Academic literature on the topic 'Newcastle disease virus genotype VII'

Class II genotype VII Newcastle disease viruses (NDV) are predominant in the Middle East and Asia despite intensive vaccination programs using conventional live and inactivated NDV vaccines. In this study, the protective efficacies of three commercial vaccine regimes involving genotype II NDV, recombinant genotype VII NDV-matched, and an autogenous velogenic NDV genotype VII vaccine were evaluated against challenge with velogenic NDV genotype VII (accession number MG029120). Three vaccination regimes were applied as follows: group-1 received inactivated genotype II, group-2 received inactivated recombinant genotype VII NDV-matched, and group-3 received velogenic inactivated autogenous NDV genotype VII vaccines given on day 7; for the live vaccine doses, each group received the same live genotype II vaccine. The birds in all of the groups were challenged with NDV genotype VII, which was applied on day 28. Protection by the three regimes was evaluated after infection based on mortality rate, clinical signs, gross lesions, virus shedding, seroconversion, and microscopic changes. The results showed that these three vaccination regimes partially protected commercial broilers (73%, 86%, 97%, respectively, vs. 8.6% in non-vaccinated challenged and 0% in non-vaccinated non-challenged birds) against mortality at 10 days post-challenge (dpc). Using inactivated vaccines significantly reduced the virus shedding at the level of the number of shedders and the amount of virus that was shed in all vaccinated groups (G1-3) compared to in the non-vaccinated group (G-4). In conclusion, using closely genotype-matched vaccines (NDV-GVII) provided higher protection than using vaccines that were not closely genotype-matched and non-genotype-matched. The vaccine seeds that were closely related to genotype VII.1.1 provided higher protection against challenge against this genotype since it circulates in the Middle East region. Updating vaccine seeds with recent and closely related isolates provides higher protection.

Genotype VII Newcastle Disease Virus (NDV) has caused a pandemic in many countries and usually causes fatal consequences in infected chickens. Although current commercial attenuated NDV vaccines can provide an ideal protection against genotype VII NDV, they cannot completely prevent the infection and viral shedding, and the genotype of some vaccine strains cannot match with the prevalent strain. In this study, in order to construct a thermostable and genotype VII-matched live attenuated vaccine, we used a thermostable genotype VIII virulent HR09 strain as the backbone and replaced its F gene with that of the genotype VII DT-2014 strain. Meanwhile, the cleavage site of F gene of DT-2014 was mutated to that of class I F protein and avirulent class II F protein, respectively. The results showed that the two chimeric viruses, designated rcHR09-CI and rcHR09-CII, shared a similar growth kinetics and thermostability with their parental HR09 strain. Mean death time (MDT) and intracerebral pathogenicity index (ICPI) tests showed that the two chimeric viruses were highly attenuated. Though both chimeric NDVs and La Sota vaccine strain could provide complete protection to immunized chickens against the challenge of virulent genotype VII ZJ1 strain, the two chimeric NDVs could induce a higher level of antibody response against ZJ1 strain and could significantly reduce the viral shedding compared with La Sota vaccine strain. In conclusion, our study constructed two chimeric thermostable genotype VII-matched NDV vaccine candidates, which provided complete protection against the challenge of virulent genotype VII NDV.

Newcastle disease virus (NDV) is distributed worldwide and has caused significant losses to the poultry industry. Almost all virulent NDV strains belong to class II, among which genotype VII is the predominant genotype in China. However, the molecular evolution and phylodynamics of class II genotype VII NDV strains in China remained largely unknown. In this study, we identified 13 virulent NDV including 11 genotype VII strains and 2 genotype IX strains, from clinical samples during 1997 to 2019. Combined NDV sequences submitted to GenBank, we investigate evolution, and transmission dynamics of class II NDVs in China, especially genotype VII strains. Our results revealed that East and South China have the most genotypic diversity of class II NDV, and East China might be the origin of genotype VII NDVs in China. In addition, genotype VII NDVs in China are presumably transmitted by chickens, as the virus was most prevalent in chickens. Furthermore, codon usage analysis revealed that the F genes of genotype VII NDVs have stronger adaptation in chickens, and six amino acids in this gene are found under positive selection via selection model analysis. Collectively, our results revealed the genetic diversity and evolutionary dynamics of genotype VII NDVs in China, providing important insights into the epidemiology of these viruses in China.

