infectious bursal disease agent: morphology by negative stain electron microscopy.the virus of infectious bursal disease of chickens was studied by immune electron microscopy. negatively-stained preparations revealed morphological similarities with both the bluetongue virus group, and the virus of infectious pancreatic necrosis of trout. results indicated that the small particle found in such preparations is a degradation product of the large particle.197550057
infectious bursal disease virus: antigen production and immunity. 1975164798
immunodeficiency in the chicken. ii. production of monomeric igm following testosterone treatment or infection with gumboro disease.chickens were treated at an early embryonal age with testosterone propionate or infected neonatally with the virus producing gumboro disease. their sera were subsequently fractionated by sephadex g-200 chromatography, and showed a complete deficiency of igg and the presence of igm which was eluted with the 7s protein fraction. purified and 125-i-labelled monomeric igm was examined by sds-acrylamide gel electrophoresis and found to contain both mu and light chains, together with a chain of interm ...1975166037
the effect of diet on the severity of losses from infectious bursal disease (gumboro) in a commercial broiler genetype.a natural outbreak of infectious bursal disease occurred in an experimental broiler flock being reared on 3 starter diets having 18.8, 21.6 and 24.0 per cent protein. groups fed the highest protein starter exhibited significantly higher mortality and had larger numbers of stunted birds.1975166366
structural and growth characteristics of two avian reoviruses.two virus strains which had been suspected to be the etiological agents of infectious bursitis (gumboro disease) and of inclusion body hepatitis of chickens were characterized by their morphology, their peptide composition and the segmented genome of their double-stranded rna to be typical reoviruses. although the 2 avian strains did not clearly differ in their serological behaviour, the size of some of their rna segments were not identical. both strains replicated in tissue cultures prepared fr ...1975170888
comparison of vaccines against infectious bursal disease. 1975171288
letter: quantitation of antibodies to infectious bursal disease. 1975171823
the roles of the infectious bursal agent and several avian adenoviruses in the hemorrhagic-aplastic-anemia syndrome and gangrenous dermatitis.the effect that breeder-flock immune status regarding the infectious bursal agent (iba) and two avian adenoviruses (dpi-1 and dpi-2) has on the susceptibility of their commercially reared delmarva broiler progeny to the hemorrhagic-aplastic-anemia syndrome and concurrent gangrenous dermatitis was determined. lack of immunity to the iba in breeder flocks was related to an increased susceptibility of progeny to anemia and dermatitis. breeder-flock immunity to the two adenoviruses tested could not ...1975173278
an outbreak of infectious bursal disease (ibd) of chickens in nigeria. 1975175539
immunodeficiency in the chicken. iv. an immunological study of infectious bursal disease.chickens inoculated orally with infectious bursal disease virus (ibdv) 1 day after hatching subsequently showed a 50% incidence of immunodeficiency but little mortality. antibody responses against ibdv and to immunization with sheep red blood cells (srbc) or human serum albumin (hsa) were suppressed. serum igg concentration was decreased while igm occurred exclusively in its 7s monomeric form (migm). an allotypic marker of chicken igm (mla) was lacking in migm derived from ibdv-infected birds. t ...1976177236
[the "vaccination reaction" syndrome of broilers after vaccination against newcastle disease and infectious bronchitis (author's transl)].in a part of the broiler flocks vaccinated against newcastle disease (n.c.d) and infectious bronchitis (i.b.), disease symptoms of lingering nature have been observed, generally in the second half of the rearing period. in a practical investigation with weekly examinations of chickens, supplemented by a serological examination of twenty-four animals per flock at the age of six weeks, it was hoped to establish the factors responsible for this "vaccination reaction". in the district under notice t ...1976179162
comparative tests on safety and potency of iba vaccines.during a comparative test on the pathogenicity and immunogenicity of a non-adapted and an embryo-adapted ida virus, following observations were made: 1) the non-adapted virus remained pathogenic as determined by weight loss and bursal lesions. clinical signs and mortality did not occur. a change in the virulence did not occur during back passages; 2) the immunosuppressive effect of the non-adapted virus was diminished by maternal antibodies; 3) the embryo-adapted virus produced little pathogenic ...1976182590
infectious bursal disease vaccine: some remarks on production and control.a vaccine against infectious bursal disease (ibd) is prepared with a strain of ibd virus attenuated in chicken embryos. safety and potency tests are carried out on embryos and chickens susceptible to ibd virus.1976182591
role of the bursa of fabricius in the pathogenicity of inclusion body hepatitis and infectious bursal disease viruses.chickens were chemically bursectomized with cyclophosphamide at 3 days old, and studies made of the effects of infection by inclusion body hepatitis virus (ibhv) and infectious bursal disease virus. in another experiment, 3-week-old chickens were infected with infectious bursal disease virus before inoculation with ibhv. interference with the bursa of fabricius by cyclophosphamide or by infectious bursal disease virus enhanced the pathogenicity of ibhv. in contrast, cyclophosphamide effects on t ...1976183647
