Showing papers on "Newcastle disease published in 2021"

A Newcastle disease virus expressing a stabilized spike protein of SARS-CoV-2 induces protective immune responses.

Abstract: Rapid development of COVID-19 vaccines has helped mitigating SARS-CoV-2 spread, but more equitable allocation of vaccines is necessary to limit the global impact of the COVID-19 pandemic and the emergence of additional variants of concern. We have developed a COVID-19 vaccine candidate based on Newcastle disease virus (NDV) that can be manufactured at high yields in embryonated eggs. Here, we show that the NDV vector expressing an optimized spike antigen (NDV-HXP-S) is a versatile vaccine inducing protective antibody responses. NDV-HXP-S can be administered intramuscularly as inactivated vaccine or intranasally as live vaccine. We show that NDV-HXP-S GMP-produced in Vietnam, Thailand and Brazil is effective in the hamster model. Furthermore, we show that intramuscular vaccination with NDV-HXP-S reduces replication of tested variants of concerns in mice. The immunity conferred by NDV-HXP-S effectively counteracts SARS-CoV-2 infection in mice and hamsters.

Molecular Characterization of Velogenic Newcastle Disease Virus (Sub-Genotype VII.1.1) from Wild Birds, with Assessment of Its Pathogenicity in Susceptible Chickens.

Abstract: Newcastle disease (ND) is considered to be one of the most economically significant avian viral diseases. It has a worldwide distribution and a continuous diversity of genotypes. Despite its limited zoonotic potential, Newcastle disease virus (NDV) outbreaks in Egypt occur frequently and result in serious economic losses in the poultry industry. In this study, we investigated and characterized NDV in wild cattle egrets and house sparrows. Fifty cattle egrets and fifty house sparrows were collected from the vicinity of chicken farms in Kafrelsheikh Governorate, Egypt, which has a history of NDV infection. Lung, spleen, and brain tissue samples were pooled from each bird and screened for NDV by real-time reverse transcriptase polymerase chain reaction (RRT-PCR) and reverse transcriptase polymerase chain reaction (RT-PCR) to amplify the 370 bp NDV F gene fragment. NDV was detected by RRT-PCR in 22 of 50 (44%) cattle egrets and 13 of 50 (26%) house sparrows, while the conventional RT-PCR detected NDV in 18 of 50 (36%) cattle egrets and 10 of 50 (20%) of house sparrows. Phylogenic analysis revealed that the NDV strains identified in the present study are closely related to other Egyptian class II, sub-genotype VII.1.1 NDV strains from GenBank, having 99.7–98.5% identity. The pathogenicity of the wild-bird-origin NDV sub-genotype VII.1.1 NDV strains were assessed by experimental inoculation of identified strains (KFS-Motobas-2, KFS-Elhamoul-1, and KFS-Elhamoul-3) in 28-day-old specific-pathogen-free (SPF) Cobb chickens. The clinical signs and post-mortem changes of velogenic NDV genotype VII (GVII) were observed in inoculated chickens 3 to 7 days post-inoculation, with 67.5–70% mortality rates. NDV was detected in all NDV-inoculated chickens by RRT-PCR and RT-PCR at 3, 7, and 10 days post-inoculation. The histopathological findings of the experimentally infected chickens showed marked pulmonary congestion and pneumonia associated with complete bronchial stenosis. The spleen showed histocytic cell proliferation with marked lymphoid depletion, while the brain had malacia and diffuse gliosis. These findings provide interesting data about the characterization of NDV in wild birds from Egypt and add to our understanding of their possible role in the transmission dynamics of the disease in Egypt. Further research is needed to explore the role of other species of wild birds in the epidemiology of this disease and to compare the strains circulating in wild birds with those found in poultry.

Phylodynamic analyses of class I Newcastle disease virus isolated in China

Abstract: Newcastle disease virus (NDV), the pathogen of Newcastle disease, has caused significant losses to the poultry industry worldwide. However, owing to its avirulence, class I NDVs have not been studied as much as class II NDVs. We aimed to epidemiologically monitor the spread of class I NDVs in China. We isolated 104 class I NDV strains from poultry in live poultry markets (LPMs) of Guangdong Province, south China, between January 2016 and December 2018. Genetic analysis revealed that all 104 isolates and most of the strains isolated from China were clustered into genotype 1.1.2 of class I NDVs. Bayesian analysis revealed that, although the United States may be the source, east and south China may be the epicentres of class I NDVs in China. In addition, in China, class I NDVs are presumably transmitted by chickens and domestic ducks as the virus is mostly prevalent in these birds. These novel findings demonstrated that class I NDVs are prevalent in south China, and it is important to perform routine surveillance and limit the numbers of different birds in different areas of LPMs to decrease the risk of intra- and interspecies transmission of NDVs.

