Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| 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 |
| proteomics applied to avian herpesviruses. | proteomics is the application of rapidly evolving high-throughput technologies that enable analysis of proteins on a large scale. recent advances in instrumentation have allowed detection, identification, and quantification of proteins with unparalleled precision and reproducibility, and this, in combination with novel bioinformatics tools, has helped to move proteomics from the simple cataloging of expressed proteins toward discovery of operating mechanisms in the biological systems. proteomics ... | 2013 | 23901746 |
| pathotyping of australian isolates of marek's disease virus in commercial broiler chickens vaccinated with herpesvirus of turkeys (hvt) or bivalent (hvt/sb1) vaccine and association with viral load in the spleen and feather dander. | to pathotype australian isolates of marek's disease virus (mdv) in commercial broiler chickens using standard methods and to evaluate early markers of pathotype. | 2013 | 23889101 |
| 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 |
| immunity to marek's disease: where are we now? | marek's disease (md) in chickens was first described over a century ago and the causative agent of this disease, marek's disease virus (mdv), was first identified in the 1960's. there has been extensive and intensive research over the last few decades to elucidate the underlying mechanisms of the interactions between the virus and its host. we have also made considerable progress in terms of developing efficacious vaccines against md. the advent of the chicken genetic map and genome sequence as ... | 2013 | 23588041 |
| efficacy of a recombinant hvt-h5 vaccine against challenge with two genetically divergent indonesian hpai h5n1 strains. | the swift evolution rate of avian influenza (ai) h5n1 virus demands constant efforts to update inactivated vaccines to match antigenically with the emerging new field virus strains. recently, a recombinant turkey herpesvirus (rhvt)-ai vaccine, rhvt-h5, expressing the ha gene of a highly pathogenic avian influenza (hpai) h5n1 clade 2.2 a/swan/hungary/499/ 2006 strain inserted into fc-126 strain of hvt vector, has been developed to combat current threats in poultry industry. here, we present the r ... | 2012 | 23402113 |
| efficacy of rhvt-ai vector vaccine in broilers with passive immunity against challenge with two antigenically divergent egyptian clade 2.2.1 hpai h5n1 strains. | in countries where avian influenza has become endemic, early vaccination of layer pullets or broilers with classical inactivated vaccines at the hatchery is no longer an option because of interference with passive immunity indirectly induced by the necessary vaccination of the breeders. on the other hand, injection of thousands of chicks from 7 to 10 days old on farms has been determined to be unreliable and, therefore, poorly efficacious. for these reasons, interest has arisen regarding a newly ... | 2012 | 23402112 |
| avirulent marek's disease virus type 1 strain 814 vectored vaccine expressing avian influenza (ai) virus h5 haemagglutinin induced better protection than turkey herpesvirus vectored ai vaccine. | herpesvirus of turkey (hvt) as a vector to express the haemagglutinin (ha) of avian influenza virus (aiv) h5 was developed and its protection against lethal marek's disease virus (mdv) and highly pathogenic aiv (hpaiv) challenges was evaluated previously. it is well-known that avirulemt mdv type 1 vaccines are more effective than hvt in prevention of lethal mdv infection. to further increase protective efficacy against hpaiv and lethal mdv, a recombinant mdv type 1 strain 814 was developed to ex ... | 2013 | 23301062 |
| a toll-like receptor 3 ligand enhances protective effects of vaccination against marek's disease virus and hinders tumor development in chickens. | marek's disease (md) is caused by marek's disease virus (mdv). various vaccines including herpesvirus of turkeys (hvt) have been used to control this disease. however, hvt is not able to completely protect against very virulent strains of mdv. the objective of this study was to determine whether a vaccination protocol consisting of hvt and a toll-like receptor (tlr) ligand could enhance protective efficacy of vaccination against md. hence, chickens were immunized with hvt and subsequently treate ... | 2012 | 22857262 |
| optimization of the protocols for double vaccination against marek's disease by using commercially available vaccines: evaluation of protection, vaccine replication, and activation of t cells. | revaccination against marek's disease is a widespread practice in some countries. the rationale of this practice is unknown, and there is no consensus in the protocols. recently, we have demonstrated that administration of the first vaccine at 18 days of embryonation followed by a more protective second vaccine at hatch (18ed/1d) reproduced systematically the benefits of revaccination under laboratory conditions. here, we have used the same model to optimize the revaccination protocols by using ... | 2012 | 22856185 |
| 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 |
| protection induced by commercially available live-attenuated and recombinant viral vector vaccines against infectious laryngotracheitis virus in broiler chickens. | viral vector vaccines using fowl poxvirus (fpv) and herpesvirus of turkey (hvt) as vectors and carrying infectious laryngotracheitis virus (iltv) genes are commercially available to the poultry industry in the usa. different sectors of the broiler industry have used these vaccines in ovo or subcutaneously, achieving variable results. the objective of the present study was to determine the efficacy of protection induced by viral vector vaccines as compared with live-attenuated iltv vaccines. the ... | 2012 | 22845318 |
| progress toward the development of polyvalent vaccination strategies against multiple viral infections in chickens using herpesvirus of turkeys as vector. | vaccination is the most cost effective strategy for the control and prevention of the plethora of viral diseases affecting poultry production. the major challenge for poultry vaccination is the design of vaccines that will protect against multiple pathogens via a single protective dose, delivered by mass vaccination. the marek disease virus and the highly pathogenic avian influenza virus cause severe disease outbreaks in chickens. vaccination with live herpesvirus of turkeys protects chickens fr ... | 2017 | 22705840 |
| dual infection and superinfection inhibition of epithelial skin cells by two alphaherpesviruses co-occur in the natural host. | hosts can be infected with multiple herpesviruses, known as superinfection; however, superinfection of cells is rare due to the phenomenon known as superinfection inhibition. it is believed that dual infection of cells occurs in nature, based on studies examining genetic exchange between homologous alphaherpesviruses in the host, but to date, this has not been directly shown in a natural model. in this report, gallid herpesvirus 2 (gahv-2), better known as marek's disease virus (mdv), was used i ... | 2012 | 22629393 |
| pathotyping of australian isolates of marek's disease virus and association of pathogenicity with meq gene polymorphism. | we report the pathotyping of six australian isolates of marek's disease virus-1 (mdv1) isolated between 1992 and 2004 and association of virulence with meq gene polymorphism. unvaccinated and herpesvirus of turkeys (hvt)-vaccinated specific pathogen free chickens were challenged at day 5 with 500 plaque forming units of marek's disease virus. the isolates induced gross marek's disease lesions in 53 to 94% of unvaccinated chickens, and hvt induced a protective index ranging from 38 to 100% by 56 ... | 2012 | 22515535 |
