Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| comparative analysis of marek's disease virus (mdv) glycoprotein-, lytic antigen pp38- and transformation antigen meq-encoding genes: association of meq mutations with mdvs of high virulence. | marek's disease (md) is a highly contagious lymphoproliferative and demyelinating disorder of chickens. md is caused by marek's disease virus (mdv), a cell-associated, acute-transforming alphaherpesvirus. for three decades, losses to the poultry industry due to md have been greatly limited through the use of live vaccines. mdv vaccine strains are comprised of antigenically related, apathogenic mdvs originally isolated from chickens (mdv-2), turkeys (herpesvirus of turkeys, hvt) or attenuated-onc ... | 2004 | 15327791 |
| abundance of ifn-alpha and ifn-gamma mrna in blood of resistant and susceptible chickens infected with marek's disease virus (mdv) or vaccinated with turkey herpesvirus; and mdv inhibition of subsequent induction of ifn gene transcription. | the effects of the very virulent rb-1b strain of marek's disease virus (mdv) and turkey herpesvirus (hvt), a vaccinal strain, on abundance of ifn mrna in the blood were investigated. mdv and hvt infection did not change the circulating level of ifn-gamma mrna 1 and 7 days p.i., but they increased ifn-alpha mrna levels slightly in genetically susceptible (to tumour development) b(13)/b(13) chickens. the total number of circulating leukocytes was unchanged and increase in message was accompanied b ... | 2004 | 15592893 |
| quail cell lines supporting replication of marek's disease virus serotype 1 and 2 and herpesvirus of turkeys. | marek's disease virus (mdv), a highly cell-associated alphaherpesvirus, can be isolated and propagated in chicken kidney cells (ckc) and chicken or duck embryo fibroblast cells (cef or def, respectively). two recently developed cell lines, cu447 and cu453, developed from methylcholanthrene-induced tumors in japanese quail, were examined for their suitability to propagate the three serotypes of mdv. the mdv strain rb-1b (serotype 1) was passaged for more than 30 passages in cu447 without causing ... | 2004 | 15666861 |
| herpesvirus of turkeys: microarray analysis of host gene responses to infection. | herpesvirus of turkeys (hvt) provides an economically important live vaccine for prevention of marek's disease (md) of chickens. md, characterized by both immunosuppression and t-cell lymphoma, is caused by another herpesvirus termed marek's disease virus (mdv). microarrays were used to investigate the response of chicken embryonic fibroblasts (cef) to infection with hvt. genes responding to hvt infection include several induced by interferon along with others modulating signal transduction, tra ... | 2004 | 14972539 |
| detection and localization of avian alphaherpesviruses in embryonic tissues following in ovo exposure. | we investigated whether chicken embryonic tissues are susceptible to infection with virulent marek's disease virus (mdv). groups of embryonic day (ed) 17 chicken embryos and 1-day-old chicks were compared for tissue sites of viral persistence of mdv and herpesvirus of turkeys (hvt) in lungs, thymuses, bursae of fabricius and spleens. mdv dna was detectable in the lungs and thymuses of embryos at 3 days post-inoculation (dpi) by in situ hybridization, while hvt dna was only present in embryonic l ... | 2004 | 15019243 |
| the efficacy of recombinant fowlpox vaccine protection against marek's disease: its dependence on chicken line and b haplotype. | earlier studies have shown that the b haplotype has a significant influence on the protective efficacy of vaccines against marek's disease (md) and that the level of protection varies dependent on the serotype of md virus (mdv) used in the vaccine. to determine if the protective glycoprotein gene gb is a basis for this association, we compared recombinant fowlpox virus (rfpv) containing a single gb gene from three serotypes of mdv. the rfpv were used to vaccinate 15.b congenic lines. nonvaccinat ... | 2004 | 15077806 |
| absolute quantitation of marek's disease virus and herpesvirus of turkeys in chicken lymphocyte, feather tip and dust samples using real-time pcr. | the further development of taqman quantitative real-time pcr (qpcr) assays for the absolute quantitation of marek's disease virus serotype 1 (mdv1) and herpesvirus of turkeys (hvt) viruses is described and the sensitivity and reproducibility of each assay reported. using plasmid dna copies, the lower limit of detection was determined to be 5 copies for the mdv1 assay and 75 copies for the hvt assay. both assays were found to be highly reproducible for ct values and calculated copy numbers with m ... | 2006 | 16290211 |