electron-microscope studies on the pathogenesis of infectious bursal disease after intrabursal application of the causal virus.intrabursal application of infectious bursal disease virus (ibdv) is of advantage in studying sequential morphological events since the time of infection of the bursa is exactly known. a highly pathogenic strain caused first clinical symptoms 12 hr postinfection (pi) and death 24-30 hr pi. these are respectively 12 and 18 hr earlier than after per-oral infection. numerous virus particles 53-58 nm in size, arrayed in a crystalline pattern and not surrounded by a membrane, are first found 6 hr pi ...1976183649
effect of infectious bursal agent on the response of chickens to newcastle disease and marek's disease vaccination.white leghorn chickens raised from one day old in an environment contaminated by the infectious bursal agent (iba) had lower geometric mean titers (gmt) as measured by the hemagglutination-inhibition (hi) test to the newcastle disease virus (ndv), than control leghorns reared in an uncontaminated environment. immunosuppression, defined as a reduction in gmt, was most pronounced at 35-56 days old for leghorns vaccinated with ndv at 1 and 28 days or at 28 days. in a separate trial with broilers, i ...1976183651
immunization of adult hens against infectious bursal disease virus. 1976183653
infectious bursal disease of chickens and vaccination. 1976185779
demonstration of eimeria tenella in bursa of fabricius of chickens.coccidial life-cytle stages were detected in the bursa of fabricius of broiler chickens inoculated with eimeria tenella, whether or not the chickens had previously been infected with infectious bursal disease virus (ibdv). chickens infected only with e. tenella had developing parasites in the lining epithelium, whereas chickens with both infections had gametocytes also in the epithelial cells surrounding numerous degenerating bursal cysts.1976186013
immunosuppressive effect of a naturally acquired subclinical bursal agent infection on vaccination against newcastle disease.a naturally acquired subclinical infection of infectious bursal agent was shown to be the probable causative factor of marked immunosuppression of newcastle disease vaccine in young chicks. old hens maintained in the same contaminated environment did not exhibit immunosuppression.1976186932
response of growing chickens to an inactivated ibd antigen in oil emulsion. 1976188221
gumboro disease and infectious bronchitis. 1977190759
effect of infectious bursal disease on the response of chickens to mycoplasma synoviae, newcastle disease virus, and infectious bronchitis 35 days of age, chickens which as 1-day-old chicks were inoculated with the infectious bursal disease virus (ibdv) had significantly lower antibody titers against mycoplasma synoviae, newcastle disease virus, and infectious bronchitis virus than did those never inoculated with ibdv. the ibdv also had a marked effect on the development of air-sac lesions. birds infected with ibdv that were later inoculated with m synoviae (day 14), newcastle disease virus (days 14 and 28) experienced an increa ...1977190926
[aplastic anemia, liver necrosis and hemorrhage in chickens after neonatal infection with infectious bursal agent]. 1977192533
the immunodepressive effect of infectious bursal agent on vaccination against newcastle disease.immunodepression due to an infectious bursal agent (iba) infection depends on the age of the birds, the time of newcastle disease (nd) vaccination and the iba strain used. the immunodepressive effect of iba on nd vaccination can be avoided by vaccinating the chicks against nd at day old or by using attenuated strains of iba in all commercial vaccines.1977193172
specific suppression of the bursa-dependent immune system of chicks with infectious bursal disease virus.chicks which had been inoculated with infectious bursal disease virus (ibdv) at 1 day of age had a severe depression of bursa-dependent humoral immune functions by day 42. antibody responses against rabbit red blood cells or to immunization with bovine serum albumin were significantly suppressed. in contrast, chicks inoculated with ibdv at 21 days of age produced near normal antibody responses as compared with the responses in noninfected control chicks. the ibdv had no significant effect on the ...1977195492
[pathomorphology of infectious bursitis in chicks].morphologic studies were carried out on birds aged 17 to 90 days, affected with gumboro disease and occasionally died from the same disease (infectious bursitis). established were hemorrhages in the leg and breast musculature, substantial enlargement of the bursa of fabricius, and lesions in the kidneys. in some cases hemorrhages were also found on the serous membrane of the parenchymal organs. the histologic investigation of the involved parenchymal organs revealed necrobiotic changes (karyopyc ...1977201083
effect of infectious bursal disease on the severity of eimeria tenella infections in broiler chicks.a study was initiated to determine whether prior exposure to infectious bursal disease virus (ibdv) influenced the susceptibility of young broiler chicks to eimeria tentella infections. when one-day-old chicks infected with ibdv were subsequently challenged with e. tenella at 7 days of age, they suffered significantly higher mortality and lesion scores than their hatchmates which were not exposed to ibdv. initial exposure to ibdv also had an effect on the development of e. tenella induced hemorr ...1977203907
effect of infectious bursal disease virus on the immunological responsiveness of the chicken.the immunological response of chickens infected at 28 days of age with infectious bursal disease virus (ibdv) was examined. cellular immunity was studied by the graft-versus-host reaction and delayed type hypersensitivity skin reactions to tuberculin. antibody responses to sheep red blood cells (s-rbc's) were tested by a direct hemagglutination test. circulating levels of immunoglobulins (ig's) igm, igg and iga were monitored by the radial immunodiffusion test. the results of the graft-versus-ho ...1977203923