| avian influenza adenovirus-vectored in ovo vaccination: target embryo tissues and combination with marek's disease vaccine. | we investigated embryo tissues targeted by replication competent adenovirus (ad)-free recombinant ad expressing a codon-optimized avian influenza (ai) h5 gene from a/turkey/wi/68 (adh5) when injected into 18-day embryonated eggs. we also evaluated the effects of concurrent in ovo vaccination with the experimental adh5 vaccine and commercially available marek's disease virus (mdv) vaccine combinations rispens/turkey herpesvirus (hvt) or hvt/sb-1. computed tomography indicates that in ovo injectio ... | 2011 | 22312988 |
| concomitant turkey herpesvirus-infectious bursal disease vector vaccine and oil-adjuvanted inactivated newcastle disease vaccine administration: consequences for vaccine intake and protection. | hatchery vaccination protocols in day-old chicks are designed to provide early priming and protection against several poultry diseases including, but not limited to, marek's disease (md), infectious bursal disease (ibd), and newcastle disease (nd). the constraint of concomitant administration of live md and ibd vaccines plus nd inactivated oil-adjuvanted vaccines (ioavs) requires improvements in vaccine technology. single-needle concomitant subcutaneous (sc) application of ibd/mdv and killed ndv ... | 2011 | 22312985 |
| A multifunctional protein encoded by turkey herpesvirus suppresses RNA silencing in Nicotiana benthamiana. | Many plant and animal viruses counteract RNA silencing-mediated defense by encoding diverse RNA silencing suppressors. We characterized HVT063, a multifunctional protein encoded by turkey herpesvirus (HVT), as a silencing suppressor in coinfiltration assays with green fluorescent protein transgenic Nicotiana benthamiana line 16c. Our results indicated that HVT063 could strongly suppress both local and systemic RNA silencing induced by either sense RNA or double-stranded RNA (dsRNA). HVT063 could ... | 2011 | 21957299 |
| Recombinant herpesvirus of turkeys as a vector-based vaccine against highly pathogenic H7N1 avian influenza and Marek's disease. | A major challenge for poultry vaccination is the design of vaccines that protect against multiple pathogens via a single protective dose delivered through mass vaccination methods. In this investigation, we examined herpesvirus of turkeys (HVT) as a vaccine vector for delivery of haemagglutinin (HA) antigen of highly pathogenic H7N1 avian influenza virus that can act as a dual vaccine against avian influenza and Marek's disease. The HVT vector was developed using reverse genetics based on an inf ... | 2011 | 21907750 |
| expression of ha of hpai h5n1 virus at us2 gene insertion site of turkey herpesvirus induced better protection than that at us10 gene insertion site. | herpesvirus of turkey (hvt) is being widely used as a vector for development of recombinant vaccines and us2 and us10 genes are often chosen as insertion sites for targeted gene expression. however, the different effects of the two genes for generation of recombinant hvt vaccines were unknown. in order to compare the effects of inserted genes in the two sites on the efficacy of the recombinant vaccines, host-protective haemagglutinin (ha) gene of the highly pathogenic avian influenza virus (hpai ... | 2011 | 21818336 |
| replication of recombinant herpesvirus of turkey expressing genes of infectious laryngotracheitis virus in specific pathogen free and broiler chickens following in ovo and subcutaneous vaccination. | replication of a recombinant herpesvirus of turkey vaccine expressing infectious laryngotracheitis virus genes (rhvt-lt) was evaluated in specific pathogen free (spf) and commercial broiler chickens after various vaccination protocols (amniotic route at embryonation day [ed] 18; intra-embryonic route at ed 19; and subcutaneous at 1 day of age [s.c.]). three experiments were conducted: in the first experiment, replication of rhvt-lt vaccine was chronologically evaluated and compared with the repl ... | 2011 | 21812719 |
| effect of diluting marek's disease vaccines on the outcomes of marek's disease virus infection when challenged with highly virulent marek's disease viruses. | dilution of marek's disease (md) vaccines is a common practice in the field to reduce the cost associated with vaccination. in this study we have evaluated the effect of diluting md vaccines on the protection against md, vaccine and challenge md virus (mdv) kinetics, and body weight when challenged with strains md5 (very virulent mdv) and 648a (very virulent plus mdv) by contact at day of age. the following four vaccination protocols were evaluated in meat-type chickens: turkey herpesvirus (hvt) ... | 2011 | 21793444 |
| field efficacy of different vaccines against infectious bursal disease in broiler flocks. | a field study was performed to determine the efficacy of three commercially available vaccines against infectious bursal disease (ibd) in commercial broilers raised in a high ibd virus (ibdv) risk area. live attenuated intermediate and intermediate plus vaccines were used in four flocks. birds were vaccinated orally at the estimated vaccination time. three broiler flocks were vaccinated subcutaneously with a turkey herpesvirus (hvt)-ibd vector vaccine at one day old. evaluation of the efficacy o ... | 2011 | 21727070 |
| roles of avian herpesvirus micrornas in infection, latency, and oncogenesis. | micrornas have been reported for the avian herpesviruses marek's disease virus 1 (mdv1; oncogenic), marek's disease virus 2 (mdv2; non-oncogenic), herpesvirus of turkeys (hvt), and infectious laryngotracheitis virus (iltv). no obvious phylogenetic relationships exist among the avian herpesvirus micrornas, but the general genomic locations of microrna clusters are conserved, with micrornas being located in the repeat regions of the genomes. in some cases, micrornas are antisense to open reading f ... | 2011 | 21683170 |
| emerging roles of chicken and viral micrornas in avian disease. | abstract: | 2011 | 21645299 |
| interferon-γ influences immunity elicited by vaccines against very virulent marek's disease virus. | vaccination of chickens with herpesvirus of turkey (hvt) confers only partial protection against challenge with a very virulent marek's disease virus (mdv). here, we evaluated the ability of recombinant chicken interferon-gamma (rchifn-γ) to enhance protective efficacy of hvt against the very virulent mdv strain, rb1b. the bioactivity of ifn-γ expressed by a plasmid expression vector was confirmed by its ability to stimulate a chicken macrophage cell line (hd11) to produce nitric oxide (no) in v ... | 2011 | 21501630 |
| compatibility of turkey herpesvirus-infectious bursal disease vector vaccine with marek's disease rispens vaccine injected into day-old pullets. | mixtures of turkey herpesvirus (hvt) and rispens poultry vaccines have been used worldwide for over 20 yr, mainly for vaccination of future layers and breeders. with increasing virulence of marek's disease (md) virus strains, vaccination strategies are evolving toward the use of vaccines combining hvt and rispens. a single vaccination either in ovo or at 1 day of age with the hvt + infectious bursal disease (ibd) vector vaccine is efficient against ibd. however, with vaccination programs that in ... | 2011 | 21500646 |
