Showing papers on "Newcastle disease published in 2007"
TL;DR: NDV vaccines formulated to be phylogenetically closer to potential outbreak viruses may provide better ND control by reducing virus transmission from infected birds.
271 citations
TL;DR: The results indicate that recombinant NDV is suitable as a bivalent live attenuated vaccine against both NDV and AIV infection in poultry and may also have potential use in high-risk human individuals to control the pandemic spread of lethal avian influenza.
Abstract: H5N1 highly pathogenic avian influenza virus (HPAIV) has continued to spread and poses a significant threat to both animal and human health. Current influenza vaccine strategies have limitations that prevent their effective use for widespread inoculation of animals in the field. Vaccine strains of Newcastle disease virus (NDV), however, have been used successfully to easily vaccinate large numbers of animals. In this study, we used reverse genetics to construct a NDV that expressed an H5 subtype avian influenza virus (AIV) hemagglutinin (HA). Both a wild-type and a mutated HA open reading frame (ORF) from the HPAIV wild bird isolate, A/Bar-headed goose/Qinghai/3/2005 (H5N1), were inserted into the intergenic region between the P and M genes of the LaSota NDV vaccine strain. The recombinant viruses stably expressing the wild-type and mutant HA genes were found to be innocuous after intracerebral inoculation of 1-day-old chickens. A single dose of the recombinant viruses in chickens induced both NDV- and AIV H5-specific antibodies and completely protected chickens from challenge with a lethal dose of both velogenic NDV and homologous and heterologous H5N1 HPAIV. In addition, BALB/c mice immunized with the recombinant NDV-based vaccine produced H5 AIV-specific antibodies and were completely protected from homologous and heterologous lethal virus challenge. Our results indicate that recombinant NDV is suitable as a bivalent live attenuated vaccine against both NDV and AIV infection in poultry. The recombinant NDV vaccine may also have potential use in high-risk human individuals to control the pandemic spread of lethal avian influenza.
265 citations
TL;DR: 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 lo NDV, the lentogenic presentation in birds, and the limitations of current rapid diagnostic tools.
Abstract: 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.
225 citations
TL;DR: 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-PCRs) assay, and were related to lentogenic class I viruses found in U.S. LBMs and wild waterfowl.
Abstract: 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.
135 citations
TL;DR: Newcastle disease virus has the potential for further development as a pretested, highly attenuated, intranasal vector to be available for expedited vaccine development for humans, who generally lack preexisting immunity against NDV.
Abstract: The international outbreak of the severe acute respiratory syndrome-associated coronavirus (SARS-CoV) in 2002-2003 highlighted the need to develop pretested human vaccine vectors that can be used in a rapid response against newly emerging pathogens. We evaluated Newcastle disease virus (NDV), an avian paramyxovirus that is highly attenuated in primates, as a topical respiratory vaccine vector with SARS-CoV as a test pathogen. Complete recombinant NDV was engineered to express the SARS-CoV spike S glycoprotein, the viral neutralization and major protective antigen, from an added transcriptional unit. African green monkeys immunized through the respiratory tract with two doses of the vaccine developed a titer of SARS-CoV-neutralizing antibodies comparable with the robust secondary response observed in animals that have been immunized with a different experimental SARS-CoV vaccine and challenged with SARS-CoV. When animals immunized with NDV expressing S were challenged with a high dose of SARS-CoV, direct viral assay of lung tissues taken by necropsy at the peak of viral replication demonstrated a 236- or 1,102-fold (depending on the NDV vector construct) mean reduction in pulmonary SARS-CoV titer compared with control animals. NDV has the potential for further development as a pretested, highly attenuated, intranasal vector to be available for expedited vaccine development for humans, who generally lack preexisting immunity against NDV.
135 citations
TL;DR: The titers of neutralizing antibodies achieved in this study suggest that the vaccine would be likely to prevent mortality and reduce morbidity caused by the H5N1 HPAIV, and is a candidate for clinical evaluation in humans.