Diseases Of Poultry In Zaria, Nigeria: A Ten Year Analysis Of Clinic Records

Abstract: A to~year study of poultry diseases diagnosed at the Avian clinic of Veterinary Teaching Hospital, Ahmadu Bello University, Zaria was conducted. In all 2999 cases were studied. The commonest diseases afflicting poultry were Newcastle disease, 31.2%, Gumboro 12.0%, Ectoparasitism 7.7%, Fowl pox 6.8%, Helminthiasis 6.6% and Coccidiosis 6.1%. Most outbreaks occurred in the months of May and June with the highest incidence in 1989. Fowl pox (FP), infectious bursal disease (180) and coccidiosis were more prevalent during the rainy season (May-October) while Newcastle disease (NCD) and Aspergillosis were more prevalent in the dry season (November - April). More cases of chronic respiratory disease (CRD), helminthiasis and salmonellosis were found in poultry over 12 weeks old while gumboro, fowl pox and · coccidiosis were found more in birds less than 7 weeks old. It was concluded from this study that viral diseases (NCD, IBO, FP) ectoparasitism and helminthiasis were the most important poultry diseases in Zaria and young birds were more susceptible. The need for an effective poultry health programme is imperative. It is therefore recommended that effective and uniform vaccination schedules should be conducted along with regular deworming and ectoparasite control to enhance poultry production. Keywords: Disease, Poultry, Zaria

Review of Poultry Recombinant Vector Vaccines.

Abstract: The control of poultry diseases has relied heavily on the use of many live and inactivated vaccines. However, over the last 30 yr, recombinant DNA technology has been used to generate many novel poultry vaccines. Fowlpox virus and turkey herpesvirus are the two main vectors currently used to construct recombinant vaccines for poultry. With the use of these two vectors, more than 15 recombinant viral vector vaccines against Newcastle disease, infectious laryngotracheitis, infectious bursal disease, avian influenza, and Mycoplasma gallisepticum have been developed and are commercially available. This review focuses on current knowledge about the safety and efficacy of recombinant viral vectored vaccines and the mechanisms by which they facilitate the control of multiple diseases. Additionally, the development of new recombinant vaccines with novel vectors will be briefly discussed.

Safety and Immunogenicity Analysis of a Newcastle Disease Virus (NDV-HXP-S) Expressing the Spike Protein of SARS-CoV-2 in Sprague Dawley Rats

Abstract: Despite global vaccination efforts, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve and spread globally. Relatively high vaccination rates have been achieved in most regions of the United States and several countries worldwide. However, access to vaccines in low- and mid-income countries (LMICs) is still suboptimal. Second generation vaccines that are universally affordable and induce systemic and mucosal immunity are needed. Here we performed an extended safety and immunogenicity analysis of a second-generation SARS-CoV-2 vaccine consisting of a live Newcastle disease virus vector expressing a pre-fusion stabilized version of the spike protein (NDV-HXP-S) administered intranasally (IN), intramuscularly (IM), or IN followed by IM in Sprague Dawley rats. Local reactogenicity, systemic toxicity, and post-mortem histopathology were assessed after the vaccine administration, with no indication of severe local or systemic reactions. Immunogenicity studies showed that the three vaccination regimens tested elicited high antibody titers against the wild type SARS-CoV-2 spike protein and the NDV vector. Moreover, high antibody titers were induced against the spike of B.1.1.7 (alpha), B.1.351 (beta) and B.1.617.2 (delta) variants of concern (VOCs). Importantly, robust levels of serum antibodies with neutralizing activity against the authentic SARS-CoV-2 USA‐WA1/2020 isolate were detected after the boost. Overall, our study expands the pre-clinical safety and immunogenicity characterization of NDV-HXP-S and reinforces previous findings in other animal models about its high immunogenicity. Clinical testing of this vaccination approach is ongoing in different countries including Thailand, Vietnam, Brazil and Mexico.

