Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| molecular characterization of h9n2 influenza viruses: were they the donors of the "internal" genes of h5n1 viruses in hong kong? | the origin of the h5n1 influenza viruses that killed six of eighteen infected humans in 1997 and were highly pathogenic in chickens has not been resolved. these h5n1 viruses transmitted directly to humans from infected poultry. in the poultry markets in hong kong, both h5n1 and h9n2 influenza viruses were cocirculating, raising the possibility of genetic reassortment. here we analyze the antigenic and genetic features of h9n2 influenza viruses with different epidemiological backgrounds. the resu ... | 1999 | 10430948 |
| characterization of the pathogenicity of members of the newly established h9n2 influenza virus lineages in asia. | the reported transmission of avian h9n2 influenza viruses to humans and the isolation of these viruses from hong kong poultry markets lend urgency to studies of their ecology and pathogenicity. we found that h9n2 viruses from north america differ from those of asia. the north american viruses, which infect primarily domestic turkeys, replicated poorly in inoculated chickens. phylogenetic analysis of the hemagglutinin and nucleoprotein genes indicated that the asian h9n2 influenza viruses could b ... | 2000 | 10662623 |
| interspecies transmission of influenza viruses: h5n1 virus and a hong kong sar perspective. | this account takes stock of events and involvements, particularly on the avian side of the influenza h5n1 'bird flu' incident in hong kong sar in 1997. it highlights the role of the chicken in the many live poultry markets as the source of the virus for humans. the slaughter of chicken and other poultry across the sar seemingly averted an influenza pandemic. this perspective from hong kong sar marks the coming-of-age of acceptance of the role of avian hosts as a source of pandemic human influenz ... | 2000 | 10799786 |
| characterization of the influenza a virus gene pool in avian species in southern china: was h6n1 a derivative or a precursor of h5n1? | in 1997, an h5n1 influenza virus outbreak occurred in chickens in hong kong, and the virus was transmitted directly to humans. because there is limited information about the avian influenza virus reservoir in that region, we genetically characterized virus strains isolated in hong kong during the 1997 outbreak. we sequenced the gene segments of a heterogeneous group of viruses of seven different serotypes (h3n8, h4n8, h6n1, h6n9, h11n1, h11n9, and h11n8) isolated from various bird species. the p ... | 2000 | 10864640 |
| continued circulation in china of highly pathogenic avian influenza viruses encoding the hemagglutinin gene associated with the 1997 h5n1 outbreak in poultry and humans. | since the outbreak in humans of an h5n1 avian influenza virus in hong kong in 1997, poultry entering the live-bird markets of hong kong have been closely monitored for infection with avian influenza. in march 1999, this monitoring system detected geese that were serologically positive for h5n1 avian influenza virus, but the birds were marketed before they could be sampled for virus. however, viral isolates were obtained by swabbing the cages that housed the geese. these samples, known collective ... | 2000 | 10864673 |
| avian-to-human transmission of h9n2 subtype influenza a viruses: relationship between h9n2 and h5n1 human isolates. | in 1997, 18 cases of influenza in hong kong (bird flu) caused by a novel h5n1 (chicken) virus resulted in the deaths of six individuals and once again raised the specter of a potentially devastating influenza pandemic. slaughter of the poultry in the live bird markets removed the source of infection and no further human cases of h5n1 infection have occurred. in march 1999, however, a new pandemic threat appeared when influenza a h9n2 viruses infected two children in hong kong. these two virus is ... | 2000 | 10920197 |
| h9n2 influenza viruses possessing h5n1-like internal genomes continue to circulate in poultry in southeastern china. | the transmission of h9n2 influenza viruses to humans and the realization that the a/hong kong/156/97-like (h5n1) (abbreviated hk/156/97) genome complex may be present in h9n2 viruses in southeastern china necessitated a study of the distribution and characterization of h9n2 viruses in poultry in the hong kong sar in 1999. serological studies indicated that h9n2 influenza viruses had infected a high proportion of chickens and other land-based birds (pigeon, pheasant, quail, guinea fowl, and chukk ... | 2000 | 11000205 |
| sequence analysis of the hemagglutinin gene of h9n2 korean avian influenza viruses and assessment of the pathogenic potential of isolate ms96. | sequence analysis of the hemagglutinin (ha) gene of five korean h9n2 avian influenza virus (aiv) isolates showed that these viruses were closely related and possibly came from the same source. phylogenetic analysis of the ha1 subunit of h9 subtype isolates revealed that korean aiv isolates were different from isolates from the poultry markets in hong kong in 1997. none of the korean aivs had multiple basic amino acids at the ha cleavage site that confer high pathogenicity to some h5 and h7 aivs. ... | 2000 | 11006999 |
| h9n2 subtype influenza a viruses in poultry in pakistan are closely related to the h9n2 viruses responsible for human infection in hong kong. | following the outbreak of h5n1 "bird flu" in hong kong in 1997, the isolation of h9n2 subtype viruses from patients in southern china and hong kong sar once again raised the spectre of a possible influenza pandemic. h9n2 viruses have recently been responsible for disease in poultry in various parts of the world and preliminary studies of the h9 haemagglutinin (ha) genes of viruses isolated during 1998 and 1999 in germany, iran, pakistan, and saudi arabia showed a close relationship to the ha gen ... | 2000 | 11112478 |
| pandemic threat posed by avian influenza a viruses. | influenza pandemics, defined as global outbreaks of the disease due to viruses with new antigenic subtypes, have exacted high death tolls from human populations. the last two pandemics were caused by hybrid viruses, or reassortants, that harbored a combination of avian and human viral genes. avian influenza viruses are therefore key contributors to the emergence of human influenza pandemics. in 1997, an h5n1 influenza virus was directly transmitted from birds in live poultry markets in hong kong ... | 2001 | 11148006 |
| cross-reactive, cell-mediated immunity and protection of chickens from lethal h5n1 influenza virus infection in hong kong poultry markets. | in 1997, avian h5n1 influenza virus transmitted from chickens to humans resulted in 18 confirmed infections. despite harboring lethal h5n1 influenza viruses, most chickens in the hong kong poultry markets showed no disease signs. at this time, h9n2 influenza viruses were cocirculating in the markets. we investigated the role of h9n2 influenza viruses in protecting chickens from lethal h5n1 influenza virus infections. sera from chickens infected with an h9n2 influenza virus did not cross-react wi ... | 2001 | 11222674 |