| comparative genomic sequence analysis of the marek's disease vaccine strain sb-1. | marek's disease virus (mdv), an oncogenic alphaherpesvirus, induces a rapid onset t-cell lymphoma and demyelinating disease in chickens. since the 1970s the disease has been controlled through mass vaccination with herpesvirus of turkeys [meleagrid herpesvirus type 1 (mehv-1)]. over time this vaccine's efficacy decreased, and in the 1980s a bivalent vaccine consisting of mehv-1 and a non-oncogenic gallid herpesvirus type 3 (gahv-3) strain known as sb-1 was introduced. the complete dna sequence ( ... | 2011 | 21336949 |
| protection against infectious laryngotracheitis by in ovo vaccination with commercially available viral vector recombinant vaccines. | infectious laryngotracheitis (ilt) is a highly contagious respiratory disease of chickens caused by infectious laryngotracheitis virus (iltv). the disease is mainly controlled through biosecurity and by vaccination with live-attenuated vaccines. the chicken embryo origin (ceo) vaccines, although proven to be effective in experimental settings, have limited efficacy in controlling the disease in dense broiler production sites due to unrestricted use and poor mass vaccination coverage. these facto ... | 2010 | 21313847 |
| further evidence of antigenic drift and protective efficacy afforded by a recombinant hvt-h5 vaccine against challenge with two antigenically divergent egyptian clade 2.2.1 hpai h5n1 strains. | in this study, we have compared the protection afforded by a recombinant turkey herpesvirus vaccine expressing the h5 gene from a clade 2.2 h5n1 strain (rhvt-h5) and a mexican-origin h5n2 inactivated vaccine, alone or in combination, against two antigenically divergent h5n1 egyptian strains isolated in 2007 and 2008. our results confirm the existence of a major antigenic drift among the egyptian h5n1 strains such that, although protection against the "classical" 2007 hpai h5n1 egyptian strain co ... | 2011 | 21292007 |
| the effect of the time interval between exposures on the susceptibility of chickens to superinfection with marek's disease virus. | marek's disease virus (mdv) is ubiquitous within commercial poultry flocks because current vaccines do not prevent mdv infection or transmission. in order for newly-evolved mdv strains to become established within a flock, it seems inevitable that any new strain would need to infect and replicate in chickens previously infected with resident mdv strains. this phenomenon is difficult to detect and there is no clear evidence that it is even possible. four experiments were performed to demonstrate ... | 2010 | 20945786 |
| marek's disease resistant/susceptible mhc haplotypes in xiayan chickens identified on the basis of blb2 pcr-rflp and blb2/bf2 sequence analyses. | 1. the aim was to analyse the variability of the blb2/bf2 genes of xiayan chickens to identify homozygous birds with resistance or susceptibility to marek's disease (md). 2. the experiment used two lines: birds from a common line were divided into group a (unvaccinated) and group b (vaccinated with herpesvirus of turkeys (hvt)); and birds from an md-resistant line were divided into group c (unvaccinated) and group d (vaccinated with hvt). they were challenged intra-abdominally with marek's disea ... | 2010 | 20924848 |
| genetics and vaccine efficacy: host genetic variation affecting marek's disease vaccine efficacy in white leghorn chickens. | marek's disease (md) is a t-cell lymphoma disease of domestic chickens induced by md virus (mdv), a naturally oncogenic and highly contagious cell-associated α-herpesvirus. earlier reports have shown that the mhc haplotype as well as non-mhc genes are responsible for genetic resistance to md. the mhc was also shown to affect efficiency of vaccine response. using specific-pathogen-free chickens from a series of 19 recombinant congenic strains and their 2 progenitor lines (lines 6(3) and 7(2)), va ... | 2010 | 20852098 |
| vaccine-induced host responses against very virulent marek's disease virus infection in the lungs of chickens. | the aim of this study was to investigate the kinetics of virus replication and cellular responses in the lungs following infection with marek's disease virus (mdv) and/or vaccination with herpesvirus of turkey (hvt) via the respiratory route. chickens vaccinated with hvt and challenged with mdv had a higher accumulation of mdv and hvt genomes in the lungs compared to the chickens that received hvt or mdv alone. this increase in virus load was associated with augmented expression of interferon (i ... | 2010 | 20600510 |
| efficacy of single dose recombinant herpesvirus of turkey infectious bursal disease virus (ibdv) vaccination against a variant ibdv strain. | the use of viral vectors for transgenic expression of immunogenic proteins is a current trend in the poultry industry. the objective of this work was to assess the protection against the variant e of infectious bursal disease virus (ibdv), conferred by day-one vaccination with a commercial recombinant herpesvirus of turkey (hvt) vaccine (vaxxitek) expressing the immunogenic viral protein 2 from a classical ibdv. in separate trials, 1-day-old specific-pathogen-free (spf) or broiler chickens were ... | 2009 | 20095167 |
| detection of virulent marek's disease virus in poultry in india. | marek's disease virus (mdv) isolated from poultry flocks in three states of india was monitored for the virus occurrence in the field. the mdv genome was isolated from feather follicles, spleen, and liver of the chicken (173 samples). twenty two samples were positive for mdv genome in pcr and belonged to the serotype 1. the sequencing of meq gene of 11 samples revealed that nucleotide sequences of the isolate ind-ka-01-06 was similar to the very virulent mdv, strain rb-1b. in situ hybridization ... | 2009 | 19941389 |
| improved vaccination against newcastle disease by an in ovo recombinant hvt-nd combined with an adjuvanted live vaccine at day-old. | the continuous outbreaks of fatal newcastle disease (nd) in commercial poultry flocks demonstrate that current vaccination strategies are not fully efficacious and should be improved by new generation of vaccines. in this context, maternally immune conventional layer chickens were vaccinated in ovo with a turkey herpesvirus recombinant expressing the fusion (f) gene of ndv (rhvt-nd) and/or at day-old with an apathogenic enterotropic live nd vaccine co-administrated or not with chitosan by oculo- ... | 2010 | 19879230 |
| full genome sequences of two reticuloendotheliosis viruses contaminating commercial vaccines. | reticuloendotheliosis virus (rev) fragments are a common contaminant in some commercial vaccines such as fowl poxvirus (fpv) and marek's disease virus. however, only those strains integrating or containing a near-intact rev provirus are more likely to cause problems in the field. we confirm here, by pcr assays and animal experiments, that vaccines against fpv and herpes virus of turkeys were contaminated with full genome sequences of rev. further, we determined the complete proviral sequence of ... | 2009 | 19848070 |
| a deletion within glycoprotein l of marek's disease virus (mdv) field isolates correlates with a decrease in bivalent mdv vaccine efficacy in contact-exposed chickens. | we examined the functional role of a naturally occurring deletion within the glycoprotein l (gl) gene of marek's disease virus (mdv) field isolates. we previously showed that this mutation incrementally increased the virulence of an mdv in contact-exposed spf leghorn chickens, when chickens shedding this virus were co-infected with herpesvirus of turkeys (hvt). in our present study, we examined this mutation using two stocks of the very virulent plus (vv+)mdv strain tk, one of which harbored thi ... | 2009 | 19630238 |