In vivo oncolytic activity of non-virulent newcastle disease virus Iraqi strain against mouse mammary adenocarcinoma

Abstract: Newcastle disease virus (NDV) is promising antitumor agent that triggers immediate cytolysis of the tumor, apoptosis and activation of the immune system. This study was aimed at testing the antiangiogenic NDV Performance on a model of breast cancer. NDV has been studied against mammalian adenocarcinoma AN3 transplanted into syngeneic immunocompetent mice through intratumoral injection to determine the antitumor activity of NDV in vivo. Histopathological sections for the treated tumor mass demonstrated proliferation of granulation tissue with substantial necrosis region. This study indicated the role of Iraqi strain NDV in reducing the volume of solid tumor when compared with untreated group which is confirmed feature that make NDV Iraqi strain as anti-tumor agents.

Genetic and biological characterization of Newcastle disease viruses circulating in Bangladesh during 2010–2017: further genetic diversification of class II genotype XIII in Southcentral Asia

Abstract: Newcastle disease virus (NDV) is endemic in Bangladesh and is a major threat to commercial poultry operations. While complete fusion (F) genes are recommended for molecular characterization and classification of NDV isolates, heretofore, only partial F gene data have been available for Bangladeshi NDVs. To this end, we obtained the full-length F gene coding sequences of 11 representative NDVs isolated in Bangladesh between 2010 and 2017. In addition, one of the viruses (MK934289/chicken/Bangladesh/C161/2010) was used in an experimental infection of chickens to establish the viral pathotype and study gross and microscopic lesions. Phylogenetic analysis provided evidence that all studied Bangladeshi isolates belong to genotype XIII.2 of class II NDVs. Six of the viruses were isolated between 2010 and 2017 and grouped together with isolates from neighbouring India during 2013-2016. Another four Bangladeshi isolates (2010-2016) formed a separate monophyletic branch within XIII.2 and showed high nucleotide distance from the isolates from India and the other six Bangladeshi viruses within the sub-genotype; however, none of these groups fulfils all classification criteria to be named as a separate sub-genotype. The eleventh Bangladeshi virus studied here (C162) was genetically more distant from the remaining isolates. It out-grouped the viruses from sub-genotypes XIII.2.1 and XIII.2.2 and showed more than 9.5 % nucleotide distance from all genotype XIII sub-genotypes. This isolate may represent an NDV variant that is evolving independently from the other viruses in the region. The experimental infection in chickens revealed that the tested isolate (C161) is a velogenic viscerotropic virus. Massive haemorrhages, congestion and necrosis in different visceral organs, and lymphoid depletion in lymphoid tissues, typical for infection with velogenic NDV, were observed. Our findings demonstrate the endemic circulation of sub-genotype XIII.2 in Southcentral Asia and further genetic diversification of these viruses in Bangladesh and neighbouring India. This constant evolution of the viruses may lead to the establishment of new genetic groups in the region. Additional historical and prospective virus and surveillance data from the region and neighbouring countries will allow a more detailed epidemiological inference.

Zoonotic potential of Newcastle disease virus: Old and novel perspectives related to public health

Abstract: Newcastle disease virus (NDV) has a worldwide distribution, causing lethal infection in a wide range of avian species. Affected birds develop respiratory, digestive and neurologic symptoms with profound immunosuppression. Mild systemic Newcastle disease (ND) infection restricted to the respiratory and neurological systems can be observed in humans and other non-avian hosts. Evidence of ND infection and its genome-based detection have been reported in Bovidae (cattle and sheep), Mustelidae (mink), Cercetidae (hamster), Muridae (mice), Leporidae (rabbit), Camelidae (camel), Suidae (pig), Cercophithecidae (monkeys) and Hominidae (humans). Owing to frequent ND outbreaks in poultry workers, individuals engaged in the veterinary field, including poultry production or evisceration and vaccine production units have constantly been at a much higher risk than the general population. A lethal form of infection has been described in immunocompromised humans and non-avian species including mink, pig and cattle demonstrating the capability of NDV to cross species barriers. Therefore, contact with infectious material and/or affected birds can pose a risk of zoonosis and raise public health concerns. The broad and expanding host range of NDV and its maintenance within non-avian species hampers disease control, particularly in disease-endemic settings.