| efficacy of zanamivir against avian influenza a viruses that possess genes encoding h5n1 internal proteins and are pathogenic in mammals. | in 1997, an avian h5n1 influenza virus, a/hong kong/156/97 (a/hk/156/97), caused six deaths in hong kong, and in 1999, an avian h9n2 influenza virus infected two children in hong kong. these viruses and a third avian virus [a/teal/hk/w312/97 (h6n1)] have six highly related genes encoding internal proteins. additionally, a/chicken/hk/g9/97 (h9n2) virus has pb1 and pb2 genes that are highly related to those of a/hk/156/97 (h5n1), a/teal/hk/w312/97 (h6n1), and a/quail/hk/g1/97 (h9n2) viruses. becau ... | 2001 | 11257037 |
| h9n2 influenza a viruses from poultry in asia have human virus-like receptor specificity. | h9n2 influenza a viruses are currently widespread in chickens, quail, and other poultry in asia and have caused a few cases of influenza in humans. in this study, we found that h9n2 viruses from hong kong live bird markets have receptor specificity similar to that of human h3n2 viruses. in addition, the neuraminidase of poultry h9n2 viruses has mutations in its hemadsorbing site, a characteristic resembling that of human h2n2 and h3n2 viruses but differing from that of other avian viruses. pecul ... | 2001 | 11277689 |
| [a strain of influenza a h9n2 virus repeatedly isolated from human population in china]. | to understand the subtype of surface proteins (hemagglutinin and neuraminidase) and antigenic character of the isolate of influenza virus, as well as to know its origin. | 2000 | 11498680 |
| cocirculation of avian h9n2 and contemporary "human" h3n2 influenza a viruses in pigs in southeastern china: potential for genetic reassortment? | pigs are permissive to both human and avian influenza viruses and have been proposed to be an intermediate host for the genesis of pandemic influenza viruses through reassortment or adaptation of avian viruses. prospective virological surveillance carried out between march 1998 and june 2000 in hong kong, special administrative region, people's republic of china, on pigs imported from southeastern china, provides the first evidence of interspecies transmission of avian h9n2 viruses to pigs and d ... | 2001 | 11559800 |
| characterization of h5n1 influenza viruses that continue to circulate in geese in southeastern china. | the h5n1 influenza virus, which killed humans and poultry in 1997, was a reassortant that possibly arose in one type of domestic poultry present in the live-poultry markets of hong kong. given that all the precursors of h5n1/97 are still circulating in poultry in southern china, the reassortment event that generated h5n1 could be repeated. because a/goose/guangdong/1/96-like (h5n1; go/gd) viruses are the proposed donors of the hemagglutinin gene of the h5n1 virus, we investigated the continued c ... | 2002 | 11739677 |
| characterization of hemagglutinin gene of influenza a virus subtype h9n2. | to determine the origin of human influenza a (h9n2) virus and the relationship among h9n2 strains isolated from different hosts, on the basis of molecular biology. | 2001 | 11779442 |
| h3n2 influenza viruses from domestic chickens in italy: an increasing role for chickens in the ecology of influenza? | in italy, multiple h3n2 influenza viruses were isolated from chickens with mild respiratory disease and were shown to replicate in the respiratory tracts of experimentally infected chickens; this finding is the first to show that h3n2 influenza viruses can replicate and cause disease in chickens. h3n2 influenza viruses in pigs on nearby farms seemed a likely source of the virus; however, antigenic and molecular analyses revealed that the gene segments of the viruses in chickens were mainly of eu ... | 2002 | 11807234 |
| protective cross-reactive cellular immunity to lethal a/goose/guangdong/1/96-like h5n1 influenza virus is correlated with the proportion of pulmonary cd8(+) t cells expressing gamma interferon. | a/goose/guangdong/1/96-like h5n1 influenza viruses now circulating in southeastern china differ genetically from the h5n1 viruses transmitted to humans in 1997 but were their precursors. here we show that the currently circulating h9n2 influenza viruses provide chickens with cross-reactive protective immunity against the currently circulating h5n1 influenza viruses and that this protective immunity is closely related to the percentage of pulmonary cd8(+) t cells expressing gamma interferon (ifn- ... | 2002 | 11967305 |
| analysis of the 1991-2000 influenza epidemic in guangdong province, china. | influenza surveillance networks in guangdong were established to investigate the epidemiological characteristics of influenza and influenza epidemics. influenza activity peaked annually from march to july in guangdong in 1991-2000; influenza h3n2 predominated in the epidemic (7 years of 10); the outbreak of influenza in 1996 was the remarkable result of antigenic drift of h3n2 strain. ten isolates of h9n2 strains were discovered from human subjects in 1998 and 1999: chicken strains isolated afte ... | 2001 | 12041555 |
| [differences in receptor specificity between the influenza a viruses isolated from the duck, chicken, and human]. | the affinity of the duck, chicken, and human influenza viruses to the host cell sialosides was determined, and considerable distinctions between duck and chicken viruses were found. duck viruses bind to a wide range of sialosides, including the short-stem gangliosides. most of the chicken viruses, like human ones, lose the ability to bind these gangliosides, which strictly correlates with the appearance of carbohydrate at position 158-160. the affinity of the chicken viruses to sialoglycoconjuga ... | 2002 | 12068641 |
| influenza activity in china: 1998-1999. | during 1989-1999, influenza a h3n2 and h1n1 subtypes and b type viruses were still co-circulating in human population in china, while influenza a (h3n2) virus was predominant strain. the two antigenically and genetically distinguishable strains of influenza b virus were also still co-circulating in men in southern china. the antigenic analysis indicated that most of the h3n2 viruses were a/panama/2007/99 (h3n2)-like strain, the most of the h1n1 viruses were antigenically similar to a/beijing/262 ... | 2002 | 12110253 |
| differences between influenza virus receptors on target cells of duck and chicken. | h5, h7, and h9 subtype influenza viruses in land-based poultry often differ from viruses of wild aquatic birds by deletions in the stalk of the neuraminidase, by the presence of additional carbohydrates on the hemagglutinin, and by occasional changes in the receptor specificity. to test whether these differences could reflect distinctions between the virus receptors in different avian species, we compared the binding of duck, chicken and human influenza viruses to cell membranes and gangliosides ... | 2002 | 12111429 |
| eight-plasmid system for rapid generation of influenza virus vaccines. | the antigenic variation of influenza a virus hemagglutinin (ha) and neuraminidase (na) glycoproteins requires frequent changes in vaccine formulation. the classical method of creating influenza virus seed strains for vaccine production is to generate 6 + 2 reassortants that contain six genes from a high-yield virus, such as a/pr/8/34 (h1n1) and the ha and na genes of the circulating strains. the techniques currently used are time-consuming because of the selection process required to isolate the ... | 2002 | 12163268 |
