| protection afforded by a recombinant turkey herpesvirus-h5 vaccine against the 2014 european highly pathogenic h5n8 avian influenza strain. | a highly pathogenic avian influenza (hpai) h5n8 (clade 2.3.4.4) virus, circulating in asia (south korea, japan, and southern china) since the beginning of 2014, reached the european continent in november 2014. germany, the netherlands, the united kingdom, italy, and hungary confirmed h5n8 infection of poultry farms of different species and of several wild bird species. unlike the asian highly pathogenic (hp) h5n1, this hp h5n8 also went transatlantic and reached the american west coast by the en ... | 2016 | 27309056 |
| efficacy of a recombinant turkey herpesvirus h5 vaccine against challenge with h5n1 clades 1.1.2 and 2.3.2.1 highly pathogenic avian influenza viruses in domestic ducks (anas platyrhynchos domesticus). | domestic ducks are the second most abundant poultry species in many asian countries and have played a critical role in the epizootiology of h5n1 highly pathogenic avian influenza (hpai).in this study, the protective efficacy of a live recombinant vector vaccine based on a turkey herpesvirus (hvt) expressing the h5 gene from a clade 2.2 h5n1 hpai strain (a/swan/hungary/4999/ 2006) (rhvt-h5/2.2), given at 3 days of age, was examined in pekin ducks (anas platyrhynchos domesticus). the vaccine was g ... | 2016 | 26953940 |
| comparison of the effectiveness of rhvt-h5, inactivated h5 and rhvt-h5 with inactivated h5 prime/boost vaccination regimes in commercial broiler chickens carrying mdas against hpai h5n1 clade 2.2.1 virus. | vaccination is the main tool implemented in egypt since 2007 to control h5n1 avian influenza. the present study aimed at comparing the effectiveness of three avian influenza vaccination regimes in commercial broiler chickens carrying high levels of maternally derived antibodies (mdas). day-old chicks were divided into four experimental groups. group i received only the rhvt-h5 vaccine (recombinant turkey herpesvirus (hvt) which carries a h5 clade 2.2 insert) administered at d1. group ii received ... | 2015 | 26023824 |
| vaccine protection of chickens against antigenically diverse h5 highly pathogenic avian influenza isolates with a live hvt vector vaccine expressing the influenza hemagglutinin gene derived from a clade 2.2 avian influenza virus. | vaccination is an important tool in the protection of poultry against avian influenza (ai). for field use, the overwhelming majority of ai vaccines produced are inactivated whole virus formulated into an oil emulsion. however, recombinant vectored vaccines are gaining use for their ability to induce protection against heterologous isolates and ability to overcome maternal antibody interference. in these studies, we compared protection of chickens provided by a turkey herpesvirus (hvt) vector vac ... | 2015 | 25613723 |
| protection conferred by recombinant turkey herpesvirus avian influenza (rhvt-h5) vaccine in the rearing period in two commercial layer chicken breeds in egypt. | the effectiveness of recombinant turkey herpesvirus avian influenza (a/swan/hungary/4999/2006(h5n1)) clade 2.2 virus (rhvt-h5) vaccine was evaluated in two layer chicken breeds (white bovans [wb] and brown shaver [bs]). one dose of rhvt-h5 vaccine was administered at day 1 and birds were monitored serologically (haemagglutination inhibition test) and virologically for 19 weeks. maternally-derived antibody and post-vaccination h5 antibody titres were measured using the chinese (a/goose/guangdong/ ... | 2014 | 25245772 |
| modified live infectious bursal disease virus (ibdv) vaccine delays infection of neonatal broiler chickens with variant ibdv compared to turkey herpesvirus (hvt)-ibdv vectored vaccine. | chickens are commonly processed around 35-45days of age in broiler chicken industry hence; diseases that occur at a young age are of paramount economic importance. early age infection with infectious bursal disease virus (ibdv) results in long-lasting immunosuppression and profound economic losses. to our knowledge, this is the first study comparing the protection efficacy of modified live (mdlv) ibdv and herpesvirus turkey (hvt)-ibdv vaccines against early age variant ibdv (varibdv) infection i ... | 2017 | 28089549 |
| characterization of two recombinant hvt-ibd vaccines by vp2 insert detection and cell-mediated immunity after vaccination of specific pathogen-free chickens. | infectious bursal disease (ibd) is an avian viral disease that causes severe economic losses in the poultry industry worldwide. the live ibd virus (ibdv) has a potential immunosuppressive effect. currently available ibdv vaccines have shortcomings, prompting the development of safer and more effective vaccination approaches, including the use of the recombinant turkey herpesvirus vaccine expressing the immunogenic structural vp2 protein of ibdv (rhvt-ibd). the objectives of this study were twofo ... | 2016 | 27897452 |
| efficacy of hvt-ibd vector vaccine compared to attenuated live vaccine using in-ovo vaccination against a korean very virulent ibdv in commercial broiler chickens. | the production performance, efficacy, and safety of two types of vaccines for infectious bursal disease virus (ibdv) were compared with in-ovo vaccination of cobb 500 broiler chickens for gross and microscopic examination of the bursa of fabricius, bursa/body weight (b/b) ratio, flow cytometry, and serologic response to newcastle disease virus (ndv) vaccination. one vaccine was a recombinant hvt-ibd vector vaccine (hvt as for herpesvirus of turkeys) and the other was an intermediate plus live ib ... | 2016 | 26944964 |
| comparison of infectious bursal disease live vaccines and a hvt-ibd vector vaccine and their effects on the immune system of commercial layer pullets. | infectious bursal disease (ibd) is an economically important disease affecting poultry production worldwide. previous experimental studies indicated that ibd live vaccination may induce transient immunosuppression, leading to suboptimal vaccine responses and therefore insufficient protection against other pathogens. layer pullets are commonly not only vaccinated against ibd within their rearing period, but also against a variety of other pathogens. therefore, it is of interest to investigate the ... | 2016 | 26743805 |