Efficacy of a turkey herpesvirus double construct vaccine (HVT-ND-IBD) against challenge with different strains of Newcastle disease, infectious bursal disease and Marek's disease viruses

Abstract: A double construct vaccine of turkey herpesvirus (HVT) was prepared that contains the fusion (F) gene from Newcastle disease virus (NDV) and the viral protein 2 (VP2) gene from infectious bursal disease virus (IBDV). Safety of the vaccine (HVT-ND-IBD) was confirmed and efficacy was evaluated after subcutaneous (SC) vaccination at 1 day of age or the in ovo route of vaccination. Challenges were performed with velogenic NDV strains (Texas GB and Herts Weybridge 33/56), with different strains of IBDV (classical strain STC; very virulent strain CS89 and variant E strain) and with Marek's disease virus (MDV) strain RB1B. Vaccination with HVT-ND-IBD induced a high level of protection against these challenges. Vaccination with HVT is often combined with Rispens CVI988 vaccine and live ND vaccines for higher and earlier, MD and ND protection, respectively. HVT-ND-IBD vaccination in combination with these vaccines showed MD protection as early as 4 days post vaccination and ND protection as early as 2 weeks post vaccination. The long protection as seen with HVT vaccination was confirmed by demonstrating protection against NDV up to 60 weeks. Finally, to evaluate the performance of the vaccine in commercial birds with maternally-derived antibodies, two field trials were performed, using in ovo vaccination in broilers and SC vaccination in combination with Rispens CVI988 vaccine in layer-type birds. The efficacy was confirmed for all components by challenges. These results demonstrate that HVT-ND-IBD is a safe and highly efficacious vaccine for simultaneous control of ND, IBD and MD. RESEARCH HIGHLIGHTS A double construct HVT vaccine with the NDV F and the IBDV VP2 genes was prepared. The vaccine protects against three important diseases: MDV, NDV and IBDV. In ovo and sub-cutaneous vaccination was evaluated in the field in commercial chickens.

Surveillance on respiratory diseases reveals enzootic circulation of both H5 and H9 avian influenza viruses in small-scale commercial layer farms of Bangladesh

Abstract: Poultry production in Bangladesh has been experiencing H5N1 highly pathogenic avian influenza (HPAI) and H9N2 low pathogenic avian influenza (LPAI) for the last 14 years. Vaccination of chickens against H5 HPAI is in practice since the end of 2012. Subsequently, the official reporting of HPAI outbreaks gradually decreased. However, the true extent of circulation of avian influenza virus (AIV) in commercial poultry production is not clear. To explore this, we conducted active surveillance in 422 small-scale commercial layer farms in 20 villages of Mymensingh and Tangail districts of Bangladesh during 2017 and 2018 for the presence of diseases with respiratory signs. A total of 88 farms with respiratory disease problems were identified and investigated during the surveillance. In addition, 22 small-scale commercial layer farms in the neighbouring areas with respiratory disease problem were also investigated on request from the farmers. Pooled samples of oropharyngeal swabs from live birds or respiratory tissues from dead birds of the farm suffering from respiratory disease problem were tested for molecular detection of avian influenza virus (AIV), Newcastle disease virus (NDV), infectious bronchitis virus (IBV), infectious laryngotracheitis virus (ILTV), Mycoplasma gallisepticum and Avibacterium paragallinarum. A total of 110 farms (88 in the surveillance site and 22 in the neighbouring region) were investigated, and one or more respiratory pathogens were detected from 89 farms. AIV was detected in 57 farms often concurrently with other pathogens. Among these 57 farms, H5, H9, both H5 and H9 or non-H5 and non-H9 AIV were detected in 28, 9, 13 or 7 farms, respectively. Birds of most of the H5 AIV-positive farms did not present typical clinical signs or high mortality. Twenty such farms were observed longitudinally, which had only 1.05%-5.50% mortality but a marked drop in egg production. This widespread circulation of H5 AIV along with H9 AIV and other pathogens in small-scale commercial layer farms, often with low mortality, reaffirms the enzootic circulation of AIV in Bangladesh, which may escape syndromic surveillance focused on unusual mortality only. To reduce public health risks, strengthening of the control programme with comprehensive vaccination, enhanced biosecurity, improved surveillance and outbreak response is suggested.

Prevalence of Newcastle Disease Virus in Commercial and Backyard Poultry in Haryana, India.

