Partial Fusion (F) Gene Analysis of Newcastle Disease Virus Detected in Pakistan during 2021-2022

Newcastle disease (ND) virus is a leading threat to commercial and domestic poultry in Pakistan. The virus infects and constitutes irreversible impairment to the nervous system, damages the respiratory system, and marks severe gastrointestinal lesions leading to heavy mortality in short-living birds and substantial losses in layers and breeders. The continuous emergence and evolution of the virus made it inclined to evade the humoral response and indirectly the circumvention of artificial active immunization. Newcastle disease is caused by the orthoavula genus of the paramyxoviridae family and has shown high genetic diversity even in their genotypes while information regarding enzootic trends of the virus is scanty in Pakistan. A total of 40 tracheal samples of NDV were collected from different commercial broiler farms and 11 isolates of NDV were identified. In the current study, we determined the genetic diversity of the Newcastle disease virus based on the partial sequencing of the fusion protein gene available in the NCBI database. Genetic analysis showed that seven isolates belonged to class I genotype VII and four belonged to class II genotype II. Interestingly, two isolates had epidemiological connections with vaccine-like class II genotype II. Our findings, concerning the recent outbreaks of class I genotype VII and class II genotype II of NDV in vaccinated commercial flocks, suggest possible potential partial mutations in the fusion protein gene. Genetic diversity and formation of the new cleavage site in an important neutralizing protein of wild strain are linked with the potency of artificial active immunization and a major cause of vaccine failure.

Overview of the immunological mechanisms in hepatitis B virus reactivation:Implications for disease progression and management strategies

Hepatitis B virus(HBV)reactivation is a clinically significant challenge in disease management.This review explores the immunological mechanisms underlying HBV reactivation,emphasizing disease progression and management.It delves into host immune responses and reactivation’s delicate balance,spanning innate and adaptive immunity.Viral factors’disruption of this balance,as are interac-tions between viral antigens,immune cells,cytokine networks,and immune checkpoint pathways,are examined.Notably,the roles of T cells,natural killer cells,and antigen-presenting cells are discussed,highlighting their influence on disease progression.HBV reactivation’s impact on disease severity,hepatic flares,liver fibrosis progression,and hepatocellular carcinoma is detailed.Management strategies,including anti-viral and immunomodulatory approaches,are critically analyzed.The role of prophylactic anti-viral therapy during immunosuppressive treatments is explored alongside novel immunotherapeutic interventions to restore immune control and prevent reactivation.In conclusion,this compre-hensive review furnishes a holistic view of the immunological mechanisms that propel HBV reactivation.With a dedicated focus on understanding its implic-ations for disease progression and the prospects of efficient management stra-tegies,this article contributes significantly to the knowledge base.The more profound insights into the intricate interactions between viral elements and the immune system will inform evidence-based approaches,ultimately enhancing disease management and elevating patient outcomes.The dynamic landscape of management strategies is critically scrutinized,spanning anti-viral and immunomodulatory approaches.The role of prophylactic anti-viral therapy in preventing reactivation during immunosuppressive treatments and the potential of innovative immunotherapeutic interventions to restore immune control and proactively deter reactivation.

MicroRNA transcriptome analysis of chicken embryo fibroblast cells infected with Newcastle disease virus variants

Variations in the pathogenicity of Newcastle disease virus(NDV),the agent causing Newcastle disease,are associated with variants of different virulence.A few studies have characterized the expression of microRNAs(miRNAs)in NDV-infected avian cells.Here,the expression of miRNAs in chicken embryo fibroblasts(CEFs)infected with Herts/33 and LaSota NDV strains(highly virulent and nonvirulent,respectively)was determined using RNA sequencing.miRNAs involved in NDV infection included 562 previously documented and 184 novel miRNAs.miRNA target genes involved transcription factors,cell apoptosis,ubiquitin-mediated proteolysis,and protein processing in the endoplasmic reticulum.Potential target genes associated with autophagy were verified by qRT-PCR.No studies have documented the miRNA profles of CEFs infected with NDVs variants.This study adds to our knowledge of the cellular miRNAs involved in NDV infection and the complex molecular mechanisms mediating virus-host interactions.The results of this study will aid the development of strategies against the chicken virus.