| effects of t-2 toxin on turkey herpesvirus-induced vaccinal immunity against marek's disease. | t-2 toxin, a very potent immunotoxic type a trichothecene, is a secondary metabolite produced primarily by fusarium spp., which grows on cereal grains and can lead to contaminated livestock feed. repeated exposure to t-2 toxin has been shown to cause immunosuppression and decrease the resistance of exposed animals to a variety of infectious diseases; however, the effects of t-2 toxin on marek's disease (md) vaccinal immunity have not been reported. four trials were conducted to determine the eff ... | 2016 | 26953944 |
| in ovo vaccination with turkey herpesvirus hastens maturation of chicken embryo immune responses in specific-pathogen-free chickens. | administration of marek's disease (md) vaccines in ovo has become a common practice for the poultry industry. efficacy of md vaccines is very high, even though they are administered to chicken embryos that are immunologically immature. we have recently demonstrated that in ovo vaccination with turkey herpesvirus (hvt) results in increased activation of t cells at hatch. our previous results suggested that in ovo vaccination with hvt might have a positive impact not only on md protection but also ... | 2015 | 26478155 |
| identification of non-essential loci within the meleagrid herpesvirus 1 genome. | meleagrid herpesvirus 1 (mehv-1) infectious bacterial artificial chromosomes (ibacs) are ideal vectors for the development of recombinant vaccines for the poultry industry. however, the full potential of ibacs as vectors can only be realised after thorough genetic characterisation, including identification of those genetic locations that are non-essential for virus replication. generally, transposition has proven to be a highly effective strategy for rapid and efficient mutagenesis of ibac clone ... | 2015 | 26307059 |
| chicken skin virome analyzed by high-throughput sequencing shows a composition highly different from human skin. | recent studies show that human skin at homeostasis is a complex ecosystem whose virome include circular dna viruses, especially papillomaviruses and polyomaviruses. to determine the chicken skin virome in comparison with human skin virome, a chicken swabs pool sample from fifteen indoor healthy chickens of five genetic backgrounds was examined for the presence of dna viruses by high-throughput sequencing (hts). the results indicate a predominance of herpesviruses from the mardivirus genus, comin ... | 2015 | 26223320 |
| quantification of rhvt-f genome load in feather follicles by specific real-time qpcr as an indicator of ndv-specific humoral immunity induced by day-old vaccination in spf chickens. | the purpose of this study was to look for a reliable molecular method for confirmation of uptake of recombinant turkey herpesvirus vaccine against newcastle disease (rhvt-f) and for use as a valuable prediction tool of newcastle disease virus (ndv)-specific immune response in chickens deprived of maternally derived antibody (mda). a quantitative real-time polymerase chain reaction (real-time qpcr) specific to rhvt-f was developed. the method was applied to various tissue samples taken from speci ... | 2015 | 25687165 |
| protection and antibody response caused by turkey herpesvirus vector newcastle disease vaccine. | newcastle disease (nd) is prevalent worldwide and causes significant clinical and economic losses to the poultry industry. current vaccine programs using live attenuated vaccines and inactivated vaccines have limitations, and new vaccines with distinct features are needed. to offer an alternative solution to control nd, a turkey herpesvirus vector newcastle disease vaccine (hvt/nd) expressing the fusion gene of newcastle disease virus (ndv) has been developed. first, immunogenicity of the hvt/nd ... | 2013 | 24597117 |
| onset and long-term duration of immunity provided by a single vaccination with a turkey herpesvirus vector nd vaccine in commercial layers. | the onset and duration of immunity provided by a recombinant nd vaccine using hvt virus as vector (rhvt-nd) was followed up to 72 weeks of age in commercial layer chickens after single application or as part of two different vaccination regimes including conventional live and killed nd vaccines. efficacy of the different vaccination programmes was checked, from 3 to 72 weeks of age, by serology as well as by challenges with a recent velogenic ndv isolate belonging to genotype vii. assessment of ... | 2014 | 24368086 |
| complete genome sequence of reticuloendotheliosis virus strain md-2, isolated from a contaminated turkey herpesvirus vaccine. | here, we present the complete genomic sequence of a reticuloendotheliosis virus (rev) isolated from a contaminated turkey herpesvirus (hvt) vaccine. this report will be helpful for epidemiological studies on rev infection in avian flocks. | 2013 | 24092783 |
| influence of the addition of antibiotics on survival of herpesvirus of turkeys. | to determine the influence of the antibiotics ceftiofur sodium from two different laboratories (a and b) and gentamycin sulfate on a marek's disease commercial vaccine herpesvirus of turkey (hvt), samples were assayed by titration in chicken embryo fibroblasts (cef). viruses were tested in vitro to establish the average number of plaque-forming units before and after different periods of incubation with the addition of the antibiotic. these tests showed no effect of gentamycin or ceftiofur a or ... | 2013 | 23901758 |
