mutations at the cleavage site of the hemagglutinin after the pathogenicity of influenza virus a/chick/penn/83 (h5n2).six variants that form plaques in chick embryo cells in the absence of trypsin have been isolated from the apathogenic avian influenza virus a/chick/pennsylvania/1/83 (h5n2). unlike the wild-type, the plaque variants contain a hemagglutinin that is cleaved in chick embryo cells and mdck cells. the variants differ also from the wild-type in their pathogenicity for chickens. nucleotide sequence and oligosaccharide analysis of the hemagglutinin have revealed that, unlike natural isolates with incre ...19892916326
glycosylation affects cleavage of an h5n2 influenza virus hemagglutinin and regulates virulence.based on nucleotide sequence analysis of the hemagglutinin (ha) gene from the virulent and avirulent a/chicken/pennsylvania/83 influenza viruses, it was previously postulated that acquisition of virulence was associated with a point mutation that resulted in loss of a glycosylation site. since there are two potential glycosylation sites in this region of the ha molecule and since all asn-xaa-thr/ser sequences in the has of different strains are not necessarily glycosylated, the question remained ...19873467357
influenza viruses and paramyxoviruses in ducks in the atlantic flyway, 1977-1983, including an h5n2 isolate related to the virulent chicken virus.from 1977 to 1983, waterfowl migrating along the atlantic flyway were annually monitored for orthomyxoviruses and paramyxoviruses in an area in central new york state. a total of 168 influenza isolates were obtained from 1,430 waterfowl. twenty-four combinations of hemagglutinin and neuraminidase subtypes were detected, with as many as 12 found in a single year. one combination, an h5n2 isolate in 1982, was closely related to the virulent chicken virus that appeared in pennsylvania in 1983. the ...19853833237
isolation of avian influenza virus (subtype h5n2) from chicken eggs during a natural outbreak.avian influenza virus (a/chicken/pennsylvania/83; h5n2) was recovered from the yolk, albumen, and shell surface of eggs obtained from naturally infected chicken flocks in pennsylvania and virginia. these findings represent the first reported isolation of avian influenza virus from the internal contents of eggs from naturally infected flocks. the need for adequate safeguards to prevent spread of the virus during commercial movement of table and hatching eggs, cracked and "checked" eggs, and egg f ...19853833221
emergence of amantadine-resistant h5n2 avian influenza virus during a simulated layer flock treatment experiment was designed to simulate field conditions in which preventive treatment is not initiated until after some chickens in a flock are infected with avian influenza (ai). twelve hens began to receive amantadine hydrochloride on the day they were inoculated (day 0) with highly pathogenic ai virus, a/chicken/pa/1370/83. these hens remained clinically normal through 8 days postinoculation (pi), but five died after day 9; mean death time (mdt) was 18 days. three of 12 hens given amantadine ...19873675425
molecular changes in a/chicken/pennsylvania/83 (h5n2) influenza virus associated with acquisition of of the unresolved questions concerning the acquisition of virulence by the a/chicken/pennsylvania/83 (h5n2) influenza virus is which gene segments other than the hemagglutinin (ha) showed changes that were relevant. to answer this question, reassortants were made possessing the hemagglutinin gene of the virulent virus and the seven other genes from the avirulent parent. since both the virulent and avirulent h5n2 strains are antigenically almost indistinguishable, it was necessary to transfer ...19863946082
circulation of influenza viruses and paramyxoviruses in waterfowl originating from two different areas of north america.migratory waterfowl and shore birds harbour a wide range of influenza viruses, some of which have been implicated in influenza outbreaks in mammals and domestic birds. in the present study, a comparison was made of two marshalling areas for different migratory flyways of waterfowl in north america over a 6-8-year period. virtually all known influenza subtypes were isolated and the predominant subtype changed from year to year. a marked difference between the two locations was that the predominan ...19853878741
highly pathogenic virus recovered from chickens infected with mildly pathogenic 1986 isolates of h5n2 avian influenza virus.a combination of in vitro and in vivo selection procedures was used to examine the possibility that certain mildly pathogenic field isolates of avian influenza (ai) virus may contain minority subpopulations of highly pathogenic virus. two mildly pathogenic h5n2 isolates, a/chicken/new jersey/12508/86 (nj12508) and a/chicken/florida/27716/86 (fl27716), recovered from chickens epidemiologically associated with urban live-bird markets, were cloned in trypsin-free chicken embryo fibroblast cultures. ...19883202767
defective interfering virus associated with a/chicken/pennsylvania/83 influenza virus.the a/chicken/pennsylvania/1/83 influenza virus, isolated from a respiratory infection of chickens, is an avirulent h5n2 virus containing subgenomic rnas (w.j. bean, y. kawaoka, j.m. wood, j.e. pearson, and r.g. webster, j. virol. 54:151-160, 1985). we show here that defective interfering particles are present in this virus population. the virus had a low ratio of plaque-forming to hemagglutinating units and produced interference with standard virus multiplication in infectious center reduction ...19873573146
vaccination as a strategy to reduce the emergence of amantadine- and rimantadine-resistant strains of a/chick/pennsylvania/83 (h5n2) influenza virus.the influenza a virus (a/chick/pennsylvania/83 (h5n2) that caused up to 80% mortality in chickens provided a model system for testing the efficacy of chemotherapeutic agents against highly virulent influenza virus. amantadine and rimantadine administered to chickens in drinking water were efficacious both prophylactically and therapeutically. however, under conditions simulating natural transmission of virus amantadine and rimantadine-resistant viruses arose and were transmitted to contact birds ...19863793657
influence of dietary calcium stress on lethality of avian influenza viruses for laying chickens.the effect of calcium stress was studied in an attempt to reproduce lethal infections in laying chickens with a/chicken/alabama/75 (h4n8) influenza virus and with two nonpathogenic h5n2 influenza viruses from the 1983-84 outbreak in the eastern united states. hens were fed calcium-deficient or standard diets for 7 to 14 days; then the calcium-deficient feed was replaced with standard feed supplemented with ad libitum oyster shell, and both groups of hens were inoculated with virus. when hens wer ...19863028353
host range of a/chicken/pennsylvania/83 (h5n2) influenza virus.the highly pathogenic a/chicken/penn./1370/83 (h5n2) avian influenza virus, which caused 80% mortality in chickens in pennsylvania, produced only mild transient illness in experimentally infected pheasants, little or no clinical signs in ring-billed gulls and pigs, and no clinical signs in pekin ducks. virus could be recovered from only the upper respiratory tract of gulls and pigs for 1-2 days. infection in ducks resulted in intestinal replication of virus in only 1 out of 12 ducks. by contrast ...19853985875