Screening of Anti-Newcastle Disease Virus Ingredients of Phyllanthus urinaria

[ Objective ] The aim of the study was to screen the antiviral ingredients of Chinese herbal medicine Phyllanthus urinaria in order to devel- op new drugs for the treatment of viral diseases of poultry. [ Method ] The whole grass of phyllanthus was respectively decocted in 75% ethanol （E） and pure water （PF）, and then the active ingredients were separately extracted in petroleum ether （PE）, ethyl acetate （EA）, and n-butyl alcohol （BU）. The extracts were inoculated on chicken embryo fibroblast （CEF） to observe their inhibitory effect on cytopathic effect （CPE） of Newcastle disease virus （NDV）, inoculated into chicken embryos to observe the changes of the hemagglutination titer of NDV, and inoculated in chickens to determine the mortality and evaluate their effect of immune protection. [ Result] The E -PE and E -BU extracts, especially E -BU extract, inhibi- ted CPE of NDV on CEF and significantly inhibited the proliferation of NDV in chicken embryo （P〈0.05） ; the survival rate of E-PE and E-BU group was extremely significantly higher than that of ribavirin group and the normal saline control （ P 〈0.01 ）, with E - PE group more higher. [ Condusion] The water extract of phyllanthus is less effective; E -PE extract and E -BU extract should effectively inhibit the CPE and proliferation in chicken embryo of NDV and also have better immune protection against NDV.

Application of Newcastle disease virus in the treatment of colorectal cancer

Colorectal cancer (CRC) is one of the main reasons of tumor-related deaths worldwide.At present,the main treatment is surgery,but the results are unsatisfactory,and the prognosis is poor.The majority of patients die due to liver or lung metastasis or recurrence.In recent years,great progress has been made in the field of tumor gene therapy,providing a new treatment for combating CRC.As oncolytic viruses selectively replicate almost exclusively in the cytoplasm of tumor cells and do not require integration into the host genome,they are safer,more effective and more attractive as oncolytic agents.Newcastle disease virus (NDV) is a natural RNA oncolytic virus.After NDV selectively infects tumor cells,the immune response induced by NDV’s envelope protein and intracellular factors can effectively kill the tumor without affecting normal cells.Reverse genetic techniques make NDV a vector for gene therapy.Arming the virus by inserting various exogenous genes or using NDV in combination with immunotherapy can also improve the anti-CRC capacity of NDV,and good results have been achieved in animal models and clinical treatment trials.This article reviews the molecular biological characteristics and oncolytic mechanism of NDV and discusses in vitro and in vivo experiments on NDV anti-CRC capacity and clinical treatment.In conclusion,NDV is an excellent candidate for cancer treatment,but more preclinical studies and clinical trials are needed to ensure its safety and efficacy.

Newcastle disease virus-based MERS-CoV candidate vaccine elicits high-level and lasting neutralizing antibodies in Bactrian camels

Middle East respiratory syndrome coronavirus （MERS-CoV）, a member of the Coronavifidae family, is the causative pathogen for MERS that is characterized by high fever, pneumonia, acute respiratory distress syndrome （ARDS）, as well as extrapul- monary manifestations. Currently, there are no approved treatment regimens or vaccines for MERS. Here~ we generated recombinant nonvirulent Newcastle disease virus （NDV） LaSota strain expressing MERS-CoV S protein （designated as rLa- MERS-S）, and evaluated its immunogenicity in mice and Bactrian camels. The results revealed that rLa-MERS-S showed similar growth properties to those of LaSota in embryonated chicken eggs, while animal immunization studies showed that rLa-MERS-S induced MERS-CoV neutralizing antibodies in mice and camels. Our findings suggest that recombinant rLa- MERS-S may be a potential MERS-CoV veterinary vaccine candidate for camels and other animals affected by MERS.

Activity of T Cells Stimulated by Hemagglutinin-neuraminidase of Newcastle Disease Virus in vivo