| novel micrornas (mirnas) encoded by herpesvirus of turkeys: evidence of mirna evolution by duplication. | herpesviruses account for 134 out of the 140 virus-encoded micrornas (mirnas) known today. here we report the identification of 11 novel mirnas encoded by herpesvirus of turkey (hvt), a virus used as a live vaccine in poultry against the highly oncogenic marek's disease virus type 1. ten of these mirnas were clustered together within the repeat long region of the viral genome, demonstrating some degree of positional conservation with other mardiviruses. close sequence and phylogenetic relationsh ... | 2009 | 19403687 |
| [construction of a recombinant hvt virus expressing the ha gene of avian influenza virus h5n1 via rde/et recombination system]. | in recent years,manipulation of large herpesvirus genomes has been facilitated by using bacterial artificial chromosome (bac) vectors. we have previously reported the construction of the bac clones (hvt bacs) of herpesvirus of turkey (hvt). with these bac clones in hand,we manipulated the genome of hvt by utilizing red/et recombination system, and developed a biologically safe live vaccine based on the hvt bacs. | 2009 | 19388268 |
| micrornas of gallid and meleagrid herpesviruses show generally conserved genomic locations and are virus-specific. | many herpesviruses, including marek's disease viruses (mdv1 and mdv2), encode micrornas. in this study, we report micrornas of two related herpesviruses, infectious laryngotracheitis virus (iltv) and herpesvirus of turkeys (hvt), as well as additional mdv2 micrornas. the genome locations, but not microrna sequences, are conserved among all four of these avian herpesviruses. most are clustered in the repeats flanking the unique long region (i/tr(l)), except in iltv which lacks these repeats. two ... | 2009 | 19328516 |
| cloning of gallid herpesvirus 3 (marek's disease virus serotype-2) genome as infectious bacterial artificial chromosomes for analysis of viral gene functions. | marek's disease virus serotype 2 (gallid herpesvirus 3) is a non-pathogenic alphaherpesvirus belonging to the mardivirus genus, used widely in live vaccines against marek's disease. although the complete genome sequence of the mdv-2 strain hprs-24 has been published, very little is known about the gene functions. as a first step for carrying out functional genomic analysis of mdv-2, the full-length genome of the mdv-2 vaccine strain sb-1 was cloned as an infectious bacterial artificial chromosom ... | 2009 | 19187788 |
| marek's disease in broiler chickens: effect of route of infection and herpesvirus of turkey-vaccination status on detection of virus from blood or spleen by polymerase chain reaction, and on weights of birds, bursa and spleen. | the polymerase chain reaction (pcr) has recently emerged as an additional tool for the monitoring and diagnosis of marek's disease. we investigated a number of factors that may influence the interpretation of pcr results in commercial broiler chickens including the effects of route of infection and herpesvirus of turkeys (hvt)-vaccination status. we also investigated the suitability of peripheral blood lymphocytes (pbl) and spleen as tissues for marek's disease virus (mdv) detection. hvt-vaccina ... | 2001 | 19184956 |
| innovation and discovery: the application of nucleic acid-based technology to avian virus detection and characterization. | polymerase chain reaction (pcr)-based approaches to the detection, differentiation and characterization of avian pathogens continue to be developed and refined. the pcrs, or reverse transcriptase-pcrs, may be general, designed to detect all or most variants of a pathogen, or to be serotype, genotype or pathotype specific. progress is being made with respect to making nucleic acid approaches more suitable for use in diagnostic laboratories. robotic workstations are now available for extraction of ... | 2001 | 19184952 |
| influence of vaccine deposition site on post-vaccinal viraemia and vaccine efficacy in broiler chickens following in ovo vaccination against marek's disease. | in ovo vaccination against marek's disease is a widely used technology in the broiler industry.a series of experiments was carried out to determine the site of vaccine deposition in the egg during automated in ovo vaccination, and the effect of vaccine deposition site and dose on vaccine responses following vaccination with cell-associated herpesvirus of turkeys in commercial broiler chickens. vaccine deposition site following automated in ovo vaccination was principally influenced by the age of ... | 2001 | 19184942 |
| targeting marek's disease virus by rna interference delivered from a herpesvirus vaccine. | live attenuated herpesvirus vaccines such as herpesvirus of turkey (hvt) have been used since 1970 for the control of marek's disease (md), a highly infectious lymphoproliferative disease of poultry. despite the success of these vaccines in reducing losses from the disease, marek's disease virus (mdv) strains have shown a continuing increase in virulence, presumably due to the inability of the current vaccines in preventing mdv replication. the highly specific and effective nature of rna interfe ... | 2009 | 18977264 |
| the effect of marek's disease vaccination on the immunisation of day-old chicks against newcastle disease, using b1 and oil emulsion vaccine. | concurrent vaccination of one-day-old chicks with 2 x 10(5) 50% embryo infectious doses of live b1 newcastle disease virus and 0.25 ml killed oil emulsion newcastle disease vaccine produced satisfactory levels of circulating haemagglutination inhibiting antibody although the recipient chicks possessed titres of maternally derived antibody as high as 10 log(2). this effect was also seen when the chicks were given turkey herpesvirus for immunisation against marek's disease. the satisfactory newcas ... | 1976 | 18777359 |
| precipitating antigens associated with marek's disease viruses and a herpesvirus of turkeys. | precipitating antigens associated with a number of marek's disease virus strains and with a turkey herpesvirus have been analyzed. the 'a' antigen has been defined as the major soluble antigen in feather follicles of infected chickens, which is identical with the major antigen usually present in supernatants of chicken kidney cell cultures infected with strains of marek's disease virus. 'bc' antigens are 2 or more antigens which are usually not noted in skin extracts but present in cultured cell ... | 1975 | 18777302 |
| differentiation between strains of marek's disease virus and turkey herpesvirus by immunofluorescence assays. | two serological types of marek's disease virus and a herpesvirus of turkeys have been differentiated by indirect immunofluorescence tests as (1) pathogenic strains of marek's disease virus (mdv) and their attenuated variants: hprs-16, hprs-16/att, hprs-b14, jm, jm/att, ga, vc and 'oldenburg', a recent field isolate; (2) apathogenic strains hprs-24 and hprs-27 of mdv; (3) herpesvirus of turkeys strain fc126 and its hvt(a-) variant. virus strains could not be distinguished on the basis of qualitat ... | 1975 | 18777301 |
| simultaneous vaccination of day-old chickens against newcastle and marek's diseases. | commercial day-old chicks vaccinated against marek's disease (md) with turkey herpesvirus (hvt) were tested for their ability to respond to a live newcastle disease vaccine (ndv) - la sota strain - administered by different routes. simultaneous vaccination of day-old birds with hvt and ndv did not affect the immune response to ndv nor the viraemia induced by hvt vaccination. md and nd vaccinations performed together, the first by the intramuscular route and the second by beak dipping, gave a val ... | 1974 | 18777255 |