evolution of the a/chicken/pennsylvania/83 (h5n2) influenza virus.the epidemiological features of the h5n2 outbreak of influenza in poultry were studied by sequencing the ha genes of several viruses isolated during the epidemic. comparison of the nucleotide sequences of the ha genes indicated there was a single introduction of virulent virus. the variation rate (silent mutations) in the ha gene of the virulent ck/penn virus was 9.0 or 14.4% per 10 years depending on the viruses compared and was similar to that in h3 ha gene of human influenza a virus. the viru ...19854036005
effects of chicken embryo age on time to death following infection by avian influenza viruses: implications for distinguishing highly pathogenic isolates.when white leghorn (wl) chick embryos ranging in age from 8 to 13 days were inoculated with a variety of avian influenza virus (aiv) isolates, strain-specific differences in embryo mean death times (mdt) were observed. non-highly pathogenic (nhp) strains killed 8 or 9 day-old embryos much more rapidly than 12 or 13 day-old embryos. highly pathogenic (hp) strains, however, were less sensitive to embryo age resulting in similar mdts in both older and younger embryos. these observations were consis ...19902166979
protection against lethal influenza with neuraminidase.the role of the neuraminidase in eliciting protection against a lethal influenza a virus [a/ck/penn/1370/83 (h5n2)] infection was investigated in chickens. isolated n2 neuraminidase administered in adjuvant did not prevent infection but did prevent systemic spread of virus and death of chickens. n2 expressed in a recombinant vaccinia virus protected chickens when administered in adjuvant but was less effective when allowed to replicate and produce pox on the chicken's comb. chickens vaccinated w ...19882452514
protection of chickens from lethal influenza virus infection by influenza a/chicken/pennsylvania/1/83 virus: characterization of the protective effect.the influenza a/chicken/pennsylvania/1/83 (h5n2) virus is the first known example of an influenza virus isolated from a natural infection which contained primarily defective interfering particles (t. m. chambers and r. g. webster, j. virol. 61, 1517-1523, 1987). in chickens, coinoculation of this virus together with the closely related but highly virulent influenza a/chicken/pennsylvania/1370/83 virus results in reduced mortality compared to virulent virus infection alone (bean et al., j. virol. ...19912053293
a pathogenesis study of highly pathogenic avian influenza virus h5n2 in chickens, using immunohistochemistry.eighteen specific pathogen-free chickens (nine hens older than 1 year and nine 15-week-old males) were inoculated with highly pathogenic avian influenza virus a/chicken/pennsylvania/1370/1983 (h5n2). birds were serially killed and tissues collected for histological and immunohistochemical evaluation. in the group of older hens, disease was acute or peracute. by immunohistochemistry, antigen was abundant in capillary endothelium in multiple organs, and staining for antigen in parenchymal cells wa ...19921469128
characterization of virulent and avirulent a/chicken/pennsylvania/83 influenza a viruses: potential role of defective interfering rnas in april 1983, an influenza virus of low virulence appeared in chickens in pennsylvania. subsequently, in october 1983, the virus became virulent and caused high mortality in poultry. the causative agent has been identified as an influenza virus of the h5n2 serotype. the hemagglutinin is antigenically closely related to tern/south africa/61 (h5n3) and the neuraminidase is similar to that from human h2n2 strains (e.g., a/japan/305/57) and from some avian influenza virus strains (e.g., a/turkey/ma ...19853973976
protection of chickens against highly pathogenic avian influenza virus (h5n2) by recombinant fowlpox viruses.two recombinant fowlpox viruses containing the avian influenza h5 hemaglutinin (ha) gene were evaluated for their ability to protect chickens against challenge with a highly pathogenic isolate of avian influenza virus (h5n2). susceptible chickens were vaccinated with the parent fowlpox vaccine virus or recombinant viruses either by wing-web puncture or comb scarification. following challenge 4 weeks later with highly pathogenic avian influenza virus, all birds vaccinated by the wing-web method w ...19911649592
reassortants with equine 1 (h7n7) influenza virus hemagglutinin in an avian influenza virus genetic background are pathogenic in chickens.reassortants possessing the hemagglutinin (ha) gene from a/equine/london/1416/73 (h7n7) [eq/lond] and five or more genes from a/chicken/pennsylvania/1370/83 (h5n2) [ck/penn] were lethal in chickens. this result demonstrates that horses can maintain influenza viruses whose has are capable of promoting virulence. thus, reassortment of equine and avian influenza virus genes could generate viruses that might be lethal in domestic poultry.19911871981
presence of avian influenza virus (aiv) subtypes h5n2 and h7n1 in emus (dromaius novaehollandiae) and rheas (rhea americana): virus isolation and serologic findings.avian influenza virus (aiv) subtypes h5n2 and h7n1 were isolated from emus (dromaius novaehollandiae) and rheas (rhea americana) in texas and north carolina. all the rheas and emus had a history of respiratory disease except one emu, which was clinically normal. the isolates were not pathogenic for chickens and turkeys under the conditions of the experiment. humoral antibodies to all known hemagglutinin (h) subtypes except h10, h13, and h14 and to all nine neuraminidase (n) subtypes were found i ...19957794192
is virulence of h5n2 influenza viruses in chickens associated with loss of carbohydrate from the hemagglutinin?the a/chick/penn/83 (h5n2) influenza virus that appeared in chickens in pennsylvania in april 1983 and subsequently became virulent in october 1983, was examined for plaque-forming ability and cleavability of the hemagglutinin (ha) molecule. the avirulent virus produced plaques and cleaved the ha only in the presence of trypsin. in contrast, the virulent virus produced plaques and cleaved the ha precursor into ha1 and ha2 in the presence or absence of trypsin. the apparent molecular weight of th ...19846516214
protection against virulent h5 avian influenza virus infection in chickens by an inactivated vaccine produced with recombinant vaccinia virus.a cloned cdna copy of the haemagglutinin (ha) gene of a/chicken/scotland/59 (h5n1) influenza virus has been expressed in vaccinia virus. this pox virus is poorly infectious or non-infectious for chickens. however, immunization of chickens with lysates of cell cultures infected with the recombinant vaccinia virus, that had been emulsified with adjuvant and which contained an estimated 0.5 microgram influenza ha, elicited a substantial neutralizing antibody response to influenza virus. challenges ...19883048009
influenza virus surveillance in waterfowl in pennsylvania after the h5n2 avian outbreak.during the latter stages of the lethal h5n2 influenza eradication program in domestic poultry in pennsylvania in 1983-84, surveillance of waterfowl was done to determine if these birds harbored influenza viruses that might subsequently appear in poultry. from late june to november 1984, 182 hemagglutinating viruses were isolated from 2043 wild birds, primarily ducks, in the same geographical area as the earlier lethal h5n2 avian influenza outbreak. the virus isolates from waterfowl included para ...19863015104