To investigate the stimulated activity of T cells and the anti-tumor properties of hemagglutinin-neuraminidase（HN） of Newcastle disease virus（NDV） strain Changchun（NDVcc）, the expression of HN gene in hepatoma cells（human HepG-2 and mouse H22 cells） infected with the recombinant adenovirus（Ad-HN） was identified by Western blot analysis and flow cytometry. Sialidase activity of NDVcc HN expressed by Ad-HN was assayed by the periodate-resorcinol method. The in vivo anti-tumor effects of NDVcc HN were evaluated in the H22 solid tumor model. Regional lymph nodes of the mouse model treated with Ad-HN were removed to harvest T lymphocytes and evaluating the specific cytotoxicity of cytotoxic T lymphocyte（CTL） and natural killer（NK） cells by an L-lactate dehydrogenase（LDH） assay, in the mean time, the secretion of cytokines was analyzed by enzyme linked immunosorbent assays（ELISA）. The results show that NDVcc HN was effectively expressed by Ad-HN in HepG-2 and H22 cells. The sialidase activity assay showed that Ad-HN significantly reduced sialic acid level of the hepatoma cells compared with the cells infected the empty adenovirus vector（Ad-mock）. When treated with Ad-HN, the growth of subcutaneous H22 primary tumors in C57BL/6 mice was suppressed, and the mean mice survival increased. In addition, the treatment of Ad-HN elicited strong NK and CTL responses, and high levels of Th1 cytokines, such as IL-2 and IFN-γ. In conclusion, NDVcc HN effectively elicits T cell-mediate anti-tumor cytotoxicity via sialidase activity and may be a novel strategy for cancer immunotherapy.

Complete Nucleotide Sequence of a Newly Avirulent Newcastle Disease Virus Hubei 92(HB92) Strain

A new avirulent, heat-resistance HB92 strain of newcastle Disease Virus (NDV) was acquired from Australia V4 strain. Its complete nucleotides sequence was first determined. The entire genome of NDV HB92 consists of 15 186 nucleotides (GenBank accession no. AY225110). It was demonstrated by sequence analysis that nucleotides homology of HB92 strain with virulent strain ZJ1 were 83.9%, and the homology compared with avirulent vaccine strain La Sota and B1 were 94.0% and 93.5%, respectively. These results might be contributive to the study of the molecular mechanism of evolution of the NDV strain HB92 and to develop the engineered recombinant vaccine. Key words newcastle disease virus - genomic sequence - sequence analysis CLC number S 852. 65 Foundation item: Supported by Hubei Natural Science Foundation (2002AB144)Biography: Pan Zhi-shu(1961-), male, Ph. D, Associate professor, research direction: molecular biology and pathogenesis of eucaryotic viruses.

Production and application of recombinant haemagglutinin neuraminidase of Newcastle disease virus

Objective:To discuss the possibility of expressing the haemagglutinin-neuraminidase（HN） protein in prokaryotic system such as Escherichia coli（E.coli） cells by cloning the full length HN gene.Methods:The full length HN gene of Newcastle Disease Virus（NDV） of size 1 734 bp was preciously isolated by RT-PCR.The sequence was assessed and submitted to Nucleic Acid Databank（NCBI） and the gene ID was EU215390.1 after cloning and sequencing.Now the assessed HN gene was subcloned into pET 32 a+ expression vector for production the HN protein in E.coli, BL21（DE3） PLYSS cells following standard protocols.The crude lysate protein from the induced positive clone was size assessed by sodium dodecyl sulfale-polyacrylamide gel electrophoresis （SDS-PAGE） and their haemagglutination（HA） property against chicken RBC was assessed by standard micro HA test.Results:The molecular size of the full HN gene of NDV as assessed by cloning and digesting the positive clone to release the insert was 1.7 kb.The expressed protein in both crude and pure form was assessed to be 63 kDa and 81 kDa,respectively.The HA activity of the crude protein of the positive clone was 1 in 40.Conclusions:This finding indicates that the fusion protein retains the biological activity of native protein in the crude form and therefore could be used as a diagnostic reagent for antibody detection and for routine assessment of immune status in commercial layer forms.

Antiviral Effects of Compound Traditional Chinese Medicine on Newcastle Disease Virus

[Objective] To investigate the mechanism of compound traditional Chinese medicine （TCM） on Newcastle disease virus （NDV） and to provide a scientific basis for the reasonable usage of antiviral drugs in clinic. [Method] The compound TCM was composed of Hedyotis diffusa, Lonicera japonica Thunb, Radix astragali and Glycyrrhiza uralensis. Different dilutions of fluid extract were prepared. Its antiviral effects on NDV were observed through three inoculation ways, first, inoculation with the medicine and NDV mixture which had been incubated at 37 ℃; second, incubating chicken embryo fibroblasts （CEF） with the medicine followed by inoculation with NDV; third, inoculation with N DV followed by incubating CEF with the medicine. The A,= was determined by M]-r [ 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） ~ method. Therapeutic indexes were used to evaluate the antiviral effects. [ Result] The minimum effective concentration of the compound TCM which acted through the three ways was 1.0 × 2^-10 1.0 × 2^-8 and 1.0 × 2^-7 g/ml, respectively. The antiviral effects of the compound TCM were the best through inoculation with the incubated medicine and NDV mixture, followed by the second method and the third method. [ Conclusion] The compound TCM can not only kill NDV directly in vitro but also inhibit viral propagation.