influence of infectious bursal disease on the development of immunity to eimeria tenella.specific-pathogen-free (spf) chicks infected with infectious bursal disease (ibdv) virus at one day of age or midway (7 days) through a two-week immunization program for eimeria tenella showed significantly less (p less than or equal to 0.05) protection against coccidal challenge as measured by lesion scores than chicks given ibdv after 14 days of coccidial immunization. the chicks showed complete protection to later coccidial challenge administered on day 21. bursae were markedly smaller from i ...1977204282
diagnosis of avian viral diseass by electron microscopy.clinical material from avian species was examined directly by electron microscopy for the presence of viruses. mycoplasma-like and coronavirus-like particles were found in chicken feces. these particles did not appear to be associated with disease and were not propagated in the laboratory. infectious bursal disease virus was readily detected in impression smears of bursas from experimentally infected birds. poxviruses were demonstrated in smears made from canarypox lesions. difficulty in disting ...1978205149
response to several avian respiratory viruses as affected by infectious bursal disease virus.after being inoculated with the infectious bursal disease virus (ibdv) at one day of age, specific-pathogen-free chickens were inoculated with either newcastle disease virus (ndv), infectious bronchitis virus (ibv), or infectious laryngotracheitis virus (iltv). their immunity was challenged 2-3 weeks later with homologous virus, and antibody titers were determined for iltv and ibv. several studies were made to determine the effects of ibdv on the development of persistent or chronic virus infect ...1978206256
transmission of immunity from inactivated infectious bursal disease oil-emulsion vaccinated parent chickens to their chicks. 1978207009
serological evidence of infection with the virus of infectious bursal disease in wild and domestic birds in nigeria. 1978207012
vaccination against infectious bronchitis and the immunosuppressive effects of infectious bursal immunosuppressive effect was demonstrated in chickens which were infected with infectious bursal disease virus (ibdv) early in life and prior to or shortly after vaccination with infectious bronchitis virus (ibv). this effect was evident by an increased susceptibility to respiratory tract infection with ibv and reduced virus-serum neutralizing antibody levels. chickens which were hatched from dams susceptible to infectious bursal disease (ibd) were less responsive to ibv immunization attempts ...1978209433
prevention of avian lymphoid leukosis by induction of bursal atrophy with infectious bursal disease viruses.five groups of genetically susceptible chickens were inoculated at hatching with lymphoid leukosis virus; four of these were given infectious bursal viruses of varying virulence at 14 days of age and one group was not inoculated (control). all chickens in the control group developed evidence of lymphoid leukosis by 180 days. two groups given relatively virulent bursal disease viruses, which destroyed bursal lymphoid cells, did not develop lymphoid leukosis. treatment with avirulent vaccines had ...1978210556
broiler-breeder vaccination against infectious bursal disease and persistence of maternal antibody in progeny. 1978210922
[attenuation of infectious bursal disease virus by serial passage through chicken embryonated eggs and chicken and duck embryonic fibroblasts (author's transl)]. 1978211726
interaction of aflatoxin with infectious bursal disease virus infection in young chickens.young white leghorn chickens fed 2.5 microgram of aflatoxin (afl) per g of diet from hatching until 4 weeks old and infected with infectious bursal disease virus (ibdv) at 3 weeks old had significantly higher mortality and more severely depressed body weights than chicks with aflatoxicosis or ibd alone. afl-ibdv chicks also had more extensive gross and microscopic changes characteristic of ibd than did ibdv-chicks. none of the treatments significantly reduced antibody responses to newcastle dise ...1978212001
experimental infection of turkeys with infectious bursal disease virus.commercial turkey poults 3 to 6 weeks old were infected experimentally by eyedrop with an infectious bursal disease virus (ibdv) inoculum obtained from chickens experiencing clinical ibd. the ibdv was passed 6 successive times in poults in an attempt to increase its pathogenicity for turkeys. regardless of passage level, the ibdv infection in poults was subclinical, with no morbidity, mortality, or gross lesions observed. the bursae of fabricius from infected poults, however, displayed various d ...1978212003
rhinotracheitis in turkey poults.a severe upper respiratory disease of young turkeys is described that resulted in high morbidity and mortality. death was due to asphyxiation produced by occlusion of the trachea or nostrils. the postmortem lesions were tracheitis, pulmonary edema, swollen livers and spleens, and a drastic reduction in bursa size. bursal necrosis and loss of tracheal epithelium were found in tissue sections from clinically affected birds. antibody to infectious bursal disease was found by agar-gel precipitin and ...1978212006
interaction between infectious bursal disease virus and newcastle disease virus in chickens.the australian strain of infectious bursal disease virus (ibdv), 002/73, affected the response of chickens to newcastle disease virus (ndv). the titre of serum antibodies to ndv in chickens infected with ibdv was significantly lower than that of birds infected with ndv alone. it also appeared that ibdv affected ndv excretion from chickens as ndv was more frequently isolated from chickens infected with ibdv, ibdv infection did not alter the pathogenicity of ndv in chickens. this australian strain ...1978213047
woodrige memorial lecture. the veterinary profession and an intensive poultry industry. 1978213871