effect of route of administration on the efficacy of a recombinant fowlpox virus against h5n2 avian influenza.a recombinant fowlpox vaccine virus containing the h5 hemagglutinin gene of avian influenza virus was administered to susceptible chickens via wing-web puncture, eye drop, instillation into the nares, and drinking water. even though there was a negligible hemagglutination-inhibition (hi) serologic response, all 10 chickens vaccinated by wing-web puncture remained without obvious signs of disease and survived challenge with a highly pathogenic strain of h5n2 avian influenza virus. all unvaccinate ...19921336657
efficacy of avian influenza oil-emulsion vaccines in chickens of various experimental avian influenza (ai) oil-emulsion vaccine was formulated with 1 part inactivated a/turkey/wisconsin/68 (h5n9) ai virus emulsified in 4 parts oil. broilers were vaccinated subcutaneously (sc) either at 1 or 3 days old or at 4 or 5 wks old. commercial white leghorn (wl) layers were vaccinated sc at 12 and 20 wks old or at only 20 wks old. maximum geometric mean hemagglutination-inhibition titers postvaccination (pv) were 1:86-1:320 for broilers, 1:597 for twice-vaccinated layers, a ...19872960309
biologic potential of amantadine-resistant influenza a virus in an avian model.amantadine has been accepted for both the treatment and prophylaxis of influenza a virus infections. although amantadine-resistant mutants have been shown to be readily generated both in the laboratory and in children treated with rimantadine, little is known about their biologic properties, such as genetic stability, transmissibility, or pathogenicity, compared with the parental virus. this study examined these properties using an avian influenza virus, a/chicken/pennsylvania/1370/83 (h5n2). va ...19892723453
tissue tropism and replicative properties of waterfowl-origin influenza viruses in chickens.waterfowl-origin influenza (wfoi) viruses were evaluated for their tissue tropism and replicative properties in chickens. the 14 wfoi isolates used in this study represented 13 different hemagglutinin-neuraminidase combinations recovered during 1987 and 1988 and included isolates possessing the h5 and h7 hemagglutinin subtypes and one isolate possessing the h5n2 combination. following intravenous challenge, the frequencies of virus recovery within individual experiments were generally higher for ...19958561736
virulent avian influenza a viruses: their effect on avian lymphocytes and macrophages in vivo and in investigate the pathogenesis of virulent avian influenza a viruses, the effect of a/turkey/ont/7732/66 (h5n9) (ty/ont), a/tern/south africa/1961 (h5n3) (tern/s.a.) and a/chicken/pennsylvania/1370/83 (h5n2) (ck/penn) on avian lymphoid cell populations was examined in vivo. previous studies have shown that infection of chickens with ty/ont resulted in the extensive destruction of lymphoid tissues. in this study, other virulent avian h5 influenza viruses, tern/s.a. or ck/penn, had little or no e ...19892685173
the neuraminidases of the virulent and avirulent a/chicken/pennsylvania/83 (h5n2) influenza a viruses: sequence and antigenic define the sequence changes that occurred in an avian influenza virus neuraminidase (na) during the evolution of virulence, we have studied the na of the virulent and avirulent a/chick/penn/83 (h5n2) influenza viruses. a comparison of the deduced amino acid sequence from these viruses shows that the virulent strain, which evolved from the avirulent by the accumulation of point mutations (bean et al., 1985), acquired four amino acid changes in the na: one in the transmembrane segment, one in t ...19852414922
susceptibility of pigeons to avian influenza.susceptibility to infection with avian influenza virus (aiv) was studied in pigeons inoculated via oculonasal (experiment 1) or intravenous (experiment 2) route. chickens were included as susceptible hosts in both experiments. two subtypes each of the highly pathogenic aiv (hpaiv; hp ck/pa h5n2 and hp ck/australia h7n7) and non-pathogenic aiv (npaiv; np ck/pa h5n2 and np emu/tx h7n1) at a dose of 10(5) embryo infective dose per bird were used as inoculum. the pigeons inoculated with hp ck/pa h5n ...19968883790
pathogenicity of three avian influenza viruses for leghorn hens of different ages.pronounced host effects on clinical responses to influenza virus infection were not observed in any of seven trials in which young (26-43 weeks) and olf (65-94 weeks) leghorn hens were inoculated with low pathogenic subtype h5n2, h4n8, or h3n2 virus. in two of seven trials, where hens were infected with h4n8 or h3n2 virus, morbidity rates were slightly higher for old hens than for young hens. these observations indicate that host age effects of the severity of uncomplicated influenza virus infec ...19968883807
chemotherapy and vaccination: a possible strategy for the control of highly virulent influenza virus.the influenza a virus [a/chicken/pennsylvania/1370/83 (h5n2)] that caused up to 80% mortality among chickens provided a model system for testing the efficacy of chemotherapeutic agents against highly virulent influenza virus. amantadine and rimantadine administered in drinking water were efficacious both prophylactically and therapeutically. however, under conditions simulating natural transmission of virus, amantadine- and rimantadine-resistant viruses arose and were transmitted to other birds ...19854009792
overlapping cytotoxic t-lymphocyte and b-cell antigenic sites on the influenza virus h5 define the recognition site of cytotoxic t lymphocytes (ctls) on influenza virus h5 hemagglutinin (ha), an h5 ha-specific ctl clone was examined for the ability to recognize monoclonal antibody-selected ha variants of influenza virus a/turkey/ontario/7732/66 (h5n9). on the basis of 51cr release assays with the variants, a ctl epitope was located near residue 168 of h5 ha. to define the epitope more precisely, a series of overlapping peptides corresponding to this region was synthesized and te ...19901700833
emergence of a potentially pathogenic h5n2 influenza virus in chickens.highly pathogenic influenza a viruses periodically infect both humans and nonhuman animals, including chickens. to gain insight into the origin of influenza outbreaks in poultry, we investigated two h5n2 viruses, a/chicken/pennsylvania/13609/93 (ck/pa/93) and a/chicken/florida/25717/93 (ck/fla/93), that had been isolated in live-bird markets in pennsylvania and florida during surveillance studies in 1993. phylogenetic analysis of the ha genes of these isolates, as well as h5n2 viruses isolated f ...19948184538
emergence of highly pathogenic virus during selective chicken passage of the prototype mildly pathogenic chicken/pennsylvania/83 (h5n2) influenza virus.the prototype mildly pathogenic a/chicken/pennsylvania/21525/83 (h5n2) avian influenza virus, which was isolated more than 5 months before the emergence of highly pathogenic virus in the major 1983 pennsylvania outbreak, was examined for the presence of minority subpopulations of highly pathogenic virus. selective serial passage of the parental mildly pathogenic virus in leghorn hens did not lead to recovery of highly pathogenic virus. however, several highly pathogenic reisolates were recovered ...19911838476
what is the potential of avirulent influenza viruses to complement a cleavable hemagglutinin and generate virulent strains?a large pool of avirulent influenza viruses are maintained in the wild ducks and shorebirds of the world, but we know little about their potential to become virulent. it is well established that the hemagglutinin (ha) is pivitol in determining virulence and that a constellation of other genes is also necessary (r. rott, m. orlich, and c. scholtissek, 1976, j. virol. 19, 54-60). the question we are asking here is the ability of avirulent influenza viruses to provide the gene constellation that wi ...19892763464