Characterization of Pigeon Paramyxoviruses (Newcastle disease virus) Isolated in Kazakhstan in 2005

Isolates of Newcastle disease virus (NDV) from deceased wild and domestic pigeons in Kazakhstan were obtained from the Almaty region during 2005 and were genotypically analyzed by using reverse transcription polymerase chain reaction (RT-PCR) with primers specific to the viral fusion (F) protein gene. Part of the amplified F protein DNA product (nucleotide sequence 47-422) and the deduced amino acid sequences were compared phylogenetically with those from strains previously reported in other geographic regions. Phylogenetic analysis indicated that the Kazakhstanian pigeon paramyxovirus type 1 (PPMV-1) isolates belong to genotype VI or 4bii. To our knowledge, this is the first reported VI isolates that possess the sequences of 112 GKRQKR116* F117 within the F0 protein. The information is fundamental to improving the efficiency of control strategies and vaccine development for NDV.

PLASMID VACCINE ENCODING HN GENE FROM NEWCASTLE DISEASE VIRUS HAS MARKED ANTITUMORAL EFFECT IN VITRO

Objective: To explore the antitumor effects of hemaagglutinin-neuraminase gene (HN gene) from Newcastle disease virus. Methods: Plasmid vaccine of pIRHN was constructed and transfected into HeLa cells. The expression of HN was analyzed by Western blot analysis, and the mode of cell death was detected by fluorescence microscope, gel electrophoresis and TUNEL assay and the expression of p53 and bcl-2 was also analyzed in transfected Hela cells. The effect of pIRHN on sialic acid contents in the Hela cell was examined. Results: pIRHN nucleic acid vaccines could be expressed in eukaryotic cell. pIRHN could induce apoptosis after HeLa cells were transfected. The effect of antitumor responses of pIRHN was correlated with the contents of sialic acid in tumor cells, and there was no prominent evidence for the relatedness of the antitumor effect with the expression of p53 and bcl-2. Conclusion: pIRHN may become a new antitumor biological agent.

Comparisons of the Pathogenicity between Pigeon-derived and Chickenderived Genotype Ⅵ Newcastle Disease Virus(NDV) Strains in Pigeons

[ Objective]This study aimed to compare differences in the pathogenicity between genotype VI Newcastle disease virus （NDV） strains from pigeons and chickens in pigeons. [ Method] Two-month-old pigeons were artificially inoculated with ZJ3 strain from chickens and WX-10-07-Pi strain from pigeons. After inoc- ulation, the clinical symptoms, pathological anatomical changes, tracheal and cloacal detoxification, and histological lesions of experimental pigeons were observed. [ Result] Both ZJ3 strain and WX-10-07-Pi strain could infect pigeons with the incidence rate of 100%, but the mortality rate was 0. The cloacal detoxification time of pigeons in WX-10-07-Pi infection group was longer, and the virus detection rate was higher; in addition, the virus could be detected in various tissues and organs of inoculated pigeons. [ Conclusion] Different genotypes of NDV are pathogenic to pigeons, but the pathogenicity is related to the features of NDV strains. Genotype VIb NDV from pigeons can be carried and discharged for a long term in pigeons, which can spread in pigeon groups more easily.

Biological Characterization and Whole Genome Sequencing of a Genotype VII Newcastle Disease Virus Strain