Abstract: The ongoing outbreak of highly pathogenic avian influenza virus (HPAIV) in birds, the incidence of transmission to humans with a resulting high mortality rate, and the possibility of a human pandemic warrant the development of effective human vaccines against HPAIV. We developed an experimental live-attenuated vaccine for direct inoculation of the respiratory tract based on recombinant avian Newcastle disease virus (NDV) expressing the hemagglutinin (HA) glycoprotein of H5N1 HPAIV (NDV-HA). Expression of the HPAIV HA gene slightly reduced NDV virulence, as evidenced by the increased mean embryo death time and reduced replication in chickens. NDV-HA was administered to African green monkeys in two doses of 2 × 10 7 infectious units each with a 28-day interval to evaluate the systemic and local antibody responses specific to H5N1 HPAIV. The virus was shed only at low titers from the monkeys, indicative of safety. Two doses of NDV-HA induced a high titer of H5N1 HPAIV-neutralizing serum antibodies in all of the immunized monkeys. Moreover, a substantial mucosal immunoglobulin A response was induced in the respiratory tract after one and two doses. The titers of neutralizing antibodies achieved in this study suggest that the vaccine would be likely to prevent mortality and reduce morbidity caused by the H5N1 HPAIV. In addition, induction of a local immune response in the respiratory tract is an important advantage that is likely to reduce or prevent transmission of the virus during an outbreak or a pandemic. This vaccine is a candidate for clinical evaluation in humans.
97 citations
TL;DR: It is revealed that genotype VIId was the major NDV strain responsible for the 2005 ND epizoonosis that occurred in China.
86 citations
TL;DR: A HN gene exchange alone within the context of the NDV Anhinga backbone failed to increase virus virulence from mesogenic to velogenic pathotype and suggests a multigenic role for NDV pathogenicity.
68 citations
TL;DR: Investigation of the immunoadjuvant effects of CpG ODN to Newcastle disease (ND) vaccine and its protective effects against ND virus in SPF chicken demonstrated that the immune responses were significantly stronger in chickens that received Cpg ODN than in the birds that received only ND vaccine.
63 citations
TL;DR: The antigenicity of KBNP-4152 was distinct from La Sota, and the expected genome size was 15,192 nt, as was the case with other recent virulent ND viruses analyzed.
Abstract: In Korea, extensive Newcastle disease (ND) vaccine programs have been implemented, but ND outbreaks continue to occur occasionally, even in well-vaccinated farms. KBNP-4152 is a virulent ND virus, which has been isolated from vaccinated chickens in Korea. In this study, we conducted a comparison of the antigenicity of KBNP-4152 with that of a vaccine strain, La Sota, via virus-neutralization (VN) and cross haemagglutination-inhibition (HI) tests, and analyzed the genomic sequences. The antigenicity of KBNP-4152 was distinct from La Sota, and the expected genome size was 15,192 nt, as was the case with other recent virulent ND viruses analyzed. Based on the partial F gene, the strain was phylogenetically classified into the VIId genotype, but was distinct from other VII viruses due to amino acid changes at (E347K) and proximal to (M354K), the major linear epitope of HN, as well as relatively low amino acid similarity of the V protein, and a truncated W protein (203 aa vs. 227 aa). Therefore, KBNP-4152 is unique among genotype VII.
46 citations
TL;DR: Rescued a highly virulent NDV isolated from a goose using the reverse genetics approach and the recombinant NDV was indistinguishable from the parental wild-type virus with respect to its growth kinetics in cell culture as well as its biological properties.