| relationship between marek's disease virus load in peripheral blood lymphocytes at various stages of infection and clinical marek's disease in broiler chickens. | vaccination with herpesvirus of turkey (hvt) vaccine provides protection against clinical marek's disease (md) but does not preclude infection with wild-type md virus (mdv). the quantity of mdv detected in circulating lymphocytes during the early period after infection may be a useful predictor of subsequent clinical md later in the life. a study was designed to quantify mdv and hvt copy number in peripheral blood lymphocytes (pbl) using real-time polymerase chain reaction between days 5 and 35 ... | 2006 | 16448942 |
| herpesvirus of turkey reconstituted from bacterial artificial chromosome clones induces protection against marek's disease. | herpesvirus of turkey (hvt) is an alphaherpesvirus that is widely used as a live vaccine against marek's disease because of its antigenic relationship with marek's disease virus (mdv). in spite of a similar genome structure, hvt has several unique genes, the functions of which are not completely understood. as a first step in carrying out detailed analysis of the functions of the hvt genes, a full-length infectious bacterial artificial chromosome (bac) clone of hvt was constructed. dna from two ... | 2006 | 16528024 |
| antiviral properties of combination peptides of hiv-1 rev nls and nes. | nuclear translocation signal has been identified as a mediator of protein shuttling between nuclear and cytoplasm. here we report that the combination of peptides from nuclear localization signal (nls) and nuclear export signal (nes) of hiv-1 rev have an antiviral activity against the herpes virus of turkey and marek's disease virus serotype 1. | 2006 | 17168825 |
| examination of the effect of a naturally occurring mutation in glycoprotein l on marek's disease virus pathogenesis. | we recently reported a comparison of glycoprotein-encoding genes of different marek's disease virus pathotypes (mdvs). one mutation found predominantly in very virulent (vv)+mdvs was a 12-bp (four-amino acid) deletion in the glycoprotein l (gl)-encoding gene in four of 23 mdv strains examined (three were vv+mdvs and one was a vvmdv). this mutation was noted in the gl of the tk (615k) strain, but not in the rl (615j) strain of mdv. these strains have identical mutations in the meq gene characteri ... | 2006 | 16617990 |
| suggesting the possible role of turkey herpesvirus or hvt-like as a predisposing factor or causative agent in multiple sclerosis. | wild birds are referred to as 'vectors' of an exogenous causative agent of ms, in particular the marek's disease virus, but this has yet to be confirmed. the epidemiology of ms shows that it occurs worldwide but that there is a high incidence of ms clusters within specific geographical distributions such as in cooler, temperate, zones in a north/south gradient from the equator. furthermore, these regions are well known as preferred zones for wintering/breeding/feeding purposes and for having a h ... | 2006 | 16777352 |
| cytokine gene expression patterns associated with immunization against marek's disease in chickens. | the present study explored the immunological correlates of protection mediated by a live bivalent vaccine consisting of herpesvirus of turkeys (hvt) and sb-1 against infection with the rb1b strain of marek's disease virus (mdv). compared to unvaccinated infected chickens, vaccinated protected birds had lower expression of interleukin (il)-6, il-10 and il-18 genes in spleen. however, there was no difference between these two groups of birds in the expression of interferon (ifn)-gamma, il-4, il-12 ... | 2007 | 17070626 |
| expression of chicken interleukin-2 by turkey herpesvirus increases the immune response against marek's disease virus but fails to increase protection against virulent challenge. | as marek's disease virus continues to evolve towards greater virulence, more efficacious vaccines will be required in the future. we expressed chicken interleukin-2 (il-2) from a turkey herpesvirus (hvt) in an attempt to increase the efficacy of hvt as a vaccine against marek's disease. the recombinant il-2/hvt was safe for in ovo vaccination, although it replicated less in the birds compared with the parent hvt strain. expression of il-2 increased the neutralizing antibody response against hvt ... | 2007 | 17364512 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| emerging roles of chicken and viral micrornas in avian disease. | abstract: | 2011 | 21645299 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| development, application, and results of routine monitoring of marek's disease virus in broiler house dust using real-time quantitative pcr. | results are presented from four studies between 2002 and 2011 into the feasibility of routinely monitoring marek's disease virus serotype 1 (mdv-1) in broiler house dust using real-time quantitative pcr (qpcr) measurement. study 1 on two farms showed that detection of mdv-1 occurred earlier on average in dust samples tested using qpcr than standard pcr and in spleen samples from five birds per shed assayed for mdv-1 by qpcr or standard pcr. dna quality following extraction from dust had no effec ... | 2013 | 23901774 |