[Objective] The aim of this paper was to study the genotype, pathogenicity and nucleotide difference between Newcastle disease virus(NDV) isolates and traditional NDV vaccine strain(La Sota). [Method] A suspected NDV strain was isolated from a chicken farm. The isolate was preliminarily determined by HA and HI tests. A pair of primers was designed based on the partial sequence of NDV F gene published in GenBank(accession No. JF950510.1). F gene was amplified by RT-PCR, cloned and sequenced. The sequencing result was compared with the F gene sequences published in GenBank, and the phylogenetic tree was constructed to analyze the genotypes. The pathogenicity of the virus was determined by mean death time(MDT) of chicken embryos, intracerebral pathogenicity index(ICPI) of one-day-old chicks and intravenous pathogenicity index(IVPI) of six-week-old chickens, respectively. Based on the NDV genome sequence published in GenBank(accession No. JF950510.1), nine pairs of primers were designed to amplify the genome sequence of the isolate, and its structure was analyzed. [Result] The length of F gene was about 500 bp, and a NDV strain of genotype VII was isolated. The MDT, ICPI and IVPI were 52.8 h, 1.675 and 2.46, respectively, indicating the isolate was a virulent strain. The whole genome sequence analysis results showed that the full genome length of the isolate was 15 192 bp, which had 6 more nu-cleotides than that of La Sota strain, and the homology between the two strains was 82.8%. [Conclusion] A virulent NDV strain of genotype Ⅶ was isolated, with low homology to La Sota strain in nucleotide sequence.

Newcastle Disease Virus Isolation and Its Prevalence in Uganda Poultry Farms

The present research work was carried out to isolate and identify Newcastle disease virus (NDV) by using haemagglutination inhibition (HI) test and HA-HI virus isolation, embryonated eggs (EE) and chicken embryo fibroblasts (CEF). A total of 95 clinical (blood, tracheal and cloacal swabs) and post-mortem (brain, lung, colon and spleen) samples were collected from chickens of field outbreaks of suspected Newcastle disease virus (NDV). The HI and HA-HI were employed to detect NDV in tissue homogenates of all the clinical and post-mortem samples as well as laboratory samples (AF and ICF). Among the four different types of post-mortem samples, virus isolation rate was found to be low in body organs. In CEF cell culture system, the rate of virus isolation from all the aforesaid samples was found to be at 100% with the exception of serum samples;while in tracheal and cloacal swabs, it was at 90%;while in serum, it was at 10%, in all clinical cases. The isolation rate of NDV was higher in CEF culture system (66.7%) compared to that of avian embryos (33.3%). Samples were inoculated and the allantoic fluid (AF) of the dead embryos and the infected culture fluid (ICF) of the CEF were harvested at 24 to 96 hours of the post-infection, respectively, which revealed that the virulent strain of NDV is highly prevalent in the region. The prevalence of NDV was established at 1.1%, 2.1% and 4.2% using HA-HI, EE, and CEF methods. Rapid detection and identification of the virus are crucial for the effective control of the disease as conventional diagnostic methods such as virus isolation on embryonated eggs followed by serological identification in haemagglutination-inhibition test are laborious and time-consuming. The speed of the diagnosis can be considerably increased by using methods based on molecular biology, e.g. reverse transcription—polymerase chain reaction. However, the genetic variability of APMV-1 isolates should be considered carefully as the potential cause for false negative results of genetic-based laboratory tests.

Establishment of a Real-time Fluorescent Quantitative RTPCR Method for Detecting NP Gene of Class Ⅰ Newcastle Disease Virus(NDV)

Newcastle disease( ND) is one of the most serious infectious diseases that infect the poultry industry.There is only one serotype of Newcastle disease virus( NDV),but NDVs can be divided into two distinct classes( class Ⅰ,and class Ⅱ) according to their genetic relationship.To develop a method for rapid quantitative detection of class Ⅰ NDV,a pair of primers and a TaqM an probe were designed and synthesized according to the conservative sequence of NP gene of class Ⅰ NDV.The positive recombinant plasmid harboring NP gene of JS-18-05 isolate was used as a positive template to establish the standard curve.A real-time fluorescent quantitative RT-PCR method was established for rapid detection of class Ⅰ NDV with strong specificity,high sensitivity and good repeatability.The established method exhibited a good linear relationship within the concentration of 102 to 108 copies of NDV,by which 1 μl of 10 copy of NDV nucleic acid could be detected in the initial template.Compared with conventional virus isolation methods,the established method had similar sensitivity and led to the same results in detecting33 class Ⅰ,class Ⅱ NDV isolates.The study provided the basis for rapid quantitative detection of class Ⅰ NDVs and further clarification of their pathogenicity and pathogenic mechanism in poultry.