Abstract: Newcastle disease virus (NDV) causes Newcastle disease (ND) in poultry. The ND is a highly contagious disease, which is endemic in several countries despite regular vaccination with live or killed vaccines. Studies on NDV in India are mostly targeted toward its detection and characterization from disease outbreaks. A surveillance study was undertaken to determine NDV prevalence throughout the state of Haryana from March 2018 to March 2020 using a stratified sampling scheme. The state was divided into three different zones and a total of 4,001 choanal swab samples were collected from backyard poultry, commercial broilers, and layers. These samples were tested for the M gene of NDV using real-time RT-PCR. Of the 4,001 samples tested, 392 were positive (9.8% apparent prevalence; 95% CI: 8.9-10.8%) for the M gene. Of these 392 M gene positive samples, 35 (8.9%; 95% CI: 6.4-12.3%) were found to be positive based on F gene real-time RT-PCR. Circulation of NDV in commercial and backyard poultry highlights the importance of surveillance studies even in apparently healthy flocks. The information generated in this study should contribute to better understanding of NDV epidemiology in India and may help formulate appropriate disease control strategies for commercial and backyard birds.

Surveillance and Genetic Characterization of Virulent Newcastle Disease Virus Subgenotype V.3 in Indigenous Chickens from Backyard Poultry Farms and Live Bird Markets in Kenya

Abstract: Kenyan poultry consists of ~80% free-range indigenous chickens kept in small flocks (~30 birds) on backyard poultry farms (BPFs) and they are traded via live bird markets (LBMs). Newcastle disease virus (NDV) was detected in samples collected from chickens, wild farm birds, and other domestic poultry species during a 2017-2018 survey conducted at 66 BPFs and 21 LBMs in nine Kenyan counties. NDV nucleic acids were detected by rRT-PCR L-test in 39.5% (641/1621) of 1621 analyzed samples, of which 9.67% (62/641) were NDV-positive by both the L-test and a fusion-test designed to identify the virulent virus, with a majority being at LBMs (64.5%; 40/62) compared to BPFs (25.5%; 22/62). Virus isolation and next-generation sequencing (NGS) on a subset of samples resulted in 32 complete NDV genome sequences with 95.8-100% nucleotide identities amongst themselves and 95.7-98.2% identity with other east African isolates from 2010-2016. These isolates were classified as a new sub-genotype, V.3, and shared 86.5-88.9% and 88.5-91.8% nucleotide identities with subgenotypes V.1 and V.2 viruses, respectively. The putative fusion protein cleavage site (113R-Q-K-R↓F 117) in all 32 isolates, and a 1.86 ICPI score of an isolate from a BPF chicken that had clinical signs consistent with Newcastle disease, confirmed the high virulence of the NDVs. Compared to genotypes V and VI viruses, the attachment (HN) protein of 18 of the 32 vNDVs had amino acid substitutions in the antigenic sites. A time-scaled phylogeographic analysis suggests a west-to-east dispersal of the NDVs via the live chicken trade, but the virus origins remain unconfirmed due to scarcity of continuous and systematic surveillance data. This study reveals the widespread prevalence of vNDVs in Kenyan backyard poultry, the central role of LBMs in the dispersal and possibly generation of new virus variants, and the need for robust molecular epidemiological surveillance in poultry and non-poultry avian species.

Generation and Evaluation of Recombinant Thermostable Newcastle Disease Virus Expressing the HA of H9N2 Avian Influenza Virus

Abstract: H9N2 avian influenza virus (AIV) has become endemic in many countries, causing great economic losses when co-infected with other pathogens. So far, several live vaccines based on Newcastle disease virus (NDV) vectors expressing influenza hemagglutinin (HA) have been developed. However, the thermostable recombinant NDV is rarely reported. In this study, using a thermostable NDV rAHR09 strain as the vector, three recombinant NDVs expressing native HA, chimeric HA ectodomain with transmembrane domain/C-terminal cytoplasmic tail domain from fusion protein of NDV, and HA ectodomain were generated, designated rAHR09-HA, rAHR09-HAF, and rAHR09-HAE. The MDT value of three recombinant NDVs was above 120 h, their ICPI value was about 0.03, and the recombinant NDVs were still infectious when treated for 100 min under 56 °C, which demonstrated that the recombinant NDVs kept the lentogenic and thermostable nature of rAHR09. The immunization data showed that rAHR09-HA and rAHR09-HAF induced a higher HI antibody titer against H9N2 AIV and NDV. After being challenged with H9N2 AIV, the rAHR09-HA and rAHR09-HAF could significantly reduce the virus shedding in cloacal and tracheal swab samples. Our results suggest that rAHR09-HA and rAHR09-HAF might be vaccine candidates against H9N2 AIV.

A Pigeon-Derived Sub-Genotype XXI.1.2 Newcastle Disease Virus from Bangladesh Induces High Mortality in Chickens.

