| infectious bursal disease virus changes the potassium current properties of chicken embryo fibroblasts. | infectious bursal disease virus (ibdv) is the causative agent of an economically significant poultry disease. ibdv infection leads to apoptosis in chicken embryos and cell cultures. since changes in cellular ion fluxes during apoptosis have been reported, we investigated the membrane ion currents of chicken embryo fibroblasts (cefs) inoculated with the cu-1 strain of ibdv using the patch-clamp recording technique. incubation of cefs with ibdv led to marked changes in their k+ outward current pro ... | 1998 | 9657954 |
| a novel technique for in-vivo assay of viral regulatory regions in genomes of animal rna viruses. | a novel in-vivo assay system for mapping and analyzing regulatory signals which promote transcription and expression of viral rna genomes is described. the system was developed using infectious bursal disease virus (ibdv), a double-stranded rna virus and vero cells which are permissive for ibdv, as a model. the model system consisted of engineered modifications of an enhancer-less pgl3-promoter vector such that deleted lengths of the 5' noncoding region of genome segment a of ibdv were positione ... | 1998 | 9672132 |
| infectious bursal disease virus polyprotein processing does not involve cellular proteases. | the larger genome segment, segment a, of infectious bursal disease virus (ibdv) encodes vp2, vp3 and vp4 as a precursor polyprotein. the viral protease, vp4, is responsible for self-processing of the polyprotein, however, there are additional secondary precursor products such as vpx whose further processing has not been defined. expression of ibdv cdnas in vitro with rabbit reticulocyte lysates in a coupled transcription-translation system and in the sindbis virus expression system (with bhk-21 ... | 1997 | 9672603 |
| the 5'-terminal 32 basepairs conserved between genome segments a and b contain a major promoter element of infectious bursal disease virus. | the regions of the infectious bursal disease virus (ibdv) genome with regulatory function are not known. in the present study, progressively deleted lengths of the 5' noncoding region of segment a were constructed in pgl3 vectors having sv40 enhancer or promoter, and a luciferase (luc) reporter gene. transient transfections of the constructs made in a promoter-less pgl3-enhancer vector when transfected in vero cells and the lysates assayed for luc expression, allowed the localization of maximal ... | 1997 | 9672609 |
| detection of infectious bursal disease virus of poultry in clinical samples by rt-pcr. | the rt-pcr technique was adopted to amplify variable region of vp2 gene of infectious bursal disease virus using three different sets of primers. these primers could generate products of 643, 474 and 552 bp sizes. the authenticity of the amplicons was confirmed by their size in agarose gel, restriction enzyme digestion and by nested pcr. out of total five clinical samples tested, ibd viral genomic rna could be detected in four by rt-pcr. restriction enzyme digestion of pcr products with stui cou ... | 1998 | 9678252 |
| rapid preparation of plasma membranes from avian lymphoid cells and fibroblasts for virus binding studies. | a simple and rapid protocol for the preparation of plasma membranes from chicken embryo fibroblasts and chicken lymphoid cells was developed. characterization of the preparations by morphological, biochemical and serological methods indicated the specific enrichment of the plasma membranes as well as cell surface proteins. binding of infectious bursal disease virus (ibdv) particles was demonstrated after immobilization of the plasma membranes, and cell type-specific differences were observed. al ... | 1998 | 9694323 |
| western blot detection of infectious bursal disease virus infection. | in order to evaluate the use of a western blot methodology for the diagnosis of infectious bursal disease virus (ibdv) infection, chickens were experimentally infected with ibdv strains and tested for the presence of viral antigens and antibodies by a blocking western blot test (bwb). the viral proteins obtained from the bursa of fabricius (bf) were transferred to a nitrocellulose membrane after sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page), and the chicken sera obtained b ... | 1998 | 9698773 |
| effect of immunostimulation on cytotoxic activity of intestinal intraepithelial lymphocytes of chickens in infectious bursal disease and eimeria tenella infections. | in chickens, intestinal intraepithelial lymphocytes (iiels) exhibit spontaneous natural killer (nk) cell like activity, by which they are active in the first line of defence on gut epithelial linings. in the present study, the cytotoxic activity of iiels was found to be drastically suppressed in chickens experimentally infected with infectious bursal disease (ibd) virus at the age of 5 weeks and also in chickens experimentally infected with eimeria tenella oocysts at the age of 8 weeks (p < 0.01 ... | 1998 | 9704505 |
| protection of broiler breeders by an inactivated combined water-in-oil-in-water viral vaccine. | a four-component vaccine, prepared by combining the single vaccines, contains subunits of newcastle disease and infectious bronchitis viruses, as well as whole inactivated infectious bursal disease and egg drop syndrome viruses. the vaccine is prepared in the form of a low-viscosity water-in-oil-in-water emulsion with low mineral oil content. heavy breeders were vaccinated at the age of 20 weeks by intramuscular administration of 0.5 ml vaccine/bird in an experiment carried out under field condi ... | 1998 | 9704508 |
| infectious bursal disease and hemorrhagic enteritis. | infectious bursal disease (ibd) of chickens and hemorrhagic enteritis (he) of turkeys are caused by infectious bursal disease virus (ibdv) and hemorrhagic enteritis virus (hev), respectively. both diseases have common features, including an acute stage followed by immunosuppression, resulting in lowered resistance to a variety of infectious agents and poor response to commonly used vaccines. the ibdv and hev infections are widespread in commercial chicken and turkey flocks, respectively. the acu ... | 1998 | 9706087 |
| poultry industry strategies for control of immunosuppressive diseases. | immunosuppression has historically cost the poultry industry in increased mortality and in performance factors during rearing. in addition, immunosuppression has had a negative impact on the ability of the poultry industry to process chickens due to associated health problems. industry strategies for controlling immunosuppression are not consistent between broiler companies. the broiler industry is refining their strategies for controlling immunosuppression based on research and field observatio ... | 1998 | 9706089 |
| immunohistochemical investigation of the tissue distribution of mannan-binding lectin in non-infected and virus-infected chickens. | this paper describes the results of immuno-histochemical staining for chicken mannan-binding lectin (mbl) in formalin-fixed tissue sections from non-infected chickens, and from chickens infected with infectious laryngotracheitis virus (iltv) or infectious bursal disease virus (ibdv). in the non-infected chickens, mbl was detected in the cytoplasm of a few hepatocytes and in the germinal centres of the caecal tonsils, whereas sections of kidney, heart muscle, spleen, cerebrum, thymus, adrenal gla ... | 1998 | 9708196 |
