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Genetic and antigenic characteristics of genotype VII.1.1 Newcastle disease viruses currently circulating in Ethiopian chickens
BackgroundNewcastle disease virus (NDV) is a causative agent of Newcastle disease (ND), a major infectious poultry disease associated with significant economic losses. Vaccination is usually effective at preventing the disease. However, in Ethiopia, ND is commonly detected in both unvaccinated and vaccinated chickens. In this study, we aimed to evaluate the pathogenicity of NDV isolated from both vaccinated and unvaccinated chickens, as well as to compare the antigenicity of the isolates with vaccine strains and genotyping by using the F-gene sequence.MethodsThe partial F gene sequences of all isolates and the mean death times (MDTs) of representative isolates were used to determine genotype and pathogenicity of the isolates. Antigenicities were assayed with the hemagglutinin inhibition (HI) and virus neutralization (VN) tests using antiserum against the vaccine Hitchner B1 (HB1), which is the most commonly used NDV vaccine in Ethiopia. Thermostability was evaluated by incubating infected allantoic fluid at 56 °C.ResultsOut of 231 samples tested, 10.8% (25/231) were positive for virus isolation. The F gene cleavage sites of all 25 isolates had 112RRQKRF117, a characteristic of virulent NDVs. The MDTs of representative isolates were less than 60 h, indicating highly virulent (velogenic) pathotypes. The HI test revealed significant differences between our isolates and the HB1 vaccine strain, but the VN test showed no antigenic difference. Phylogenetic analysis based on the partial F gene sequences showed that all the isolates belonged to sub-genotype VII.1.1 of genotype VII, which is closely related to NDV strains from the Middle East and Eritrea. Thermostability test showed two of the 25 isolates were thermostable.DiscussionAlthough the HI test indicates antigenic differences between the velogenic Ethiopian isolates and the HB1 vaccine, the VN test showed that the vaccine could protect infections with these isolates. Phylogenetic analysis showed that all studied isolates belong to sub-genotype VII.1.1 of genotype VII, diverging from previously reported genotype XXI in Ethiopia.ConclusionsIn Ethiopia, NDV genotype VII 1.1 is widely distributed. Since these viruses showed the same antigenicity as the HB1 vaccine in VN test, the occurrence of ND in vaccinated chickens may be due to vaccine failure caused by inadequate management or immunosuppression due to other infectious diseases.
Journal Article
Prevalence of Newcastle disease and associated risk factors in domestic chickens in the Indian state of Odisha
Newcastle disease (ND), caused by Newcastle disease virus (NDV), is a contagious disease that affects a variety of domestic and wild avian species. Though ND is vaccine-preventable, it is a persistent threat to poultry industry across the globe. The disease represents a leading cause of morbidity and mortality in chickens. To better understand the epidemiology of NDV among commercial and backyard chickens of Odisha, where chicken farming is being prioritized to assist with poverty alleviation, a cross-sectional study was conducted in two distinct seasons during 2018. Choanal swabs ( n = 1361) from live birds (commercial layers, broilers, and backyard chicken) and tracheal tissues from dead birds ( n = 10) were collected and tested by real-time reverse transcription polymerase chain reaction (RT-PCR) for the presence of matrix (M) and fusion (F) genes of NDV. Risk factors at the flock and individual bird levels (health status, ND vaccination status, geographical zone, management system, and housing) were assessed using multivariable logistic regression analyses. Of the 1371 samples tested, 160 were positive for M gene amplification indicating an overall apparent prevalence of 11.7% (95% CI 10.1–13.5%). Circulation of virulent NDV strains was also evident with apparent prevalence of 8.1% (13/160; 95% CI: 4.8–13.4%). In addition, commercial birds had significantly higher odds (75%) of being infected with NDV as compared to backyard poultry ( p = 0.01). This study helps fill a knowledge gap in the prevalence and distribution of NDV in apparently healthy birds in eastern India, and provides a framework for future longitudinal research of NDV risk and mitigation in targeted geographies—a step forward for effective control of ND in Odisha.