pathobiology of h5n2 mexican avian influenza virus infections of determine the association between specific structural changes in the hemagglutinin gene and pathogenicity of avian influenza viruses (aivs), groups of 4-week-old white plymouth rock chickens were inoculated intravenously or intranasally with aivs of varying pathogenicities isolated from chickens in central mexico during 1994-1995. mildly pathogenic (mp) viruses had a common hemagglutinin-connecting peptide sequence of pro-gln-arg-glu-thr-arg decreases gly and had restricted capability for rep ...19979396136
molecular changes in virulent mutants arising from avirulent avian influenza viruses during replication in 14-day-old embryonated eggs.the emergence of virulent avian influenza viruses in poultry is unpredictable. to gain insight into the mechanism for this event, we sought to identify the molecular changes in virulent mutants that occur during replication in 14-day-old embryonated chicken eggs. after three passages in 14-day-old eggs, avirulent h5 viruses with the k/r-k-k/t-r sequence at the hemagglutinin (ha) cleavage site became virulent in chickens, concomitantly acquiring high ha cleavability, whereas those with the r-e-t- ...19957831837
efficacy of inactivated h5n2 influenza vaccines against lethal a/chicken/queretaro/19/95 infection.the control and eventual eradication of h5n2 influenza virus from domestic poultry in mexico is dependent on the use of avian influenza (ai) vaccine strategies. this study was performed to determine the amount of hemagglutinin (ha) antigen required to control the signs of disease from a highly pathogenic h5n2 influenza virus (a/chicken/ queretaro/19/95) and the amount of antigen required to prevent shedding of virus from vaccinated birds. six commercial inactivated water in oil h5n2 vaccines ava ...19989645315
standardization of inactivated h5n2 influenza vaccine and efficacy against lethal a/chicken/pennsylvania/1370/83 infection.the hemagglutinin concentration of beta-propiolactone-inactivated influenza vaccine containing a/duck/n.y./189/82 (h5n2) virus was measured by single-radial-immunodiffusion (srd) test. after administration of vaccine to chickens in freund's complete adjuvant, vaccine efficacy was assessed by challenge with lethal a/chicken/penn./1370/83 (h5n2) virus. srd potency values correlated with post-vaccination antibody levels and protection against infection.19854074253
comparison of the transmission characteristics of low and high pathogenicity avian influenza a virus (h5n2).low pathogenicity avian influenza a strains (lpai) of the h5 and h7 type are noted for their ability to transform into highly pathogenic counterparts (hpai). here we compare the transmission characteristics in poultry of lpai h5n2 (a/chicken/pennsylvania/83) and corresponding hpai virus by means of transmission experiments. in the experiments, five inoculated animals are placed in a cage with five contact animals, and the infection chain is monitored by taking blood samples, and samples from the ...200314596543
avian influenza in the western hemisphere including the pacific islands and australia.between 1997 and 2001, there was one report of highly pathogenic avian influenza (hpai) in the western hemisphere and pacific basin. in 1997, in new south wales, australia, an outbreak caused by avian influenza (ai) virus subtype h7n4 involved both chickens and emus. all other reports of infections in poultry and isolations from wild bird species in the region pertained to low pathogenicity (lp) ai virus. animal health officials in canada reported isolations of subtypes h1, h6, h7, and h10 from ...200314575067
effect of vaccine use in the evolution of mexican lineage h5n2 avian influenza outbreak of avian influenza (ai) caused by a low-pathogenic h5n2 type a influenza virus began in mexico in 1993 and several highly pathogenic strains of the virus emerged in 1994-1995. the highly pathogenic virus has not been reported since 1996, but the low-pathogenic virus remains endemic in mexico and has spread to two adjacent countries, guatemala and el salvador. measures implemented to control the outbreak and eradicate the virus in mexico have included a widespread vaccination program ...200415254209
an arg-lys insertion at the hemagglutinin cleavage site of an h5n2 avian influenza isolate.recent isolations of h5n2 subtype avian influenza (ai) viruses in north america have raised questions concerning their origin, transmission to commercial poultry, and potential for virulence. one ratite-origin isolate of low pathogenicity, a/emu/tx/39924/93 (h5n2), was subjected to a procedure that rapidly selects and/or amplifies highly pathogenic (hp) strains. the resulting highly virulent derivative had an altered hemagglutinin (ha) gene containing an additional six nucleotides at position 97 ...19968879123
haematological and histological findings in birds experimentally infected with highly pathogenic h5n2 avian influenza virus.experimental infection of specific-pathogen-free (spf) leghorn chickens with a highly pathogenic h5n2 avian influenza virus produced cellular hyperplasia in the bone marrow at 36 hours post infection (hpi) and haematological evidence of monocytosis, thrombocytopenia and heterophilia was also detected. an early, significant and progressive haematological change was thrombocytopenia starting at 24 hpi without an increase of prothrombin time. the findings suggest that highly pathogenic avian influe ...200516363150
origin and molecular changes associated with emergence of a highly pathogenic h5n2 influenza virus in october of 1993, there was decreased egg production and increased mortality among mexican chickens, in association with serologic evidence of an h5n2 influenza virus. first isolated from chickens in may of 1994, after spreading widely in the country, the virus caused only a mild respiratory syndrome in specific pathogen-free chickens. because eradication of the virus by destruction of infected birds posed major obstacles to the poultry industry in mexico, we were able to conduct a "field expe ...19957483266
[generation of attenuated h5n1 and h5n2 subtypes of influenza virus recombinants by reverse genetics system].the ha connecting peptide at cleavage site, pqrerrkkr / gl, of an h5n1 subtype avian influenza virus (aiv) was replaced with pqresr / gl, and then the modified ha gene was cloned into the transcription/expression vector, phw2000, constructing a plasmid named phw524-ha. the na (n1) gene from the h5n1 virus and the na (n2) gene from an h9n2 aiv were also cloned into phw2000 separately, resulting in plasmids phw506-na and phw206-na. with the organization of phw524-ha, phw506-na or phw206-na, and si ...200515847163
heterogeneity in the haemagglutinin gene and emergence of the highly pathogenic phenotype among recent h5n2 avian influenza viruses from mexico.molecular changes in the haemagglutinin (ha)-coding regions and proteolytic cleavage sites from multiple h5n2 subtype viruses isolated during a recent outbreak of avian influenza (ai) in central mexico have been characterized. eighteen isolates, collected during a 15 month period (october 1993 to january 1995) from six central states, were sequenced. none of the 18 predicted ha1 amino acid sequences were identical and changes were not restricted to a specific region of the sequence. phylogenetic ...19968757992