| humoral and cell-mediated immunopotentiation in vaccinated chicken layers by thymic hormones and zinc. | the humoral and cell-mediated immunities to a trivalent killed vaccine, administered subcutaneously to white leghorn-chicken layers at 29 and 31 weeks of age, and containing antigens of infectious bronchitis virus (ibv), infectious bursal disease virus (ibdv), and newcastle disease virus (ndv), were quantitated in five vaccinated and one unvaccinated-control group. four out of the five vaccinated groups were immunopotentiated by various combinations of zinc and thymic hormones administered intra ... | 1998 | 9713942 |
| pathogenicity and immunosuppressive properties of infectious bursal disease virus field isolates and commercial vaccines in india. | the pathogenicity and immunosuppressive properties of two field isolates of infectious bursal disease. virus (ibdv) and five commercial ibdv live virus vaccines marketed in india were evaluated in this study. the pathogenicity of the wild type viruses and vaccines were based on mortality, the bursa:body weight ratio and microscopic lesions in the bursa in 3-week-old chicks that received these viruses. the immunosuppressive effects of these viruses were evaluated by measuring the antibody respons ... | 1998 | 9719845 |
| study of leg weakness in two commercial broiler flocks. | the major causes of leg weakness/lameness were investigated in two male commercial broiler flocks. the numbers of dead and lame birds culled from the flocks each day were recorded by the flock managers. forty-four lame birds and 22 sound birds were examined postmortem during a period of six weeks and the proximal and distal end of each femur, tibiotarsus and tarsometatarsus were examined histologically. attempts were made to isolate bacteria and viruses from the proximal end of each femur. blood ... | 1998 | 9725184 |
| critical amino acid changes in vp2 variable domain are associated with typical and atypical antigenicity in very virulent infectious bursal disease viruses. | classical serotype 1 infectious bursal disease viruses (ibdv), but not very virulent (vv) isolates, react with neutralizing monoclonal antibody (nmab) 3 in virus neutralization tests or antigen-capture elisa. two other nmabs, 6 and 8, bind to both classical and most vv strains, but not to the atypical 94,432 and 91,168 vv strains, respectively. the basis for such reactivities was investigated by sequencing the genome region encoding the vp2 major immunogenic domain. in classical, variant, vaccin ... | 1998 | 9739340 |
| generation of infectious pancreatic necrosis virus from cloned cdna. | we developed a reverse genetics system for infectious pancreatic necrosis virus (ipnv), a prototype virus of the birnaviridae family, with the use of plus-stranded rna transcripts derived from cloned cdna. full-length cdna clones of the ipnv genome that contained the entire coding and noncoding regions of rna segments a and b were constructed. segment a encodes a 106-kda precursor protein which is cleaved to yield mature vp2, nonstructural protease, and vp3 proteins, whereas segment b encodes th ... | 1998 | 9765436 |
| restriction fragment length polymorphism analysis of highly virulent strains of infectious bursal disease viruses from holland, turkey, and taiwan. | strains of highly virulent infectious bursal disease virus (hvibdv) from turkey (oa, oe), holland (hol), and taiwan (pt, il) were characterized by reverse transcriptase/polymerase chain reaction-restriction fragment length polymorphism (rt/pcr-rflp) analysis and compared with the united states of america (usa) classic (stc) and variant (md, in) serotype 1 viruses and serotype 2 oh strain. a primer pair that amplified a 743-bp fragment of the vp2 gene was used. the rflp profiles of the rt/pcr pro ... | 1998 | 9777147 |
| simplified sample processing combined with a sensitive nested polymerase chain reaction assay for detection of infectious bursal disease virus in the bursa of fabricus. | a rapid and sensitive protocol for the detection and amplification of infectious bursal disease virus (ibdv) rna in the bursa of fabricius was developed. by digestion with proteinase k and subsequent extraction with phenol and chloroform, ibdv rna was efficiently released from a single bursa. ibdv rna extraction time was shortened to 4 hr, compared with 24 hr with the traditional method, and only one bursa was needed instead of five. this more simplified procedure resulted in a significant reduc ... | 1998 | 9777148 |
| coding region of segment a sequence of a very virulent isolate of ibdv--comparison with isolates from different countries and virulence. | we determined the sequence of the coding region of segment a, coding for the viral proteins (vps) vp2, vp4, and vp3, of a very virulent (vv) infectious bursal disease virus (ibdv) isolated in israel and named ibdvks. we compared the deduced amino acid sequences of the proteins of the new isolate with those of the same proteins from several ibdv isolates, as published in recent years. the amino acid sequences of vp3 and vp4 of the israeli isolate were 1.9%-2.3% different from the sequences of the ... | 1998 | 9777150 |
| a comparison of two rna isolation methods for double-stranded rna of infectious bursal disease virus. | infectious bursal disease virus (ibdv), a member of the birnaviridae family, contains a bisegmented double-stranded rna (dsrna) genome. the segments are linked covalently at 5' termini by a large (90 kda) viral genomic protein that migrates similar to viral rna dependent rna polymerase of ibdv. a proteinase k digestion based approach and acid-guanidium-phenol-chloroform (agpc) rna extraction method were used to extract dsrna of ibdv from infected bursae. after extraction, dsrna of ibdv was purif ... | 1998 | 9779617 |
| alteration of chicken heterophil and macrophage functions by the infectious bursal disease virus. | the effects of the infectious bursal disease virus (ibdv) on chicken heterophils and macrophages are reported. short-term incubation of ibdv with heterophils causes an activation of cellular oxidative burst, a decrease in phagocytosis and cellular migration, and an increase in cellular adherence to the ibdv-infected chicken embryo fibroblasts. under electron microscopic examination, heterophils show condensed chromatin and packets of intact granules, either free or being phagocytized by macropha ... | 1998 | 9790874 |
| fluorescence spectroscopy monitoring of the conformational restraint of formaldehyde- and glutaraldehyde-treated infectious bursal disease virus proteins. | interaction of native proteinaceous antigens during the recognition and the effector phases of an immune response leads to antigenic conformational modifications which may elicit additional specific immune response. protein cross-linking and conformation restraining formaldehyde and glutaraldehyde have been extensively used in vaccine preparation, but the relative efficiencies of conformational restraint at concentrations similar to those used in vaccine preparation have not been investigated. w ... | 1998 | 9796050 |
| biochemical and hormonal changes associated with experimental infection of chicks with infectious bursal disease virus. | the inoculation of chicks with the infectious bursal disease (ibd) virus manifested typical clinical signs indicative of ibd viral infection. the inoculated birds seroconverted and showed significantly decreased total protein, lipid and a decrease in the albumin to globulin ratio. a significant increase was seen in the concentration of corticosterone and thyroxine but not in the triiodothyronine level. | 1998 | 9852766 |