Abstract: Newcastle disease virus (NDV) is a pathogen that is important in the poultry industry worldwide. Specifically, the virulent (velogenic) NDV is a particular threat because it has now occurred frequently worldwide. The outbreaks caused by highly virulent NDV in waterfowl and especially in goose flocks, have led to greater concern in recent years as aquatic birds were previously resistant to most virulent NDV strains from chickens. The molecular determinants of host tropism, virulence and emergence of NDV isolated from diseased goose flocks are poorly understood. In the present study, we rescued a highly virulent NDV isolated from a goose using the reverse genetics approach. Infectious virus was successfully generated by cotransfection of a full-length cDNA clone of the NDV strain ZJ1 with helper plasmids. The recombinant NDV was indistinguishable from the parental wild-type virus with respect to its growth kinetics in cell culture as well as its biological properties. A recombinant NDV expressing green fluorescent protein (GFP) was generated, and GFP was subsequently detected in cells and various organs from the infected chickens.
TL;DR: Oral immunization with HN-transgenic tobacco provides a potential means of protecting chickens from NDV and further modified animal experiments would be needed to increase the immunity of HN by co-administration of classical adjuvants or other trials.
Abstract: Newcastle disease is one of the most important pathogens of domestic poultry including chickens. The hemagglutinin-neuraminidase (HN) of Newcastle disease virus is the principal target of neutralizing and protective antibodies against Newcastle disease. In this paper, we transformed tobacco plants with Agrobacterium tumefaciens EHA105 to generate the plants expressing HN of Newcastle disease virus (NDV). The insertion and copy numbers of HN gene in the genomic DNA of phosphinothricin-resistant plants were confirmed by PCR and Southern blot, respectively. The presence of the HN-specific transcript in the total RNAs of the leaves of transgenic plants was verified by Northern analysis. The recombinant HN proteins were detected by Western blot analysis using a polyclonal antibody against GST–HN fusion proteins. The highest level of expression of HN in leaves of transgenic plants was approximately 0.069% of the total soluble protein. ELISA assay showed that the recombinant protein extracted from transformants has normal immunoactivity. Transgenic tobacco expressing HN of NDV with sterilized PBS was fed to 6-week-old chickens. Immunized chickens developed slightly high titers of anti-HN serum IgG compared with those of the wild type plant. These results suggest that oral immunization with HN-transgenic tobacco provides a potential means of protecting chickens from NDV. Further modified animal experiments would be needed to increase the immunity of HN by co-administration of classical adjuvants or other trials.
TL;DR: 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.
Abstract: 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.
TL;DR: This is the first report of the presence of influenza A virus and NDV in wild birds in the English-speaking Caribbean.
Abstract: Zoonotic transmission of an H5N1 avian influenza A virus to humans in 2003-present has generated increased public health and scientific interest in the prevalence and variability of influenza A viruses in wild birds and their potential threat to human health. Migratory waterfowl and shorebirds are regarded as the primordial reservoir of all influenza A viral subtypes and have been repeatedly implicated in avian influenza outbreaks in domestic poultry and swine. All of the 16 hemagglutinin and nine neuraminidase influenza subtypes have been isolated from wild birds, but waterfowl of the order Anseriformes are the most commonly infected. Using 9-to-11-day-old embryonating chicken egg culture, virus isolation attempts were conducted on 168 cloacal swabs from various resident, imported, and migratory bird species in Barbados during the months of July to October of 2003 and 2004. Hemagglutination assay and reverse transcription-polymerase chain reaction were used to screen all allantoic fluids for the presence of hemagglutinating agents and influenza A virus. Hemagglutination positive-influenza negative samples were also tested for Newcastle disease virus (NDV), which is also found in waterfowl. Two influenza A viruses and one NDV were isolated from Anseriformes (40/168), with isolation rates of 5.0% (2/40) and 2.5% (1/40), respectively, for influenza A and NDV. Sequence analysis of the influenza A virus isolates showed them to be H4N3 viruses that clustered with other North American avian influenza viruses. This is the first report of the presence of influenza A virus and NDV in wild birds in the English-speaking Caribbean.
TL;DR: In this article, the authors describe the differential immune response to virulent Newcastle disease virus (NDV) in birds differing in cell-mediated immunity, as measured by response to phytohaemagglutinin-P.