susceptibility of chicks to infectious bursal disease (ibd) following vaccination of their parents with live ibd vaccine.vaccination of parent chickens with a commercial live infectious bursal disease (ibd) vaccine under field conditions at varying ages and by different routes resulted in variable susceptibility to the disease in their chicks. there was little correlation between the methods of vaccination and the levels of immunity in the chicks. there was some evidence that levels of transferred immunity decreased with the age of the parents. of five flocks examined, the onset of susceptibility to ibd occurred a ...1978213872
[clinico-epizootologic studies in gumboro disease].the disease was established on a poultry dressing combine, affecting birds at the age of three to eleven weeks. it ran its course with clinical symptoms and epizootiology that were characteristic of it. a total of 8778 birds or 10% succumbed to the disease. its notification on a newly built poultry dressing combine made it reasonable to believe that possibility existed of its transmission through the hatcheries. the outbreak occurred almost simultaneously with the inadequate feeding that was adm ...1978214935
loss of virulence in a small plaque mutant of the infectious bursal disease virus.a variant strain cu-1 m was established from the infectious bursal disease virus strain cu-1. this variant strain forms smaller plaques than the wild type; it has a retarded growth rate, does not lead to an overt disease in chickens and causes only minor lesions in the bursa of fabricius. infection with this strain induces solid protective immunity against infection with the virulent virus.1979218535
virus-neutralization versus agar-gel precipitin tests for detecting serological response to infectious bursal disease virus.the virus-neutralization (vn) test was found much more sensitive than the agar-gel precipitin (agp) test for detecting prior exposure to infectious bursal disease (ibd). many sera that were negative in the agp test were found to have vn antibodies, and virtually all sera in a commercial flock were free of precipitin but had vn titers. vn titers varied widely on a flock basis, and revaccination of an 8-month-old flock through the drinking water did not alter the antibody titers. inoculation of ma ...1978219827
infectious bursal disease virus infection attempts in turkeys and coturnix quail.attempts failed to infect coturnix quail with infectious bursal disease (ibd) virus by exposure at 7, 14, 21, and 31 days old. there were no clinical signs or gross and microscopic changes in the bursa of fabricius, and serologic tests and virus isolation attempts from cloacal swabs were negative. turkeys of two breeds exposed to ibd virus at 6 or 8 weeks old showed no clinical signs or lesions in the bursa of fabricius, and the virus could not be isolated from cloacal swabs. they did respond se ...1978219828
experimental induction of hemorrhagic-aplastic anemia in chickens. i. etiology.exposure to infectious bursal disease virus (ibdv) at 1 day old followed by inclusion body hepatitis virus (ibhv) inoculation at 36 days produced typical lesions of hemorrhagic-aplastic anemia syndrome (has). the lesions included severe anemia, widespread hemorrhages, and dermatitis. has could not be induced in the first 4 weeks of life in chickens inoculated at one day old with ibhv alone or in combination with ibdv. it was concluded that the immunosuppressive effects of ibdv failed to alter th ...1978219831
experimental induction of hemorrhagic-aplastic anemia in chickens. ii. serum protein changes.the serologic response of chickens to infectious bursal disease virus (ibdv) and inclusion body hepatitis virus (ibhv) was analyzed. inoculation at one day old with either ibdv or ibhv significantly (p less than 0.05) reduced levels of serum gamma-globulins at 4 weeks postinoculation. this response was not elicited by inoculation of ibdv together with ibhv. birds with experimentally induced or naturally occurring hemorrhagic anemia syndrome (has) had serum proteins quantitatively and qualitative ...1978219832
immune response and pathogenicity of different strains of infectious bursal disease virus applied as vaccines.eight strains of infectious bursal disease virus (ibdv) were characterized by the criteria of immunity and pathogenicity engendered in young chickens. some strains have been used commercially, and the others are potential candidates for vaccines. they were administered by drinking water, eyedrop, vent drop, and subcutaneous and aerosol routes. the viruses varied widely in pathogenicity in terms of bursal damage, morbidity, and mortality. immunity induced with different routes of administration a ...1978219835
immunosuppressive effects of the infectious bursal agent and relationships to other poultry diseases. 1976220631
the use of an inactivated infectious bursal disease oil emulsion vaccine in commercial broiler parent chickens. 1979222040
standardization of the quantitative agar gel precipitin test for antibodies to infectious bursal disease. 1979225328
growth of infectious bursal disease virus with plaque formation in chick embryo fibroblast cell culture.the wa69 isolant of infectious bursal disease virus (ibdv) induced cytopathic effects and plaque formation in chick embryo fibroblast (cef) cultures after serial passages in embryonated eggs and then in cef cultures. the plaque-forming agent was cloned (designated wa69 clone) and identified as ibdv on the basis of serologic response in inoculated birds and its antigenic relationship to other known ibdv isolants. the wa69 clone replicated rapidly in cef cultures, reaching peak titers at 48 hours ...1979226052
immune-complex involvement in the pathogenesis of infectious bursal disease virus in chickens.frozen kidney sections from chickens inoculated with infectious bursal disease virus (ibdv) were stained with fluorescein-conjugated rabbit anti-chicken gamma-globulin. fluorescence was observed in the renal glomeruli of infected chickens, indicating that gamma-globulins, probably in the form of immune complexes, had lodged in the glomeruli of ibdv-infected chickens. this suggests that immune complexes may play an important role in the pathogenesis of ibdv infections in chickens.1979226053