| seroprevalence of infectious bursal disease virus in free-living wild birds in japan. | serum samples collected from 739 free-living wild birds of 44 species from gifu, mie and hyogo prefectures in japan during the period 1989 to 1997 were tested for antibodies to infectious bursal disease virus (ibdv) serotypes 1 and 2 by a virus neutralization test. serological evidence of infection with serotypes 1 and 2 was found in 15 (2%) of the sera of 6 species and 36 (4.9%) of the sera of 11 species, respectively. antibodies to ibdv were detected from both sedentary and migratory species. ... | 1998 | 9853315 |
| sequence analysis of the vp2 hypervariable region of nine infectious bursal disease virus isolates from mainland china. | the vp2 hypervariable region of infectious bursal disease virus (ibdv) from nine mainland chinese strains was amplified by reverse transcriptase/nested polymerase chain reaction and cloned into pgem-t vector. the nine isolates, which were from the center (hn3), the north (bj-1, b2/28, hd96), the east (js-18 and ah-2), the northeast (d11-2, c4-2), and the west (ts) of china, were sequenced and compared with each other and with six reference ibdv sequences. clustering analysis separated the nine i ... | 1998 | 9876846 |
| formation of virus-like particles when the polyprotein gene (segment a) of infectious bursal disease virus is expressed in insect cells. | the baculovirus expression vector system was used to examine the expression of the full-length infectious bursal disease virus (ibdv) segment a cdna, which encodes the structural proteins in a polyprotein precursor that is autocatalytically cleaved to vpx, vp3, and vp4. no vp2 was observed in lysates of recombinant baculovirus infected cells indicating the lack of processing of vpx to vp2 in this system. virus-like particles (vlp) were purified from the infected insect cells, and on negative sta ... | 1999 | 9918334 |
| some characteristics of a cellular receptor for virulent infectious bursal disease virus by using flow cytometry. | a flow cytometric virus binding assay that directly visualizes the binding of infectious bursal disease virus (ibdv) to its target cells was established. the chicken b lymphoblastoid cell line, lscc-bk3, which is permissive for ibdv infection, bound high levels of the virus. another b lymphoblastoid cell line, lscc-1104-b1, bound low levels of the virus, although it was nonpermissive. no virus binding was detected in nonpermissive t lymphoblastoid cell lines. in the binding assay to heterogeneou ... | 1998 | 9930190 |
| adaptation of very virulent infectious bursal disease virus to chicken embryonic fibroblasts by site-directed mutagenesis of residues 279 and 284 of viral coat protein vp2. | the full-length rna genomes of a chicken embryonic fibroblast (cef)-nonpermissive, very virulent infectious bursal disease virus (ibdv) (strain hk46) were amplified into cdnas by reverse transcription-pcr. the full-length cdnas were sequenced and subcloned into a eukaryotic expression vector, from which point mutations were introduced into the vp2 region by site-directed mutagenesis. the wild-type and mutated plasmids were transfected directly into cefs to examine their ability to generate cef-p ... | 1999 | 10074133 |
| lysis of myelocytes in chickens infected with infectious bursal disease virus. | in specific-pathogen-free chickens infected with the highly virulent hps-2 strain or virulent reference gbf-1 strain of infectious bursal disease virus (ibdv), pathologic changes of the bone marrow were investigated. on histologic examination, bone marrow lesions were prominent in the hps-2 group but only mild in the gbf-1 group. the bone marrow of the hps-2 group showed severe lysis and depletion of heterophil myelocytes with pyknotic nuclear alteration 2-3 days after inoculation. on examinatio ... | 1999 | 10098643 |
| sequence analysis of australian infectious bursal disease viruses. | | 1999 | 10197249 |
| successful treatment of decompensated chronic viral hepatitis by bursal disease virus vaccine. | three cases of women with chronic liver inflammation caused by hepatitis b (two) and c (one) viral infections, were followed up to twelve years after diagnosis. as conventional therapy was ineffective and the patients progressed into decompensated liver disease, they were superinfected with massive doses of an attenuated variant (mth-68/b) of the apathogenic avian bursal disease virus (a double-stranded rna virus from the birnaviridae family). clinical symptoms and biochemical abnormalities were ... | 1999 | 10216467 |
| failure of viral protein 3 of infectious bursal disease virus produced in prokaryotic and eukaryotic expression systems to protect chickens against the disease. | in recent years, infectious bursal disease virus (ibdv) has become a serious economic problem as a result of the emergence of new and very virulent strains. most of the antibodies produced against ibdv are for the structural proteins viral protein (vp) 2 (vp2) and vp3. the purpose of this study was to test the potential of recombinant vp3 to induce protective antibodies. the gene for vp3 was isolated from a virulent strain of the virus and cloned into prokaryotic (escherichia coli) and eukaryoti ... | 1999 | 10216754 |
| viral protein 1 sequence analysis of three infectious bursal disease virus strains: a very virulent virus, its attenuated form, and an attenuated vaccine. | comparisons between sequences of very virulent, virulent, and attenuated strains of the infectious bursal disease virus (ibdv) may indicate sites on the genome co-inciding with virulence. in an attempt to detect if such sites exist on the coding region of segment b, viral protein 1 (vp1) (encoded for by segment b) of a very virulent israeli virus, il3; its attenuated strain, il4; and the attenuated winterfield vaccine 2512 were cloned and sequenced. a comparison was made among them and with six ... | 1999 | 10216760 |
| protection of chickens against very virulent infectious bursal disease virus (ibdv) and marek's disease virus (mdv) with a recombinant mdv expressing ibdv vp2. | to develop a herpes virus vaccine that can induce immunity for an extended period, a recombinant marek's disease (md) virus (mdv) cvi-988 strain expressing infectious bursal disease virus (ibdv) host-protective antigen vp2 at the us2 site (rmdv) was developed under the control of an sv40 early promoter. chickens vaccinated with the rmdv showed no clinical signs and no mortality and 55% of the chickens were considered protected histopathologically after challenge with very virulent ibdv (vvibdv), ... | 1999 | 10329546 |
| sequence comparison of the vp2 variable region of infectious bursal disease virus isolates from vietnam. | the variable region in the vp2 gene of twenty-three infectious bursal disease virus (ibdv) isolates, collected in vietnam in 1997 and 1998, was amplified as cdna by using the reverse transcription-polymerase chain reaction and sequenced. analysis of amino acid substitutions and phylogenetic relationships of the deduced amino acid sequences (residues 206-350) showed that the nineteen vietnamese vv ibdvs clustered with the european vv ibdvs, japanese vv ibdvs and chinese vv strains, and that the f ... | 1999 | 10342297 |
| susceptibility of local nigerian and exotic chickens to infectious bursal disease by contact exposure. | one hundred 6-week-old susceptible cockerels were inoculated with a pathogenic strain of infectious bursal disease virus (ibdv) and kept in the same pen as 100 each of 6-week-old pullets, local chickens and broilers. the cockerels developed depression and diarrhoea on day 3 post inoculation (pi) and most of the pullets and some of the local chickens and broilers showed similar signs on day 4 pi. loss in weight was severe and similar in the pullets and local chickens, being significantly greater ... | 1999 | 10371006 |