Abstract: Newcastle disease virus (NDV) is a significant pathogen of poultry; however, variants also affect other species, including pigeons. While NDV is endemic in Bangladesh, and poultry isolates have been recently characterized, information about viruses infecting pigeons is limited. Worldwide, pigeon-derived isolates are commonly of low to moderate virulence for chickens. Here, we studied a pigeon-derived NDV isolated in Bangladesh in 2010. To molecularly characterize the isolate, we sequenced its complete fusion gene and performed a comprehensive phylogenetic analysis. We further studied the biological properties of the virus by estimating mean death time (MDT) and by experimentally infecting 5-week-old naive Sonali chickens. The studied virus clustered in sub-genotype XXI.1.2 with NDV from pigeons from Pakistan isolated during 2014–2018. Deduced amino acid sequence analysis showed a polybasic fusion protein cleavage site motif, typical for virulent NDV. The performed in vivo pathogenicity testing showed a MDT of 40.8 h, and along with previously established intracerebral pathogenicity index of 1.51, these indicated a velogenic pathotype for chickens, which is not typical for pigeon-derived viruses. The experimental infection of chickens resulted in marked neurological signs and high mortality starting at 7 days post infection (dpi). Mild congestion in the thymus and necrosis in the spleen were observed at an advanced stage of infection. Microscopically, lymphoid depletion in the thymus, spleen, and bursa of Fabricius were found at 5 dpi, which progressed to severe in the following days. Mild to moderate proliferation of glial cells was noticed in the brain starting at 2 dpi, which gradually progressed with time, leading to focal nodular aggregation. This study reports the velogenic nature for domestic chickens of a pigeon-derived NDV isolate of sub-genotype XXI.1.2. Our findings show that not all pigeon-derived viruses are of low virulence for chickens and highlight the importance of biologically evaluating the pathogenicity of NDV isolated from pigeons.

Genomic and biological characteristics of Avian Orthoavulavirus-1 strains isolated from multiple wild birds and backyard chickens in Pakistan

Abstract: Circulation of the dominant sub-genotype VII.2 of Avian Orthoavulavirus-1 (AOAV-1) is affecting multiple poultry and non-poultry avian species and causing significant economic losses to the poultry industry worldwide. In countries where ND is endemic, continuous monitoring and characterization of field strains are necessary. In this study, genetic characteristics of eleven AOAV-1 strains were analyzed isolated from wild birds including parakeets (n = 3), lovebird parrot (n = 1), pheasant (n = 1), peacock (n = 1), and backyard chickens (n = 5) during 2015–2016. Genetic characterization (genome size [15,192 nucleotides], the presence of typical cleavage site [112−RRQKRF−117]) and biological assessment (HA log 27 to 29 and intracerebral pathogenicity index [ICPI] value ranging from 1.50 to 1.86) showed virulent AOAV-1. Phylogenetic analysis showed that the studied isolates belonged to sub-genotype VII.2 and genetically very closely related (> 98.9%) to viruses repeatedly isolated (2011–2018) from commercial poultry. These findings provide evidence for the existence of epidemiological links between poultry and wild bird species in the region where the disease is prevalent. The deduced amino acid analysis revealed several substitutions in critical domains of fusion and hemagglutinin-neuraminidase genes. The pathogenesis and transmission potential of wild bird-origin AOAV-1 strain (AW-Pht/2015) was evaluated in 21-day-old chickens that showed the strain was highly virulent causing clinical signs and killed all chickens. High viral loads were detected in different organs of the infected chickens correlating with the severity of lesions developed. The continuous monitoring of AOAV-1 isolates in different species of birds will improve our knowledge of the evolution of these viruses, thereby preventing possible panzootic.

Comparison of genomic and antigenic properties of Newcastle Disease virus genotypes II, XXI and VII from Egypt do not point to antigenic drift as selection marker.