an infectious bursal disease virus outbreak in 14- and 15-week-old chickens.infectious bursal disease virus (ibdv) observed in a flock of 14- and 15-week-old chickens was typical of the acute symptomatic ibdv infections more common in younger birds. high flock morbidity was indicated by a marked decrease in feed consumption, although deaths were not excessive. at necropsy, affected birds had small hemorrhages in thigh muscles, creamy-yellow-colored bursae of fabricius with prominent longitudinal striations, and swollen mottled kidneys. histopathologic examination reveal ...1979226055
infectious bursal disease viral infections. i. complement and virus-neutralizing antibody response following infection of susceptible chickens.complement (c) titers were decreased at 3 days postinfection, and virus-neutralizing (vn) antibody was detectable at 3 or 4 days postinfection in chickens with infectious bursal disease virus (ibdv). clotting times were prolonged in all groups tested during the acute phase of the disease. mortality appeared to be associated with the severity of decrease in c titer. the results suggest that the mortality and many of the clinical signs seen with infectious bursal disease are associated with: 1) a ...1979226056
biophysical and biochemical characterization of five animal viruses with bisegmented double-stranded rna genomes.infectious pancreatic necrosis virus of fish, infectious bursal disease virus of chickens, tellina virus and oyster virus of bivalve molluscs, and drosophila x virus of drosophila melanogaster are naked icosahedral viruses with an electron microscopic diameter of 58 to 60 nm. the genome of each of these viruses consists of two segments of double-stranded rna (molecular weight range between 2.6 x 10(6) and 2.2 x 10(6), and the virion, capsid proteins fall into three size class categories (large, ...1979228080
biochemical studies with infectious bursal disease virus: comparison of some of its properties with infectious pancreatic necrosis virus.infectious bursal disease (ibd) virus was purified from the bursae of infected chickens. two morphologically indistinguishable populations of virus particles were separated in sucrose gradients and possessed sedimentation coefficients of 295s and 460s. both populations contained rna and had identical polypeptide compositions. ibd virus banded at a density of 1.31 g/ml in cscl and at 1.24 g/ml in sodium potassium tartrate. ibd virus contained two rna segments with mol. wts. of 2.4x10(6) and 2.2x1 ...1979228637
peptide map comparison of the proteins of infectious bursal disease virus.the genome of infectious bursal disease virus consists of two segments of double-stranded rna of 2.5 x 10(6) and 2.2 x 10(6) molecular weight. polyacrylamide gel electrophoresis of purified virus resolved four structural polypeptides: vp-1 (90,000), vp-2 (41,000), vp-3 (35,000), and vp-4 (28,000). peptide map comparisons of radioiodinated virion proteins indicated no precursor-product relationship between them. the possible relationship between the size of the virus genome and the number and siz ...1979229260
measurement of immunosuppression in chickens caused by infectious bursal disease vaccines using brucella abortus strain 19.the serological response of chicks to brucella abortus strain 19 was monitored over a period of seven weeks to assess the degree of immunosuppression caused by vaccination at one day of age with two infectious bursal disease vaccines. one of the vacy. this vaccine caused severe immunosuppression judged by the minimal serological response following b abortus inoculation. the test also detected a significant delay caused by the other vaccine in the development of the serological response but the m ...1979230558
studies on interferon induction by infectious bursal disease virus (ibdv). ii. interferon production in white leghorn chickens infected with an attenuated or pathogenic isolant of ibdv.infectious bursal disease virus (ibdv) isolants that differed in virulence for chickens, were compared as to: 1) induction of interferon in serum and tissues; and 2) stimulation of ibdv serum antibody. specific-pathogen-free chickens were infected at one day and four weeks of age by the subcutaneous and intranasal routes of inoculation. the pathogenic isolant induced a more generalized interferon response than the attenuated isolant, independent of age or route of inoculation. pathogenic ibdv st ...1979230805
immunofluorescent studies of early virus propagation after oral infection with infectious bursal disease virus (ibdv). 1979231357
serological prevalence of infectious bursal disease in madhya pradesh and maharashtra. 1979231575
further morphological characterization and structural proteins of infectious bursal disease outer layer surrounding the capsid of infectious bursal disease virus was evident from electron micrographs of intact virus particles having diameters of 62 to 63 nm. the capsid was found to be composed of large morphological units or capsomeres, measuring about 12 nm in diameter. the architecture of the capsid appears to be that of t = 3 symmetry, with a probable 32 morphological units by rotational enhancement of image detail. structural proteins of infectious bursal disease virus consist o ...1979232182
response of susceptible versus immune chicks to killed, live-modified, and wild infectious bursal disease virus vaccines.modified infectious bursal disease virus (ibdv) administered ocularly to either susceptible or passively immune chicks did not induce protection against bursal atrophy by wild ibdv, while intramuscular (im) or intrabursal (ib) injection protected susceptible chickens. no protection was obtained in passively immune chickens vaccinated im or ib. susceptible and passively immune chickens vaccinated with a single dose of killed-virus suspension (kvs) did not become resistant to wild ibdv challenge. ...1979232653