Abstract: This paper describes for the first time the differential immune response to virulent Newcastle disease virus (NDV) in birds differing in cell-mediated immunity, as measured by response to phytohaemagglutinin-P. To explore potential host-pathogen interactions, peripheral blood mononuclear cells (PBMC) were collected from 40 extreme responder birds (20 birds each from high and low cell-mediated immunity lines). PBMC cultures were stimulated by virulent NDV and temporal expression profiles of interferon-gamma (IFN-gamma), and inducible nitric oxide synthase (iNOS) mRNA was evaluated by semiquantitative reverse transcription polymerase chain reaction (PCR). To further explore the correlation of iNOS mRNA expression and nitric oxide (NO) production, we assayed the culture supernatants for NO. NO production, as well as iNOS and IFN-gamma mRNA expression, was significantly (P < 0.05) higher in the line with higher cell-mediated immunity. In our study, a significant (P < 0.05) difference was observed between the lines for IFN-gamma promoter polymorphism for the TspEI site. The high cell-mediated immunity line mostly revealed the genotype (GG) with a 168-bp fragment. On the other hand, this genotype was not predominant in the low cell-mediated immunity line. Later, quantitative real-time PCR demonstrated higher (P < 0.01) IFN-gamma mRNA transcription in the genotype GG in response to NDV. This difference in promoter region may be responsible for differential IFN-gamma mRNA transcription in chicken lines. Furthermore, birds of high cell-mediated immunity line showed better adaptive immunity to booster NDV vaccination as revealed by an enhanced antibody titre. Thus, this study provides baseline data on the effect of phytohaemagglutinin-P response-based selection on immune responses to virulent NDV and the data could be of immense importance to poultry geneticist and immunologist attempting to breed poultry for disease resistance.
TL;DR: It is concluded that monensin and salinomycin augment the anti-NDV and anti-ADV immune responses in broiler chickens, which supports their use in poultry flocks.
Abstract: Immunization against Angara disease virus (ADV), a serotype 4 avian adenovirus, and Newcastle disease virus (NDV), an avian paramyxovirus serotype 1, is the mainstay of a broiler vaccination programme, while polyether ionophores usually form an essential component of a broiler medication programme in most parts of India and Pakistan. The role of polyether ionophores in the protective immune responses of broiler chickens vaccinated and challenged with ADV and NDV was investigated. A total of 1600 birds were divided into eight groups of 200 birds each. First four groups were vaccinated against NDV and ADV, while the remaining four served as unvaccinated controls. The first 3 groups of birds were administered salinomycin, monensin and cyclophosphamide (CYP), respectively. The last group served as an untreated control. The same treatment schedule was also followed for the next four unvaccinated groups. The post-vaccination and post-challenge serological responses to NDV and ADV, body and lymphoid organ weight gains, post-challenge survival rate and detection of NDV and ADV in the tissues of infected birds were evaluated. Birds administered salinomycin showed a significant stimulation of protective immune responses against both NDV and ADV as compared to the untreated and CYP-treated birds. Monensin also enhanced the protective immune responses against both viruses but the effect was not statistically significant. Thus, it is concluded that monensin and salinomycin augment the anti-NDV and anti-ADV immune responses in broiler chickens, which supports their use in poultry flocks.
TL;DR: The developed dRT‐PCR assay is a rapid, cost‐effective tool, which provides powerful novel means for the early diagnosis of avian influenza and Newcastle disease.