Objective: This study aimed to produce hyperimmune serum against genotype VII Newcastle disease virus (NDV) with several applications. Materials and Methods: Production of hyperimmune serum against genotype VII NDV was performed on eight New Zealand white rabbits divided into four groups. Rabbits were immunized three times on the 1st day, the 14th day, and the 30th day. Blood sampling was carried out on the 8th day after the third immunization. Results: All groups showed the same pattern of hemagglutination inhibition (HI) titer results. HI titers would peak on the 5th or the 9th day after the second immunization, then decrease until the 3rd day after the third immunization, and increase again on the 5th day after the third immu¬nization. Rabbits immunized intravenously showed higher HI titers than the other groups. These results indicate that the intravenous route for hyperimmune serum production against genotype VII Newcastle disease virus greatly affects the immune response result. Conclusions: The production of hyperimmune serum by intravenous immunization three times was able to produce the highest titer of 210 at 38 days. The agar gel precipitation test and the Western blot assay showed that the hyperimmune serum was specific for the Newcastle disease antigen.

Newcastle Disease Virus (NDV) genotype VII is a highly pathogenic Orthoavulavirus that has caused multiple outbreaks among poultry in Egypt since 2011. This study aimed to observe the prevalence and genetic diversity of NDV prevailing in domestic and wild birds in Egyptian governorates. A total of 37 oropharyngeal swabs from wild birds and 101 swabs from domestic bird flocks including chickens, ducks, turkeys, and pelicans, were collected from different geographic regions within 13 governorates during 2019–2020. Virus isolation and propagation via embryonated eggs revealed 91 swab samples produced allantoic fluid containing haemagglutination activity, suggestive of virus presence. The use of RT-PCR targeted to the F gene successfully detected NDV in 85 samples. The geographical prevalence of NDV was isolated in 12 governorates in domestic birds, migratory, and non-migratory wild birds. Following whole genome sequencing, we assembled six NDV genome sequences (70–99% of genome coverage), including five full F gene sequences. All NDV strains carried high virulence, with phylogenetic analysis revealing that the strains belonged to class II within genotype VII.1.1. The genetically similar yet geographically distinct virulent NDV isolates in poultry and a wild bird may allude to an external role contributing to the dissemination of NDV in poultry populations across Egypt. One such contribution may be the migratory behaviour of wild birds; however further investigation must be implemented to support the findings of this study. Additionally, continued genomic surveillance in both wild birds and poultry would be necessary for monitoring NDV dissemination and genetic diversification across Egypt, with the aim of controlling the disease and protecting poultry production.