| the meleagrid herpesvirus 1 genome is partially resistant to transposition. | the propagation of herpesvirus genomes as infectious bacterial artificial chromosomes (ibac) has enabled the application of highly efficient strategies to investigate gene function across the genome. one of these strategies, transposition, has been used successfully on a number of herpesvirus ibacs to generate libraries of gene disruption mutants. gene deletion studies aimed at determining the dispensable gene repertoire of the meleagrid herpesvirus 1 (mehv-1) genome to enhance the utility of th ... | 2013 | 23901750 |
| expression of chicken parvovirus vp2 in chicken embryo fibroblasts requires codon optimization for production of naked dna and vectored meleagrid herpesvirus type 1 vaccines. | meleagrid herpesvirus type 1 (mehv-1) is an ideal vector for the expression of antigens from pathogenic avian organisms in order to generate vaccines. chicken parvovirus (chpv) is a widespread infectious virus that causes serious disease in chickens. it is one of the etiological agents largely suspected in causing runting stunting syndrome (rss) in chickens. initial attempts to express the wild-type gene encoding the capsid protein vp2 of chpv by insertion into the thymidine kinase gene of mehv- ... | 2013 | 23861017 |
| advancement in vaccination against newcastle disease: recombinant hvt ndv provides high clinical protection and reduces challenge virus shedding with the absence of vaccine reactions. | newcastle disease (nd) is a highly contagious disease of chickens causing significant economic losses worldwide. due to the limitation in their efficacy, current vaccination strategies against nd need improvements. this study aimed to evaluate a new-generation nd vaccine for its efficacy in providing clinical protection and reducing virus shedding after challenge. broiler chickens were vaccinated in ovo or subcutaneously at hatch with a turkey herpesvirus-based recombinant vaccine (rhvt) express ... | 2012 | 22856183 |
| enhancement of spontaneous bursal lymphoma frequency by serotype 2 marek's disease vaccine, sb-1, in transgenic and non-transgenic line 0 white leghorn chickens. | a significant incidence of bursal lymphomas with long latencies was noted in transgenic breeders carrying a benign defective subgroup a avian leukosis provirus, alva6, in their germline and maintained free of exposure to avian retroviruses. serotype 2 marek's disease (md) vaccine virus, strain sb-1, a component of the bivalent md vaccine used to vaccinate the breeders, was suspected as a contributory factor in the increased bursal lymphoma incidence. although these bursal lymphomas had several c ... | 1999 | 26911501 |
| temporary removal: homologous and heterologous antigenic matched vaccines containing different h5 hemagglutinins provide variable protection of chickens from the 2014 u.s. h5n8 and h5n2 clade 2.3.4.4 highly pathogenic avian influenza viruses. | the publisher regrets that this article has been temporarily removed. a replacement will appear as soon as possible in which the reason for the removal of the article will be specified, or the article will be reinstated. the full elsevier policy on article withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal. | 2017 | 28456525 |
| laboratory methods for assessing and licensing influenza vaccines for poultry. | avian influenza vaccines for poultry are based on hemagglutinin proteins, and protection is specific to the vaccine subtype. over 113 billion doses have been used between 2002 and 2010 for high pathogenicity avian influenza control. no universal vaccines are currently available. the majority of avian influenza vaccines are inactivated whole influenza viruses that are grown in embryonating eggs, inactivated, emulsified in oil adjuvant systems, and injected into chickens. live virus-vectored vacci ... | 2014 | 24899430 |
| in ovo evaluation of floramax®-b11 on marek´s disease hvt vaccine protective efficacy, hatchability, microbiota composition, morphometric analysis, and salmonella enteritidis infection in broiler chickens. | three experiments were conducted to evaluate the effect of in ovo administration of floramax®-b11 (fm) on marek´s disease (md) herpesvirus of turkeys (hvt) vaccine protective efficacy, hatchability, microbiota composition, morphometric analysis, and salmonella enteritidis (se) infection in chickens. experiment 1 consisted of 3 trials. in trials 1 and 2, d 18 white leghorn 15i5x71 embryos were randomly distributed in 4 groups: 1) hvt vaccinated in ovo and no marek's disease virus (mdv) challenge; ... | 2017 | 28160004 |
| efficacy of various hvt vaccines (conventional and recombinant) against marek's disease in broiler chickens: effect of dose and age of vaccination. | herpesvirus of turkeys (hvt) has been successfully used as a marek's disease (md) vaccine for more than 40 yr. either alone (broiler chickens) or in combination with vaccines of other serotypes (broilers, broiler breeders, and layers), hvt is used worldwide. in recent years, several vector vaccines based on hvt (rhvt) have been developed. at present, there are both conventional hvt and rhvts in the market, and it is unknown if all of them confer the same level of protection against md. the objec ... | 2016 | 27610727 |
| the combination of attenuated newcastle disease (nd) vaccine with rhvt-nd vaccine at 1 day old is more protective against nd virus challenge than when combined with inactivated nd vaccine. | the recurrent outbreaks of fatal newcastle disease (nd) in commercial poultry flocks throughout the world indicate that routine vaccinations are failing to sufficiently induce the high levels of immunity necessary to control nd. there is a need for vaccination programmes that could be initiated at 1-day-old for mass application and which would induce a long-lasting immunity, with no need for a booster vaccination at a later age. in this context, the duration of immunity delivered by a vaccinatio ... | 2014 | 24283258 |