pathogenicity and diagnosis of h5n2 mexican avian influenza viruses in chickens.chickens were inoculated with one of five h5n2 mexican-origin avian influenza virus (aiv) isolates to determine their pathogenicity for chickens and to determine the ability of routine virologic and serologic tests to detect infections. in laboratory infections, three aivs, h5/94, m5/94, and j12/94, produced sporadic illness and death and were categorized as mildly pathogenic. q1/95 produced illness and death in all inoculated chickens and was categorized as highly lethal and highly pathogenic ( ...19979201397
avian influenza virus subtypes inside and outside the live bird markets, 1993-2000: a spatial and temporal relationship.between 1993 and 2000, gallinaceous birds, waterfowl, and environmental specimens from the live bird markets (lbms) of the northeastern united states and non-lbm premises were tested for the presence of avian influenza virus (aiv), pathogenic properties of aiv subtypes, especially of hemagglutinin (h) subtypes h5 and h7, and a possible association between lbm and non-lbm infections. ten h subtypes of aiv were isolated from the lbm specimens: h1, h2, h3, h4, h5, h6, h7, h9, h10, and h11. during t ...200212061638
characterization of avian h5n1 influenza viruses from poultry in hong kong.the transmission of avian h5n1 influenza viruses to 18 humans in hong kong in 1997 with six deaths established that avian influenza viruses can transmit to and cause lethal infection in humans. this report characterizes the antigenic and biological properties of the h5n1 influenza viruses isolated from chickens, ducks, and geese from farms and poultry markets in hong kong during 1997 and compares them with those of virus isolated from the index human case. each of the h5n1 viruses from hong kong ...19989878612
new avian influenza a virus subtype combination h5n7 identified in danish mallard ducks.during the past years increasing incidences of influenza a zoonosis have made it of uppermost importance to possess methods for rapid and precise identification and characterisation of influenza a viruses. we present here a convenient one-step rt-pcr method that will amplify full-length haemagglutinin (ha) and neuraminidase (na) directly from clinical samples and from all known subtypes of influenza a. we applied the method on samples collected in september 2003 from a danish flock of mallards w ...200515763149
preparation of a standardized, efficacious agricultural h5n3 vaccine by reverse genetics.options for the control of emerging and reemerging h5n1 influenza viruses include improvements in biosecurity and the use of inactivated vaccines. commercially available h5n2 influenza vaccine prevents disease signs and reduces virus load but does not completely prevent virus shedding after challenge with h5n1 virus. by using reverse genetics, we prepared an h5n3 vaccine whose hemagglutinin is 99.6% homologous to that of a/ck/hk/86.3/02 (h5n1). we used the internal genes of a/pr/8/34 and the h5 ...200314554086
efficacy of recombinant fowl poxvirus vaccine in protecting chickens against a highly pathogenic mexican-origin h5n2 avian influenza virus.internationally and nationally, governments and the poultry industries have used various strategies to control avian influenza (ai), ranging from a minimum of living with mildly pathogenic ai virus (aiv) infections to the other extreme of implementing a total quarantine-slaughter approach for eradication of highly pathogenic (hp) forms of the disease. however, recent economic considerations in various countries have prompted a broader reevaluation of vaccination as one of several tools to be use ...19979454926
characterization of recent h5 subtype avian influenza viruses from us the us, the isolation of h5 subtype avian influenza (ai) viruses has been uncommon in commercial chickens and turkeys, although sporadic isolations have been made from the live bird markets or its supply chain since 1986. in 2002, two different outbreaks of h5 ai occurred in commercial chicken or turkey operations. the first occurred in texas and was identified as a h5n3 subtype ai virus. the second outbreak was caused by a h5n2 virus isolated from a turkey farm in california. in this study w ...200415223555
comparative pathology of chickens experimentally inoculated with avian influenza viruses of low and high pathogenicity.pathologic changes and distribution of viral antigen as determined by immunohistochemistry were compared among 4-wk-old specific-pathogen-free chickens inoculated intratracheally with avian influenza virus (aiv) isolates of either low or high pathogenicity. viruses of low pathogenicity, previously characterized as mildly pathogenic (mp), included a/chicken/pennsylvania/21525/83 (h5n2) (mp-penn) and a/chicken/alabama/7395/75 (h4n8) (mp-alab). viruses of high pathogenicity included a/chicken/penns ...19979087329
isolation and characterization of avian influenza viruses, including highly pathogenic h5n1, from poultry in live bird markets in hanoi, vietnam, in 2001.since 1997, outbreaks of highly pathogenic (hp) h5n1 and circulation of h9n2 viruses among domestic poultry in asia have posed a threat to public health. to better understand the extent of transmission of avian influenza viruses (aiv) to humans in asia, we conducted a cross-sectional virologic study in live bird markets (lbm) in hanoi, vietnam, in october 2001. specimens from 189 birds and 18 environmental samples were collected at 10 lbm. four influenza a viruses of the h4n6 (n = 1), h5n2 (n = ...200515767421
failure of a recombinant fowl poxvirus vaccine containing an avian influenza hemagglutinin gene to provide consistent protection against influenza in chickens preimmunized with a fowl pox vaccine.vaccines against mildly pathogenic avian influenza (ai) have been used in turkeys within the united states as part of a comprehensive control strategy. recently, ai vaccines have been used in control programs against highly pathogenic (hp) ai of chickens in pakistan and mexico. a recombinant fowl pox-ai hemagglutinin subtype (h) 5 gene insert vaccine has been shown to protect specific-pathogen-free chickens from hp h5 ai virus (aiv) challenge and has been licensed by the usda for emergency use. ...200010737653
assessment of the ability of ratite-origin influenza viruses to infect and produce disease in rheas and chickens.pathobiologic characteristics were determined for three mildly pathogenic (mp) ratite-origin avian influenza viruses (aivs). ratite-origin aivs produced respiratory disease in rheas, and virus was reisolated from oropharyngeal and cloacal swabs on days 2-6 postinoculation. inoculation of two ratite-origin aivs in the upper respiratory tract of chickens resulted in viral infections, but the mean chicken infectious dose (cid50) for a/emu/texas/39924/93 (h5n2) (emu/texas) virus was 500-fold lower t ...19968790896
cross-protection among lethal h5n2 influenza viruses induced by dna vaccine to the hemagglutinin.inoculation of mice with hemagglutinin (ha)-expressing dna affords reliable protection against lethal influenza virus infection, while in chickens the same strategy has yielded variable results. here we show that gene gun delivery of dna encoding an h5 ha protein confers complete immune protection to chickens challenged with lethal h5 viruses. in tests of the influence of promoter selection on vaccine efficacy, close correlations were obtained between immune responses and the dose of dna adminis ...19979094608