Antibodies to Newcastle Disease Virus in Egg Yolks of Great Cormorant (<i>Phalacrocorax carbo</i>) at Qinghai Lake

Newcastle disease virus (NDV) is not considered as cause of serious disease in humans. But, recent data make it clear that, under particular circumstances, it is indeed possible for NDV to cause severe human respiratory disease. Newcastle Disease infection has been reported in many bird species. Cormorants that inhabit at the Qinghai-Tibet Plateau are mainly represented by Great Cormorant (Phalacrocorax carbo sinensis), which is distributed mainly on the Qinghai Lake area. Cormorants are considered as one of the main NDV-reservoir. We conducted the study for the presence of antibodies to Newcastle disease virus by hemagglutination inhibition test in yolks. We got 50% of seropositive yolks to Newcastle disease virus. These results show that NDV circulates in the Qinghai Lake population of cormorants. We first used the technique of detection of antibodies to Newcastle disease virus in the egg yolk for study the circulation of the virus in cormorants and demonstrated its effectiveness. We should carefully monitor cases of pneumonia in the population of people living around the lake and assess the causes of the disease.

Rescue and Preliminary Application of a Recombinant Newcastle Disease Virus Expressing Green Fluorescent Protein Gene

把 ZJI 紧张基于纽卡斯尔疾病病毒(NDV ) 的完全的染色体顺序，七份教材被设计为构造 plasmid pNDV/ZJI 放大 cDNA 碎片，它包含了 NDV ZJI 紧张的全身的 cDNA。与三助手 plasmids， pCIneoNP， pCIneoP 和 pCIneoL， pNDV/ZJI 当时是进表示 T7 RNA 聚合酶的 BSR-T7/5 房间的 cotransfected。在进受胎的鸡肉的 transfected 房间文化上层清液的接种以后，从 specific-pathogen-free (SPF ) 的鸡蛋结队，传染 NDV ZJI 紧张成功地被救。格林荧光灯蛋白质(GFP ) 基因被放大并且插入了到 NDV 全身的 cDNA 产生标注 GFP 的 recombinant plasmid pNDV/ZJIGFP。在进 BSR-T7/5 房间的结果的 plasmid 和三支持 plasmids 的 cotransfection 以后， recombinant NDV， NDV/ZJIGFP，被救。特定的绿荧光在 BSR-T7/5 和鸡胚胎成纤维细胞(CEF ) 房间 48h 被观察感染以后，显示 GFP 基因被表示在一相对高级。NDV/ZJIGFP 被 oculonasal 线路接种进 10-day-old SPF 鸡。四天感染以后的、强壮的绿荧光能在肾和 tracheae 被检测，显示标注 GFP 的 NDV 能是的 recombinant 为 NDV 传播和致病的分析的一个很有用的工具。关键词纽卡斯尔疾病病毒(NDV )- 格林荧光灯蛋白质(GFP )- 营救 - 表示 CLC 数字 S831.7 基础条款：给中国(No.30630048 )

Multiple RT-PCR Detection of H5,H7,and H9 Subtype Avian Influenza Viruses and Newcastle Disease Virus

Objective:This paper focuses on the multiple detection RT-PCR technology of H5,H7,AND H9 subtype avian influenza viruses and Newcastle disease virus,and points out the specific detection methods and detection procedures of avian influenza and Newcastle disease virus.Methods:The genes of Newcastle disease virus carrying out the HA gene sequence of H5,H7 and H9 subtype AIV in GenBank were used to establish a strategy for simultaneous detection of three subtypes of avian influenza virus and Newcastle disease virus.Results:The results showed that the program can detect and distinguish H5,H7 and H9 subtype avian influenza viruses and Newcastle disease virus at one time.Conclusion:Multiple RT-PCR detection method has high detection sensitivity and can detect and determine different subtypes of avian influenza virus and Newcastle disease virus quickly and accurately,therefore,it has a crucial role in the detection and control of avian influenza H5,H7 and H9 subtypes and Newcastle disease.

The Influence of Newcastle Disease Virus Major Proteins on Virulence

The Newcastle disease virus(NDV)negative-strand RNA genome contains six genes.These genes encode nucleoprotein(NP),phosphoprotein(P),matrix protein(M),fusion protein(F),hemagglutinin-neuraminidase(HN),and RNA-dependent RNA polymerase(L)proteins.The six proteins affect the virulence of NDV in different ways,but available information on the six proteins is disparate and scattered across many databases and sources.A comprehensive overview of the proteins determining NDV virulence is lacking.This review summarizes the virulence of NDV as a complex trait determined by these six different proteins.