| organ culture of chicken bursa as a model to study the pathogenicity of infectious bursal disease virus isolates. | in vitro study with chicken bursal organ culture was attempted to assess the pathogenicity of locally isolated infectious bursal disease virus (ibdv) initially isolated from the bursa of naturally infected birds. in bursal organ culture, lymphoblastic transformation was noticed as early as 24 hr postinoculation and reached maximum at 72 hr postinoculation. the other microscopic changes were increased number of macrophages and formation of plasma cells. the ibdv antigen was detected 24 hr onward ... | 1999 | 10396628 |
| correlation of enzyme-linked immunosorbent assay titers with protection against infectious bursal disease virus. | we examined the utility of baculovirus-expressed infectious bursal disease virus (ibdv) proteins to act as antigens in the enzyme-linked immunosorbent assay (elisa). the three ibdv protein antigens tested included 1) a truncated vp2, 2) whole vp2, and 3) the polyprotein products vp2, vp3, and vp4. serum samples from 2-wk-old commercially reared broilers were collected and tested in the three elisas. serum samples were obtained from 34 different commercial broiler flocks. an average of 14 serum s ... | 1999 | 10396631 |
| antigenic and molecular characterization of three infectious bursal disease virus field isolates. | three infectious bursal disease field viruses, identified as u28, 3212, and miss and isolated in the early 1980s from the southeastern united states, were characterized both antigenically and genotypically. a panel of monoclonal antibodies (mabs) was utilized in an antigen-capture enzyme-linked immunosorbent assay (elisa) for antigenic characterization. the elisa data indicated that u28 and the delaware variants are antigenically related. the 3212 and the gls variants were more closely related a ... | 1999 | 10396632 |
| in ovo vaccination of specific-pathogen-free chickens with vaccines containing multiple agents. | we used in ovo technology to protect chickens against multiple diseases by inoculating vaccines containing mixtures of live viral agents. a single in ovo injection of a vaccine containing serotypes 1, 2, and 3 of marek's disease virus (mdv), a vaccine strain of serotype 1 infectious bursal disease virus (ibdv), and recombinant fowl pox vaccine with hn and f genes of newcastle disease virus (rfp-ndv) induced protection against virulent mdv, ibdv, newcastle disease virus, and fowl poxvirus. the mu ... | 1999 | 10396643 |
| restriction fragment length polymorphisms in the vp2 gene of infectious bursal disease viruses from outside the united states. | infectious bursal disease viruses (ibdvs) were identified in bursa samples from chickens reared outside the united states. all samples were obtained from commercially reared chicken flocks experiencing signs typical of infectious bursal disease. the reverse transcriptase/polymerase chain reaction (rt/pcr) technique was used to detect the viruses and restriction fragment length polymorphism (rflp) was used to compare a 743-bp region of the vp2 gene among the viruses detected. the 81 ibdvs detecte ... | 1999 | 10396645 |
| chimeric infectious bursal disease virus-like particles expressed in insect cells and purified by immobilized metal affinity chromatography. | chimeric virus-like particles (vlps) of infectious bursal disease virus (ibdv) were produced by coinfecting spodoptera frugiperda (sf-9) insect cells with two recombinant baculoviruses, vibd-7 and vedlh-22. vibd-7 encodes vp2, vp3, and vp4 of the ibdv structural proteins. vedlh-22 encodes vp2 with five histidine residues at the carboxy-terminus (vp2h). coinfection produced hybrid vlps composed of vp2, vp2h, and vp3. the additional histidine residues on vp2h enabled the efficient purification of ... | 1999 | 10397829 |
| vp1, the putative rna-dependent rna polymerase of infectious bursal disease virus, forms complexes with the capsid protein vp3, leading to efficient encapsidation into virus-like particles. | a cdna corresponding to the coding region of vp1, the putative rna-dependent rna polymerase, of infectious bursal disease virus (ibdv) was cloned and inserted into the genome of a vaccinia virus inducible expression vector. the molecular mass and antigenic reactivity of vp1 expressed in mammalian cells are identical to those of its counterpart expressed in ibdv-infected cells. the results presented here demonstrate that vp1 is efficiently incorporated into ibdv virus-like particles (vlps) produc ... | 1999 | 10400796 |
| response of embryonic chicken lymphocytes to in ovo exposure to lymphotropic viruses. | to examine effects of virus exposure on embryonic lymphoid organ structure, apoptosis, and lymphoid cell subpopulations. | 1999 | 10451200 |
| tissue culture infectivity of different strains of infectious bursal disease virus is determined by distinct amino acids in vp2. | two types of strains of serotype i of infectious bursal disease virus (ibdv) have been described, on the basis of their ability (ibdv-tc) or inability (ibdv-bu) to infect chicken embryonic cells in culture. however, both types infect b lymphocytes in the bursa of fabricius of young chickens. to determine the molecular basis for tissue culture infectivity, virus recombinants with chimeric segments a were constructed from ibdv-tc and ibdv-bu by reverse genetics. the region responsible for the diff ... | 1999 | 10466805 |
| seroprevalence of infectious bursal disease in non-vaccinated indigenous and exotic chickens on selected farms around gaborone, botswana. | sera from nine out of 30 (30.0%) apparently healthy unvaccinated indigenous (tswana) chickens had precipitating antibodies to infectious bursal disease (ibd) virus using the agar gel precipitation test. similarly, sera from 11 out of 49 (22.4%) chickens of exotic breeds with no history of vaccination against ibd were positive for antibodies against the virus. | 1999 | 10486831 |
| proteolytic processing in infectious bursal disease virus: identification of the polyprotein cleavage sites by site-directed mutagenesis. | the infectious bursal disease virus (ibdv), a member of the birnaviridae family, is the causative agent of an immune depressive disease that affects domesticated and wild avian species. the expression strategy of ibdv includes the synthesis of a 110-kda polyprotein containing the capsid precursor polypeptides. the polyprotein is autocatalitically processed rendering three polypeptides: nh2-vpx-vp4-vp3-cooh. we have carried out a systematic analysis, using a series of plasmids encoding polyprotei ... | 1999 | 10489352 |
| recovery of antibody-producing ability and lymphocyte repopulation of bursal follicles in chickens exposed to infectious bursal disease virus. | we studied the long-term effect of infectious bursal disease virus (ibdv) in chickens. specifically, the restoration of virus-induced bursal lesions and the duration of humoral immunodeficiency were examined. one-week-old specific-pathogen-free chickens were intraocularly inoculated with an intermediate vaccine strain (ibdv-vac) or a virulent strain (im-ibdv). at intervals postinoculation (pi), chickens were examined for histopathologic lesions. at 1, 3, 5, 10, or 15 wk pi, the chickens were inj ... | 1999 | 10494408 |
| experimental inoculation of avian polyomavirus in chemically and virally immunosuppressed chickens. | the purpose of this series of experiments was to determine the effect of various types of immunosuppressive treatments (cyclophosphamide, infectious bursal disease virus [ibdv], chicken anemia virus [cav], and combination infection with ibdv and cav) on susceptibility of chickens to challenge with avian polyomavirus. in the first experiment, chickens were chemically bursectomized with intraperitoneal injections of cyclophosphamide; in the second study, chickens were orally inoculated with ibdv; ... | 1999 | 10494416 |