effect of gene constellation and postreassortment amino acid change on the phenotypic features of h5 influenza virus reassortants.reassortants between a low-pathogenic avian influenza virus strain a/duck/primorie/2621/2001 (h5n2) and a high-yield human influenza virus strain a/puerto rico/8/34 (h1n1) were generated, genotyped and analyzed with respect to their yield in embryonated chicken eggs, pathogenicity for mice, and immunogenicity. a reassortant having ha and na genes from a/duck/primorie/2621/2001 virus and 6 genes from a/puerto rico/8/34 virus (6:2 reassortant) replicated efficiently in embryonated chicken eggs, th ...200717294090
detection of h5 avian influenza viruses by antigen-capture enzyme-linked immunosorbent assay using h5-specific monoclonal antibody.the unprecedented spread of highly pathogenic avian influenza virus subtype h5n1 in asia and europe is threatening animals and public health systems. effective diagnosis and control management are needed to control the disease. to this end, we developed a panel of monoclonal antibodies (mabs) against the h5n1 avian influenza virus (aiv) and implemented an antigen-capture enzyme-linked immunosorbent assay (ac-elisa) to detect the h5 viral antigen. mice immunized with denatured hemagglutinin (ha) ...200717344345
inactivated north american and european h5n2 avian influenza virus vaccines protect chickens from asian h5n1 high pathogenicity avian influenza virus.high-pathogenicity (hp) avian influenza (ai) virus of the h5n1 subtype has caused an unprecedented epizootic in birds within nine asian countries/regions since it was first reported in 1996. vaccination has emerged as a tool for use in managing the infection in view of future eradication. this study was undertaken to determine whether two divergent h5n2 commercial vaccine strains, one based on a european and the other a north american low-pathogenicity ai virus, could protect chickens against a ...200616595307
resistance of immune-suppressed pigeons to subtypes h5n2 and h6n1 low pathogenic avian influenza virus.resistance to infection with avian influenza virus (aiv) was studied in healthy and immune-suppressed pigeons, which were treated with the immunosuppressant cyclophosphamide (cy) before infection. two subtypes of low pathogenic aiv (lpaiv; ck/tw/h5 and ck/tw/h6) were inoculated via the oculonasal route. nested reverse transcriptase-polymerase chain reaction (nested rt-pcr) and virus isolation were used as detection methods. the cy-treated and -untreated pigeons in both experiments did not shed v ...200616863079
h5n2 avian influenza outbreak in texas in 2004: the first highly pathogenic strain in the united states in 20 years?in early 2004, an h5n2 avian influenza virus (aiv) that met the molecular criteria for classification as a highly pathogenic aiv was isolated from chickens in the state of texas in the united states. however, clinical manifestations in the affected flock were consistent with avian influenza caused by a low-pathogenicity aiv and the representative virus (a/chicken/texas/298313/04 [tx/04]) was not virulent for experimentally inoculated chickens. the hemagglutinin (ha) gene of the tx/04 isolate was ...200516103192
microassay for measuring thermal inactivation of h5n1 high pathogenicity avian influenza virus in naturally infected chicken meat.a precise, reproducible microassay was developed to measure thermal inactivation of high pathogenicity avian influenza (hpai) virus in chicken meat. small pieces of breast or thigh meat (0.05 g) from chickens infected with a/chicken/pennsylvania/1370/1983 (h5n2) (pa/83) or a/chicken/korea/es/2003 (h5n1) (korea/03) hpai viruses were tested for inactivation in the heating block of a thermocycler. korea/03 infected thigh and breast meat had higher virus concentrations (10(6.8) and 10(5.6) mean embr ...200616481058
avian influenza a virus subtype h5n2 in a red-lored amazon parrot.a 3-month-old red-lored amazon parrot (amazona autumnalis autumnalis) was evaluated for severe lethargy.200616426196
[tetravaccine--new fundamental approach to prevention of influenza pandemic].according to opinion of who's experts, development and use of tetravaccine, which contains both interdemic and pandemic (h5n1) serotypes of influenza viruses, is one of the most promising approaches to control possible influenza pandemic. results of recently obtained data from clinical trials allowed experts from who to make a conclusion that protective immunity against avian influenza virus can be achieved after 2-doses immunization, when the immune system will be primed to hemagglutinin after ...200717882832
use of avian influenza vaccination in hong kong.outbreaks of h5n1 highly pathogenic avian influenza (hpai) that occurred in hong kong up until february/march 2002 were controlled by stamping out. with endemic presence of the virus in the region and large daily importation of poultry to hong kong, the administration considered that further risk management measures, in addition to improved biosecurity and enhanced surveillance, were necessary to prevent outbreaks. vaccination using a killed h5n2 vaccine was evaluated over a 12-month period in t ...200616447504
genome characterisation of the newly discovered avian influenza a h5n7 virus subtype denmark, in 2003, a previously unknown subtype combination of avian influenza a virus, h5n7 (a/mallard/denmark/64650/03), was isolated from a flock of 12,000 mallards. the h5n7 subtype combination might be a reassortant between recent european avian influenza a h5, h7, and a third subtype, possibly an h6. the haemagglutinin and the acidic polymerase genes of the virus were closely related to a low-pathogenic danish h5n2 virus a/duck/denmark/65041/04 (h5n2). the neuraminidase gene and the non- ...200717115305
subtyping of influenza a isolates in taiwan--2003 to 2004.some isolated influenza strains are untypable. the possibility that a novel and potentially lethal strain, such as h5 virus, might be one of these untypable strains remains a major concern. this study investigated the nature of untypable influenza strains in taiwan.200617098691
characterization of a newly developed chicken 44k agilent microarray.the development of microarray technology has greatly enhanced our ability to evaluate gene expression. in theory, the expression of all genes in a given organism can be monitored simultaneously. sequencing of the chicken genome has provided the crucial information for the design of a comprehensive chicken transcriptome microarray. a long oligonucleotide microarray has been manually curated and designed by our group and manufactured using agilent inkjet technology. this provides a flexible and po ...200818237426
generation of reassortant influenza vaccines by reverse genetics that allows utilization of a diva (differentiating infected from vaccinated animals) strategy for the control of avian influenza.vaccination of poultry with inactivated influenza vaccine can be an effective tool in the control of avian influenza (ai). one major concern of using inactivated vaccine is vaccine-induced antibody interference with serologic surveillance and epidemiology. in the united states, low pathogenicity h5 and h7 subtype ai viruses have caused serious economic losses in the poultry industry. most of these viruses also have the accompanying n2 subtype and no h5n1 or h7n8 subtype ai viruses have been iden ...200415297071
