensions. The latex particles were sensitised with globulins and were used for antigen detection. Of the 258 samples tested, 165 samples were positive by this kit which was compared for its efficacy with the standard OIE approved haemagglutination (HA) and haemagglutination inhibition (HI) tests. No significant difference (P > 0.05) was observed between the tests. The sensitivity and specificity of the developed test was 94.19% and 87.63% respectively.

Animals↗

[Characterization of a recombinant Listeria monocytogenes strain containing the fusion protein gene of Newcastle disease virus].

Homologous recombination was utilized for construction of a recombinant strain of L. monocytogenes carrying a gene from the Newcastle diseases virus by insertional mutation targeting its listeriolysin O gene (hly). The gene encoding fusion protein of the Newcastle disease virus (NDV-F) was used as the model heterologous gene. The F gene was inserted into hly downstream to its promoter and signal sequence by overlapping extension polymerase chain reaction, which was then subcloned into the shuttle plasmid pKSV7 for allelic exchange with L. monocytogenes chromosome. PCR amplification of the target genes indicated insertion of the F gene into the chromosome DNA of L. monocytogenes. RT-PCR showed transcription of F gene from the recombinant L. monocytogenes strain. Comparisons were then made between the recombinant strain and its wild parent strain in terms of the hemolytic activity, adhesion and invasiveness to cultured HeLa cells, virulence to mice and chicken embryos, and growth kinetics in broth medium as well as its stability upon repeated subculturing and serial passages in mice. The recombinant L. monocytogenes lost its hemolytic activity on the blood agar and had no hemolytic titer from its culture supernatants as compared with the titer of 24 in the supernatant from the wild parent strain. The recombinant strain also had lower adhesiveness (P > 0.05) and significantly lower relative invasiveness to the HeLa cells than its wild type strain (P < 0.05). Such insertional mutation resulted in reduced virulence, about 3.7 logs and 6.5 logs less than its parent strain L. monocytogenes 10403S as shown by the 50% lethal dose assays in the mouse and chicken embryonated egg models respectively. The recombinant strain was relatively stable as shown by amplification of the target gene NDV-F from its genomic DNA after subculturing in BHI broth or in mice for 5 times.

Animals↗

Efficacy of viable and inactivated Newcastle disease virus vaccines in turkeys.

Market turkeys spray-vaccinated at 20 days of age with viable Newcastle disease virus (NDV) vaccine and challenged 7 weeks postvaccination failed to yield NDV by tracheal swabbing 4 days postchallenge but demonstrated serologic evidence of infection. Birds vaccinated subcutaneously with inactivated oil-emulsion (OE) NDV vaccine had virologic and serologic evidence of infection. Breeder hens vaccinated by spray with commercial La Sota vaccine at 19 weeks of age and revaccinated subcutaneously with OE vaccine at 32 weeks of age had an adequate level of resistance against a drop in egg production but demonstrated serologic evidence of infection when challenged with velogenic NDV at 38 weeks of age.

Aerosols↗

Newcastle disease virus (NDV) vaccine based on immunization with avian cells expressing the NDV hemagglutinin-neuraminidase glycoprotein.

Newcastle disease virus (NDV) is a paramyxovirus that bears two envelope glycoproteins at the virion surface. These proteins, fusion and hemagglutinin-neuraminidase (HN), are involved in the immune response against NDV infection. Recombinant cells constitutively expressing at their surface the HN protein from the velogenic Texas strain were generated by introducing the HN gene with a helper-free AEV-based vector. These recombinant cells were used to immunize chickens by various protocols, and birds were subsequently challenged with a lethal NDV injection. Both NDV protection and serologic response were observed.

Animals↗

Isolation of the pigeon PMV-1 variant of Newcastle disease virus from imported pheasants (Phasianus colchicus).

Isolation of a virulent pigeon paramyxovirus 1 (PPMV-1) strain of Newcastle disease virus (NDV) from pheasants imported for release is reported. Although no clinical signs or postmortem lesions suggesting NDV infection were detected, the intestine was processed for attempted virus isolation as part of a surveillance programme on wild-bird populations. The potential role of pheasants as carriers of the disease, and the importance of developing surveillance programmes for wild bird populations is discussed.

Animals↗

An occurrence of Newcastle disease in pigeons: virological and serological studies on the isolates.

The antigenic and pathogenetic relationship between pigeon Newcastle disease virus (NDV) isolates during outbreaks of 1982 in Italy and reference pathogen and non-pathogen NDV-strains were investigated. The pigeon-isolates were slow-eluters and showed a thermostability at 56 degrees C of over 30 min. They proved to be lentogenic as measured by the mean-death-time in chicken-embryos, and between lentogenic and mesogenic as measured by the Hanson test. They failed to produce plaques in chicken-embryo-fibroblasts and showed high pathogenicity for experimentally infected pigeons, low-pathogenicity for quails and were not pathogenic for chickens. They were antigenically different from the LaSota strain as measured by the cross-HI-test and induced considerable seroconversion in inoculated animals. The existence of a lentogenic neurotropic pigeon-pathogenic strain was considered.

Animals↗

Response of turkeys to simultaneous vaccination with hemorrhagic enteritis and Newcastle disease viruses.