| european-like pathogenic infectious bursal disease viruses in brazil. | | 1999 | 10501589 |
| serum levels of chicken mannan-binding lectin (mbl) during virus infections; indication that chicken mbl is an acute phase reactant. | mannan-binding lectin (mbl) is a serum collectin which is believed to be an opsonin of the innate immune defence against various microorganisms. mbl is a minor acute phase reactant in man. we investigated the concentration of serum mbl in chickens infected with infectious bronchitis virus (ibv) and infectious laryngotracheitis virus (iltv). the concentration of serum mbl increased about twofold (from approximately 6 to 12 microg/ml) due to these viral infections. the concentration peaked 3-7 day ... | 1999 | 10507370 |
| amplification and cloning of infectious bursal disease virus genomic rna segments by long and accurate pcr. | improved methods of reverse transcription, polymerase chain reaction (pcr) amplification, and cloning of full-length coding region of both strands of infectious bursal disease virus (ibdv) variant strain e genome were developed. denaturation of ibdv rna by heat in the presence of primers and use of a reverse transcriptase lacking rnase-h activity produced full-length coding region and partial non-coding region cdna copies of the viral genomic segments. digestion of the rna component of rna-cdna ... | 1999 | 10507413 |
| [gumboro vaccine]. | | 1999 | 10549091 |
| poultry vaccines: an analysis of the animal trials required for vaccine testing and the way to reduce or refine these tests. | the testing of vaccines for use in chickens requires a large number of animal trials. especially for poultry vaccines, quality testing of each batch consists of testing for extraneous agents in chickens for all products and potency tests for inactivated products. for the licensing of a vaccine a number of safety and efficacy tests is necessary. the safety testing covers dose and overdose studies, and the influence on reproductive performances and immunological functions. for live vaccines some a ... | 1999 | 10566779 |
| self-assembly of the infectious bursal disease virus capsid protein, rvp2, expressed in insect cells and purification of immunogenic chimeric rvp2h particles by immobilized metal-ion affinity chromatography. | a gene encoding a structural protein (vp2) of a local strain (p3009) of infectious bursal disease virus (ibdv) was cloned and expressed using the baculovirus expression system to develop a subunit vaccine against ibdv infection in taiwan. the expressed rvp2 proteins formed particles of approximately 20-30 nm in diameter. those particles were partially purified employing sucrose density gradient ultracentrifugation, and the purified particles were recognized by a monoclonal antibody against the v ... | 2000 | 10581441 |
| enhancing yield of infectious bursal disease virus structural proteins in baculovirus expression systems: focus on media, protease inhibitors, and dissolved oxygen. | structural proteins of the poultry pathogen, infectious bursal disease virus (ibdv), were expressed in the baculovirus/insect cell expression system. to date, several reports have indicated that animal virus structural proteins are expressed only at low yield in this system. in this article, several factors were examined to enhance yield. these include medium, dissolved oxygen level, and the addition (in vivo and in vitro) of protease inhibitors. specifically, two media were compared, and sf-900 ... | 1999 | 10585191 |
| storage of viruses on filter paper for genetic analysis. | the purpose of this study was to develop a method to store viruses on filter paper without the need for special conditions for future use of the genetic material. two non-enveloped viruses were used as models. infectious bursal disease virus (ibdv), a double-stranded rna virus that infects chickens, belongs to the birnaviridae family. hemorrhagic enteritis virus (hev), with double-stranded dna, belongs to the adenoviridae family. three different solutions were found suitable for loading the viru ... | 1999 | 10598079 |
| efficient rescue of infectious bursal disease virus from cloned cdna: evidence for involvement of the 3'-terminal sequence in genome replication. | to study the mechanism of replication of infectious bursal disease virus (ibdv), and to determine factors on the ibdv rna which are involved in viral replication, we used cloned full-length cdna of both the a- and b-segments to generate infectious ibdv. infectious ibdv was rescued from plasmids that contained full-length ibdv cdna behind a t7 promoter, by transfecting these plasmids into cells which were infected with a recombinant fowlpox virus that expressed t7 rna polymerase. by using the cdn ... | 1999 | 10600604 |
| persistent infection with chicken anaemia virus and some effects of highly virulent infectious bursal disease virus infection on its persistency. | chicken anaemia virus (cav) infectivity and the effect of highly virulent infectious bursal disease virus (hv ibdv) infection on cav's infectivity were examined in chickens inoculated with cav or inoculated dually with cav and hv ibdv. five chickens inoculated dually with hv ibdv at 35 days old and then with cav at 40 days old exhibited no clinical signs of disease, but showed atrophic bursae of fabricius when necropsied 4 weeks later. upon examining the chickens at 7 days postinoculation (dpi) ... | 1999 | 10607503 |
| synthesis in escherichia coli of avian reovirus core protein varsigmaa and its dsrna-binding activity. | the genome segment s2 of p6ian reovirus (arv) s1133 was cloned and sequenced. the entire s2 nucleotide sequence is 1325 bp long with one long open reading frame that encodes a protein of 415 amino acids, corresponding to varsigmaa, a major core protein of arv. s2 possesses a pentanucleotide, tcatc, at the 3'-terminus of its plus strand, common to other known genome segments of arv and to 10 genome segments of mammalian reovirus. amino acid sequence analysis revealed that varsigmaa contains a car ... | 2000 | 10612658 |
| a non-canonical lon proteinase lacking the atpase domain employs the ser-lys catalytic dyad to exercise broad control over the life cycle of a double-stranded rna virus. | we have identified a region related to the protease domain of bacterial and organelle atp-dependent lon proteases in virus protein 4 (vp4) of infectious bursal disease virus strain p2 (ibdvp2), a two-segmented double-stranded rna virus. unlike canonical lons, ibdvp2 vp4 possesses a proteinase activity though it lacks an atpase domain. ser652 and lys692 of ibdvp2 vp4 are conserved across the lon/vp4 family and are essential for catalysis. lys692 has the properties of a general base, increasing th ... | 2000 | 10619850 |
| interactions in vivo between the proteins of infectious bursal disease virus: capsid protein vp3 interacts with the rna-dependent rna polymerase, vp1. | little is known about the intermolecular interactions between the viral proteins of infectious bursal disease virus (ibdv). by using the yeast two-hybrid system, which allows the detection of protein-protein interactions in vivo, all possible interactions were tested by fusing the viral proteins to the lexa dna-binding domain and the b42 transactivation domain. a heterologous interaction between vp1 and vp3, and homologous interactions of pvp2, vp3, vp5 and possibly vp1, were found by co-express ... | 2000 | 10640560 |