| comparison of loop-mediated isothermal amplification and pcr for the detection and differentiation of marek's disease virus serotypes 1, 2, and 3. | the previously conducted study on loop-mediated isothermal amplification (lamp) has shown its usefulness for the detection of marek's disease virus (mdv) virulent field strains. the current study improves the previously designed lamp method with an additional pair of loop primers, which accelerates the reaction, and describes two other lamp procedures for the specific detection of fc126 strain of turkey herpesvirus and nonpathogenic sb-1 strain. the developed lamp procedures were also confirmed ... | 2013 | 23901773 |
| a deletion in the glycoprotein l (gl) gene of u.s. marek's disease virus (mdv) field strains is insufficient to confer increased pathogenicity to the bacterial artificial chromosome (bac)-based strain, rb-1b. | marek's disease (md) is a highly transmissible, herpesvirus-associated malignancy of chickens and turkeys caused by marek's disease virus (mdv). md is currently controlled through the use of nonsterilizing vaccines composed of antigenically related, apathogenic herpesviruses mardivirus 2 (mdv-2), meleagrid herpesvirus 1 (herpesvirus of turkeys, hvt), or attenuated mdv-1 strain cvi988 (rispens). since the mid-1960s, field strains of mdv have increased in virulence, due, in part, to the widespread ... | 2013 | 23901769 |
| application of a new bivalent marek's disease vaccine does not interfere with infectious bronchitis or newcastle disease vaccinations and proves efficacious. | a possible interference after marek's disease (md) vaccination using an experimental bivalent vaccine, consisting of a redesigned cvi-988/rispens-type mdv-1 strain and herpesvirus of turkeys, with vaccination against infectious bronchitis (ib) virus (ibv) or newcastle disease (nd) virus (ndv) was examined. day-old specific-pathogen-free chicks were concomitantly vaccinated with the bivalent md vaccine (either intramuscularly or subcutaneously) and with commercially available vaccines against nd ... | 2013 | 23901767 |
| inhibition of toll-like receptor 2-mediated nf-kappab activation in vero cells with herpesvirus of turkeys. | in a previous study, vaccination with a live bivalent vaccine consisting of herpesvirus of turkeys (hvt) and sb-1 was found to be associated with distinct cytokine expression patterns and the modulation of cytokine responses in the spleen. this vaccine could play a role in mediating protection against infection with the rb1b strain of marek's disease virus. in the present study, vectors for chicken toll-like receptor 1 (chtlr1) and 2 (chtlr2) expression were constructed and transfected into vero ... | 2013 | 23901754 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| safety and efficacy of a turkey herpesvirus vector laryngotracheitis vaccine for chickens. | turkey herpesvirus vector laryngotracheitis vaccine (hvt/lt) expressing the glycoprotein b gene of laryngotracheitis virus (ltv) has been developed. in vitro growth kinetics of hvt/lt were similar to those of parental turkey herpesvirus (hvt), fc-126 strain. genetic and phenotypic stabilities of hvt/lt after in vitro (in cell culture) or in vivo (in chickens) passage were confirmed by various assays, including southern blot analysis, western blot analysis, and an indirect immunofluorescence assa ... | 2013 | 24689173 |
| detection of infectious laryngotracheitis virus antibodies by glycoprotein-specific elisas in chickens vaccinated with viral vector vaccines. | two glycoproteins of infectious laryngotracheitis virus (iltv), gi and gb, were expressed in baculovirus and purified for the development of iltv recombinant protein-based elisas. the ability of gb and gi elisas to detect iltv antibodies in chickens vaccinated with viral vector vaccines carrying the iltv gb gene, vectormune fp-lt (the commercial fowlpox vector laryngotracheitis vaccine) and vectormune hvt-lt (commercial turkey herpesvirus vector laryngotracheitis vaccine), was evaluated using se ... | 2013 | 23901757 |