| early immune responses and profiling of cell-mediated immunity-associated gene expression in response to rhvt-ibd vaccination. | infectious bursal disease (ibd) remains a major threat to the poultry industry. recombinant herpesvirus of turkey (rhvt)-ibd vaccines have been successfully used to induce a protective immune response against ibd. however, the capacity for rhvt-ibd vaccines to induce early protection without detectable antibodies, and the underlying mechanisms mediating specific cell-mediated responses in the early stages following vaccination, have been poorly investigated. therefore, in this study, specific pa ... | 2018 | 29290477 |
| application of loop-mediated isothermal amplification assay in the detection of herpesvirus of turkey (fc 126 strain) from chicken samples in nigeria. | this study was designed to optimize and apply the use of loop-mediated isothermal amplification (lamp) as an alternative to conventional polymerase chain reaction (pcr) for the detection of herpesvirus of turkeys (hvt) (fc 126 strain) in vaccinated and non-vaccinated poultry in nigeria. | 2017 | 29263603 |
| the efficacy of recombinant turkey herpesvirus vaccines targeting the h5 of highly pathogenic avian influenza virus from the 2014-2015 north american outbreak. | the outbreak of highly pathogenic avian influenza virus in north american poultry during 2014 and 2015 demonstrated the devastating effects of the disease and highlighted the need for effective emergency vaccine prevention and control strategies targeted at currently circulating strains. this study evaluated the efficacy of experimental recombinant turkey herpesvirus vector vaccines with three different inserts targeting the hemagglutinin gene of an isolate from the recent north american influen ... | 2018 | 29180030 |
| protection of commercial turkeys following inactivated or recombinant h5 vaccine application against the 2015u.s. h5n2 clade 2.3.4.4 highly pathogenic avian influenza virus. | between december 2014 and june 2015, north america experienced the largest recorded foreign animal disease outbreak with over 47 million poultry dead or euthanized from viral exposure to a clade 2.3.4.4 h5 highly pathogenic avian influenza (hpai) epizootic. soon after the epizootic began, the u.s. department of agriculture (usda) began testing the efficacy of different vaccines as a possible future control strategy. the aim of these studies were to evaluate the efficacy three h5 vaccines to aid ... | 2017 | 28895870 |
| different kinetics of chicken interferon-alpha signalling transduction responses following immunization of broiler chickens with different newcastle disease virus vaccines and infection with virulent genotype viid strain. | newcastle disease virus (ndv) is a highly contagious and notifiable avian disease leading to grave economic losses in the poultry industry. although the immune responses against ndv have been widely investigated, little is known regarding the virus interaction with the host innate immune responses. in this study, we tested the effect of different commercially applied newcastle disease vaccines as well as virulent ndv genotype viid on the expression pattern of the upstream regulator and downstrea ... | 2020 | 33146541 |
| mardivirus infection and persistence in feathers of a chicken model harboring a local autoimmune response. | herpesvirus of turkey (hvt) is commonly used as a vaccine to protect chickens against marek's disease. following vaccination, hvt infects feathers where it can be detected in all chicken lines examined. unlike the parental brown line (bl), smyth line (sl) chickens develop vitiligo, due to autoimmune destruction of melanocytes in feathers. previous reports showed a strong inflammatory response in smyth chickens' feathers at vitiligo onset, that subsided once melanocytes were destroyed, and depigm ... | 2020 | 33092272 |
| a herpesvirus of turkey-based vector vaccine reduces transmission of newcastle disease virus in commercial broiler chickens with maternally derived antibodies. | newcastle disease is one of the most important infectious poultry diseases worldwide and is associated with high morbidity, mortality, and economic loss. in several countries, vaccination is applied to prevent and control outbreaks; however, information on the ability of vaccines to reduce transmission of nd virus (ndv) is sparse. here we quantified the transmission of velogenic ndv among 42-day-old broilers. chickens were either vaccinated with a single dose of a vector vaccine expressing the f ... | 2020 | 33081359 |
| 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. | 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 ib ... | 2020 | 33063529 |
| effectiveness of a simultaneous rhvt-f(nd) and rhvt-h5(ai) vaccination of day-old chickens and the influence of ndv- and aiv-specific mda on immune response and conferred protection. | the recombinant herpesvirus of turkey (rhvt) vaccines targeting newcastle disease (nd) and h5nx avian influenza (ai) have been demonstrated efficient in chickens when used individually at day-old. given the practical field constraints associated with administering two vaccines separately and in the absence of a currently available bivalent rhvt vector vaccine expressing both f(nd) and h5(ai) antigens, the aim of this study was to investigate whether interference occurs between the two vaccines w ... | 2020 | 32948028 |
| marek's disease virus oncogene meq expression in infected cells in vaccinated and unvaccinated hosts. | marek's disease (md) vaccines are unique in their capability to prevent md lymphomas as early as a few days after vaccination, despite the fact that they do not eliminate virulent viruses from the host. to help understand the mechanism behind this unique md vaccine effect, we compared the expression of mdv oncoprotein meq among cd4+ t cells between vaccinated and unvaccinated birds. chickens were vaccinated by an md vaccine, herpesvirus of turkeys, and then challenged by a recombinant virulent m ... | 2020 | 32891023 |