| induction of protective immunity in chickens immunised with plasmid dna encoding infectious bursal disease virus antigens. | direct dna inoculations were used to determine the efficacy of gene immunisation of chickens to elicit protective immune responses against infectious bursal disease virus (ibdv). the vp2 gene of ibdv strains gp40 and d78, and the vp2-vp4-vp3 encoding segment of strain d78 were cloned in an expression vector which consisted of human cytomegalovirus (hcmv) immediate early enhancer and promoter, adenovirus tripartite leader sequences and sv40 polyadenylation signal. for purification of vaccine-qual ... | 1999 | 10641338 |
| generation of full-length cdna of the two genomic dsrna segments of infectious bursal disease virus. | to determine the complete nucleotide sequence of infectious bursal disease virus (ibdv) isolates, an efficient method was developed to generate full-length cdna of both the genomic a- and b-segments. reverse transcription was carried out at the highest possible temperature (50 degrees c) for the reverse transcriptase enzyme, and the single stranded cdna was subsequently amplified by using an optimized pcr. the double stranded, full-length cdna was efficiently cloned into a high copy number plasm ... | 2000 | 10644086 |
| chimeras in noncoding regions between serotypes i and ii of segment a of infectious bursal disease virus are viable and show pathogenic phenotype in chickens. | two serotypes, i and ii, have been identified for infectious bursal disease virus (ibdv), a member of the family birnaviridae: here, the generation by reverse genetics of ibdv chimeras in segment a of the bisegmented genome is reported. the 5- and 3'-noncoding regions (ncrs) of a serotype ii strain were exchanged with the ncrs of a full-length cdna clone of segment a of a serotype i strain. isolated chimeric viruses were characterized in cell culture and susceptible chickens. the results show th ... | 2000 | 10644853 |
| the vp2 variable region of african and german isolates of infectious bursal disease virus: comparison with very virulent, "classical" virulent, and attenuated tissue culture-adapted strains. | 11 african and two german ibdv strains isolated in the mid '80s from field outbreaks in vaccinated and unvaccinated chicken flocks displayed features of very virulent (vv) ibdv strains. the sequence data of the vp2 variable region and phylogenetic analysis confirm that these strains can be grouped within vv ibdv strains which appeared at the same time on the three continents africa, asia, and europe. strain cu-1wt, responsible for severe ibd outbreaks in germany 13 years earlier, showed some rel ... | 2000 | 10664410 |
| active residues and viral substrate cleavage sites of the protease of the birnavirus infectious pancreatic necrosis virus. | the polyprotein of infectious pancreatic necrosis virus (ipnv), a birnavirus, is processed by the viral protease vp4 (also named ns) to generate three polypeptides: pvp2, vp4, and vp3. site-directed mutagenesis at 42 positions of the ipnv vp4 protein was performed to determine the active site and the important residues for the protease activity. two residues (serine 633 and lysine 674) were critical for cleavage activity at both the pvp2-vp4 and the vp4-vp3 junctions. wild-type activity at the p ... | 2000 | 10666235 |
| tissue print hybridisation and reverse transcriptase pcr in the detection of infectious bursal disease viruses in bursal tissues. | the genome segments of infectious bursal disease viruses (ibdv) in the bursa of fabricius from experimently infected chickens or field samples were detected by tissue print hybridization (tph) with subsequent reverse transcriptase (rt)- polymerase chain reaction (pcr). bursae were imprinted onto nylon membrane and then hybridized with a cloned digoxigenin (dig)-labeled cdna probe. tissue prints on nylon membrane were readily distinguished from control prints by color development and differences ... | 2000 | 10684766 |
| performance of an rt-nested pcr elisa for detection of newcastle disease virus. | a sensitive and specific rt-nested pcr coupled with an elisa detection system for detecting newcastle disease virus is described. two nested pairs of primer which were highly specific to all the three different pathotypes of ndv were designed from the consensus fusion gene sequence. no cross-reactions with other avian infectious agents such as infectious bronchitis virus, infectious bursal disease virus, influenza virus, and fowl pox virus were observed. based on agarose electrophoresis detectio ... | 2000 | 10713378 |
| immunoadjuvant activities of e. coli- and plasmid-expressed recombinant chicken ifn-alpha/beta, ifn-gamma and il-1beta in 1-day- and 3-week-old chickens. | in the present study we assessed the capacity of recombinant e. coli- or plasmid-expressed chicken interferons (ifn) and chicken il-1beta, to exert immunostimulatory activities for humoral immune responses, in day-old and adult chickens. we observed that both recombinant e. coli-expressed chicken ifn-alpha/beta and ifn-gamma facilitated the induction of a primary and also a secondary antibody response, using tetanus toxoid (tt) as a bacterial model antigen, in immunologically mature 3-week-old c ... | 2000 | 10715530 |
| measuring infectious bursal disease virus rna in blood by multiplex real-time quantitative rt-pcr. | a quantitative reverse transcription polymerase chain reaction (rt-pcr) protocol for assessing infectious bursal disease virus (ibdv) rna levels in blood was developed using the abi prism 7700 sequence detection system coupled with taqman chemistry. to control for variations in sampling and processing between samples 28s rrna was co-amplified in a multiplex reaction and used to quantify total rna. relative quantification and standardisation was achieved using a log10 dilution series of rna extra ... | 2000 | 10716338 |
| immunocytochemical techniques to investigate the pathogenesis of infectious micro-organisms and the concurrent immune response of the host. | for poultry as well as for mammalian species used for scientific research, many immunocytochemical techniques have been developed to investigate in detail the interaction between infectious micro-organisms and the nonspecific and specific immune systems of the host. in this review three techniques have been described with all technical details necessary to perform them correctly: (1) single immunocytochemical staining to detect the infectious micro-organisms in situ at their site of infection, ( ... | 2000 | 10717284 |
| infectious bursal disease virus of chickens: pathogenesis and immunosuppression. | infectious bursal disease virus (ibdv) is an important immunosuppressive virus of chickens. the virus is ubiquitous and, under natural conditions, chickens acquire infection by the oral route. igm+ cells serve as targets for the virus. the most extensive virus replication takes place in the bursa of fabricius. the acute phase of the disease lasts for about 7-10 days. within this phase, bursal follicles are depleted of b cells and the bursa becomes atrophic. abundant viral antigen can be detected ... | 2000 | 10717289 |
| role of ser-652 and lys-692 in the protease activity of infectious bursal disease virus vp4 and identification of its substrate cleavage sites. | the polyprotein of infectious bursal disease virus (ibdv), an avian birnavirus, is processed by the viral protease, vp4. previous data obtained on the vp4 of infectious pancreatic necrosis virus (ipnv), a fish birnavirus, and comparative sequence analysis between ibdv and ipnv suggest that vp4 is an unusual eukaryotic serine protease that shares properties with prokaryotic leader peptidases and other bacterial peptidases. ibdv vp4 is predicted to utilize a serine-lysine catalytic dyad. replaceme ... | 2000 | 10725424 |