characterization of immunosuppression in chickens by infectious bursal disease virus.chickens were infected with infectious bursal disease (ibd) virus in ovo or at different times posthatching to 6 weeks of age. the b- and t-cell responses in the lymphoid tissues and blood were examined sequentially to 8 weeks of age by using indirect immunofluorescence. the proportion of b-cells was consistently lower in infected birds than in controls, especially in chicks infected as embryos or at 1 day old. the proportion of t-cells increased following these early infections but was slightly ...1979232660
interaction of infectious bursal disease and coccidiosis in layer replacement chickens.during a floor-pen study on anticoccidial programs for layer-replacement pullets, there was a natural outbreak of infectious bursal disease (ibd). the interaction of coccidiosis and ibd was characterized by: excessive deaths from coccidiosis; and apparent failure of some anticoccidial drug treatments. immunity to coccidiosis was not blocked by the ibd infection, although immunity was less in some treatments than would be expected with the degree of coccidiosis exposure.1979232661
prevalence of precipitating antibodies against mycoplasmas and viruses in egg-laying flocks in northern jutland.antibodies against infectious laryngotracheitis virus, influenavirus and newcastle disease virus were not demonstrated. the prevalence of infections caused by adeno- and reovirus in egg-laying flocks was 85 and 74% respectively. approximately 25% of the flocks had antibodies against infectious bronchitis virus and infectious bursal disease virus. a raised prevalence of antibodies against mycoplasmas was found with increasing age.1978643540
isolation of chicken anaemia virus from broiler chickens.chicken anaemia virus (cav) infection was demonstrated, by both serology and virus isolation, in 1- to 6-week-old broiler chickens originated from various parent flocks in hungary. total losses in the broiler flocks were estimated at 7 to 8% and about 25% of the chickens failed to reach target body mass by the 7th week of life. the clinical signs, postmortem lesions and histopathological changes of the affected chickens were similar to those of naturally occurring cav-induced infectious anaemia ...19921298167
use of an inactivated infectious bursal disease oil emulsion vaccine in commercial layer chicks.commercial layer chicks of different ages were inoculated with either one-fifth, two-fifths or a full dose of an inactivated infectious bursal disease oil emulsion vaccine and then challenged with virulent virus. the partial doses given at seven or 10 days old gave only partial protection. a full dose given at 10, 14 or 28 days old failed to give full protection but a full dose administered at seven days old protected all the chicks after each challenge.19921311882
investigations of environmental conditions during cluster indicate probable vectors of unknown exogenous agent(s) of multiple sclerosis.during the tail-end of an active cluster several environmental investigations indicated that wildbirds were very probably the vectors of the unknown exogenous agent of ms. canine distemper and genetic-autoimmune theories were very definitely eliminated because of the unusual pattern of the cluster. studies of several avian pathogens unveiled marek's (mdv) and/or ibd (gumboro) as the most likely candidates for exogenous agent of ms.19921312422
a monoclonal antibody capture enzyme-linked immunosorbent assay for detecting antibodies to infectious bursal disease virus.a monoclonal antibody capture enzyme-linked immunosorbent assay (mab-elisa) for antibodies to infectious bursal disease virus (ibdv) in chicken sera was developed and compared with conventional elisa. when sera from farm chickens were tested by the two elisas and serum neutralization (sn), the correlation rate between sn and mab-elisa was 100% (49/49), and that between sn and conventional elisa was 81.6% (40/49). in mab-elisa, all of the sera that were antibody-negative by sn had low absorbance ...19921313039
isolation of virulent infectious bursal disease virus from field outbreaks with high mortality in japan. 19921313701
search for the origin of multiple sclerosis by first identifying the intensive study of environmental conditions during the final stages in an active cluster area, an attempt is made to crack the enigmatic deadlock concerning the origin and etiological cause of multiple sclerosis (ms). previous investigations of other cluster areas have emphasized the probability that the outbreaks of ms were most likely caused by an unknown exogenous environmental agent, but unfortunately, the studies were conducted several years after the epidemics had occurred, making it vi ...19921316536
recent advances in avian virology.selected, recent research on the following avian diseases, and their causative viruses, has been reviewed: chicken anaemia, infectious bursal disease, turkey rhinotracheitis, avian nephritis, fowlpox, influenza, infectious bronchitis and turkey enteritis.19921319788
antigen dependent adjuvant activity of a polydispersed beta-(1,4)-linked acetylated mannan (acemannan).the adjuvant properties of a polydispersed beta-(1,4)-linked acetylated mannan, acemannan (ace-m), were evaluated. day-old broiler chicks were randomly selected and allocated to four flocks (vac 1-4). the vac 1 flock was sham vaccinated with saline. the vac 2 flock was vaccinated with an oil-based vaccine (breedervac iii; newcastle disease virus (ndv), infectious bursal disease virus (ibdv) and infectious bronchitis virus). the vac 3 flock was vaccinated with a vaccine-ace-m mixture, and the vac ...19921320308
tissue-print hybridization using a non-radioactive probe for the detection of infectious bursal disease virus.tissue-print hybridization was evaluated as a simplified means for detection of infectious bursal disease virus (ibdv) in the bursa of fabricius from infected chickens. the assay employed a biotin-labeled synthetic oligonucleotide as a probe. the bound probe was detected using a color assay consisting of streptavidin conjugated to alkaline phosphatase. bursae were imprinted onto nitrocellulose and then hybridized with the biotinylated probe. bursal prints from ibdv-infected chickens were readily ...19921320859