| natural cases and an experimental study of h9n2 avian influenza in commercial broiler chickens of iran. | since 1998, an epidemic of avian influenza has occurred in the iranian poultry industry. the agent was pathotyped as non-highly pathogenic and subtyped as an h9n2 avian influenza virus. therefore it did not require eradication. however, frequent incidences of high mortality were observed commonly on broiler farms. no other species of bird were affected. the circulation of the virus and mixed infection with other respiratory pathogens, particularly infectious bronchitis virus and mycoplasma galli ... | 2002 | 12396348 |
| [comparison of sequences of the hemagglutinin gene and phylogenetical analysis of h9 subtype avian influenza viruses isolated from some regions in china]. | in order to explore the genetic mutaions of the hemagglutinin(ha) gene and the law of molecular epidemiology of h9 subtype avian influenza viruses in china, 23 h9 subtype avian influenza viruses(aivs) were isolated from 12 provinces of china in recent years. their nucleotide sequences of cdna of ha gene were determined by rt-pcr and sequencing. their nucleotide and putaive amino acid sequences homology was compared. the results showed that their nucleotide sequence homology was from 94.1% to 100 ... | 2002 | 12557368 |
| [recombinant fowlpox virus expressing ha from subtype h9n2 of avian influenza virus and its protective immunity against homologous challenge in chickens]. | the hemagglutinin (ha) gene from the aiv, a/chicken/china/f/1998(h9n2), was amplified with the rt-pcr technique and directionally inserted into transferring vector 1175, resulted in recombinant transferring vector 1175ha. in order to generate recombinant fowlpox virus expressing ha(rfpv-ha), the recombinant transferring vector 1175ha was used to transfect the chicken embryo fibroblasts(cef) pre-infected with wide type fowlpox virus. then, by selection of blue plaques on the cef overlaid with aga ... | 2002 | 12557550 |
| [discovery of men infected by avian influenza a (h9n2) virus]. | to understand whether the avian influenza a(h9n2) virus can infect men or not. | 1999 | 12569771 |
| the influenza virus gene pool in a poultry market in south central china. | we surveyed influenza activity in a live poultry market in central china for 16 months, isolating viruses from 1% of 6360 fecal samples. we obtained multiple h3n6, h9n2, h2n9, h3n3, and h4n6 isolates and single h1n1 and h3n2 isolates. two distinct h3 molecules were identified; other hemagglutinin subtypes were phylogenetically homogeneous. the h3n6 viruses (9 genotypes) and h9n2 viruses (4 genotypes) were genetically heterogeneous, whereas the h2n9, h3n3 and h4n6 viruses had single genotypes. th ... | 2003 | 12573572 |
| [virological and serological surveys for h9n2 subtype of influenza a virus in chickens and men in shenzhen city]. | to understand the distribution of influenza a h9n2 virus in chickens and men in shenzhen area. | 2002 | 12665894 |
| the next influenza pandemic: lessons from hong kong. | pandemic influenza is a zoonosis. studies on influenza ecology conducted in hong kong since the 1970s in which hong kong essentially functioned as an influenza sentinel post indicated that it might be possible, for the first time, to have influenza preparedness at the baseline avian level. this appreciation of influenza ecology facilitated recognition of the h5n1 'bird flu' incident in hong kong in 1997 in what was considered to be an incipient pandemic situation, the chicken being the source of ... | 2003 | 12675938 |
| generation and evaluation of a high-growth reassortant h9n2 influenza a virus as a pandemic vaccine candidate. | h9n2 subtype avian influenza viruses (aivs) are widely distributed in avian species and were isolated from humans in hong kong and guangdong province, china in 1999 raising concern of their potential for pandemic spread. we generated a high-growth reassortant virus (g9/pr8) that contains the hemagglutinin (ha) and neuraminidase (na) genes from the h9n2 avian influenza virus a/chicken/hong kong/g9/97 (g9) and six internal genes from a/puerto rico/8/34 (pr8) by genetic reassortment, for evaluation ... | 2003 | 12706686 |
| phylogenetic analysis of the hemagglutinin genes of twenty-six avian influenza viruses of subtype h9n2 isolated from chickens in china during 1996-2001. | the complete coding region of hemagglutinin genes from 26 influenza a viruses of h9n2 subtype isolated from chicken flocks in china during 1996-2001 was amplified and sequenced. sequence analysis and phylogenetic studies of h9n2 subtype viruses on the basis of data of 26 viruses in this study and 71 selected strains available in the genbank were conducted. the results revealed that all the mainland china isolates showed high homology (94.19%-100%) and were assigned to a special sublineage in the ... | 2003 | 12713166 |
| seroprevalence of avian influenza virus and its relationship with increased mortality and decreased egg production. | to evaluate the occurrence of avian influenza viruses (aiv) infections in southern pakistan, an enzyme-linked immunosorbent assay was initially used to screen sera from broiler, layer and broiler breeder flocks for the presence of antibodies to type a influenza viruses. data from this survey showed high levels of aiv antibodies, indicating unrecognized aiv infection occurring in these flocks. based on this information a second investigation was undertaken in selected broiler-breeder, broiler and ... | 2003 | 12850918 |
| phylogenetic analysis of neuraminidase gene of h9n2 influenza viruses prevalent in chickens in china during 1995-2002. | the neuraminidase (na) genes of 12 h9n2 influenza virus strains isolated from diseased chickens in different farms in mainland china during 1995-2002 were amplified and sequenced. amino acids at hemadsorbing (hb) site of these isolates are different from those of a/quail/hong kong/g1/97-like viruses and a/chicken/korea/96-like viruses. neuraminidases of the 12 strains had a deletion of 3 amino acid residues at positions 63-65 as compared to that of a/turkey/wisconsin/189/66, while those of korea ... | 2003 | 14501198 |
| generation and characterization of a cold-adapted influenza a h9n2 reassortant as a live pandemic influenza virus vaccine candidate. | h9n2 subtype influenza a viruses have been identified in avian species worldwide and were isolated from humans in 1999, raising concerns about their pandemic potential and prompting the development of candidate vaccines to protect humans against this subtype of influenza a virus. reassortant h1n1 and h3n2 human influenza a viruses with the internal genes of the influenza a/ann arbor/6/60 (h2n2) (aa) cold-adapted (ca) virus have proven to be attenuated and safe as live virus vaccines in humans. u ... | 2003 | 14505926 |
| h9n2 influenza viruses prevalent in poultry in china are phylogenetically distinct from a/quail/hong kong/g1/97 presumed to be the donor of the internal protein genes of the h5n1 hong kong/97 virus. | ten h9n2 influenza virus strains isolated from diseased chickens in different farms in china during 1995 to 1999 were antigenically and genetically characterized. the haemagglutinins of the isolates were not related to those of a/quail/hong kong/g1/97 (h9n2) (qa/hk/g1/97), but were closely related to that of a/chicken/hong kong/g9/97 (h9n2) (ck/hk/g9/97). the neuraminidase of these isolates had a deletion of three amino acid residues at positions 63 to 65 as compared with those of ck/hk/g9/97, w ... | 2003 | 14522712 |