| lyophilized turkey herpesvirus (hvt): stability of vaccine and minimum protective dose. | the research reported showed that: the stability of cell-free hvt vaccine, lyophilized and sealed under vacuum, is very high: after one year at 4 degrees -6 degrees c and after 10 days at 37 degrees c the titre decreased only about 0.4 log(10)', the stability of the vaccine, when reconstituted for use in the diluent (sucrose-phosphate buffer), is high (80%) for at least 2 hours; the degree of protection, found in 3 tests, was about 90% with an inoculum of 20 to 100 pfu, and the pd50 was 4.9 pfu ... | 1974 | 18777253 |
| differential effect of maternal antibodies on efficacy of cellular and cell-free marek's disease vaccines. | the protective efficacy of cell-free and cell-associated turkey herpesvirus (hvt) vaccines against marek's disease (md) was determined by a quantitative protective dose 50% (pd(50)) assay in susceptible chicks from hvt-vaccinated, md-exposed dams or from genetically comparable, isolation-reared, specific pathogen free dams. comparison within trials showed that cell-associated and cell-free vaccines were equally efficacious in chicks lacking maternal antibodies (median pd(50)s were about 1-4 plaq ... | 1979 | 18770437 |
| anti-viral immunity against marek's disease virus infected chicken kidney cells. | the mechanism of immunity conferred by herpesvirus of turkeys (hvt) was investigated using marek's disease virus (mdv)-infected chicken kidney cell (ckc) cultures as target cells. peripheral blood lymphocytes (pbl) from normal or hvt-vaccinated chickens killed mdv-infected target cells in the presence of anti-mdv or anti-hvt serum, whereas normal lymphocytes and hvt-sensitised lymphocytes themselves had no specific cytotoxic effect. cell-mediated cytotoxicity of pbl from hvt-vaccinated chicken w ... | 1979 | 18770425 |
| differences between early and late membrane antigens on cultured cells infected with herpesvirus of turkeys. | the synthesis of membrane antigen (ma) and intracellular antigen (ia) in arginine-deficient cultures infected with herpesvirus of turkeys (hvt) and their antigenic relationships were examined. by the indirect immunofluorescence test, two kinds of ma were detected using anti-hvt chicken serum [early appearing ma (ema) and late appearing ma (lma)], but few ia positive cells were detected. absorption of the serum by ma positive cells resulted in reduction of reactivity to ma but not to ia. differen ... | 1979 | 18770424 |
| inactivation of a turkey herpesvirus by ultra-violet light. | the sensitivity to inactivation by ultraviolet light of the pb 1 strain of herpesvirus of turkeys (hvt) was determined and compared with the relative sensitivity of pseudo-rabies virus (prv), another member of the herpesvirus group. hvt (pb1) was 6.3 times more resistant than prv when assayed in chick embryo fibroblasts. the survival curve of hvt (strain pb1) had one component and the survival curve of prv had two components. survival curves of hvt and prv in chick embryo fibroblasts treated wit ... | 1979 | 18770421 |
| transient effect of cyclophosphamide on vaccinal immunity to marek's disease. | cyclophosphamide treatment of chicks abrogated the induction of immunity against marek's disease (md) by the herpesvirus of turkeys, but immunity eventually developed if a sufficient interval was allowed to elapse between vaccination and challenge. vaccinated, cyclophosphamide-treated chicks showed severe suppression of antibody and immunoglobulin production even when immunity to md was present, suggesting that resistance was not mediated by humoral immunity. bursa and thymus weights of chicks w ... | 1978 | 18770381 |
| [potency tests with hvt-, mhv- and jmv vaccines against marek's disease]. | turkey herpesvirus (hvt)(fc 126) vaccine made in w. germany, marek's herpesvirus (mhv) (cvi 988) vaccine used in the netherlands and experimental jmv vaccine were tested in laboratory and field trials for protection against marek's disease. the tests were carried out with 780 spf chicks and 3200 commercial white leghorn chicks (with maternally derived antibodies to hvt and mhv). there were no differences in potency of hvt- and mhv vaccines. both vaccines showed increased protection with an incre ... | 1978 | 18770372 |
| quantitative pathogenicity of marek's disease virus and vaccine virus strains in chickens: macroscopical aspects. | two virulent strains (jm and k) and one vaccine strain (cvi 988) of marek's disease virus (mdv), together with two vaccine strains of the herpesvirus of turkeys (hvt) (fc 126 and pb-thv 1), all in the cell-associated state, were administered intramuscularly at 3.7 log tcid50 per dose to day-old spf white leghorn chickens. a control group of chicks received uninfected cells. the pathological parameters studied were onset and duration of clinical symptoms, mortality, bird weight and macroscopical ... | 1978 | 18770360 |
| cross-protection between jmv marek's disease-derived tumour transplant, marek's disease and turkey herpesviruses. | cross-protection tests were conducted using attenuated jmv (jmv-a) marek's disease-derived lymphoblasts, glutaraldehyde-treated jmv tumour cells, attenuated marek's disease virus (mdv, strain hprs-16/att) and turkey herpesvirus (hvt, strain fc126) as vaccines, and virulent jmv and mdv (hprs-16) for challenge. the jmv and jmv-a preparations were free of mdv, leukosis and reticuloendotheliosis viruses. vaccination of chickens with attenuated mdv or with hvt provided good protection against both jm ... | 1977 | 18770345 |
| [investigations on the mode of transmission of the herpesvirus of turkeys in vitro]. | fluorescent microscopic and immuno-histochemical methods, and cytochalasin b, were used to investigate the mode of transmission of the herpesvirus of turkeys in vitro. the results obtained indicated that a paramount requirement for the transmission of the herpesvirus of turkeys in vitro is the formation of virus-containing cytoplasmic protrusions. the addition of cytochalasin b to the cell culture medium prevented the formation of plaques. however, this effect was reversible. | 1977 | 18770310 |
| the effect of bursectomy on vaccination against marek's disease with the herpesvirus of turkeys. | protection against marek's disease following vaccination with the herpesvirus of turkeys was significantly impaired but not abolished by ablation of the bursa-dependent lymphoid system by surgery and x-irradiation. it was concluded that the humoral immune system is relatively more important in vaccinal immunity induced by the herpesvirus of turkeys compared with that induced by attenuated marek's disease virus. | 1980 | 18770297 |
| a quantitative sequential study of viraemia and neutralising antibody to hvt and mdv in a commercial flock vaccinated with hvt. | levels of viraemia due to the herpesvirus of turkeys (hvt) and neutralising antibodies to hvt and marek's disease virus (mdv) were followed in a flock of commercial broiler breeders held in commercial premises and vaccinated at 1-day-old with hvt. the flock was sampled at 3, 5 and 8 weeks of age and then at 4-weekly intervals until 32 weeks of age. the mean viraemia titre was highest at 3 and 5 weeks and then fell to a low level by 16 weeks where it remained until 32 weeks of age. at all samplin ... | 1980 | 18770292 |