digoxigenin-labeled nucleic acid probe for the detection of infectious bursal disease virus in infected cells.a cdna probe was synthesized from the vp-4 region of a virulent field isolate of infectious bursal disease virus (ibdv). the probe was labeled during synthesis with a non-radioactive steroid hapten, digoxigenin. the probe was used to develop a hybridization assay to detect the presence of ibdv in infected cell-culture and tissue suspensions from the bursa of fabricius of infected chickens. the test was rapid, reproducible, and sensitive, and it could detect four serologic subtypes of ibdv, inclu ...19921320860
molecular detection of infectious bursal disease virus by polymerase chain reaction.the polymerase chain reaction (pcr) technique was applied to the detection of infectious bursal disease virus (ibdv). reverse transcription followed by the pcr was used to amplify a portion of ibdv genome. a set of primers that specify a 150-base-pair segment of ibdv genome was chosen from an australian strain of ibdv. standard challenge strain and variant strains a, d, e, g, and gls-5 of ibdv serotype 1 and oh strain of serotype 2 from infected bursae were subjected to reverse transcription, fo ...19921320861
isolation and propagation of infectious bursal disease virus using the ovine kidney continuous cell line.twenty-six samples known to contain infectious bursal disease virus (ibdv) were examined by virus-isolation attempts on ovine kidney (ok) cell line, vero cell line, and chicken embryo fibroblast (cef) cultures. virus was isolated from two of 26 samples, three of 26 samples, and three of 25 samples on ok, vero, and cef cultures, respectively. however, in contrast to ibdv replication in vero and cef cultures, isolated virus was unable to induce serially sustained cytopathic effects (cpe) during su ...19921320862
relationship of common avian pathogen antibody titers in so-called chicken anemia agent (caa)-antibody-positive chicks to titers in caa-antibody-negative chicks.antibody titers for infectious bursal disease virus (ibdv), infectious bronchitis virus, newcastle disease virus, and reovirus from chicks with chicken anemia agent (caa) antibodies were compared with antibody titers from their caa-antibody-negative counterparts. these comparisons were made in 396 chickens that were 1 day, 2 weeks, 8-9 weeks, 10 weeks, 17 weeks, or 29-32 weeks old. only one serum sample was collected from any given chick or chicken. there were no significant differences between ...19921320864
effect of cell-culture passage on the pathogenicity and immunogenicity of two variant strains of infectious bursal disease virus.two variant strains of infectious bursal disease virus, in and e, were adapted and passaged in an established cell line (bgm-70) 30 times and 40 times, respectively. passage in cell culture resulted in loss of pathogenicity. however, both viruses maintained their antigenicity and immunogenicity, as demonstrated by the immunofluorescence and virus-neutralization tests and by the satisfactory protection induced by vaccinating specific-pathogen-free (spf) chickens with inactivated preparations of b ...19921320871
susceptibility of chicken monocytic cell lines to infectious bursal disease virus. 19921322719
virus disease as a consequence of viral pathogenicity and the anti-viral immune response.the brief description of two virus systems, influenza and infectious bursal disease, shows enigmatically how at least two requirements must be met to render a virus pathogenic: the array of the whole genome rather than the formation of a particular "pathogenicity gene" and the capacity of the host cell to provide the appropriate microenvironment for an optimal posttranslational processing of structural proteins. in the case of influenza viruses this relates particularly to the cleavability of th ...19921326273
genetic mechanisms of antigenic variation in infectious bursal disease virus: analysis of a naturally occurring variant virus.the major immunogenic protein vp2 from a pathogenic field isolate (variant a virus) of infectious bursal disease virus (ibdv) was cloned and sequenced to examine antigenic variations. the vp2 open reading frame consists of 1509 nucleotides and codes for a 503 amino acid protein. overall, the vp2 amino acid sequence of the variant a virus shares 98.6% identity with vp2 genes from other published ibdv strains. however, within the central region of vp2 (amino acids 222-334) lies a highly divergent ...19921329340
occurrence of acute infectious bursal disease with high mortality in japan and pathogenicity of field isolates in specific-pathogen-free chickens.highly virulent infectious bursal disease virus (ibdv) was isolated from field cases, and the pathogenicity of the isolates was examined in specific-pathogen-free chickens. chickens inoculated with the isolates developed severe clinical disease with a high mortality rate. histopathologically, infectious bursal disease was characterized by bursal and thymic necrosis, aplastic anemia, acute hepatitis with fatty change, and systemic inflammatory response. in addition to functional abnormalities in ...19921329709
use of polymerase chain reaction for efficient cloning of dsrna segments of infectious bursal disease virus.a method is described for efficient cloning of the large rna segment of infectious bursal disease virus (ibdv) after reverse transcription and cdna amplification. complementary dna segments of ibdv were prepared using reverse transcriptase and specific primers homologous to the conserved region at the 3' end of the ibdv sequence. the resulting cdna segments were amplified using taq dna polymerase and a pair of specific primers. three separate primer pairs were used for amplification, each yieldi ...19921329714