| evaluation of pathogenic potential of avian influenza virus serotype h9n2 in chickens. | recently seven isolates of avian influenza virus (aiv) serotype h9n2 recovered from an outbreak of ai were analyzed on the basis of their biological and molecular characteristics. all the isolates belonged to the low-pathogenicity group of aiv. to further evaluate their pathogenic potential in association with other organisms, an isolate was inoculated experimentally in chickens using different routes and subsequently challenged with infectious bronchitis virus, ornithobacterium rhinotracheale o ... | 2003 | 14575070 |
| avian influenza (h9n2) outbreak in iran. | an epidemic of avian influenza (ai) (h9n2) occurred in broiler chicken farms in iran during 1998-01. mortality between 20% and 60% was commonly observed on the affected farms. mixed infections of the influenza virus with other respiratory pathogens, particularly infectious bronchitis virus and mycoplasma gallisepticum, were thought to be responsible for such high mortality, which resulted in great economic losses. clinical signs included swelling of the periorbital tissues and sinuses, typical r ... | 2003 | 14575072 |
| the quest of influenza a viruses for new hosts. | there is increasing evidence that stable lineages of influenza viruses are being established in chickens. h9n2 viruses are established in chickens in eurasia, and there are increasing reports of h3n2, h6n1, and h6n2 influenza viruses in chickens both in asia and north america. surveillance in a live poultry market in nanchang, south central china, reveals that influenza viruses were isolated form 1% of fecal samples taken from healthy poultry over the course of 16 months. the highest isolation r ... | 2003 | 14575076 |
| safety evaluation in chickens of candidate human vaccines against potential pandemic strains of influenza. | two candidate formalin-inactivated vaccines, made from high-growth reassortant viruses with the ha and na genes from avian viruses in a background of genes derived from a/puerto rico/8/34 (pr8), were prepared against h5n1 and h9n2 subtypes (designated as h5n1/pr8 and h9n2/pr8, respectively). these viruses bear the genotypes, antigenicity, and attenuation in mouse models that are desirable in candidate vaccines. the pathogenicity of the newly generated avian-human reassortant vaccine viruses was ... | 2003 | 14575088 |
| the impact of a monthly rest day on avian influenza virus isolation rates in retail live poultry markets in hong kong. | retail live poultry markets (lpms) may act as a reservoir of avian influenza viruses (aiv). in this study we test the hypothesis that a rest day in the lpms where the stalls are completely emptied of poultry, cleansed, and restocked will reduce the isolation rates of avian influenza viruses. the isolation rate of h9n2 subtype viruses from chicken was significantly lower after the rest day than prior to it, indicating its impact in reducing transmission. in contrast, newcastle disease virus (ndv) ... | 2003 | 14575106 |
| sequence of ha gene of avian influenza a/chicken/guangdong/ss/1994 (h9n2) virus. | the rna of the hemagglutinin (ha) gene of a/chicken/guangdong/ss/1994 (h9n2) was reverse transcription-polymerase chain reaction amplified, and the cdna was cloned into a plasmid vector. the complete coding sequence of the ha gene was sequenced and included 1683 nucleotides, which encoded for a protein of 560 amino acids. the potential glycosylation sites related to ha protein function were highly conserved. the amino acid sequence of the ha proteolytic cleavage was g-s-s-r/g. this cleavage site ... | 2003 | 14575125 |
| generation and characterization of an h9n2 cold-adapted reassortant as a vaccine candidate. | h9n2 subtype avian influenza viruses have been identified in avian species worldwide, and infections in pigs were confirmed in hong kong in 1998. subsequently, h9n2 viruses were isolated from two children in hong kong in 1999, and five human infections were reported from china, raising the possibility that h9n2 viruses pose a potential pandemic threat for humans. these events prompted us to develop a vaccine candidate to protect humans against this subtype of influenza a viruses. reassortant h1n ... | 2003 | 14575127 |
| differences between influenza virus receptors on target cells of duck and chicken and receptor specificity of the 1997 h5n1 chicken and human influenza viruses from hong kong. | to study whether influenza virus receptors in chickens differ from those in other species, we compared the binding of lectins and influenza viruses with known receptor specificity to cell membranes and gangliosides from epithelial tissues of ducks, chickens, and african green monkeys. we found that chicken cells contained neu5ac alpha(2-6)gal-terminated receptors recognized by sambucus nigra lectin and by human viruses. this finding explains how some recent h9n2 viruses replicate in chickens des ... | 2003 | 14575133 |
| phylogenetic analysis of hemagglutinin and neuraminidase genes of h9n2 viruses isolated from migratory ducks. | genetic analysis indicated that the pandemic influenza strains derived from wild aquatic birds harbor viruses of 15 hemagglutinin (ha) and 9 neuraminidase (na) antigenic subtypes. surveillance studies have shown that h9n2 subtype viruses are worldwide in domestic poultry and could infect mammalian species, including humans. here, we genetically analyzed the ha and na genes of five h9n2 viruses isolated from the migratory ducks in hokkaido, japan, the flyway of migration from siberia during 1997- ... | 2003 | 14618090 |
| attenuation of a human h9n2 influenza virus in mammalian host by reassortment with an avian influenza virus. | in order to develop a surrogate virus strain for production of an inactivated influenza vaccine against a human h9n2 virus, a/hong kong/1073/99 (hk1073: h9n2) was co-infected in embryonated chicken eggs with an apathogenic avian influenza virus, a/duck/czechoslovakia/56 (dk/cz: h4n6), for gene segment reassortment. multiple-gene reassortants obtained were examined for replication in mammalian hosts in vitro and in vivo by infecting mdck cells and by intranasal administration to hamsters, respect ... | 2004 | 15221539 |
| the interferon-alpha genes from three chicken lines and its effects on h9n2 influenza viruses. | the interferon-alpha genes from three chicken lines were cloned by a direct pcr technique, and the effects of recombinant protein expressed in a prokaryotic system on highly pathogenic h9n2 influenza viruses were investigated. the cloned chifn-alpha gene encoded a protein of 193 amino acids with a signal sequence of 31 amino acids and mature peptides of 162 amino acids. comparison of chifn-alpha sequences, detected six amino acids substitutions at positions 50, 58, 65, 81, 181, and 183. homology ... | 2004 | 15248602 |