Since it was discovered in 1926 in England and Indonesia, Newcastle Disease Virus (NDV), especially from Genotype VII (GVII), has caused death in chickens that have been vaccinated using the NDV vaccine Genotype II (GII), known as a heterologous vaccine. Vaccines from the GVII strain, also known as homologous vaccines, have prevented NDV outbreaks. Determination of the differences between the two vaccines was done using a transcriptomic method to determine the response of chickens at the genetic level; with serology approach and viral loading counting; and differences between the two strains genetically using whole-genome sequences. Thirty, three-week-old specific-pathogen-free (SPF) chickens were divided into three groups. The first group was a negative control, the second group was vaccinated with GIIvacc, and the third group was vaccinated with GVIIvacc. Treatment groups were immunized with vaccines on day 14 and day 28. Sera were obtained from all groups on day 28 for the serology tests. On day 42, the spleen was collected for transcriptomic. Meanwhile, the whole genome sequence samples were obtained from the NDV outbreak in 2015 in Indonesia, Genotype II strain, and challenge strain to determine vaccine effectiveness Spleen transcriptomic showed that GVIIvacc down-regulates the neuroinflammation pathway but increases the communication activity among neurons as part of the synaptogenesis pathway. Thus, it is speculated that suppressing the neuroinflammation pathway is associated with protecting the nervous system in chickens from excess leukocytes and cytokine activity. Meanwhile, GIIvacc only prevents apoptosis by suppressing PERK/ ATF4/CHOP as part of the unfolded protein response (UPR) pathway. Thus, the use of GVIIvacc should be considered in countries where GVII strain causes NDV outbreaks. The transcriptomic result aligned with serological and challenged virus test that homologous vaccine (GVIIvacc) gave better protection by reducing the viral shedding and had higher protective antibodies than a heterologous vaccine (GIIvacc). In particular, the Hemagglutination Inhibition (HI) test showed that antibody titers were higher when tested with homologous antigen. However, the cleavage site of the Fusion (F) protein from GII and GVII were used as alternative antigens in an ELISA, did not perform well to obtain the relevant antibody titer. After being challenged with GVII, viral shedding from vaccinated chickens with GVIIvacc was significantly reduced compared to chickens vaccinated with GIIvacc. Both chicken groups showed no clinical signs. The whole-genome sequence and phylogenetic tree results showed that GVII is still the dominant NDV strain that causes NDV outbreaks in Indonesia. In addition, ITA strains for testing the vaccine's efficacy belong to GVI. Hence, using GVI as a heterologous strain from the field as a challenge strain for effective vaccine testing should be considered in veterinary laboratories, especially in Indonesia. All the results from my research study suggested that to combat NDV, the vaccine, antigen for antibody titer, and antigen as challenge strain for effectivity vaccine need to be homologous or coming from the NDV genotype, which causes an outbreak in the field.
Thesis (Ph.D.) -- University of Adelaide, School of Animal and Veterinary Sciences, 2021

Since it was reported in Indonesia in 1926, Newcastle disease (ND) is an endemic disease in Indonesia resulting in devastating economic losses in poultry. Despite heavy vaccination programs, NDV infection still occurs among commercial chicken farms, including vaccinated birds in Southeast Asia, especially in Indonesia. Therefore, the first objective was to detect and perform full genome sequencing of highly virulent circulating NDVs in vaccinated chicken flocks to identify the most adequate NDV strains as vaccine candidates. Our full genome sequencing analysis on two selected isolates from vaccinated birds in Indonesia has shown that both of them belong to highly virulent NDV-GVII.2 strains, while only 0.4% of the vaccine strains used in this country are genotype VII. Moreover, sequencing analysis of the existing genotype VII vaccine revealed that it has significant differences from GI vaccine strain, which is not sufficiently representative of genotype VII viruses. This finding illustrates that virulent NDV-GVII.2 strains are mainly responsible for the high morbidity and mortality of recent ND outbreaks in poultry in Indonesia. Virulent NDV-GVII strains were previously characterised as immunopathological phenotypes triggering severe tissue damage probably through apoptosis and necrosis of lymphoid tissues. However, the underlying molecular mechanism of pathogenesis of ND remains to be fully understood. Hence, the second objective was to identify and characterise the molecular mechanism of lymphotropic behaviour of NDV-GVII by focusing on detecting key biomarkers and cellular immune response signalling pathways that contribute to severe lymphocyte destruction in infected birds using RNA sequencing, bioinformatics tools and PPI network analysis. Transcriptomic profiling indicates that virulent NDV-GVII significantly downregulates immunologically regulated genes and innate immune regulating pathways including fMLP signalling in neutrophils, Fcy receptor-mediated phagocytosis in macrophages and monocytes, and leukocyte extravasation signalling and NF-kB activation by viruses. These transcriptional changes may lead to widespread immunosuppression and enhanced replication of the virus. As a result, the host’s immune response may be diminished, delayed, incomplete or display overly strong induction that can cause severe tissue damage. This finding also implies that virulent NDV-GVII strains appear to possess the capability to inhibit the induction of immune responses by targeting lymphocytes and destroying these cells, which may be one indispensable factor of the pathogenesis of NDV-GVII. Moreover, PPI network analysis revealed that the top three significantly enriched gene modules were phagocytosis, immune response-related terms, and glutamate receptor signalling pathway. We identified novel genes EGF, LPAR5, AGT, AGTR1, RAC2, CD4, CD3D, IL7R, NPY, GRM3, and GRAP2 as potential biomarkers. This study provides valuable information to help understand novel immune evading mechanisms of highly pathogenic NDV-GVII from a host-pathogen interaction point of view. Interactions between the virus and the host determine the success of the viral infection. Hence, the third objective was to identify any particular genes of the virus that may have an important role in virulence and pathogenicity by profiling the transcription of virus in infected birds. This study revealed the transcriptional gradient of these highly pathogenic NDV-GVII genes: NP:P:M:F:HN:L, in which there were a slight attenuations at the NP:P and HN:L gene boundaries. Our result also provides a fully comprehensive qRT-PCR protocol for measuring viral transcript abundance that may be more convenient for laboratories where accessing HTS is not feasible.
Thesis (Ph.D.) -- University of Adelaide, School of Animal and Veterinary Sciences, 2022