The effects of single and combined vaccination of turkeys against hemorrhagic enteritis virus (HEV) and Newcastle disease virus (NDV) were investigated. Dual vaccination of turkeys with NDV-B1 and HEVp30 or marble spleen disease virus (MSDV) enhanced white mottling of the spleens and the apoptosis rate in spleen cells (P < 0.05). In addition, simultaneously vaccinated turkeys had fewer HEV-infected spleen cells at 4 days postvaccination than turkeys given HEVp30 or MSDV alone. The anti-HEV antibody response was significantly reduced at 14 days postvaccination (P < 0.05), whereas the anti-NDV antibody response was enhanced (P < 0.05) in turkeys vaccinated with HEVp30 + NDV-B1. Further, the effect of dual vaccination on macrophage function was studied. Spleen cells from NDV-B1-vaccinated turkeys were primed to produce nitric oxide (NO) after stimulation in vitro with lipopolysaccharide. Spleen cells from HEVp30- or MSDV-vaccinated turkeys did not produce NO after in vitro stimulation. In dual-vaccinated turkeys, the priming effect of NDV-B1 was reduced in comparison with single-inoculated birds.

Adenoviridae Infections↗

Newcastle disease virus nucleocapsid protein: self-assembly and length-determination domains.

The nucleocapsid protein (NP) of Newcastle disease virus expressed in E. coli assembled as ring- and herringbone-like particles. In order to identify the contiguous NP sequence essential for assembly of these particles, 11 N- or C-terminally deleted NP mutants were constructed and their ability to self-assemble was tested. The results indicate that a large part of the NP N-terminal end, encompassing amino acids 1 to 375, is required for proper folding to form a herringbone-like structure. In contrast, the C-terminal end covering amino acids 376 to 489 was dispensable for the formation of herringbone-like particles. A region located between amino acids 375 to 439 may play a role in regulating the length of the herringbone-like particles. Mutants with amino acid deletions further from the C-terminal end (84, 98, 109 and 114 amino acids) tended to form longer particles compared to mutants with shorter deletions (25 and 49 amino acids).

Animals↗

Hemagglutinating and fusogenic activities of Newcastle disease virus: studies on receptor binding specificity and pH-induced conformational changes.

Vaccinal and wild strains of Newcastle Disease virus (NDV) were analyzed for cell receptor binding and fusogenic biological properties associated with their HN (hemagglutinin-neuraminidase) and F (fusion protein) surface structures respectively. The evaluation of the biological activities of HN and F was carried out respectively by determination of hemagglutinating titers and hemolysis percentages, using erythrocytes from various animal origins at different pH values. Significant differences in hemagglutination titers for some strains of NDV were detected, when interacting with goose, sheep, guinea-pig and human "O" group erythrocytes at neutral pH. Diversity of hemolysis percentages was observed between different NDV strains at acid pH. These analysis were developed to evaluate particular aspects of the actual influence of the receptor specificity and pH on the receptor binding and fusogenic processes of Newcastle Disease viruses.

Animals↗

Newcastle disease virus and Chlamydia psittaci in free-living raptors from eastern Germany.

Organ samples from free-living raptors from the federal states of Berlin and Brandenburg in eastern Germany were tested for Newcastle disease virus (NDV; n = 331) and Chlamydia psittaci (n = 39) by polymerase chain reaction (PCR). In 18 individuals NDV nucleic acids were detected. These samples originated from barn owls (Tyto alba; n = 15, 28%), tawny owl (Strix aluco; n = 1, 5%), common buzzard (Buteo buteo, n = 1, 1%), and European kestrel (Falco tinnunculus; n = 1, 4%). In 29 (74%) of 39 samples C. psittaci was detected. Chlamydia psittaci is common in free-living birds of prey in the investigated area.

Animals↗

INHIBITION OF RIBONUCLEIC ACID SYNTHESIS IN NEWCASTLE DISEASE VIRUS-INFECTED CELLS BY PUROMYCIN AND 6-AZAURIDINE.

Wilson, D. E. (Rensselaer Polytechnic Institute, Troy, N.Y.), and P. LoGerfo. Inhibition of ribonucleic acid synthesis in Newcastle disease virus-infected cells by puromycin and 6-azauridine. J. Bacteriol. 88:1550-1555. 1964.-Puromycin and 6-azauridine were used to inhibit protein and ribonucleic acid (RNA) synthesis during Newcastle disease virus replication. Viral RNA, measured by the incorporation of uridine-2-C(14), increased rapidly 6 to 7 hr after infection and reached a peak at 12 hr. Viral RNA synthesis was inhibited by puromycin added at the time of infection or at any time up to 4 hr after infection, but not thereafter. 6-Azauridine (3 mg/ml) inhibited over 90% of the viral RNA synthesis and inhibited protein synthesis to a small extent. Infected cells synthesized more viral RNA than did untreated controls when exposed to azauridine alone for 5 hr, followed by puromycin alone for 9 hr. It was concluded that immediately after virus infection, virus-specific proteins, which are necessary for viral RNA synthesis, were synthesized. Virus-specific protein synthesis may occur even when viral RNA synthesis is greatly inhibited. After virus-specific protein synthesis has taken place, viral RNA synthesis may take place when protein synthesis is almost totally inhibited.

Animals↗