Journal Article
Antigenic differences among Newcastle disease virus strains of different genotypes used in vaccine formulation affect viral shedding after a virulent challenge
Strains of Newcastle disease virus (NDV) can be separated into genotypes based on genome differences even though they are antigenically considered to be of a single serotype. It is widely recognized that an efficacious Newcastle disease (ND) vaccine made with any NDV does induce protection against morbidity and mortality from a virulent NDV challenge. However, those ND vaccines do not protect vaccinates from infection and viral shed from such a challenge. Vaccines prepared from ND viruses corresponding to five different genotypes were compared to determine if the phylogenetic distance between vaccine and challenge strain influences the protection induced and the amount of challenge virus shed. Six groups of 4-week-old specific pathogen-free Leghorn chickens were given oil-adjuvanted vaccines prepared from one of five different inactivated ND viruses including strains B1, Ulster, CA02, Pigeon84, Alaska196, or an allantoic fluid control. Three weeks post-vaccination, serum was analyzed for antibody content using a hemagglutination inhibition assay against each of the vaccine antigens and a commercial NDV ELISA. After challenge with virulent CA02, the birds were examined daily for morbidity and mortality and were monitored at selected intervals for virus shedding. All vaccines except for the control induced greater than 90% protection to clinical disease and mortality. The vaccine homologous with the challenge virus reduced oral shedding significantly more than the heterologous vaccines. NDV vaccines formulated to be phylogenetically closer to potential outbreak viruses may provide better ND control by reducing virus transmission from infected birds.
Journal Article
Field outbreak investigation and immunoinformatic analysis suggest potential immune evasion by Newcastle disease virus Sub-Genotype XIV.2 in Nigeria
Poultry production is one of the fastest-growing agricultural sub-sectors in Nigeria. However, it faces numerous challenges, mainly from frequent Newcastle disease (ND) outbreaks even in vaccinated flocks, causing huge economic losses. The recurring outbreaks raise concerns about the efficacy of ND vaccine and the need to understand the immunomodulatory mechanism of the ND virus (NDV). This study investigated a recent outbreak of NDV that resulted in 95% mortality in a vaccinated broiler parent stock in Nigeria by utilizing immunoinformatic tools to elucidate the possible immune evasion features of the disease-causing NDV. Genetic analysis of the complete fusion gene showed that the NDV isolate belong to sub-genotype XIV.2, a virulent strain prevalent in Nigeria. Predicted immunogenic peptides from the sub-genotype XIV.2 proteins revealed notable amino acid variations (R114Q, V118I, A220V) in both Major Histocompatibility Complex class I and II epitopes compared to common NDV vaccine and other prominent field strains. Modelling and structural validation of the BF2*2101 chicken allele showed 99% residues within the allowed regions in Ramachandran plot and − 6.61 Z-score, confirming its reliability. Immune simulation indicated that LaSota-Komorov prime-boost vaccine-simulation could not confer protection against sub-genotype XIV.2 virus simulated-challenge, despite eliciting humoral immune response. These results provide a valuable insight for developing ND vaccines that could effectively counter the immune cell interference of sub-genotype XIV.2, although further experimental validation is needed to characterize key biological interactions. A multifaceted approach encompassing improved biosecurity and the development of an effective sub-genotype XIV.2-matched vaccine is crucial to mitigate the persistent threat of ND in Nigeria.
Journal Article
Harry Miller's run
The Junior Great North Run is coming soon to Newcastle Upon Tyne and Liam needs to train. But his elderly neighbor, Harry, needs a hand moving and Liam is asked to help. Little does he know that Harry ran in the Great Run as a young lad and has a very interesting story to tell!
Book
The Application of Newcastle Disease Virus (NDV): Vaccine Vectors and Tumor Therapy
Newcastle disease virus (NDV) is an avian pathogen with an unsegmented negative-strand RNA genome that belongs to the Paramyxoviridae family. While primarily pathogenic in birds, NDV presents no threat to human health, rendering it a safe candidate for various biomedical applications. Extensive research has highlighted the potential of NDV as a vector for vaccine development and gene therapy, owing to its transcriptional modularity, low recombination rate, and lack of a DNA phase during replication. Furthermore, NDV exhibits oncolytic capabilities, efficiently eliciting antitumor immune responses, thereby positioning it as a promising therapeutic agent for cancer treatment. This article comprehensively reviews the biological characteristics of NDV, elucidates the molecular mechanisms underlying its oncolytic properties, and discusses its applications in the fields of vaccine vector development and tumor therapy.
Journal Article