碩士
國立屏東科技大學
獸醫學系所
100
Newcastle disease virus (NDV) is a highly virulent pathogens of poultrys. Since the recently high occurrence of the Newcastle disease (ND) have been found correlated with the antigenic variation of the causative velogenic viscerotropic NDV (VVNDV)，9 isolates of NDV isolated during 2008 to 2010 were chosed to run of its pathogenicity evaluation in term of mean death time (MDT) in chicken embryos, cross hemagglutination- inhibition (HI) test for figuring out of its R-value, phylogenetic analysis of its F gene nucleotide sequence and comparison of the F gene deduced amino acid sequence with the corresponding strains retrieved from GenBank. All the 9 isolates were found with MDT of 44-52 hour and classified as the VVNDV，phylogenetically grouping asⅦe4 basis on the F gene nucleotide analysis and all characterized with 5 deduced amino acids changes (L23-F、I26-T、T29-A、S30-N和T90-A)on its F protein. Seven inactivated ND oil emulsion vaccines (OEV) with monovalent or bivalent antigens prepared from 5 variant genotype of NDVs (VII-V158、III-Ishii、II-VH、II- LaSota及III-Sato) were used for immunizing a group of leghorn males preimmunized with B1 and LaSota live ND vaccines. All the chickens were bled at 3 and 6 weeks post vaccination of the ND inactivated OEV. Each group was then divided into 2 subgroups. Each subgroup was then orally challenged with the Sato strain or a mixture of 4 isolates of genotype VII NDVs (NDV-VII-4). The protectivity of each subgroup against Sato strain challenge was all over 80%. Meanwhile only the subgroup immunized with the vaccine containing the V158 antigen provided 100% protectivity against NDV-VII-4 challenge. In order to figuring out the quanitity of antigen for putting in the inactivated ND vaccine, 4 isolates (V158,V165,V223 and V301) of genotype VII NDV antigen prepared from chicken embryo allantoic fluid or cell culture were used for preparing 16 aluminum hydroxide type vaccines at 4 levels (4X, 2X, 1X and 0.5X) of antigen for immunizing a group of leghorn males preimmunized with B1 and LaSota live ND vaccines. All the chickens were bled at 3 weeks post vaccination of the ND inactivated vaccine. Each group was then orally challenged with the NDV-VII-4. At 7 days post challenges, all the conrol group chickens were died out. Meanwhile all the inactivated NDV immunized provided 100% protection except the groups of the chickens immunized with the inactivated vaccine containing the V165 antigen origeiated from chicken embryo. The above 4 strains of VII genotype NDV is good for using as ND inactivated vaccine producing seed.