Abstract: Newcastle disease (ND), caused by avian orthoavulavirus type‐1 (NDV), is endemic in poultry in many regions of the world and causes continuing outbreaks in poultry populations. In the Middle East, genotype XXI, , used to be present in poultry in Egypt but has been replaced by genotype VII. We investigated whether virus evolution contributed to superseding and focused on the antigenic sites within the Hemagglutinin‐Neuraminidase (HN) spike protein. Full length sequences of an NDV genotype VII isolate currently circulating in Egypt was compared to a genotype XXI isolate that was present as co‐infection with vaccine type viruses (II) in a historical virus isolated in 2011. Amino acid differences in the HN glycoprotein for both XXI and VII viruses amounted to 11.7% and 11.9 %, respectively, compared to the La Sota vaccine type. However, mutations within the globular head (aa 126‐570), bearing relevant antigenic sites, were underrepresented (aa divergence of 8.8% and 8.1 % compared to 22.4% and 25.6% within the protein domains encompassing cytoplasmic tail, transmembrane part and stalk regions (aa 1‐125) for genotypes XXI and VII, respectively). Nevertheless, reaction patterns of HN‐specific monoclonal antibodies inhibiting receptor binding revealed differences between vaccine type viruses and genotype XXI and VII viruses for epitopes located in the head domain. Accordingly, compared to Egyptian vaccine type isolates and the La Sota vaccine reference strain, single aa substitutions in 6 of 10 described neutralizing epitopes of HN were found. However, the same alterations in neutralization sensitive epitopes were present in old genotype XXI as well as in newly emerged genotype VII isolates. In addition, isolates were indistinguishable by polyclonal chicken sera raised against different genotypes including vaccine viruses. These findings suggest that factors other than antigenic differences within the HN protein account for facilitating the spread of genotype VII versus genotype XXI viruses in Egypt.

Comparison of two attenuated infectious bursal disease vaccine strains focused on safety and antibody response in commercial broilers.

Abstract: Background and Aim Infectious bursal disease (IBD) or Gumboro disease is one of the most detrimental diseases in the poultry industry worldwide. Previous scientific studies have shown that live IBD vaccination might induce transient immunosuppression, leading to suboptimal vaccine responses, and therefore lack of protection against other infectious diseases; therefore, selecting an IBD vaccine in commercial farms is a concern. This study aims to compare two commercially attenuated IBD vaccines (intermediate and intermediate-plus strains) in terms of safety and antibody response to IBD and Newcastle disease viruses (NDV) in commercial broilers. Materials and Methods Overall, 216 Cobb broiler chickens were divided into three groups based on the IBD vaccine strain administered: V217 strain (Group 1), M.B. strain (Group 2), and an unvaccinated group (Group 3). Groups 1 and 2 were orally vaccinated with Hitchner B1 NDV vaccine strain 7 days after IBD vaccination. Blood samples were collected at IBD vaccination day (15 days of age) and at 7, 14, 21, and 28 days post-IBD vaccination. The immunosuppressive effects of the IBD vaccination were determined by NDV antibody response, the bursa:body weight (B:BW) ratio, and the histopathological lesion scores of the bursa of Fabricius. Phylogenetic analysis was also performed. Results Phylogenetic analysis revealed that the M.B. strain belonged to a very virulent IBD strain, whereas the V217 strain belonged to a classical IBD virus strain. NDV antibody titers of the two vaccinated groups increased after ND vaccination, reaching their maximum at 14 days post-ND vaccination and decreasing thereafter. The V217 group presented the highest NDV humoral response from 7 days post-vaccination (dpv) to the end of the study. The mean NDV antibody titer of the V217 group was significantly (p<0.05) higher than that of the M.B. group at 14 dpv. In addition, the V217 strain-induced lower bursal lesions post-IBD vaccination and a higher B: BW ratio at 7 and 21 dpv compared to the M.B. group. The higher B: BW ratio, lower bursal lesions, and higher ND antibody response present in the V217 group indicate that the V217 strain induces lower immunosuppressive effects compared to the M.B. strain. Conclusion The results of this study indicate that IBD vaccine selection merits consideration, as avoiding the immunosuppressive effects induced by live IBD vaccination and the consequent impact on response to other vaccines is important.

Evaluating Disease Threats to Sustainable Poultry Production in Africa: Newcastle Disease, Infectious Bursal Disease, and Avian Infectious Bronchitis in Commercial Poultry Flocks in Kano and Oyo States, Nigeria.