| in situ hybridization, immunohistochemistry, and in situ reverse transcription-polymerase chain reaction for detection of infectious bursal disease virus. | development of molecular techniques for the detection of infectious bursal disease virus (ibcv) is an important area of research. an in situ hybridization (ish) test was developed with a 491-bp cdna fragment derived from the vp2 gene of ibdv. the fragment was amplified and simultaneously labeled with incorporation of digoxigenin-11-dutp in a nested polymerase chain reaction (pcr) assay. the resulting digoxigenin-labeled 491-bp nested pcr product was used as probe for ish to detect and localize i ... | 2000 | 10737657 |
| cloning and expression of the vp2 gene of an infectious bursal disease virus. | a serotype i infectious bursal disease virus (ibdv) strain hz96 was isolated in hangzhou, china, in 1996 and attenuated by adaptation to chicken embryo fibroblast cells. the vp2 gene of strain hz96 was amplified by reverse transcription-polymerase chain reaction, cloned, and sequenced. compared with the vp2 sequences of other ibdv strains, hz96 is most related to two attenuated strains, cu-1 and pbg98, and two attenuated chinese strains, harbin and cj801bkf. hz96 shares nucleotide sequence homol ... | 2000 | 10737658 |
| effect of thymus extract on immunologic reactivity of chicken vaccinated with infectious bursal disease virus. | the effects of crude thymus extract on the immune response and protection against challenge with virulent infectious bursal disease virus (ibdv) were studied in one-day-old chick. oral administration of thymus extract (1 ml/kg) markedly and significantly increased the total protein, albumin, globulin, tri-iodothyronine (t3), thyroxine (t4) and the body weight gain in one-day-old chick. in addition, it increased the total lymphocytic count over four weeks after administration. although vaccinatio ... | 1999 | 10458105 |
| immunopotentiating effects of azadirachta indica (neem) dry leaves powder in broilers, naturally infected with ibd virus. | effects of feeding of powdered dry leaves of a. indica (ai) were investigated on humoral and cell mediated immune responses, in a flock of broilers which had survived an outbreak of infectious bursal disease (ibd). ai (2 g/kg) treatment significantly enhanced the antibody titres against new castle disease virus (ncdv) antigen and also potentiated the inflammatory reactions to 1. chloro-2,4-di- nitro benzene (dncb) inskin contact test. the results indicate that ai could be beneficial in immunosup ... | 1998 | 10085786 |
| the working mechanism of an immune complex vaccine that protects chickens against infectious bursal disease. | the role of immune complexes (icx) in b-cell memory formation and affinity maturation allow for their potential use as vaccines. recently, a new immune complex vaccine has been developed that is currently under field trials conducted in commercial poultry. this immune complex vaccine is developed by mixing live intermediate plus infectious bursal disease virus (ibdv) with hyperimmune ibdv chicken serum (ibdv-icx vaccine). here we have investigated the infectivity of this vaccine as well as the n ... | 1998 | 9824516 |
| differentiation of infectious bursal disease virus strains by restriction analysis of rt-pcr-amplified vp2 gene sequences. | the techniques of reverse transcription-polymerase chain reaction (rt-pcr) and restriction analysis were used to differentiate highly virulent indian field isolates of infectious bursal disease virus (ibdv) from vaccine strains. primers were designed to amplify the variable region of vp2 gene coding for major virus neutralizing epitopes. the 552 bp pcr products generated from four vaccine strains and five field isolates were digested with restriction enzymes drai, hhai, mvai, stui, styi, and taq ... | 1999 | 10749370 |
| dual-viral vector approach induced strong and long-lasting protective immunity against very virulent infectious bursal disease virus. | to induce strong protective immunity against very virulent infectious bursal disease virus (vvibdv) in chickens, two viral vector systems, marek's disease and fowlpox viruses expressing the vvibdv host-protective antigen vp2 (rmdv, rfpv), were used. most of chickens vaccinated with the rfpv or rmdv alone, or vaccinated simultaneously with both at their hatch (rmdv-rfpv(1d)), were protected against developing clinical signs and mortality; however, only zero to 14% of the chickens were protected a ... | 2000 | 10753704 |
| ibdv-induced bursal t lymphocytes inhibit mitogenic response of normal splenocytes. | we examined the suppressive activity of bursal t cells induced by infectious bursal disease virus (ibdv) in inbred (15x7) and outbred commercial specific-pathogen-free (spf) chickens. the suppressive activity was measured by the ability of bursal and splenic t cells from ibdv-infected chickens to inhibit mitogenic responses of normal splenocytes. the bursacytes but not the splenocytes of ibdv-infected chickens inhibited the mitogenic responses of normal splenocytes. the mitogenic inhibition by t ... | 2000 | 10760389 |
| effect of ascorbic acid supplementation on the immune response of chickens vaccinated and challenged with infectious bursal disease virus. | one-day-old chickens were divided into two groups and reared under similar conditions. one group was fed a diet supplemented with 1000ppm ascorbic acid and the other group was fed an identical diet, but not supplemented with ascorbic acid. both groups were vaccinated against infectious bursal disease (ibd) at 7 days of age and challenged orally with 4x10(5) of 50% embryo-lethal-dose ibdv 14 days later. the number of anti-ibdv antibody secreting cells, production of interleukin-2 (il-2) by spleno ... | 2000 | 10760396 |
| characterization of avian reovirus non structural protein sigmans synthesized in escherichia coli. | the coding region of avian reovirus s1133 genomic segment s4, encoding the non structural protein sigmans, was inserted into expression vector pet28a and the protein was expressed in escherichia coli bl21(de3) as a fusion protein containing a c-terminal peptide with six tandem histidines (his-tag). the expressed protein (esigmans) consistent with the expected molecular size of the avian reovirus protein sigmans synthesized in infected cells was readily purified by his-bind resin. the esigmans wa ... | 2000 | 10773313 |
| ascorbic acid supplementation improved antibody response to infectious bursal disease vaccination in chickens. | the purpose of the present study was to determine if supplementation of ascorbic acid (aa) to the diet would have a beneficial effect on infectious bursal disease (ibd) vaccination of chickens for protection against infectious bursal disease virus (ibdv) infection. two hundred forty specific pathogen-free (spf) chickens were divided into eight experimental groups. a 2 x 2 x 2 factorial arrangement in a completely randomized design was used; aa supplementation at 1,000 ppm in the diet, vaccinatio ... | 2000 | 10824956 |
| a ribozyme targeted to rna polymerase gene of infectious bursal disease virus effectively cleaves and inhibits expression of the viral gene product. | five hammerhead-type ribozymes were designed and cloned to cleave infectious bursal disease virus (ibdv) rna and inhibit protein synthesis from cloned full-length viral cdna genes. two ribozymes (r1 and r2) were directed to the large viral rna segment gene and three ribozymes (r3, r4, and r5) were directed to the small viral rna segment gene. targets for the ribozymes were produced from cloned full-length coding regions of both small and large viral rna segment genes. ribozymes and their corresp ... | 1999 | 10825922 |