| continuing evolution of h9n2 influenza viruses in southeastern china. | h9n2 influenza viruses are panzootic in domestic poultry in eurasia and since 1999 have caused transient infections in humans and pigs. to investigate the zoonotic potential of h9n2 viruses, we studied the evolution of the viruses in live-poultry markets in hong kong in 2003. h9n2 was the most prevalent influenza virus subtype in the live-poultry markets between 2001 and 2003. antigenic and phylogenetic analysis of hemagglutinin (ha) showed that all of the 19 isolates found except one belonged t ... | 2004 | 15280470 |
| isolation and identification of swine influenza recombinant a/swine/shandong/1/2003(h9n2) virus. | ten influenza virus isolates were obtained from infected pigs from different places in shandong province showing clinical symptoms from october 2002 to january 2003. all 10 isolates were identified in china's national influenza research center as influenza a virus of h9n2 subtype. the complete genome of one isolate, designated a/swine/shandong/1/2003(h9n2), was sequenced and compared with sequences available in genbank. the results of analyses indicated that the sequence of a/swine/shandong/1/20 ... | 2004 | 15310468 |
| [characterization of ha and na genes of swine influenza a (h9n2) viruses]. | to understand the origin of ha and na genes of swine influenza a (h9n2) viruses isolated from pigs in the mainland of china and on basis of these to reveal the pathogenicity of them in pigs. | 2004 | 15340516 |
| co-infection of staphylococcus aureus or haemophilus paragallinarum exacerbates h9n2 influenza a virus infection in chickens. | h9n2 influenza viruses are frequently isolated from chicken meat and bone marrow imported from china to japan since 2001. these isolates were experimentally inoculated into specific pathogen-free chickens intranasally. viruses were recovered from the meat and bone marrow of birds showing no overt signs. on the other hand, chickens co-infected with h9n2 virus and either staphylococcus aureus or haemophilus paragallinarum showed clinical signs severer than those shown by birds infected only with t ... | 2004 | 15503199 |
| genetic conservation of hemagglutinin gene of h9 influenza virus in chicken population in mainland china. | the hemagglutinin (ha) genes of 12 h9n2 influenza virus strains isolated from chickens in mainland china during the period 1995-2002 were genetically analyzed. all the isolates possessed the same amino acid motif -r-s-s-r/g-l- at the cleavage site of ha. except for the conserved amino acids, as is the case in the other avian influenza viruses, located in the receptor binding site, all of the 12 isolates possessed n at amino acid position 183; a, t, or v at position 190; k at position 137, wherea ... | 2004 | 15550773 |
| [discoveries of avian influenza a(h9n2) virus in chickens and men infected by h9n2 virus in guangzhou area]. | to understand the epidemic status of avian influenza a virus in chickens and men in guangzhou area and to prevent men suffering from avian influenza a (h5n1) virus. | 2004 | 15640850 |
| development of enzyme-linked immunosorbent assay with nucleoprotein as antigen for detection of antibodies to avian influenza virus. | during the avian influenza outbreak of 2003-04 in southeast asia, two avian influenza viruses (aiv), one of h5n1 subtype and the other h9n2 subtype, were isolated and identified from local farms. the nudeoprotein (np) gene of the h5n1 ai isolate was cloned, and the segment encoding amino acid 47-384, which covers its major antigenic domains, was subcloned and expressed in e. coli. subsequently, the np (47-384) expression product was purified and used as the diagnostic antigen to develop a np-bas ... | 2004 | 15666868 |
| avian influenza viruses in korean live poultry markets and their pathogenic potential. | we surveyed live-poultry markets in korea in 2003 and isolated 9 h9n2, 6 h3n2, and 1 h6n1 influenza viruses. antigenic and phylogenetic analyses showed that all 9 h9n2 isolates were of a/chicken/korea/25232-96006/96-like lineage (which caused disease in chickens in korea in 1996) but were different from h9n2 viruses of southeastern china. they had at least 4 genotypes and replicated in chickens but not in mice. the h3n2 and h6n1 viruses were new to korea and were probably reassortants of avian i ... | 2005 | 15680418 |
| 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 = ... | 2005 | 15767421 |
| [is avian influenza a risk for humans?]. | avian influenza is an infectious disease of birds, caused by type a strains of the influenza virus. the disease, which was first identified in italy more than 100 years ago, occurs worldwide. avian influenza viruses are mainly distributed by migratory birds. different mammals like swine, horse and finally humans are susceptible for avian influenza viruses. the high possibility of genomic changes like gene shift and drift is caused by the segmented rna genome. during the avian flu outbreak in eas ... | 2005 | 15812719 |
| [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 ... | 2005 | 15847163 |
| [generation of a/chicken/shanghai/f/98 (h9n2) avian influenza virus from eight plasmids]. | eight-plasmid system was used for the generation of avian influenza virus (aiv) strain a/chicken/shanghai/f/98 (h9n2) which was isolated in china in 1998. in this plasmid-based expression system, viral cdna was inserted beteen the rna polymerase i (pol i) promoter and terminator sequences. the entire pol i transcription unit was flanked by an rna polymerase ii (pol ii) promoter and a poly (a) site. twenty-four hours after the transfection of eight expression plasmid into cos1 cells, the supernat ... | 2005 | 15989229 |
| phylogenetic analysis of eight genes of h9n2 subtype influenza virus: a mainland china strain possessing early isolates' genes that have been circulating. | h9n2 subtype influenza virus has become worldwide and prevalent in china. previous studies illustrated that at least three sublineages had been established in terrestrial poultry of eurasian avian. in this presentation, eight full-length genes of an h9n2 strain, a/chicken/shanghai/f/98 (ck/sh/f/98) were obtained. sequence analysis and phylogenetic studies were conducted by comparing eight genes with those of all the available h9n2 strains from the genbank. the results showed that four genes (ha, ... | 2005 | 16025241 |
| evolution of h9n2 influenza viruses from domestic poultry in mainland china. | h9n2 viruses have circulated in domestic poultry in mainland china since 1994, and an inactivated vaccine has been used in chickens to control the disease since 1998. the present study analyzed 27 h9n2 avian influenza viruses that were isolated from chickens and ducks from 1996 to 2002. infection studies indicated that most of the viruses replicate efficiently but none of them is lethal for spf chickens. however, these viruses exhibit different phenotypes of replication in a mouse model. five vi ... | 2005 | 16026813 |
| [do pigs play a role in human infection with avian influenza a h9n2 viruses]. | to understand whether pigs play a role in human infection with avian influenza a h9n2 viruses. | 2005 | 16027771 |
| genetic analysis of the nonstructural (ns) genes of h9n2 chicken influenza viruses isolated in china during 1998-2002. | h9n2 subtype avian influenza viruses are widespread in domestic poultry. genetic analysis indicated that three lineages of h9n2 viruses have been established in eurasia and only one lineage is present on chicken farms in mainland china. here, ns1 genes of eight h9n2 chicken influenza viruses, isolated in mainland china during 1998-2002, were completely sequenced and phylogenetically analyzed. by comparison, the homology of the ns1 of the a/chicken/neimenggu/zh/02 (ck/nm/zh/02) strain had a high ... | 2005 | 16175338 |