| a new herpesvirus isolated from black storks (ciconia nigra). | an infectious agent was isolated from livers, spleens and bone marrow of two black storks (ciconia nigra l.) originating from the same source. pathological lesions consisted of small whitish focal areas in livers, spleens and bone marrow. the isolated agent was sensitive to chloroform and its multiplication was inhibited by 5-iodine-2-deoxy-uridine. it passed filters with a pore diameter of 220 nm and greater but not 100 nm filters. electron microscopic examination revealed numerous nucleocapsid ... | 1980 | 18770269 |
| failure of attenuated marek's disease virus and herpesvirus of turkeys antigens to protect against the jmv marek's disease-derived transplant able tumour. | chickens immunised with chick embryo fibroblasts infected with attenuated marek's disease virus or with the herpesvirus of turkeys and inactivated with glutaraldehyde were not protected against the lethal effects of inoculation with the marek's disease-derived tumour transplant, jmv, although such immunisation protected against experimentally induced marek's disease. it is concluded that there may be virus-coded antigenic determinants that are peculiar to oncogenic marek's disease viruses and la ... | 1980 | 18770257 |
| local tumours induced in chickens by continuous cell lines of the jmv marek's disease tumour transplant. | marek's disease (md) tumour cell lines rpl-1 and jmv-1 were shown to express high oncogenic potential if inoculated intramuscularly. no more than 10(3) cells per dose were needed to cause primary tumours at the site of inoculation in 50% of 2-day-old chickens, but more than jo(6) to more than 10(7) cells were required to cause a 50% mortality due to lymphoblastic leukaemia as another parameter of oncogenicity. herpesvirus of turkeys (hvt) was nonprotective against local tumour development of the ... | 1980 | 18770245 |
| stimulation of local solid tumour development of the nonproducer marek's disease tumour transplant jmv by virus-induced immunosuppression. | chickens could be protected against lethal lymphoblastic leukaemia due to the nonproducer jmv marek's disease (md) tumour transplant by infection with the herpesvirus of turkeys (hvt) or various strains of md virus. however, solid jmv tumours developed in md virus-infected birds at the site of intramuscular or subcutaneous transplantation, but tumours never developed at the site of md virus inoculation. the incidence and extent of local tumour growth, the development of metastases and the inhibi ... | 1980 | 18770243 |
| short- and long-term stability studies on four lyophilised and one cell-associated turkey herpesvirus vaccines against marek's disease of chickens. | one cell-associated and four lyophilised turkey herpesvirus (hvt) vaccines of different manufacturers were investigated comparatively in respect of the stability of their infectivity. all titrations were performed in primary chicken embryo fibroblast cell cultures and repeated seven times. the obtained data were computerised and statistically analysed. the long term stability study employed vaccine ampoules containing only lyophilised hvt. after appropriate storage in a refrigerator (4 degrees c ... | 1980 | 18770236 |
| characterisation of two highly oncogenic strains of marek's disease virus. | the rb-1b and ala-8 strains of marek's disease (md) virus, which were isolated from chickens with md and which had been vaccinated with the herpesvirus of turkeys (hvt), were evaluated for their oncogenic potential in genetically susceptible (p-line) and resistant (n-line, pdrc) chickens. rb-1b and ala-8 were both highly oncogenic, causing a high incidence of md in both susceptible and resistant birds. vaccination of p-line birds with sb-1 or hvt did not protect satisfactorily against rb-1b. how ... | 1982 | 18770225 |
| protection by attenuated and polyvalent vaccines against highly virulent strains of marek's disease virus. | tests confirmed that turkey herpesvirus (hvt) vaccine protected chickens poorly against challenge with the highly virulent md5 strain of marek's disease (md) virus, especially in chickens with homologous hvt antibodies. the naturally avirulent sb-1 vaccine virus was likewise poorly protective against challenge with the md5 strain. homologous antibodies reduced the protective efficacy of both vaccines, but sb-1 was not affected by hvt antibodies. in order to provide better protection against stra ... | 1982 | 18770172 |
| the expression of marek's disease tumour-associated surface antigen in various avian species. | marek's disease tumour-associated surface antigen (matsa) was detected on lymphoid cells from chickens infected with marek's disease virus (mdv) or the herpesvirus of turkeys (hvt), from a chicken-quail hybrid infected with mdv, and from turkeys infected with the ga strain of mdv, but not on cells from turkeys infected with hvt or the hprs-16 strain of mdv or from mdv-infected japanese quails or bobwhite quails, despite the presence of lymphomas in some japanese quails. two complementary explana ... | 1984 | 18766850 |
| polyvalent marek's disease vaccines: safety, efficacy and protective synergism in chickens with maternal antibodies. | three marek's disease (md) vaccines were evaluated for safety and protective efficacy in chickens with maternal antibodies against serotype 1, 2 and 3 md viruses and in chickens with no maternal antibodies. the vaccines were: (1) md11/75c, an attenuated serotype 1 md virus, (2) a trivalent mixture of md virus strains md11/75c and sb-1, and turkey herpesvirus (hvt) strain fc 126, and (3) bivalent mixtures of these three viruses. these vaccines were compared with hvt or sb-1 vaccines in some trial ... | 1984 | 18766823 |
| effects of avian viruses on cultured chicken bone-marrow-derived macrophages. | cultured chicken bone-marrow-derived macrophages have been assayed for their susceptibility to infection with various avian viruses. three criteria of infection were employed: (1) virus-induced alterations in cell morphology ; (2) presence of intracellular viral antigens detectable by immunofluorescence; (3) kinetics of virus release by infected macrophages. macrophages proved to be resistant to marek's disease virus (mdv), herpesvirus of turkeys (hvt-fc126), infectious bronchitis virus (ibv) an ... | 1983 | 18766776 |
| depression of vaccinal immunity to marek's disease by infection with chicken anaemia agent. | chicken anaemia agent (caa) depressed protective vaccinal immunity against marek's disease (md) when vaccinated chicks were inoculated with caa at 1 to 14 days of age. in chicks inoculated with caa alone, a typical caa infection as manifested by early mortality, decrease in haematocrit value, severe lymphoid depletion in the lymphoid organs, and aplasia of the bone marrow occurred only when one-day-old chicks were inoculated. when both turkey herpesvirus (hvt) and caa were inoculated, a typical ... | 1988 | 18766691 |
| embryo vaccination of chickens with turkey herpesvirus: characteristics of the target cell of early viral replication in embryonic lung. | inoculation of turkey herpesvirus (hvt) into chicken eggs at the 17th day of embryonation resulted in recovery of high titres of the virus from the lung of the embryo. infection of the lung was not characterised by extensive virus-induced cell lysis because in situ viral internal antigen (via) of hvt was not detected. examination of single cell suspensions of lungs from embryos at peak viral activity revealed that the target cells of virus infection were adherent and lacked surface antigens dete ... | 1987 | 18766646 |
| isolation of chicken anaemia agent and marek's disease virus from chickens vaccinated with turkey herpesvirus and lesions induced in chicks by inoculating both agents. | a disease that was characterised by high mortality, necrotic lesions, severe thymic and bursal atrophy, as well as marek's disease (md) lesions, occurred in two young layer chicken flocks vaccinated with turkey herpesvirus (hvt) at hatching. an agent similar to the chicken anaemia agent, designated caa82-2, and a virulent md virus strain, designated md82-2, were isolated from the kidneys of affected chickens. dual inoculation of young chicks with both agents resulted in early mortality associate ... | 1987 | 18766615 |