Abstract: Summary
A duplex reverse transcription-polymerase chain reaction (dRT-PCR) assay has been developed for the simultaneous, rapid and specific detection/discrimination of avian influenza virus (AIV) and Newcastle disease virus (NDV). Primers targeting the matrix protein gene (M) of AIV and the fusion protein gene (F) of NDV were evaluated experimentally with 13 AIV and 19 NDV strains. PCR products of the expected size of 144 bp and 316 bp were amplified from AIV/NDV samples, respectively, while no cross-reaction was observed with negative controls or with 16 other avian pathogens. The endpoint of detection was defined as approximately 10+0.5 50% egg infectious dose (EID50)/0.2 ml for AIV and 10+2.2 EID50/0.2 ml for NDV. The assay was able to detect AIV/NDV with similar sensitivity in spiked stool samples and in specimens from vaccinated birds. The developed dRT-PCR assay is a rapid, cost-effective tool, which provides powerful novel means for the early diagnosis of avian influenza and Newcastle disease.
TL;DR: Isolated Newcastle disease virus demonstrated identical monoclonal antibody binding profiles as well as 99% sequence homology in the 635-bp fusion gene sequence compared with ENDV recovered from infected commercial egg layer poultry during the 2002 outbreak.
Abstract: Flies were collected by sweep net from the vicinity of two small groups of "backyard" poultry (10-20 chickens per group) that had been identified as infected with exotic Newcastle disease virus (family Paramyxoviridae, genus avulavirus, ENDV) in Los Angeles County, CA, during the 2002-2003 END outbreak. Collected flies were subdivided into pools and homogenized in brain-heart infusion broth with antibiotics. The separated supernatant was tested for the presence of ENDV by inoculation into embryonated chicken eggs. Exotic Newcastle disease virus was isolated from pools of Phaenicia cuprina (Wiedemann), Fannia canicularis (L.), and Musca domestica L., and it was identified by hemagglutination inhibition with Newcastle disease virus antiserum. Viral concentration in positive pools was low (<1 egg infectious dose50 per fly). Isolated virus demonstrated identical monoclonal antibody binding profiles as well as 99% sequence homology in the 635-bp fusion gene sequence compared with ENDV recovered from infected commercial egg layer poultry during the 2002 outbreak.
TL;DR: The present results suggest that the CEF-adapted NDV, which is avirulent, is circulating among waterfowl populations.
Abstract: A field isolate of Newcastle disease virus (NDV) isolated from northern pintail (Anas acuta) in Tohoku district, northeast Japan, was characterized. Phylogenetic analysis of the fusion protein indicated that the isolate belonged to genotype I and was closely related to isolates from the Far East corresponded to the migration route for this bird species. The isolate had the typical avirulent cleavage site of the fusion protein 112GKQGR*L117. In addition, pathogenicity tests indicated the isolate to have avirulent characteristics. However, the isolate has been shown to cause fusion cytopathic effects and form plaques on chicken embryo fibroblasts (CEF) in the absence of trypsin. The present results suggest that the CEF-adapted NDV, which is avirulent, is circulating among waterfowl populations.
TL;DR: It is demonstrated that the synergistic effects of provax-chIFN-gamma plus LMS as the adjuvants in NDV DNA vaccination could be used to improve protective efficacy in chickens.
Abstract: Both humoral and cell-mediated immune responses are important to protect animals from initial acute viral infection and establishment of chronic infection. Adjuvants for DNA vaccines can influence the balance between humoral and cell-mediated immunities. In this study, a DNA vaccine encoding the hemagglutinin–neuraminidase and fusion genes of Newcastle disease virus (NDV) incorporated with chicken interferon(provax-chIFN-γ) cDNA as a molecular adjuvant and levamisole (LMS) as a chemical adjuvant was tested for its efficacy in protection against NDV lethal challenge. Compared with DNA vaccine alone, the DNA vaccine with provax-chIFN-γ plus LMS induced significantly higher humoral and cell-mediated responses, as shown by higher levels of hemagglutination inhibition (HI) titers and T cell proliferation. In addition, the DNA vaccine with provax-chIFN-γ plus LMS formulation increased the expression of IFN-γ, interleukin (IL)-2, IL-4, IL-12, and IL-13, suggesting that the effectiveness of the IFN-γ and LMS form...