vaccination of chickens against h5n1 avian influenza in the face of an outbreak interrupts virus transmission.vaccination of chickens with a commercially available killed h5n2 vaccine was being evaluated as an additional tool to enhanced biosecurity measures and intensive surveillance for control of highly pathogenic avian influenza subtype h5n1 disease in hong kong in 2002. in december 2002 to january 2003, there were outbreaks of h5n1 disease in waterfowl in two recreational parks, wild water birds, several poultry markets and five chicken farms. in addition to quarantine, depopulation of the affected ...200415370037
vaccines developed for h5 highly pathogenic avian influenza in china.since the first detection of highly pathogenic h5n1 avian influenza virus from sick goose in guangdong province in china in 1996, scientists in china started to develop vaccines for avian influenza pandemic preparedness. an h5n2 inactivated vaccine was produced from a low pathogenic virus, a/turkey/england/n-28/73, and was used for the buffer zone vaccination in the h5n1 outbreaks in 2004 in china. we also generated a low pathogenic h5n1 reassortant virus a/harbin/re-1/2003 (re-1) that derives i ...200617135510
newcastle disease virus expressing h5 hemagglutinin gene protects chickens against newcastle disease and avian influenza.newcastle disease virus (ndv)-expressing avian influenza virus (aiv) hemagglutinin (ha) of subtype h5 was constructed by reverse genetics. a cloned full-length copy of the genome of the lentogenic ndv strain clone 30 was used for insertion of the orf encoding the ha of the highly pathogenic aiv isolate a/chicken/italy/8/98 (h5n2) in the intergenic region between the ndv fusion and hemagglutinin-neuraminidase (hn) genes. remarkably, two species of ha transcripts were detected in cells infected wi ...200616717197
low pathogenicity h5n2 avian influenza outbreak in japan during the the end of may 2005, a low-pathogenicity avian influenza (lpai) virus of subtype h5n2 was isolated for the first time from chickens in japan. through active and epidemiological surveillance, 5.78 million chickens on 41 farms were found to be affected and 16 h5n2 viruses were isolated. antigenic analysis revealed antigenic similarity of these isolates. phylogenetic analysis showed that they originated from a common ancestor and clustered with the h5n2 strains prevalent in central america that ...200717524576
characterization of h5n2 influenza a viruses isolated from chickens in japan.a low pathogenic avian influenza virus of the h5n2 subtype was isolated for the first time from layer chickens in japan in 2005. surveillance in trading restriction zones and epidemiologically related farms revealed 41 seropositive farms, and 16 h5n2 viruses were isolated and characterized from nine of these farms. that these viruses were genetically and antigenically similar to each other suggested that these isolates were derived from a common origin. complete genomic characterization of all e ...200717494611
efficacy of a fowlpox-vectored avian influenza h5 vaccine against asian h5n1 highly pathogenic avian influenza virus challenge.a recombinant fowlpox-avian influenza (ai) h5 vaccine (rfp-aiv-hs) expressing the hemagglutinin of the a/turkey/ireland/1378/83 h5n8 ai isolate has been used in central america since 1998 to control h5n2 low pathogenicity ai. previously, this vaccine was shown to induce full protection against a panel of h5 highly pathogenic (hp) ai isolates, including hpai h5n1. here, we evaluate the efficacy of rfp-aiv-h5 against escalating doses of hpai h5n1 a/chicken/ southkorea/es/03 isolate and against the ...200717494618
characterization of an influenza a h5n2 reassortant as a candidate for live-attenuated and inactivated vaccines against highly pathogenic h5n1 viruses with pandemic potential.we generated a high-growth 7:1 reassortant (len17/h5) that contained the hemagglutinin (ha) gene from non-pathogenic a/duck/potsdam/1402-6/86 (h5n2) virus and other genes from the cold-adapted (ca) attenuated a/leningrad/134/17/57 (h2h2) strain. len17/h5 demonstrated an attenuated phenotype in mice and did not infect chickens. mice administered len17/h5 either as a live-attenuated intranasal vaccine or as an inactivated intramuscular vaccine were substantially protected from lethal challenge wit ...200617050041
effect of vaccination on transmission of hpai h5n1: the effect of a single vaccination dose on transmission of highly pathogenic avian influenza h5n1 in peking ducks.the highly pathogenic h5n1 avian influenza virus is widespread among domestic ducks throughout southeast asia. many aspects of the poultry industry and social habits hinder the containment and eradication of ai. vaccination is often put forward as a tool for the control of ai. however, vaccination will only lead to eradication when it reduces the virus spread to such an extent that herd immunity is obtained. to study the effect of a single vaccination dose on the transmission of h5n1 in domestic ...200717494575
[monitoring influenza a virus and newcastle disease virus in migratory waterfowls in sanjiang natural reserve of heilongjiang province].in order to monitor the present situation of avian influenza virus (aiv) and newcastle disease virus (ndv) in migratory waterfowls effectively, 158 tracheal and cloacal swab samples for wild birds were collected from sanjiang natural reserve during migratory seasons in october 2005, april 2006 and october 2006.200819160826
avian influenza in north and south america, 2002-2005.between 2002 and 2005, three outbreaks of highly pathogenic avian influenza (hpai) occurred in the americas: one outbreak in chile (h7n3) in 2002, one outbreak in the united states (h5n2) in 2004, and one outbreak in canada (h7n3) in 2004. the outbreak in chile was limited to a large broiler breeder operation and a nearby turkey flock and represented the first outbreak of hpai in that country. the outbreak of hpai in the united states occurred in texas and was limited to one premise where chicke ...200717494549
experimental study to determine if low-pathogenicity and high-pathogenicity avian influenza viruses can be present in chicken breast and thigh meat following intranasal virus inoculation.two low-pathogenicity (lp) and two high-pathogenicity (hp) avian influenza (ai) viruses were inoculated into chickens by the intranasal route to determine the presence of the ai virus in breast and thigh meat as well as any potential role that meat could fill as a transmission vehicle. the lpai viruses caused localized virus infections in respiratory and gastrointestinal (gi) tracts. virus was not detected in blood, bone marrow, or breast and thigh meat, and feeding breast and thigh meat from vi ...200515839417
avian influenza: genetic evolution under vaccination pressure.antigenic drift of avian influenza viruses (aivs) has been observed in chickens after extended vaccination program, similar to those observed with human influenza viruses. to evaluate the evolutionary properties of endemic aiv under high vaccination pressure (around 2 billion doses used in the last 12 years), we performed a pilot phylogenic analysis of the hemagglutinin (ha) gene of aivs isolated from 1994 to 2006. this study demonstrates that mexican low pathogenicity (lp) h5n2-aivs are constan ...200818218105
epitope mapping of the hemagglutinin molecule of a highly pathogenic h5n1 influenza virus by using monoclonal antibodies.we mapped the hemagglutinin (ha) antigenic epitopes of a highly pathogenic h5n1 influenza virus on the three-dimensional ha structure by characterizing escape mutants of a recombinant virus containing a/vietnam/1203/04 (h5n1) deltaha and neuraminidase genes in the genetic background of a/puerto rico/8/34 (h1n1) virus. the mutants were selected with a panel of eight anti-ha monoclonal antibodies (mabs), seven to a/vietnam/1203/04 (h5n1) virus and one to a/chicken/pennsylvania/8125/83 (h5n2) virus ...200717881439