| alteration of immunological parameters in infectious bronchitis vaccinated-specific pathogen-free broilers after the use of different infectious bursal disease vaccines. | the vaccines currently available to control infectious bursal disease (ibd) include live-attenuated and inactivated vaccines, immune-complex vaccines, and vaccines consisting of viral constructs of herpesvirus of turkeys genetically engineered to express vp2 surface protein. to evaluate the impact of vaccines on the chicken immune system, 2 animal trials were performed in specific pathogen-free broiler chickens. in trial 1, birds were either vaccinated when they are one-day old with a dual recom ... | 2020 | 32867979 |
| protection conferred by commercial ndv live attenuated and double recombinant hvt vaccines against virulent california 2018 newcastle disease virus (ndv) in chickens. | vaccines against virulent newcastle disease virus (ndv) are widely available and can be protective, but improved vaccination protocols are needed to prevent clinical disease and reduce virus circulation. the present study evaluated the efficacy of two commercial vaccines alone or in combination: a live attenuated ndv vaccine (lv) and a recombinant herpesvirus of turkeys vector expressing the fusion protein of ndv and the virus protein 2 of infectious bursal disease virus (rhvt-nd-ibd). chickens ... | 2020 | 32591288 |
| comparative molecular characterization of three gallid alphaherpesvirus type 3 strains 301b/1, hprs24, and sb-1. | marek's disease (md) is a highly contagious lymphoproliferative disease of chickens caused by gallid alphaherpesvirus type 2. gallid alphaherpesvirus type 3 (gahv-3) strain 301b/1 was previously shown to be an effective md vaccine with synergistic efficacy when used as a bivalent vaccine with turkey herpesvirus. since the nucleotide sequences of only two gahv-3 strains have been determined, we sought to sequence the 301b/1 genome using illumina miseq technology. phylogenomic analysis indicated t ... | 2020 | 32550618 |
| in ovo vaccination with herpesvirus of turkey enhances innate and cellular responses in meat-type chickens: effect of vaccine dose and strain. | in ovo vaccination with herpesvirus of turkey (hvt) or recombinant hvt (rhvt) is commonly used in meat-type chickens. previous studies showed that in ovo vaccination with hvt enhances innate, cellular, and humoral immune responses in egg-type chicken embryos. this study evaluated if in ovo vaccination with hvt hastens immunocompetence of commercial meat-type chickens and optimized vaccination variables (dose and strain of hvt) to accelerate immunocompetence. a conventional hvt vaccine was given ... | 2020 | 32505441 |
| molecular characterisation and phylogenetic analysis of marek's disease virus in turkish layer chickens. | 1. there is no current data about the genotypes of marek's disease virus (mdv) in turkish poultry flocks; hence, this study was performed to analyse cvi988/rispens, turkey herpesvirus (hvt) vaccine viruses and mdv field viruses as well as to perform phylogenetic analysis of mdv in turkish layer chickens. 2. in 2017 and 2018, a total of 602 spleen samples from 49 layer flocks were collected from the marmara, west black sea and aegean regions. dna was extracted from the spleen samples and the samp ... | 2020 | 32316760 |
| laboratory methods for assessing and licensing influenza vaccines for poultry. | avian influenza (ai) vaccines for poultry are based on hemagglutinin (ha) proteins, and protection is specific to the subtype. an estimated 313 billion doses have been used between 2002 and 2018 for high pathogenicity ai control. no universal vaccines are currently available. the majority of ai vaccines are inactivated whole influenza viruses that are grown in embryonating chicken eggs, emulsified in oil adjuvant systems, and injected subcutaneously or intramuscularly. live virus-vectored vaccin ... | 2020 | 32170691 |
| novel insights into the roles of bcl-2 homolog nr-13 (vnr-13) encoded by herpesvirus of turkeys in the virus replication cycle, mitochondrial networks, and apoptosis inhibition. | the bcl-2 (b cell lymphoma 2)-related protein nr-13 plays a major role in the regulation of cell death in developing avian b cells. with over 65% sequence similarity to the chicken nr-13, herpesvirus of turkeys (hvt) vnr-13, encoded by the hvt079 and hvt096 genes, is the first known alphaherpesvirus-encoded bcl-2 homolog. hvt-infected cells were reported to be relatively more resistant to serum starvation, suggested that vnr-13 could be involved in protecting the cells. here, we describe crispr/ ... | 2020 | 32161176 |
| vaccinal efficacy of molecularly cloned gallid alphaherpesvirus 3 strain 301b/1 against very virulent marek's disease virus challenge. | marek's disease virus (mdv), a causative agent of marek's disease, has evolved its virulence partly because the current control strategies fail to provide sterilizing immunity. gallid alphaherpesvirus 3 (gahv-3) and turkey herpesvirus have been developed as bivalent vaccines to improve upon the level of protection elicited by single formulations. since the in vitro passage of vaccines can result in attenuation, a gahv-3 strain 301b/1 was cloned as a bacterial artificial chromosome (bac) by inser ... | 2020 | 32134378 |
| chickens can durably clear herpesvirus vaccine infection in feathers while still carrying vaccine-induced antibodies. | marek's disease (md) is a major disease of chickens induced by marek's disease virus (mdv) associated to lethal lymphomas. current md vaccines protect against lymphomas, but fail to prevent infection and shedding. the control of mdv shedding is crucial in order to eradicate this highly contagious virus. like pathogenic mdv, md vaccines infect the feather follicles of the skin before being shed into the environment. md vaccines constitute excellent models to study virus interaction with feathers, ... | 2020 | 32093754 |