TL;DR: Interference with NDV replication was not reflected in a reduction in Newcastle disease challenge of immunity findings when combination Mass + NDV products manufactured by vaccine companies were tested.
Abstract: The potential for infectious bronchitis virus (IBV) and Newcastle disease virus (NDV) replication interference was evaluated using quantitative reverse transcription–polymerase chain reaction (qRT-PCR). Fourteen-day-old broiler chickens were inoculated via eyedrop with live commercial vaccine strains of IBV and NDV alone or in combination to directly evaluate IBV and NDV replication in the trachea at 1, 3, and 5 days after vaccination. Commercial NDV vaccine strains used were B1, VG/GA, and C2. The vaccine strains of IBV tested were Massachusetts (Mass) and Arkansas (Ark). The NDV + Mass vaccines used were commercially manufactured combined products. The NDV + Ark vaccines used were commercial vaccines manufactured as single entity products that were administered by eyedrop to opposite eyes of each chicken. As measured by qRT-PCR, the replication of NDV strains B1, VG/GA, and C2 did not interfere with the growth of IBV Mass and Ark strain vaccines in the combined vaccine treatment groups. Combina...
Dissertation•
20 Jun 2007
TL;DR: The high incidence of infectious laryngotracheitis virus (ILTV), the high correlation between the observed clinical signs and the ILTV detection, and the results of differential diagnosis demonstrated that ILTV was the causative agent of the outbreak of respiratory disease observed in Bastos region, Sao Paulo, Brazil.
Abstract: Trachea, lung, and conjunctive samples from 51 commercial layer farms from Bastos region, Sao Paulo, Brazil, were submitted to nested-PCR and virus isolation in SPF chicken embryos for ILT diagnosis. This region experienced an outbreak characterized by respiratory signs, decrease in egg production and increased mortality. Out of the 51 tested field samples, 23 were positive for ILT by nested-PCR, 22 were positive after the virus isolation, and 24 were positive when both techniques were used. Newcastle disease virus, Avian pneumovirus, or Mycoplasma gallisepticum were not detected. Infectious bronchitis virus was detected in one farm and Mycoplasma synoviae was detected in eight farms. The high incidence of infectious laryngotracheitis virus (ILTV) detection, the high correlation between the observed clinical signs and the ILTV detection, and the results of differential diagnosis demonstrated that ILTV was the causative agent of the outbreak of respiratory disease observed in Bastos region, Sao Paulo, Brazil.
TL;DR: For the first time, it is demonstrated that the NDV vaccine had an interfering effect with the pathogenesis of the intermediate as well as the intermediate plus IBDV vaccine.
Abstract: SUMMARY. Different infectious bursal disease virus (IBDV) live vaccines (intermediate, intermediate plus) were compared for their immunosuppressive abilities in specific-pathogen-free (SPF) layer-type chickens or commercial broilers. The Newcastle disease virus (NDV) vaccination model was applied to determine not only IBDV-induced immunosuppression but also bilateral effects between IBDV and NDV. None of the IBDV vaccines abrogated NDV vaccine–induced protection. All NDV-vaccinated SPF layers and broilers were protected against NDV challenge independent of circulating NDV antibody levels. Sustained suppression of NDV antibody development was observed in SPF layers, which had received the intermediate plus IBDV vaccine. We observed a temporary suppression of NDV antibody development in broilers vaccinated with one of the intermediate, as well as the intermediate plus, IBDV vaccines. Different genetic backgrounds, ages, and residual maternal antibodies might have influenced the pathogenesis of IBDV in the different types of chickens. Temporary suppression of NDV antibody response in broilers was only seen if the NDV vaccine was administered before and not, as it was speculated previously, at the time the peak of IBDV-induced bursa lesions was detected. For the first time, we have demonstrated that the NDV vaccine had an interfering effect with the pathogenesis of the intermediate as well as the intermediate plus IBDV vaccine. NDV vaccination enhanced the incidence of IBDV bursa lesions and IBDV antibody development. This observation indicates that this bilateral effect of an IBDV and NDV vaccination should be considered in the field and could have consequences for the performance of broiler flocks.