| [phylogenetic analysis of the surface glycoprotein genes of an aquatic bird origin influenza virus isolate a/duck/yangzhou/233/2002 (h6n2)]. | several h6 subtype avian a influenza viruses were isolated from aquatic birds in some live bird markets when we surveyed the ecology of the influenza in east china for more than two years and identified by specific rt-pcr. in this paper, the hemagglutinin (ha) and neuraminidase (na) gene of one representative virus named a/duck/yangzhou/233/ 2002 (h6n2) (dk/yz/233/02) had been sequenced. phylogenetic analysis of the h6 gene sequences available in the influenza sequence database showed that the d ... | 2005 | 16245856 |
| [genetic mutations of heamagglutinin genes of h9n2 subtype influenza a viruses in the field in a five-year period]. | infection in chicken flocks on a farm, where ai outbreak took place in 1998, was monitored in a four-year consecutive period and 22 h9n2 subtype viruses were isolated. the ha gene and antigenicity of 9 strains among isolates were compared with that of isolate of 1998. the results indicated that mutations of ha genes of h9 subtype influenza a viruses were observed during five years. however these mutations of ha genes didn't lead to sufficient antigenic variation to change the cross-protective pa ... | 2003 | 16276889 |
| [genetic characterization of the entire genome of an h9n2 avian influenza virus a/chicken/shanghai/f/98]. | eight full-length genes of an h9n2 subtype avian influenza virus a/chicken/shanghai/f/ 98(h9n2), were amplified by rt-pcr and rapid amplification of cdna ends (race) and sequenced. the results of phylogenetic analysis showed that a/chicken/shanghai/f/98 was entirely different from quail/hong kong/g1/97 which was directly related to human infection with avian influenza virus in hong kong, whereas its ha, na, m and ns genes belonged to a/chicken/beijing/ 1/94-like sublineage with the nucleotide ho ... | 2003 | 16276916 |
| [sequence analysis of ns1 gene of some h9n2 subtype influenza viruses isolated from chickens in china]. | the nonstructural protein (ns1) genes of eight h9n2 subtype influenza virus strains isolated from diseased chickens on different farms during 1996 - 2001 were amplified and sequenced. the nucleotide and deduced amino acid sequences of ns1 genes of these isolates were compared. the results showed that the homologies of nucleotide and amino acid of the isolates were 96.5% - 99.5% and 94.5 - 98.6%, respectively. these indicated that ns1 genes of h9n2 influenza viruses isolated in china were well co ... | 2003 | 16281550 |
| [cloning of full-length genes of h5n1 subtype avian influenza virus strain a/duck/shandong/093/2004 and analysis of the sequences]. | the eight full-length genes, including the 5' and 3' ends of h5n1 subtype avian influenza virus (a/duck/ shandong/093/2004) were amplified by using the universal primers and h5 specific primers. the method used for the amplification of avian influenza virus's full-length sequence was more easily and rapidly than that of rapid amplification of cdna ends assay (race). the amplified segments were cloned into the t vector pcr 2.1, respectively. three to five positive clones of each gene were sequenc ... | 2005 | 16342757 |
| evaluation of the espline influenza a&b-n kit for the diagnosis of avian and swine influenza. | the espline influenza a&b-n kit was evaluated for its applicability to the rapid diagnosis of influenza in chickens and pigs. the kit specifically detected viral antigens in tracheal swabs and tissue homogenates of the trachea, liver, spleen, and colon of chickens inoculated with a highly pathogenic avian influenza virus strain, a/chicken/yamaguchi/7/04 (h5n1), at 48 hr post-inoculation (p.i.) as well as in the tracheal and cloacal swabs and tissue homogenates of dead chickens. for those infecte ... | 2005 | 16365531 |
| detection of antibodies to the nonstructural protein (ns1) of avian influenza viruses allows distinction between vaccinated and infected chickens. | to differentiate avian influenza virus (aiv)-infected chickens vs. chickens immunized with inactivated avian influenza virus, an enzyme-linked immunosorbent assay (elisa) was developed using a recombinant nonstructural protein (ns1) as the diagnostic antigen, which was cloned from an aiv h9n2 subtype strain isolated during the avian influenza outbreak of 2003-04 and expressed in escherichia coli. antibodies to the aiv ns1 protein was only detected in the sera of chickens experimentally infected ... | 2005 | 16404988 |
| ecology and molecular epidemiology of h9n2 avian influenza viruses isolated in israel during 2000-2004 epizootic. | the first two isolates of h9n2 influenza virus were picked up from turkey and chicken hosts in may 2000, but the actual epizootic of the low pathogenicity avian influenza (lpai) h9n2 virus started in december 2001, following a 1.5-year period of silence, during which the h10n7 and h6n3 influenza viruses were isolated sporadically. the outbreak of the h9n2 influenza began in northern israel, from where the epizootic spread all over the country. damage was relatively limited because of the widespr ... | 2006 | 16447512 |
| [molecular mechanism affecting route of transmission for h9n2 subtype aiv]. | the available evidence suggests that h9 subtype avian influenza virus (aiv) did not circulate in chicken flocks in china until the early 1990s. however, the pandemic of h9 subtype ai, which started in summer of 1998, spread very rapidly to more than 20 provinces within several months. obviously, the virus responsible for the 1998 pandemic was quite different from the virus isolated in early 1990s. in order to investigate the molecular mechanism affecting the route of transmission for h9n2 aivs, ... | 2006 | 16579464 |
| protection against avian influenza h9n2 virus challenge by immunization with hemagglutinin- or neuraminidase-expressing dna in balb/c mice. | avian influenza viruses of h9n2 subtype are widely spread in avian species. the viruses have recently been transmitted to mammalian species, including humans, accelerating the efforts to devise protective strategies against them. in this study, an avian influenza h9n2 virus strain (a/chicken/jiangsu/7/2002), isolated in jiangsu province, china, was used to infect balb/c mice for adaptation. after five lung-to-lung passages, the virus was stably proliferated in a large quantity in the murine lung ... | 2006 | 16580631 |
| differential expression of chemokines and their receptors in adult and neonatal macrophages infected with human or avian influenza viruses. | in 1997, avian influenza virus h5n1 was transmitted directly from chicken to human and resulted in a severe disease that had a higher mortality rate in adults than in children. the characteristic mononuclear leukocyte infiltration in the lung and the high inflammatory response in h5n1 infection prompted us to compare the chemokine responses between influenza virus-infected adult and neonatal monocyte-derived macrophages (mdms). the effects of avian influenza virus a/hong kong/483/97 (h5n1) (h5n1 ... | 2006 | 16741883 |