| transcriptional analyses of innate and acquired immune patterning elicited by marek's disease virus vaccine strains: turkey herpesvirus (hvt), marek's disease virus 2 (strain sb1), and bivalent vaccines (hvt/sb1 and hvt-lt/sb1). | marek's disease (md) is a complex pathology of chickens caused by md virus (mdv) 1 and is observed as paralysis, immune suppression, neurologic signs, and the rapid formation of t-cell lymphomas. the incidence of md in commercial broilers is largely controlled via vaccination, either in ovo or at hatch with live attenuated vaccines, i.e., turkey herpesvirus (hvt) or a bivalent combination of hvt with the mdv 2 strain (sb1). to further extend the protection conferred by bivalent hvt/sb-1, recombi ... | 2019 | 31865682 |
| molecular characterization of a marek's disease virus strain detected in tumour-bearing turkeys. | marek's disease (md) is a lymphoproliferative disease caused by gallid alphaherpesvirus 2 (gahv-2), which primarily affects chickens. however, the virus is also able to induce tumours in turkeys, albeit less frequently than in chickens. this study reports the molecular characterization of a gahv-2 strain detected in a flock of italian meat-type turkeys exhibiting visceral lymphomas. sequencing and phylogenetic analysis of the meq gene revealed that the turkey gahv-2 has molecular features of hig ... | 2020 | 31702386 |
| towards a mechanistic understanding of the synergistic response induced by bivalent marek's disease vaccines to prevent lymphomas. | marek's disease (md) is a lymphoproliferative disease of chickens caused by marek's disease virus (mdv), an oncogenic α-herpesvirus. since 1970, md has been controlled by widespread vaccination; however, more effective md vaccines are needed to counter more virulent mdv strains. the bivalent vaccine combination of sb-1 and herpesvirus of turkey (hvt) strain fc126 has been widely used. nonetheless, the mechanism(s) underlying this synergistic effect has not been investigated. | 2019 | 31515142 |
| a recombinant turkey herpesvirus expressing f and hn genes of avian avulavirus-1 (aavv-1) genotype vi confers cross-protection against challenge with virulent aavv-1 genotypes iv and vii in chickens. | newcastle disease (nd) is responsible for significant economic losses in the poultry industry. the disease is caused by virulent strains of avian avulavirus 1 (aavv-1), a species within the family paramyxoviridae. we developed a recombinant construct based on the herpesvirus of turkeys (hvt) as a vector expressing two genes: f and hn (hvt-ndv-f-hn) derived from the aavv-1 genotype vi ("pigeon variant" of aavv-1). this recombinant viral vaccine candidate was used to subcutaneously immunize one gr ... | 2019 | 31450681 |
| influence of marek's disease virus vaccines on chicken melanoma differentiation-associated gene 5-dependent-type i interferon signal transduction pathway with a highlight on their secondary impact on the immune responses post newcastle disease virus vaccination. | marek's disease virus (mdv) leads to a lytic infection of b-lymphocytes in chickens, and also latently infects t-lymphocytes. although marek's disease vaccines have been widely in use, little is known about the innate immune response of this important livestock vaccine. in this study, we tested the effect of different commercially applied marek's disease vaccines on the expression pattern of selected genes related to chicken interferon-alpha (chifn-α) (melanoma differentiation associated gene 5 ... | 2019 | 31383309 |
| evaluation of vaccination against infectious laryngotracheitis (ilt) with recombinant herpesvirus of turkey (rhvt-lt) and chicken embryo origin (ceo) vaccines applied alone or in combination. | the chicken embryo origin (ceo) infectious laryngotracheitis (ilt) live attenuated vaccines, although capable of protecting against disease and reducing challenge virus replication, can regain virulence. recombinant ilt vaccines do not regain virulence but are partially successful at blocking challenge virus replication. the objective of this study was to evaluate the effect of rhvt-lt vaccination on ceo replication and how this vaccination strategy enhances protection and limits challenge virus ... | 2019 | 31304770 |
| protection efficacy of a recombinant herpesvirus of turkey vaccine against infectious laryngotracheitis virus administered in ovo to broilers at three standardized doses. | infectious laryngotracheitis (ilt) is a highly contagious respiratory disease of chickens that produces significant economic losses to the poultry industry. the disease is caused by gallid alpha herpesvirus-1 (gahv-1), commonly known as the infectious laryngotracheitis virus (iltv). vaccination remains necessary for the control of the disease. due to the inherent virulence of live attenuated vaccines, in particular that of the chicken embryo origin (ceo) vaccines, the use of ilt viral vector rec ... | 2019 | 31251537 |
| study of efficacy and replication of recombinant vector vaccines by using turkey herpesvirus combined with other marek's disease vaccines. | several recombinant turkey herpesviruses (rhvts) have been developed within the past decades, and they are now used commercially worldwide. in broiler chickens, rhvts are usually administered alone, but in long-living birds they are used in combination with marek's disease (md) vaccines of other serotypes (i.e., cvi988). the objectives of this work were to 1) evaluate protection against md conferred by hvt and two rhvts when combined with cvi988 and 2) optimize the use of rhvt in combination wit ... | 2019 | 31251535 |
| evaluation of protective efficacy when combining turkey herpesvirus-vector vaccines. | turkey herpesvirus (hvt) is widely used as a vaccine against marek's disease in chickens and recently as a vector for foreign genes from infectious bursal disease virus, newcastle disease (nd) virus, infectious laryngotracheitis (ilt) virus, and avian influenza virus. advantages of hvt-vector vaccines are that the vaccines do not contain live respiratory viruses or live infectious bursal disease virus able to replicate and cause disease or embryo mortality, they can be administered at hatch or i ... | 2019 | 31251522 |