| protection from ibdv-induced bursal damage by a recombinant fowlpox vaccine, fpibd1, is dependent on the titre of challenge virus and chicken genotype. | expression of the vp2 capsid protein of infectious bursal disease virus (ibdv) in an vaccine strain of fowlpox has produced an experimental recombinant vaccine, fpibd1. successful vaccination with fpibd1 was dependent on the titre of challenge virus for high titres of challenge virus were able to overcome protection induced by fpibd1 whereas challenge with a low titre of virus did not. the genotype of chicken also has an important effect on the outcome of challenge possibly as a result of the ma ... | 2000 | 10869768 |
| heat lability of five strains of infectious bursal disease virus. | an extensive world trade environment has created a need for many nations to protect their food animal industries against the importation of pathogenic microorganisms. we initiated studies to determine how cooking conditions would affect the viability of different infectious bursal disease virus (ibdv) strains. five different viral strains were tested. the strains included two serotype 1 variant viruses, del-a and md; two serotype 1 classic viruses, stc and d78; and a serotype 2 virus, oh. a 100- ... | 2000 | 10875765 |
| infectious bursal disease live vaccines: changes in the virus population during serial passage in chickens and chicken embryo fibroblast cells. | two attenuated infectious bursal disease virus strains used as commercial live vaccine were passaged five successive times in specific-pathogen-free chickens and chicken embryo fibroblast (cef) cells. both attenuated strains increased in virulence during the passage in susceptible chickens as evidenced by the decrease in bursa/body weight ratios. a direct nucleotide sequence analysis of the vp2 hypervariable domain amplified by the reverse transcription-polymerase chain reaction revealed that th ... | 2000 | 10879907 |
| effects of hydrostatic pressure on the structure and biological activity of infectious bursal disease virus. | the effects of high hydrostatic pressure on the structure and biological activity of infectious bursal disease virus (ibdv), a commercially important pathogen of chickens, were investigated. ibdv was completely dissociated into subunits at a pressure of 240 mpa and 0 degrees c revealed by the change in intrinsic fluorescence spectrum and light scattering. the dissociation of ibdv showed abnormal concentration dependence as observed for some other viruses. electron microscopy study showed that mo ... | 2000 | 10880972 |
| antigenic properties and diagnostic potential of baculovirus-expressed infectious bursal disease virus proteins vpx and vp3. | the routine technique for detecting antibodies specific to infectious bursal disease virus (ibdv) is a serological evaluation by enzyme-linked immunosorbent assay (elisa) with preparations of whole virions as the antigens. to avoid using complete virus in the standard technique, we have developed two new antigens through the expression of the vpx and vp3 genes in insect cells. vpx and especially vp3 were expressed at high levels in insect cells and simple to purify. the immunogenicity of both pr ... | 2000 | 10882666 |
| rescue of very virulent and mosaic infectious bursal disease virus from cloned cdna: vp2 is not the sole determinant of the very virulent phenotype. | many recent outbreaks of infectious bursal disease in commercial chicken flocks worldwide are due to the spread of very virulent strains of infectious bursal disease virus (vvibdv). the molecular determinants for the enhanced virulence of vvibdv compared to classical ibdv are unknown. the lack of a reverse genetics system to rescue vvibdv from its cloned cdna hampers the identification and study of these determinants. in this report we describe, for the first time, the rescue of vvibdv from its ... | 2000 | 10888607 |
| antigenic and sequence heterogeneity of infectious bursal disease virus strains isolated in australia. | six recently isolated field strains of infectious bursal disease virus (ibdv) were compared to vaccine strains at the antigenic and genetic level to ascertain the level of heterogeneity among australian ibdv strains. five strains, 01/94, 02/95, 03/95, 04/95 and 08/95, isolated at four locations in the state of victoria, were antigenic variants. they failed to react with monoclonal antibodies directed against two different epitopes on the vp2 protein which were present in vaccine strains and one ... | 2000 | 10893155 |
| rocket immunoelectrophoresis in the diagnosis of infectious bursal disease. | the rocket immunoelectrophoresis (rie) test was used for the qualitative detection and quantitative estimation of infectious bursal disease virus (ibdv) specific antigen in experimentally infected chickens and samples collected from suspected outbreaks. the ibdv specific antigen was detected in the bursae of experimentally inoculated chickens up to 5 days post infection (pi) by the agar gel precipitation (agp) test and 7 days pi by the rie test. the rie detected ibdv specific antigen in a signif ... | 2000 | 10907288 |
| evaluation of a filter paper blood sampling technique for quantitative assessment of antibodies to infectious bursal disease virus. | | 2000 | 10907289 |
| infectious bursal disease (gumboro disease). | infectious bursal disease (ibd) (gumboro disease) has been described throughout the world, and the socio-economic significance of the disease is considerable world-wide. various forms of the disease have been described, but typing remains unclear, since antigenic and pathotypic criteria are used indiscriminately, and the true incidence of different types is difficult to determine. moreover, the infection, when not fatal, leads to a degree of immunosuppression which is often difficult to measure. ... | 2000 | 10935278 |
| characteristics of bursal t lymphocytes induced by infectious bursal disease virus. | infectious bursal disease virus (ibdv) is an avian lymphotropic virus that causes immunosuppression. when specific-pathogen-free chickens were exposed to a pathogenic strain of ibdv (im), the virus rapidly destroyed b cells in the bursa of fabricius. extensive viral replication was accompanied by an infiltration of t cells in the bursa. we studied the characteristics of intrabursal t lymphocytes in ibdv-infected chickens and examined whether t cells were involved in virus clearance. flow cytomet ... | 2000 | 10982331 |
| significance of infectious bursal disease serology in an integrated quality control program under european epidemiologic conditions. | in this study performed between 1993 and 1997, infectious bursal disease virus (ibdv) antibody titers and performance data were recorded in a vertically integrated monitoring scheme in order to make a follow-up from day-old parents down to the broilers at slaughter. all measured data were used two by two in a simple correlation study to calculate the degree to which they were linearly correlated. it appeared that high and/or uniform antibody titers in the parents were correlated with increased d ... | 2000 | 11007008 |
| sequence of precursor polyprotein gene (segment a) of infectious bursal disease viruses isolated in korea. | the coding regions of segment a of two recent korean very virulent (vv) infectious bursal disease virus (ibdv) isolates (kk1 and ksh) and one atypical ibdv isolate (k310) were amplified by reverse transcriptase-polymerase chain reaction, sequenced, and compared with published sequences for ibdv. the overall amino acid sequence similarity of the kk1 and ksh strains compared with foreign vvibdv strains was between 97.43% and 98.02%. the kk1 and ksh strains, like vvibdv strains, share unique amino ... | 2000 | 11007021 |