| molecular immunophenotyping of lungs and spleens in naive and vaccinated chickens early after pulmonary avian influenza a (h9n2) virus infection. | in a respiratory-infection-model with the avian influenza a h9n2 virus we studied lung and splenic immune reactions in chickens using a recently developed 5k chicken immuno-microarray. groups of chickens were either mock-immunized (referred to as non-immune), vaccinated with inactivated viral antigen only (immune) or with viral antigen in a water-in-oil (w/o) immunopotentiator (immune potentiated). three weeks after vaccination all animals were given a respiratory infection. immune potentiated b ... | 2006 | 16781024 |
| reverse transcriptase-polymerase chain reaction-enzyme linked immunosorbent assay for rapid detection of avian influenza virus subtype h9n2. | the performance of a simplified nucleoprotein (np) and hemagglutinin-subtype-9 (h9) based reverse transcriptase-polymerase chain reaction-enzyme linked immunosorbent assay (rt-pcr-elisa) for the detection of avian influenza virus (aiv) subtype h9n2 was compared to the standard the virus isolation method and serology testing using hemagglutination (ha) and hemagglutination inhibition (hi) tests. the h9-based rt-pcr-elisa was 100% sensitive when compared to virus isolation method in detecting h9n2 ... | 2006 | 16820981 |
| characterization of h9n2 influenza a viruses isolated from chicken products imported into japan from china. | we characterized eleven h9n2 influenza a viruses isolated from chicken products imported from china. genetically they were classified into six distinct genotypes, including five already known genotypes and one novel genotype. this suggested that such multiple genotypes of the h9n2 virus have possibly already become widespread and endemic in china. two isolates have amino-acid substitutions that confer resistance to amantadine in the m2 region, and this supported the evidence that this mutation m ... | 2007 | 16824249 |
| characterization of chicken interleukin 2 receptor alpha chain, a homolog to mammalian cd25. | to identify chicken il-2r alpha chain (chcd25), the cdna of chcd25 was cloned and mapped onto chicken chromosome 1. the polyclonal and monoclonal antibodies raised from the recombinant chcd25 specifically bound to the cell surface of splenic mononuclear cells (smc) and inhibited chicken il-2-dependent proliferation of t cells. flow cytometry analysis revealed that chcd25 molecules could be expressed on the surface of monocytes/macrophages, thrombocytes, cd4+ and cd8+ cells as well as tissue cell ... | 2006 | 16831435 |
| molecular epizootiology of recurrent low pathogenic avian influenza by h9n2 subtype virus in korea. | the first outbreak of low pathogenic avian influenza (lpai), h9n2 virus subtype, in 1996 prompted an eradication response, but lpai returned to korea in 1999. the relationship between the first and the recurrent viruses is unclear. to determine the molecular epizootiology of recurrent lpai, we performed phylogenetic analysis with partial nucleotide sequences of four gene segments (ha, na, np and pb2) from eight chicken-origin h9n2 viruses. the recurrent h9n2 viruses showed higher nucleotide simi ... | 2006 | 16854644 |
| outbreaks of avian influenza h6n2 viruses in chickens arose by a reassortment of h6n8 and h9n2 ostrich viruses. | the first recorded outbreak of avian influenza (ai) in south african chickens (low pathogenicity h6n2) occurred at camperdown, kwazulu/natal province (kzn) in june 2002. to determine the source of the outbreak, we defined the phylogenetic relationships between various h6n2 isolates, and the previously unpublished gene sequences of an h6n8 virus isolated in 1998 from ostriches in the leeu gamka region (a/ostrich/south africa/kk98/98). we demonstrated that two distinct genetic h6n2 lineages (sub-l ... | 2007 | 16927114 |
| genetic characterization of the h9n2 influenza viruses circulated in the poultry population in israel. | the partial nucleotide sequences of the hemagglutinin (ha) genes of 72 h9n2 influenza viruses isolated from chickens and turkeys in israel during the period 2000-2005 were genetically analyzed. the isolates possessed the three types of amino acid motif -r-s-s-r/g-l-, -r-s-n-r/g-l-, and -r-s-k-r/g-l- at the cleavage site of ha. phylogenetic analyses showed that all israeli isolates belonged to the same group which further divided into three closely related sub-groups. the ha genes of these isolat ... | 2006 | 16954048 |
| safety and immunogenicity of nonadjuvanted and mf59-adjuvanted influenza a/h9n2 vaccine preparations. | influenza a/h9n2 viruses can infect humans and are considered to be a pandemic threat. effective vaccines are needed for these and other avian influenza viruses. | 2006 | 17029131 |
| [generation high yield vaccine strain wholly derived from avian influenza viruses by reverse genetics]. | highly pathogenic avian influenza a (hpai) viruses of the h5n1 subtypes caused enormous economical loss to poultry farms in china and southeastern asian countries. the vaccination program is a reliable strategy in controlling the prevalence of these disastrous diseases. the six internal genes of the high-yield influenza virus a/goose/dalian/3/01 (h9n2), the hemagglutinin (ha) gene of a/goose/hlj/qfy/04 (h5n1) strain, and the neuraminidase gene from a/duck/germany/1215/73 (h2n3) reference strain ... | 2006 | 17037192 |
| [cloning, prokaryotic expression of chicken interferon-alpha gene and study on antiviral effect of recombinant chicken interferon-alpha]. | the full length of chicken interferon alpha (chifn-alpha) gene was amplified by the polymerase chain reaction (pcr) from total liver genome of sanhuang meat-chicken and sequenced. the amplified gene was about 582bp. the coding region for mature protein (489bp) was subcloned into pet-28a(+). the recombinant plasmid pet-28a(+)-ifnalpha was identified by enzyme digestion and dna sequencing. data of sds-page and western-blot indicated that a 22kd fusion protein was expressed in the form of inclusion ... | 2006 | 17037195 |
| development and evaluation of a das-elisa for rapid detection of avian influenza viruses. | rapid detection of avian influenza virus (aiv) infection is critical for control of avian influenza (ai) and for reducing the risk of pandemic human influenza. a double antibody sandwich enzyme-linked immunosorbent assay (das-elisa) was developed for this purpose. the method employed a monoclonal antibody (mab) as the capture antibody and rabbit polyclonal igg labeled with horseradish peroxidase as the detector antibody, and both antibodies were against type-specific influenza a nucleoprotein (n ... | 2006 | 17039829 |
| continuing evolution of h9 influenza viruses in korean poultry. | we analyzed the evolution of h9 influenza viruses isolated from korean chicken farms from 2002 to 2004. korean h9 viruses formed two antigenically distinct groups: those isolated from 1996 to mid-2003, and those isolated from late 2003 through 2004. most of the 2004 isolates showed greater cross-reactivity with the second group than with the first group. phylogenetic analysis of the 12 viruses studied revealed three genotypes of h9n2 viruses and showed that reassortment had occurred. one isolate ... | 2007 | 17056087 |