| immune responses upon in ovo hvt-ibd vaccination vary between different chicken lines. | the genotype of chickens is assumed to be associated with variable immune responses. in this study a modern, moderate performing dual-purpose chicken line (dt) was compared with a high-performing layer-type (lt) as well as a broiler-type (bt) chicken line. one group of each genotype was vaccinated in ovo with a recombinant herpesvirus of turkeys expressing the virus protein vp2 of the infectious bursal disease virus (hvt-ibd) while one group of each genotype was left hvt-ibd unvaccinated (contro ... | 2019 | 31247248 |
| impact of hvt vaccination on splenic mirna expression in marek's disease virus infections. | marek's disease is a lymphoproliferative disease of chickens caused by marek's disease virus. similar to other herpesviruses, marek's disease virus (mdv) encodes its own small non-coding regulatory rnas termed micrornas (mirnas). we previously found that the expression profile of these viral mirnas is affected by vaccination with herpesvirus of turkeys (hvt). to further characterize mirna-mediated gene regulation in mdv infections, in the current study we examine the impact of hvt vaccination on ... | 2019 | 30764490 |
| recombinant turkey herpesvirus expressing h9 hemagglutinin providing protection against h9n2 avian influenza. | h9n2 avian influenza viruses (aivs) were prevailing in chickens, causing great economic losses and public health threats. in this study, turkey herpesviruses (hvt) was cloned as an infectious bacterial artificial chromosomes (bac). recombinant hvt (rhvt-h9) containing hemagglutinin (ha) gene from h9n2 virus were constructed via galactokinase (galk) selection and clustered regularly interspaced short palindromic repeats/associated 9 (crispr/cas9) gene editing system. the recombinant rhvt-h9 showe ... | 2019 | 30641481 |
| long-term protection against a virulent field isolate of infectious laryngotracheitis virus induced by inactivated, recombinant, and modified live virus vaccines in commercial layers. | infectious laryngotracheitis (ilt) is an acute respiratory disease of chickens controlled through vaccination with live-modified attenuated vaccines, the chicken embryo origin (ceo) vaccines and the tissue-culture origin (tco) vaccines. recently, novel recombinant vaccines have been developed using herpesvirus of turkey (hvt) and fowl pox virus (fpv) as vectors to express iltv immunogens for protection against ilt. the objective of this study was to assess the protection efficacy against ilt ind ... | 2019 | 30640536 |
| efficacy of a recombinant turkey herpesvirus ai (h5) vaccine in preventing transmission of heterologous highly pathogenic h5n8 clade 2.3.4.4b challenge virus in commercial broilers and layer pullets. | outbreaks caused by the highly pathogenic avian influenza virus (hpaiv) h5n8 subtype clade 2.3.4.4 were first reported in 2014 in south korea then spread very rapidly in asia, to europe, and for the first time, to north america. efficacy of a recombinant hvt-ai (h5) vaccine (rhvt-h5) to provide clinical protection as well as to significantly reduce the shedding of an h5n8 challenge virus has already been demonstrated in spf chickens. the aim of our studies was to test the efficacy of the same rh ... | 2018 | 30584541 |
| the effects of in ovo administration of encapsulated toll-like receptor 21 ligand as an adjuvant with marek's disease vaccine. | marek's disease virus (mdv) is the causative agent of a lymphoproliferative disease, marek's disease (md) in chickens. md is only controlled by mass vaccination; however, immunity induced by md vaccines is unable to prevent mdv replication and transmission. the herpesvirus of turkey (hvt) vaccine is one of the most widely used md vaccines in poultry industry. vaccines can be adjuvanted with toll-like receptor ligands (tlr-ls) to enhance their efficacy. in this study, we examined whether combinin ... | 2018 | 30401976 |
| single nucleotide polymorphism genotyping analysis shows that vaccination can limit the number and diversity of recombinant progeny of infectious laryngotracheitis viruses from the united states. | infectious laryngotracheitis (iltv; gallid alphaherpesvirus 1) causes mild to severe respiratory disease in poultry worldwide. recombination in this virus under natural (field) conditions was first described in 2012 and more recently has been studied under laboratory conditions. previous studies have revealed that natural recombination is widespread in iltv and have also demonstrated that recombination between two attenuated iltv vaccine strains generated highly virulent viruses that produced wi ... | 2018 | 30242009 |
| maternal antibody inhibition of recombinant newcastle disease virus vectored vaccine in a primary or booster avian influenza vaccination program of broiler chickens. | maternally-derived antibodies (mda) provide early protection from disease, but may interfere with active immunity in young chicks. in highly pathogenic avian influenza virus (hpaiv)-enzootic countries, broiler chickens typically have mda to newcastle disease virus (ndv) and h5 hpaiv, and their impact on active immunity from recombinant vectored vaccines is unclear. we assessed the effectiveness of a spray-applied recombinant ndv vaccine with h5 aiv insert (rndv-h5) and a recombinant turkey herpe ... | 2018 | 30241684 |
| effectiveness of different avian influenza (h5) vaccination regimens in layer chickens on the humoral immune response and interferon-alpha signalling immune marker. | avian influenza (ai) vaccines are widely used to control and eliminate the ongoing avian influenza virus epidemic in egypt. a strict vaccination policy with inactivated ai vaccines has been widely applied, however the virus still circulating, evolving and causing great negative impact to the poultry sector in egypt. therefore, an updated poultry vaccination policy using different vaccine technologies might be valuable as an innovative additional control strategy of aiv in egypt. in the present s ... | 2018 | 29619666 |