| enhancement of natural killer cell activity by marek's disease vaccines. | vaccination against marek's disease with herpesvirus of turkeys (hvt) has been reported to cause increased natural killer (nk) cell activity as detected in vitro against lscc-rp9 target cells. the effect of vaccination with sb-1 (a nononcogenic chicken herpesvirus), hvt and the hvt/sb-1 combination on nk cell activation was compared in marek's disease susceptible (p-2) and resistant (n-2) chickens. birds were vaccinated at 7 days of age and nk cell activity was measured between 3 and 42 days aft ... | 1987 | 18766591 |
| cellular and cytokine responses in feathers of chickens vaccinated against marek's disease. | in marek's disease virus infection, feather follicle epithelium (ffe) constitutes the site of formation of infectious virus particles and virus shedding. the objective of this study was to characterize cellular and cytokine responses as indicators of cell-mediated immune response in ffe and associated feather pulp following immunization against marek's disease. analysis of feather tips collected between 4 and 28 days post-immunization (d.p.i.) from chickens vaccinated post-hatch with either cvi9 ... | 2008 | 18722673 |
| [reconstituting turkey herpesvirus with bacterial artificial chromosome clones]. | herpesvirus of turkey (hvt) is an alpherpesvirus and widely used as a live vaccine against marek's disease (md) because of its antigenic relationship with marek's disease virus (mdv). | 2008 | 18720848 |
| efficacy and safety of cell associated vaccines against marek's disease virus grown in a continuous cell line from chickens. | the marek's disease virus (mdv) vaccine strains cvi 988 and herpes virus of turkeys (hvt) strain fc126, usually are grown in primary chicken embryo fibroblasts (cef). we found that the strains could be grown also in the so-called jbj-1 cell line to titres in the same range as when chicken embryo fibroblasts were used. the jbj-1 cell line is a fibroblast-like continuous chicken cell line, which can be grown in flat bottom tissue culture flasks, roller bottles and on micro carriers. we investigate ... | 2008 | 18706949 |
| marek's disease virus isolates with unusual tropism and virulence for ocular tissues: clinical findings, challenge studies and pathological features. | outbreaks of marek's disease (md) were diagnosed in two flocks from the same company. clinical signs, mainly blindness (>90%), but also depression, mild paralysis, and 11 to 12% mortality by 20 weeks of age were observed. md virus, serotype 1 was isolated. the isolates were designated nc-1 (flock 1) and nc-2 (flock 2). challenge experiments were conducted with these isolates and with two reference md virus strains (jm/102w and md5) in unvaccinated, turkey herpesvirus- (hvt) vaccinated and bivale ... | 1991 | 18680042 |
| replication of marek's disease virus in chicken feather tips containing vaccinal turkey herpesvirus dna. | the presence of herpesvirus of turkeys (hvt) dna in the feather tips of chickens vaccinated with hvt was assessed by dot blot hybridisation with a probe specific for hvt and lacking homology to mdv dna. only small amounts of hvt dna were detected in the feather tips of chickens that were vaccinated or left in contact with hvt vaccinated chickens. however when chickens were challenged with virulent mdv, hvt dna was detected in the feather tips of vaccinated chickens and the largest amount was det ... | 1991 | 18679997 |
| further characterisation of a variant type of turkey herpesvirus which releases large quantities of cell-free viruses into culture medium. | a variant type of turkey herpesvirus (hvt/vt) which releases large quantities of cell-free virus into its culture medium was compared with the prototype of the fc 126 strain of hvt (hvt/wt) as to the biological and serological characteristics. the lack of replication-defective hvt/vt in chickens was considered to be due to the inability of the virus to infect and replicate in lymphocytes and not to temperature-sensitive defects at 41 degrees c. no obvious antigenic differences were found between ... | 1989 | 18679841 |
| effects of age at infection with serotype 2 marek's disease virus on enhancement of avian leukosis virus-induced lymphomas. | inoculation of susceptible, 15i5 x 7i chickens with serotype 2 marek's disease virus (mdv) at various ages had no influence on the development of avian leukosis virus (alv)-induced viraemia or antibody in chickens infected with alv and turkey herpesvirus (hvt) at hatch. however, the incidence of alv-induced lymphoma (ll) was significantly higher in chickens infected with alv and hvt at hatch and inoculated with serotype 2 mdv up to 6 weeks of age than in chickens receiving serotype 2 mdv at 8 to ... | 1993 | 18671041 |
| load of challenge marek's disease virus dna in blood as a criterion for early diagnosis of marek's disease tumors. | outbreaks of marek's disease (md) in vaccinated flocks still occur sporadically and lead to economic losses. unfortunately, adequate methods to predict md outbreaks are lacking. in the present study, we have evaluated whether high load of challenge md virus (mdv) dna in peripheral blood could aid in the early diagnosis of md and in monitoring efficacy of vaccines against md. one experiment was conducted to simulate field conditions by combining various vaccines (turkey herpesvirus [hvt] and hvt ... | 2008 | 18646447 |
| enhancement of reticuloendotheliosis virus-induced bursal lymphomas by serotype 2 marek's disease virus. | the effect of serotype 2 and 3 marek's disease virus (mdv) vaccines on the pathogenesis of reticuloendotheliosis virus (rev)-induced bursal and non-bursal lymphomas was examined in chickens of rprl lines 15i(5) x 7(1) and 6(3) x 0, respectively. at hatch, chickens were vaccinated with strain 301b/1 of serotype 2 mdv or strain fc126 of turkey herpesvirus (hvt), a serotype 3 mdv and inoculated with spleen necrosis virus (snv), a non-defective strain of rev. in another experiment, bursas from 14-we ... | 1996 | 18645839 |
| functional homologies between avian and human alphaherpesvirus vp22 proteins in cell-to-cell spreading as revealed by a new cis-complementation assay. | vp22, encoded by the ul49 gene of marek's disease virus (mdv), is indispensable for virus cell-to-cell spreading. we show herein that mdv ul49 can be functionally replaced with avian and human viral orthologs. replacement of mdv vp22 with that of avian gallid herpesvirus 3 or herpesvirus of turkey, whose residue identity with mdv is close to 60%, resulted in 73 and 131% changes in viral spreading, respectively. in contrast, vp22 replacement with human herpes simplex virus type 1 resulted in 14% ... | 2008 | 18632866 |
| molecular cloning and sequence analysis of the duck enteritis virus ul5 gene. | duck enteritis virus (dev) is a herpesvirus that causes an acute, contagious, and fatal disease. in the present article, the dev ul5 gene was cloned and sequenced from a vaccine virus. according to the consensus sequence of herpesvirus ul5 and ul3 gene degenerate oligonucleotide primers were designed and were used in the polymerase chain reaction (pcr) to amplify dna products with 4577 bp in size. dna sequence analysis revealed a 2568 bp open reading frame (orf) encoding a 855 amino acid polypep ... | 2008 | 18582977 |