surveillance of avian and swine influenza in the swine population in taiwan, 2004.we conducted serological and virological surveillance of pig farms in taiwan from areas epidemic for low pathogenic avian influenza virus (aiv), h5n2 subtype, in order to determine the prevalence of aiv and swine influenza virus (siv) in 2004.200818629419
pathogenicity and transmission studies of h5n2 parrot avian influenza virus of mexican lineage in different poultry 2004, a low pathogenic h5n2 influenza virus (a/parrot/ca/6032/04) was identified in a psittacine bird for the first time in the united states. sequence and phylogenetic analysis of the hemagglutinin gene grouped the parrot isolate under the mexican lineage h5n2 viruses (subgroup b) with highest similarity to recent chicken-origin isolates from guatemala. antigenic analysis further confirmed the close relatedness of the parrot isolate to mexican lineage viruses, the highest cross-reactivity be ...200818077111
h5 antibody detection by blocking enzyme-linked immunosorbent assay using a monoclonal antibody.many commercial enzyme-linked immunosorbent assays (elisas) are unable to differentiate antibody responses to different avian influenza virus (aiv) subtypes. developing an elisa for specifically detecting the h5 antibody is the purpose of this study. four monoclonal antibodies (mabs) were raised using a/duck/yunlin/04 (h5n2). they were confirmed as being specific to h5. two of these antibodies showed hemagglutination inhibition (hi) activity using the hi test. using immunodot blot assays, three ...200818459308
influenza neuraminidase antibodies provide partial protection for chickens against high pathogenic avian influenza of chickens against avian influenza (ai) is mostly attributed to production of antibodies against the viral glycoprotein hemagglutinin, whereas less is known about the protective role of antibodies to the other surface glycoprotein neuraminidase (na). therefore, vaccines encoding na antigen (e.g., dna and alphavirus-based virus like replicon particles (vrp)) or baculovirus-expressed recombinant na (rn2) were tested for their ability to protect against highly pathogenic ai (hpai) in ch ...200717350145
protective avian influenza in ovo vaccination with non-replicating human adenovirus vector.protective immunity against avian influenza virus was elicited in chickens by single-dose in ovo vaccination with a non-replicating human adenovirus vector encoding an h5n9 avian influenza virus hemagglutinin. vaccinated chickens were protected against both h5n1 (89% hemagglutinin homology; 68% protection) and h5n2 (94% hemagglutinin homology; 100% protection) highly pathogenic avian influenza virus challenges. this vaccine can be mass-administered using available robotic in ovo injectors which ...200717055126
preliminary evaluation of diagnostic tests for avian influenza using the markov chain monte carlo (mcmc) method in an emergency june 2005, an outbreak of avian influenza (ai) caused by a low pathogenic h5n2 virus was identified in japan. a serological surveillance was conducted because the infected chickens did not show any clinical signs. the markov chain monte carlo method was used to evaluate the performances of serological hi and agp tests because there was not enough time when the surveillance was initiated to conduct a test evaluation. the sensitivity of the agp test (0.67) was lower than that of the hi test (0. ...200717611370
protection against mouse and avian influenza a strains via vaccination with a combination of conserved proteins np, m1 and ns1.experimental data accumulated over more than a decade indicate that cross-strain protection against influenza may be achieved by immunization with conserved influenza proteins. at the same time, the efficacy of immunization schemes designed along these lines and involving internal influenza proteins, mostly np and m1, has not been sufficient.200718784792
level of protection of chickens against highly pathogenic h5 avian influenza virus with newcastle disease virus based live attenuated vector vaccine depends on homology of h5 sequence between vaccine and challenge virus.vaccination of poultry against avian influenza is of high priority, in particular after the dramatic spread of subtype h5n1 in asia, africa and europe. newcastle disease virus (ndv) has been developed as a vector for the expression of the main immunogen of avian influenza virus, hemagglutinin (ha). an ndv vector based vaccine has several advantages. it allows easy serological differentiation between infected and vaccinated animals by the detection of antibodies against non-ha influenza proteins. ...200818395947
highly pathogenic avian influenza viruses with low virulence for chickens in in vivo tests.four avian influenza viruses have been recognized that have genetic coding for highly pathogenic avian influenza viruses, but do not show virulence for chickens. the two different mechanisms that prevent this potential being expressed have been determined for a/chicken/pennsylvania/1/83 (h5n2) and a/goose/guandong/2/96 (h5n1), but neither of these applies to a/turkey/england/87-92bfc/91 (h5n1) or a/chicken/texas/298313/04 (h5n2).200717899457
experimental assessment of the pathogenicity of two avian influenza a h5 viruses in ostrich chicks (struthio camelus) and chickens.virus excretion, immune response, and, for chickens, deaths were recorded in 3-week-old ostriches and chickens inoculated by either the intramuscular or intranasal route with one of two influenza a viruses of subtype h5. one of the viruses, a/turkey/england/50-92/91 (h5n1) (50/92), was highly pathogenic for chickens causing 5/5 deaths by each route of inoculation. the other virus, a/ostrich/denmark-q/72420/96 (h5n2) (72420/96), isolated from ostriches in quarantine in denmark during 1996, was of ...199818484019
h5n1 avian influenza virus induces apoptotic cell death in mammalian airway epithelial recent years, the highly pathogenic avian influenza virus h5n1 has raised serious worldwide concern about an influenza pandemic; however, the biology of h5n1 pathogenesis is largely unknown. to elucidate the mechanism of h5n1 pathogenesis, we prepared primary airway epithelial cells from alveolar tissues from 1-year-old pigs and measured the growth kinetics of three avian h5 influenza viruses (a/crow/kyoto/53/2004 [h5n1], a/duck/hong kong/342/78 [h5n2], and a/duck/hong kong/820/80 [h5n3]), th ...200818787012
human h5n2 avian influenza infection in japan and the factors associated with high h5n2-neutralizing antibody titer.h5n2 avian influenza virus infection of humans has not been reported thus far. the first h5n2 avian influenza infection of poultry in japan occurred in ibaraki.200818603824
a recombinant vesicular stomatitis virus replicon vaccine protects chickens from highly pathogenic avian influenza virus (h7n1).highly pathogenic avian influenza viruses (hpaiv) of subtypes h5 and h7 cause fatal disease in poultry (fowl plague) but also have zoonotic potential. currently commercially available vaccines often do not provide sufficient protection and do not allow easy discrimination between vaccinated and infected birds. therefore, vaccination of domestic poultry against h5 and h7 hpaiv is not allowed in many countries, or is only possible after special permission has been provided. we generated a recombin ...200919135116
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