immune dysfunction following infection with chicken anemia agent and infectious bursal disease virus. ii. alterations of in vitro lymphoproliferation and in vivo immune determine the functional impact of alterations in lymphocyte concentrations and ratios following infection with chicken anemia agent (caa) alone or in combination with infectious bursal disease virus (ibdv) on the immune system of young chickens, in vitro lymphoproliferation assays and in vivo responses to vaccination with several common viral agents were assessed at various time intervals post-inoculation (pi). concanavalin a (con a), phytohemagglutinin (pha) and pokeweed mitogen (pwm) stimu ...19921333677
biological roles of the major capsid proteins and relationships between the two existing serotypes of infectious bursal disease virus.neutralizing monoclonal antibodies (n-mabs) were produced against infectious bursal disease virus (ibdv) of serotypes 1 and 2. the n-mabs recognizing the major antigenic proteins vp2 and vp3, were characterized using different strains of ibdv representing the existing two serotypes and a variant subtype of serotype 1. the biological properties of these viral antigens as defined by the mabs in vitro, were studied utilizing post-adsorption virus neutralization tests and fluorescence-activated cell ...19921333752
subclinical infectious bursal disease in an integrated broiler production operation.a field study was designed to determine the prevalence of subclinical infectious bursal disease (ibd) in broiler chickens from a commercial poultry company. bursae of fabricius (bf) from two vaccinated and three nonvaccinated broiler flocks were evaluated histologically, and antibody profiles of these broiler and matched parent breeder flocks were established. lesions of ibd, including lymphoid necrosis, stromal edema, and infiltrates of heterophils and macrophages, were first detected in bf at ...19921333817
detection of infectious bursal disease virus in digested formalin-fixed paraffin-embedded tissue sections by polymerase chain reaction. 19921333820
detection of infectious bursal disease virus infection using the polymerase chain reaction.the method of reverse transcription (rt) followed by the polymerase chain reaction (pcr) was used to amplify two different fragments of the infectious bursal disease virus (ibdv) genome. two sets of primer framed two different regions within the genes coding for proteins vp2 and vp3, respectively. both sequences were detected in five strains of ibdv, whereas, none were obtained from uninfected control cells. the sensitivity of rt-pcr was carried out on nucleic acids from the ibdv infected cell c ...19921335456
infectious bursal disease of poultry: antigenic structure of the virus and control.the present knowledge of genome organisation, structural basis of pathogenicity and antigenicity of infectious bursal disease virus (ibdv) are briefly reviewed. the current situation of ibdv infection in various countries is stated and recommendations for improved vaccination schemes are given.19921336239
structural proteins of classic and variant strains of infectious bursal disease viruses.structural polypeptides of six tissue-culture-origin (bgm-70 continuous cell line) infectious bursal disease viruses representing classic and variant strains of serotype 1 and one serotype 2 strain were analyzed and compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. additionally, two of the variant strains were propagated in vivo in bursa of fabricius and compared with those grown in cell culture. differences among the structural proteins of serotype 1 viruses were minor and ...19921336659
response of b congenic chickens to infection with infectious bursal disease virus.six congenic lines of chickens that differ from the parental inbred line rprl-15i5 for genes in the major histocompatibility (b) complex were used to study the influence of the b haplotypes on the response of chickens to infection with virulent infectious bursal disease virus (ibdv) at 1 day or 4 weeks of age, and on the antibody response to vaccination with live or inactivated oil-emulsion (oe) ibdv vaccines at 7 weeks of age. ibdv-induced immunodepression and lesions in the bursa, spleen, and ...19921336660
immunosuppressive effect of a highly virulent infectious bursal disease virus isolated in japan.the immunosuppressive effect of infectious bursal disease virus (ibdv) on vaccination against newcastle disease (nd) was compared among 2-, 3-, and 4-week-old chickens inoculated with the highly virulent ibdv field isolate 90-11 and the reference serotype 1 strain gbf-1. in all age groups, isolate 90-11 severely suppressed antibody response to nd vaccination and protective vaccinal immunity against nd. in contrast, chickens inoculated with strain gbf-1 and vaccinated with nd vaccine were well pr ...19921336662
naturally occurring-neutralizing monoclonal antibody escape variants define the epidemiology of infectious bursal disease viruses in the united states.a panel of two non-neutralizing and six neutralizing monoclonal antibodies (mabs) were used in antigen-capture enzyme immunoassays (ac-elisa) to examine the antigenicity of 1301 wild type infectious bursal disease viruses (ibdv) isolated from different poultry flocks throughout the united states over a three year period. analysis of these isolates with protective, neutralizing mabs directed against the vp2 structural protein of ibdv showed that four antigenically distinct groups of serotype 1 ib ...19921333761
immune dysfunction following infection with chicken anemia agent and infectious bursal disease virus. i. kinetic alterations of avian lymphocyte subpopulations.the potential effect of chicken anemia agent (caa) alone or in combination with infectious bursal disease virus (ibdv) on the immune system of young chickens was determined by measuring alterations in hematocrit values, lymphoid organ-to-body weight ratios and lymphoid cell concentrations at 4, 7, 10, 14, 17, 21, 28 and 42 days post-inoculation (pi). lymphocyte subpopulations were identified and counted by flow cytometry using cell suspensions stained with monoclonal antibodies (mabs) for panlym ...19921333676
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