| inhibition of marek's disease virus replication by retroviral vector-based rna interference. | rna interference (rnai) is a promising antiviral methodology. we recently demonstrated that retroviral vectors expressing short-hairpin rnas (shrna-mirs) in the context of a modified endogenous micro-rna (mirna) can be effective in reducing replication of other retroviruses in chicken cells. in this study, similar rnai vectors are shown to inhibit replication of the avian herpesvirus, marek's disease virus (mdv, also known as gallid herpesvirus type 2), and its close relative, herpesvirus of tur ... | 2008 | 18570965 |
| kinetics of marek's disease virus (mdv) infection in broiler chickens 1: effect of varying vaccination to challenge interval on vaccinal protection and load of mdv and herpesvirus of turkey in the spleen and feather dander over time. | two experiments in commercial broiler chickens vaccinated with herpesvirus of turkeys (hvt) and challenged with marek's disease virus (mdv) investigated the effects of the vaccination-to-challenge interval (vci) on vaccinal protection against marek's disease, and the kinetics of mdv and hvt load in the spleen and feather dander determined using real-time quantitative polymerase chain reaction. experiment 1 in isolators tested vci of 2, 4 and 7 days, while experiment 2 in floor pens tested vci of ... | 2008 | 18568648 |
| comparison of the genomes of 15 avian herpes-virus isolates by restriction endonuclease analysis. | differentiation of herpesvirus isolates has been performed mostly on the basis of biological properties and serology. in this study, 15 herpesvirus isolates from different species of birds were compared by restriction endonuclease analysis of genomic dna. all herpesviruses were isolated in europe or are used as vaccine viruses there. the isolates could be differentiated into seven groups based on restriction patterns. the largest group contains isolates from passeriform and psittacine birds and ... | 1997 | 18483909 |
| expression of cytokine genes following pre- and post-hatch immunization of chickens with herpesvirus of turkeys. | induction of immune response as characterised by expression of cytokine genes in the spleen following immunization of pre- and post-hatch chickens with herpesvirus of turkeys (hvt) vaccine was studied. the pattern of expression of ifn-gamma and il-10 genes in pre-hatch immunized chickens was different from that observed in post-hatch hvt immunized chickens. this expression pattern of cytokine genes was associated with significantly higher hvt transcripts in pre-hatch immunized chickens than in p ... | 2008 | 18406020 |
| antibody response of chickens to serotype 1, 2, or 3 marek's disease vaccines based on elisa with infected cells as antigen. | an enzyme-linked immunosorbent assay (elisa) was applied to evaluate the antibody response of commercial white leghorn chickens to vaccination against marek's disease (md) at hatch (day 0) with serotype-1 (rispens), -2 (sb-1), or -3 (turkey herpesvirus, hvt) vaccine virus and to challenge on day 21 with md virus. antigens for the test were whole chicken embryo fibroblast cells infected with rispens, sb-1, or hvt. the chickens were progeny of stock that had been vaccinated with hvt, and on day 21 ... | 2007 | 18251413 |
| determination of optimal conditions for thawing and diluting cell-bound cvi 988 marek's disease vaccine and stability of the diluted vaccine. | the cell-associated vaccine strain cvi 988, which is the active component of several commercial marek's disease vaccines, normally is frozen and stored in liquid nitrogen. in order to ascertain good efficacy of the vaccine, it is crucial that the right procedures are followed for thawing and diluting of the virus. in the study presented here, ampoules containing the frozen product were taken from storage in liquid nitrogen and were thawed in a water bath at 27 c, which is similar to a lukewarm b ... | 2007 | 18251410 |
| characterization of lorf11, a unique gene common to the three marek's disease virus serotypes. | the unique open reading frame 11 (lorf11) of marek's disease virus (mdv) is present in all three serotypes of mdv and is located in the unique long region of the mdv genome. in the serotype 1 md5 genome, lorf11 comprises 2711 nucleotides and encodes a predicted protein of 903 amino acids. in order to study the biological function of lorf11 we deleted it from the mdv cosmid a6 by using the reca-assisted restriction endonuclease cleavage method. the recombinant cosmid, a6deltalorf11, was transfect ... | 2007 | 18251393 |
| a recombinant turkey herpesvirus expressing chicken interleukin-2 increases the protection provided by in ovo vaccination with infectious bursal disease and infectious bronchitis virus. | in ovo vaccination remains an attractive option for the mass application of vaccines to poultry, ensuring a uniform application of vaccine in a cost-effective manner. however, the number of vaccines that can be delivered safely by this method is limited. several infectious bursal disease virus (ibdv) vaccines can be given in ovo though most are delivered post-hatch and there are no currently licensed embryo-safe infectious bronchitis virus (ibv) vaccines. reduction in the dose of vaccines given ... | 2007 | 17996994 |
| effects of vaccine dose, virus challenge dose and interval from vaccination to challenge on protection of broiler chickens against marek's disease virus challenge. | to examine the effects of varying the doses of turkey herpesvirus (hvt) vaccine and marek's disease virus (mdv) challenge at two intervals after vaccination on the protection of chickens against challenge with mdv. | 2007 | 17760936 |
| quantitative profiling of the shedding rate of the three marek's disease virus (mdv) serotypes reveals that challenge with virulent mdv markedly increases shedding of vaccinal viruses. | the shedding profile of marek's disease virus serotype 1 (mdv1, virulent), serotype 2 (mdv2, vaccinal) and herpesvirus of turkeys (hvt, vaccinal) in commercial broiler chickens was determined by measuring the daily rate of production of feather dander from chickens housed in isolators and by quantifying the viral load of each of these serotypes in the dander using quantitative real-time pcr (qpcr). mdv1 and hvt viruses were detectable in dander filtered from isolator exhaust air from day 7 and m ... | 2007 | 17622613 |
| marek's disease virus research in the post-sequencing era: new tools for the study of gene functions and virus-host interactions. | despite the fact that the causative agent of marek's disease was described more than 30 years ago, and that subsequently many classical biological studies have been carried out on the marek's disease virus (mdv), detailed analysis of its gene functions has been hampered by lack of suitable research tools. information on the primary structure of mdv-1 and its serologically related viruses, mdv-2 and herpesvirus of turkeys, is now available. this review focuses on the introduction of the modern an ... | 2003 | 17585455 |
| use of a vectored vaccine against infectious bursal disease of chickens in the face of high-titred maternally derived antibody. | interference by maternally derived antibody (mda) is a major problem for the vaccination of young chickens against infectious bursal disease (ibd). the choice of the timing of vaccination and of the type (degree of attenuation) of modified-live vaccine (mlv) to use is often difficult. an ibd vectored vaccine (vhvt13), in which turkey herpesvirus (hvt) is used as the vector, was recently developed. this vaccine is administered once at the hatchery, either in ovo or by the subcutaneous route, to 1 ... | 2007 | 17560594 |