TL;DR: White Pekin ducks from all groups, vaccinated or not, did not show any ND clinical signs, demonstrating that these birds are not susceptible to ND clinical disease.
Abstract: A total of 120 Pekin ducks were distributed at random into four experimental groups, vaccinated or not against Newcastle disease (ND): G1 (Ulster 2C strain), G2 (B1 strain), G3 (LaSota strain), and G4 (nonvaccinated group). At 60 days of age, all groups were challenged with a pathogenic ND virus (NDV) suspension, and a group of specific pathogen free (SPF) chicks (G5) was also inoculated. Cloacal and tracheal swabs from all birds were collected after six, 14, 20, and 30 days postchallenge for virus isolation. NDV was isolated in 100% of SPF chicks. Pekin ducks from all groups, vaccinated or not, did not show any ND clinical signs, demonstrating that these birds are not susceptible to ND clinical disease. In the control group (G4), the virus was isolated 20 to 30 days after challenge, suggesting their possible NDV carrier state. In the vaccinated groups, no virus was isolated. This demonstrates that vaccination of white Pekin ducks against NDV is important to reduce NDV shedding in the field.
TL;DR: Line 0 chicks that had been infected by contact were protected and so the unsafe in ovo vaccination of a minority could protect the majority.
Journal Article•
TL;DR: It is found that benzalkonium chloride (BC) is an effective virucidal agent against influenza, Newcastle disease, and avian infectious bronchitis viruses even in the presence of a concentrated protein.
Abstract: General theories on the inactivation of viruses in the presence of a concentrated protein, such as the allantoic fluid of chicken eggs, are not useful. That is, although sodium hypochlorite and sodium hydroxide are generally known as strong virucidal agents, they do not sufficiently inactivate viruses in allantoic fluid. We found that benzalkonium chloride (BC) is an effective virucidal agent against influenza, Newcastle disease, and avian infectious bronchitis viruses even in the presence of a concentrated protein. BC is easily biodegradable by activated sludge and is not very harmful to humans. We strongly recommend BC as a useful virucidal agent, especially in the manufacture of vaccines for these viruses.
TL;DR: There is an urgent need for a global implementation of recommended test procedures and/or the inclusion of international reference sera in these studies.
Abstract: The results of global proficiency testing schemes (PTS) for serological tests to detect antibodies against infectious bursal disease virus (IBDV) and Newcastle disease virus (NDV) in chicken serum,...
TL;DR: An epidemiological investigation into Newcastle disease in village poultry farming was carried out for 12 months in Ambohimangakely and Moramanga, two agro-ecologic zones of Madagascar and showed that the disease, responsible for 44.3% of all the mortality recorded during the twelve-month period, was Newcastle disease.
Abstract: An epidemiological investigation into Newcastle disease in village poultry farming was carried out for 12 months (from May 1999 to June 2000) in Ambohimangakely and Moramanga, two agro-ecologic zones of Madagascar. The thirty families that were surveyed stated that they had incurred losses from an epizootic with high mortality rates at least once prior to the investigation. The results of serological tests and virus isolation showed that the disease, responsible for 44.3% of all the mortality recorded during the twelve-month period, was Newcastle disease. Maximum incidence of the disease (71%), affecting 75% of the families, occurred in October 1999, and seroprevalence often reached 100% after the outbreak had ended. The infection was brought to the villages either by newly introduced hens or recovered birds. All forms of Newcastle disease (epidemic, endemic and asymptomatic) were observed. The way farmers reacted contributed to the spread of the virus within a village and to neighbouring locations.
TL;DR: The dynamic range of this NDV NASBA detection method is comparable to virus culture and therefore the NDVNASBA method is a potential alternative for NDV screening and surveillance.