| detection and molecular characterization of a highly oncogenic marek's disease virus from vaccinated hens in turkey. | marek's disease (md) is a highly contagious neoplastic disease of chickens associated with economic losses, often due to visceral lymphomas. the etiological agent is md virus serotype 1 (mdv-1), also called gallid alphaherpesvirus 2 (gahv-2). despite intensive vaccination, mdv is constantly evolving and maintaining its presence in the world. the aim of this study was to genetically analyze a highly oncogenic mdv/tur/2019 strain obtained from a poultry farm in turkey's elazig province in 2019. ge ... | 2021 | 34130472 |
| efficacy of two vaccines against recent emergent antigenic variants of clade 2.3.2.1a highly pathogenic avian influenza viruses in bangladesh. | h5n1 highly pathogenic avian influenza viruses (hpaivs) have caused outbreaks in poultry in bangladesh since 2007. while clade 2.2.2 and 2.3.4.2 hpaivs have not been detected since 2012, clade 2.3.2.1a viruses have caused continuous outbreaks since 2012 despite the use of vaccines. in this study, we evaluated the efficacy of two h5 vaccines licensed in bangladesh, re-6 inactivated vaccine, and a recombinant herpesvirus of turkeys vaccine with an h5 insert (rhvt-h5), for protection against recent ... | 2021 | 33910774 |
| effects of administration of probiotic lactobacilli on immunity conferred by the herpesvirus of turkeys vaccine against challenge with a very virulent marek's disease virus in chickens. | several vaccines have been used to control marek's disease (md) in chickens. however, the emergence of new strains of marek's disease virus (mdv) imposes a threat to vaccine efficacy. therefore, the current study was carried out to investigate whether concurrent administration of probiotics with the herpesvirus of turkeys (hvt) vaccine enhances its protective efficacy against mdv infection. in this regard, a cocktail comprised of four lactobacillus species was administered with hvt to chicken em ... | 2021 | 33781599 |
| efficacy of recombinant marek's disease virus vectored vaccines with computationally optimized broadly reactive antigen (cobra) hemagglutinin insert against genetically diverse h5 high pathogenicity avian influenza viruses. | the genetic and antigenic drift associated with the high pathogenicity avian influenza (hpai) viruses of goose/guangdong (gs/gd) lineage and the emergence of vaccine-resistant field viruses underscores the need for a broadly protective h5 influenza a vaccine. here, we tested experimental vector herpesvirus of turkey (vhvt)-h5 vaccines containing either wild-type clade 2.3.4.4a-derived h5 inserts or computationally optimized broadly reactive antigen (cobra) inserts with challenge by homologous an ... | 2021 | 33715903 |
| control, elimination, and monitoring of infectious laryngotracheitis in a multiage commercial layer pullet farm in canada. | a multiage commercial layer pullet operation with a history of chicken embryo (ceo) modified live infectious laryngotracheitis (ilt) virus vaccination suffered severe ilt breaks in 2017. the initial sequencing revealed that the circulating virus was of vaccine origin. changes to the timing and dosage of ceo ilt vaccine failed to control the outbreak. the clinical resolution of the outbreak occurred with the transition to a turkey herpesvirus vector vaccine given in hatchery followed by a tissue ... | 2021 | 33647967 |
| a broad spectrum hvt-h5 avian influenza vector vaccine which induces a rapid onset of immunity. | current methods to combat highly pathogenic avian influenza (hpai) outbreaks in poultry rely on stamping out and preventive culling, which can lead to high economic losses and invoke ethical resistance. emergency vaccination could be an alternative as vaccination is one of the most efficient and cost-effective measures to protect poultry from hpai infection, preventing spreading to other poultry and greatly reducing the potential transmission to humans. current conventional inactivated ai vaccin ... | 2021 | 33483211 |
| in vivo inhibition of marek's disease virus in transgenic chickens expressing cas9 and grna against icp4. | marek's disease (md), caused by md herpesvirus (mdv), is an economically important disease in chickens. the efficacy of the existing vaccines against evolving virulent stains may become limited and necessitates the development of novel antiviral strategies to protect poultry from mdv strains with increased virulence. the crispr/cas9 system has emerged as a powerful genome editing tool providing an opportunity to develop antiviral strategies for the control of mdv infection. here, we characterize ... | 2021 | 33450980 |
| an outbreak in three-yellow chickens with clinical tumors of high mortality caused by the coinfection of reticuloendotheliosis virus and marek's disease virus: a speculated reticuloendotheliosis virus contamination plays an important role in the case. | both reticuloendotheliosis and marek's disease are neoplastic diseases of chickens caused by reticuloendotheliosis virus (rev) and marek's disease virus (mdv), respectively. the infection of rev or mdv may lead to clinical tumors and also result in immunosuppression and easily allow secondary infection by other pathogens. here, we investigated a breeder flock of three-yellow chickens in southern china that had been vaccinated with cvi988/rispens at hatching and had experienced depression, weakne ... | 2020 | 33357681 |
| two cases of marek's disease in backyard turkeys. | in two independent submissions, a 3-yr-old, dead bourbon red turkey tom from a zoo and a royal palm turkey hen from a backyard flock were submitted for necropsy. both birds had been kept together with chickens. findings of the necropsy of the first turkey were an enlarged and dark liver with many pale white foci and a few small white nodules, pale and enlarged spleen, prominent thymus, mottled and pale kidneys, and pale and enlarged testes. findings of the necropsy of the second turkey were a da ... | 2020 | 33205183 |