| newcastle disease virus (ndv) recombinants expressing infectious laryngotracheitis virus (iltv) glycoproteins gb and gd protect chickens against iltv and ndv challenges. | infectious laryngotracheitis (ilt) is a highly contagious acute respiratory disease of chickens caused by infectious laryngotracheitis virus (iltv). the disease is controlled mainly through biosecurity and vaccination with live attenuated strains of iltv and vectored vaccines based on turkey herpesvirus (hvt) and fowlpox virus (fpv). the current live attenuated vaccines (chicken embryo origin [ceo] and tissue culture origin [tco]), although effective, can regain virulence, whereas hvt- and fpv-v ... | 2014 | 24829337 |
| role of virus-encoded micrornas in avian viral diseases. | with total dependence on the host cell, several viruses have adopted strategies to modulate the host cellular environment, including the modulation of microrna (mirna) pathway through virus-encoded mirnas. several avian viruses, mostly herpesviruses, have been shown to encode a number of novel mirnas. these include the highly oncogenic marek's disease virus-1 (26 mirnas), avirulent marek's disease virus-2 (36 mirnas), herpesvirus of turkeys (28 mirnas), infectious laryngotracheitis virus (10 mir ... | 2014 | 24662606 |
| 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 |
| 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 |
| 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 |
| efficient marek's disease virus (mdv) and herpesvirus of turkey infection of the qm7 cell line that does not contain latent mdv genome. | marek's disease virus (mdv; also known as gallid herpesvirus 2, mdv-1) causes oncogenic disease in chickens producing clinical signs that include lymphomas, visceral tumours, nerve lesions, and immunosuppression. mdv vaccines are widely used and mostly produced using primary cells: chicken embryo fibroblast cells, duck embryo fibroblast cells, chicken embryo kidney cells or chicken kidney cells. an immortalized cell line that can be used to manufacture the virus has long been desired. in this re ... | 2014 | 25204414 |
| host genetic resistance to marek's disease sustains protective efficacy of herpesvirus of turkey in both experimental and commercial lines of chickens. | marek's disease (md) remains a continual threat to the poultry industry worldwide as the md virus continues evolving in virulence. md has been controlled primarily by intensive use of vaccines since 1969. based on the antigenic and pathogenic differences of the viruses that the vaccines were derived from, commercially available md vaccines are classified into three categories, mdv-1, -2, and -3 vaccines. this study was designed to compare the protective efficacy of mdv-1 (cvi988/rispens) and mdv ... | 2014 | 24530405 |
| 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 |
| 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 |
| 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 |
| understanding the molecular basis of disease is crucial to improving the design and construction of herpesviral vectors for veterinary vaccines. | viral infections are associated with production losses in many animal production industries. important examples of this are marek's disease (md) and bovine respiratory disease (brd) which are significant issues in the chicken and cattle industries, respectively. viruses play key roles in md and brd development and consequently have also been utilised in vaccination strategies to control these diseases. despite the widespread availability and use of vaccines to control these diseases both are sti ... | 2015 | 26387436 |
| construction of recombinant hvt expressing pmpd, and immunological evaluation against chlamydia psittaci and marek's disease virus. | chlamydia psittaci (c. psittaci) is an obligate intracellular zoonotic pathogen that can be transmitted to humans from birds. no efficacious commercial vaccine is available for clearing chlamydial infection due to lack of potential vaccine candidates and effective delivery vehicles. herpesvirus of turkeys (hvt) is an efficacious commercially available vaccine against marek's disease virus (mdv). in this study, a recombinant hvt-delivered vaccine against c. psittaci and marek's disease was develo ... | 2015 | 25893439 |
| evaluation of the protection efficacy of a serotype 1 marek's disease virus-vectored bivalent vaccine against infectious laryngotracheitis and marek's disease. | laryngotracheitis (lt) is a highly contagious respiratory disease of chickens that produces significant economic losses to the poultry industry. traditionally, lt has been controlled by administration of modified live vaccines. in recent years, the use of recombinant dna-derived vaccines using turkey herpesvirus (hvt) and fowlpox virus has expanded, as they protect not only against the vector used but also against lt. however, hvt-based vaccines confer limited protection against challenge, with ... | 2015 | 26473676 |