| an outbreak of avian influenza subtype h9n8 among chickens in south korea. | low pathogenic avian influenza subtype h9n8 was diagnosed on a korean native chicken farm in gyeonggi province, south korea, in late april 2004. clinical signs included moderate respiratory distress, depression, mild diarrhoea, loss of appetite and a slightly elevated mortality (1.4% in 5 days). pathologically, mucopurulent tracheitis and air sacculitis were prominently found with urate renal deposition. the isolated a/chicken/kr/164/04 (h9n8) had an ala-ser-gly-arg (a/s/g/r) motif at the cleava ... | 2006 | 17121732 |
| biological and molecular characterization of avian influenza virus (h9n2) isolates from iran. | three influenza a virus (h9n2) isolates obtained from three separate broiler flocks with variable mortality rates were cloned twice in embryonated spf chicken eggs by limiting dilution. biological properties of these isolates were examined in 4-week-old spf chickens and chick embryo fibroblast (cef) cultures. the isolates neither caused mortality in the inoculated chickens nor produced cpe in cell cultures, indicating low pathogenicity. pcr products of 486 bp containing the sequences for hemaggl ... | 2006 | 17131934 |
| characterization of avian h9n2 influenza viruses from united arab emirates 2000 to 2003. | our aim was to establish the phylogenetic relation of h9n2 avian viruses in the middle east to other asian h9n2 lineages by characterization of 7 viruses isolated from united arab emirates (2000-2003). all these viruses had an additional basic amino acid at the hemagglutinin-connecting peptide; 6 contained a mutation associated with increased affinity toward human-like sialic acid substrates. the viruses' surface glycoproteins and most internal genes were >90% similar to those of a/quail/hong ko ... | 2007 | 17157891 |
| reassortment and modification of hemagglutinin cleavage motif of avian/wsn influenza viruses generated by reverse genetics that correlate with attenuation. | avian influenza associated with h9n2 and h5n1 subtypes of avian influenza viruses (aivs) has raised great concerns in china. to study this problem, reverse genetics has been employed. three reassortants, rgh9n2, rgh5n1 and rgh5n2, were prepared and compared. their hemagglutinin (ha) and neuraminidase (na) genes originated from chinese aiv isolates of h9n2 or h5n1 subtype, while the rest of their genes were derived from a/wsn/33(h1n1) virus (wsn). in the h5 ha reassortants, the multibasic cleavag ... | 2006 | 17177609 |
| development of indirect enzyme-linked immunosorbent assay with nucleoprotein as antigen for detection and quantification of antibodies against avian influenza virus. | avian influenza (ai) is a serious infectious disease caused by avian influenza virus (aiv) belonging to type a orthomyxovirus. in the present study, we developed an indirect enzyme-linked immunosorbent assay (elisa) employing e. coli-expressed full-length nucleoprotein (np) of h9n2 avian influenza virus for the detection and quantification of antibodies against aiv nucleoprotein. the np-elisa was compared with the ai agar gel propagation (agp) test, haemagglutination inhibition (hi) test, and id ... | 2007 | 17225082 |
| 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) ... | 2007 | 17344345 |
| the quail and chicken intestine have sialyl-galactose sugar chains responsible for the binding of influenza a viruses to human type receptors. | the receptor specificity of influenza viruses is one factor that allows avian influenza viruses to cross the species barrier. the recent transmissions of avian h5n1 and h9n2 influenza viruses from chickens and/or quails to humans indicate that avian influenza viruses can directly infect humans without an intermediate host, such as pigs. in this study, we used two strains of influenza a virus (a/pr/8/34, which preferentially binds to an avian-type receptor, and a/memphis/1/71, which preferentiall ... | 2007 | 17389652 |
| a latex agglutination test for the rapid detection of avian influenza virus subtype h5n1 and its clinical application. | a rapid and simple latex agglutination test (lat) for the detection of avian influenza virus (aiv) subtype h5n1 in chicken allantoic fluids, tracheal swabs, and tissues was developed. monoclonal antibodies against the hemagglutinin glycoprotein of h5n1 were covalently coupled onto the surface of carboxylated latex bead using a water-soluble carbodiimide to obtain sensitized latex particles (slp). these slps strongly agglutinated in the presence of allantoic fluid containing h5n1, but not fluids ... | 2007 | 17402609 |
| partial protection against challenge with the highly pathogenic h5n1 influenza virus isolated in japan in chickens infected with the h9n2 influenza virus. | the protective effect of the a/ck/yoko/aq55/01 (h9n2) avian influenza virus against the highly pathogenic h5n1 virus, i.e., a/ck/yama/7/04 (genotype v), was examined. three 5-week-old chickens were inoculated intranasally with the h9n2 virus (10(8.6) eid(50)/head) and were kept with two contact chickens. all of the infected chickens were reinoculated with the same virus at 20 weeks of age, and 10 days later, they were challenged intranasally with the h5n1 virus (10(4.0) eid(50)/head). five chick ... | 2007 | 17426917 |
| 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 ... | 2007 | 17494549 |
| appearance of serum antibodies against the avian influenza nonstructural 1 protein in experimentally infected chickens and turkeys. | in order to support eradication efforts of avian influenza (ai) infections in poultry, the implementation of "differentiation of infected from vaccinated animals" (diva) vaccination strategies has been recommended by international organizations. these systems enable the detection of field exposure in vaccinated flocks, and through this detection, infected flocks may be properly managed, thus interrupting the perpetuation of the infectious cycle. a promising system, based on the detection of anti ... | 2007 | 17494555 |
| phylogenetic analysis of low-pathogenicity avian influenza h6n2 viruses from chicken outbreaks (2001-2005) suggest that they are reassortants of historic ostrich low-pathogenicity avian influenza h9n2 and h6n8 viruses. | low-pathogenicity (lpai) and high-pathogenicity (hpai) avian influenza viruses are periodically isolated from south african ostriches, but during 2002 the first recorded outbreak of lpai (h6n2) in south african chickens occurred on commercial farms in the camperdown area of kwazulu/natal (kzn) province. sequence analysis of all eight genes were performed and phylogenetic analysis was done based on the hemagglutinin and neuraminidasc sequences. results from phylogenetic analyses indicated that th ... | 2007 | 17494567 |
| surveillance for avian influenza in nepal 2004-2005. | highly pathogenic avian influenza has not been reported in nepal to date. surveillance for the presence of avian influenza viruses was conducted in 16 districts of nepal from february 2004 to december 2005. four hundred forty-six serum samples were collected from ducks, chickens, and pigeons and tested for antibodies to all influenza a viruses by competitive enzyme-linked immunosorbent assay (c-elisa). any sera positive by c-elisa were tested for antibodies to h5, h7, and h9 influenza viruses by ... | 2007 | 17494581 |