Abstract: The growth of the poultry industry in Nigeria is constrained by major poultry diseases, despite the implementation of vaccination programs. This study aimed to assess the level of protection against Newcastle disease (ND), infectious bursal disease (IBD), and avian infectious bronchitis (IB) afforded by current vaccination schedules and characterize the circulating virus strains in commercial poultry flocks in Nigeria. A cross-sectional study was conducted on 44 commercial poultry farms in Oyo and Kano states of Nigeria. Serum and tissue samples and data on flock, clinical and vaccination records were collected on each farm. Farms were classified as being protected or not protected against ND, IBD and IB based on a defined criterion. Real-time reverse transcription polymerase chain reaction (rRT-PCR) testing was performed for each target virus on tissue samples and positive samples were sequenced. A total of 15/44 (34.1%), 35/44 (79.5%), and 1/44 (2.3%) farms were considered to be protected against ND, IBD, and IB, respectively, at the time of sampling. NDV RNA was detected on 7/44 (15.9%) farms and sequences obtained from 3/7 farms were characterized as the lentogenic strain. Infectious bursal disease virus (IBDV) RNA was detected on 16/44 (36.4%) farms tested; very virulent (vv) IBDV and non-virulent (nv) IBDV strains were both detected in 3/16 (18.8%) positive samples. Sequences of IBDV isolates were either clustered with a group of genotype 3 virulent IBDV strains or were related to vaccine strains MB and D78 strains. IBV RNA was detected on 36/44 (81.8%) farms, with variant02, Massachusetts, 4/91, and Q1 variants detected. Sequences of IBV isolates were either clustered with the vaccines strains Massachusetts M41 and H120 or were most closely related to the D274-like strains or a clade of sequences reported in Nigeria and Niger in 2006 and 2007. This study revealed that most study farms in Oyo and Kano states did not have adequate protective antibody titers against IBV and NDV and were therefore at risk of field challenge. Infectious bursal disease virus and IBV RNA were detected on farms with a history of vaccination suggesting potential vaccination failure, or that the vaccine strains used mismatch with the circulating strains and are therefore not protective.

A Newcastle disease virus-vector expressing a prefusion-stabilized spike protein of SARS-CoV-2 induces protective immune responses against prototype virus and variants of concern in mice and hamsters

Abstract: Rapid development of coronavirus disease 2019 (COVID-19) vaccines and expedited authorization for use and approval has been proven beneficial to mitigate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread and given hope in this desperate situation. It is believed that sufficient supplies and equitable allocations of vaccines are necessary to limit the global impact of the COVID-19 pandemic and the emergence of additional variants of concern. We have developed a COVID-19 vaccine based on Newcastle disease virus (NDV) that can be manufactured at high yields in embryonated eggs. Here we provide evidence that the NDV vector expressing an optimized spike antigen (NDV-HXP-S), upgraded from our previous construct, is a versatile vaccine that can be used live or inactivated to induce strong antibody responses and to also cross-neutralize variants of concern. The immunity conferred by NDV-HXP-S effectively counteracts SARS-CoV-2 infection in mice and hamsters. It is noteworthy that vaccine lots produced by existing egg-based influenza virus vaccine manufacturers in Vietnam, Thailand and Brazil exhibited excellent immunogenicity and efficacy in hamsters, demonstrating that NDV-HXP-S vaccines can be quickly produced at large-scale to meet global demands.

Preparation and evaluation of avian influenza (h9) and newcastle disease (thermostable i-2 strain) bivalent vaccine for commercial poultry

Abstract: The goal of current research was production of bivalent adjuvant based inactivated I-2 strain of Newcastle Disease (ND) and Avian Influenza (AI) vaccine and to compare efficacy with commercially available bivalent inactivated vaccine. Experiment was carried out on one-day-old broiler chicks by dividing them into 3 groups A, B & C. Vaccine was injected on 7, 14, 21 and 28 day. Blood samples were collected on 7, 14, 21, 28 and 35 day. Results of Hemagglutination Inhibition (HI) test presented the geometric mean titers of group A and B were <1:4, 1:18.8, 1:115.2, 1:358.4, 1:128 & <1:4, 1:8.4, 1:36.8, 1:56, 1:22.4 respectively for AI. Similarly the geometric mean titers of group A and B were <1:4, 1:19.6, 1:89.6, 1:320, 1:115.2 & <1:4, 1:9.2, 1:25.6, 1:36.8, 1:22.4, respectively for ND. However, control group showed <1:4 geometric mean titer. The challenge was given on 28th day and birds were monitored for next 7 days for clinical signs. The chicks of group A showed no clinical signs of diseases (AI, ND). However, in group B 60% morbidity and 90% mortality was recorded on 4th and 6th day of post challenge, respectively. While 100% mortality was recorded in control group.

gga-miR-1603 and gga-miR-1794 directly target viral L gene and function as a broad-spectrum antiviral factor against NDV replication.

Abstract: As the causative agent of Newcastle disease (ND), Newcastle disease virus (NDV) has seriously restricted the development of the poultry industry. Previous research has shown that miRNAs, members of...