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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
characterization of adaptation of an avian influenza a (h5n2) virus to a mammalian host.we have used the mouse model to monitor the acquisition of virulence of a non-pathogenic influenza a virus upon adaptation to a new mammalian host. an avian strain, a/mallard duck/pennsylvania/10218/84 (h5n2) (mld/pa/84) was adapted to mice by 23 serial lung-to-lung passages until a highly virulent mouse-adapted (ma) variant (mld/pa/84-ma) emerged. this ma variant was characterized and compared to the parental strain as well as some of its intermediate passage variants. ma variant caused broncho ...200010989685
prevention and treatment of bronchopneumonia in mice caused by mouse-adapted variant of avian h5n2 influenza a virus using monoclonal antibody against conserved epitope in the ha stem region.the effects of monoclonal antibody (mab) c179 recognizing a conformational epitope in the middle of the hemagglutinine (ha) stem region were examined in a mouse model in the experiments of prevention and treatment of lethal bronchopneumonia caused by influenza a virus of h5 subtype. to model the lethal infection, avian nonpathogenic strain a/mallard duck/pennsylvania/10218/84 (h5n2) was adapted to mice. this resulted in highly pathogenic pneumovirulent mouse-adapted (ma) variant, which was chara ...200011003481
avian paramyxoviruses and influenza viruses isolated from mallard ducks (anas platyrhynchos) in new zealand.a comprehensive study using virological and serological approaches was carried out to determine the status of live healthy mallard ducks (anas platyrhynchos) in new zealand for infections with avian paramyxoviruses (apmv) and influenza viruses (aiv). thirty-three viruses isolated from 321 tracheal and cloacal swabs were characterized as: 6 aiv (two h5n2 and four h4n6), 10 apmv-1 and 17 apmv-4. of 335 sera samples tested for aiv antibodies, 109 (32.5%) sera were positive by nucleoprotein-blocking ...200212111409
update on molecular epidemiology of h1, h5, and h7 influenza virus infections in poultry in north america.avian influenza is endemic in wild birds in north america, and the virus routinely has been transmitted from this reservoir to poultry. influenza, once introduced into poultry, can become endemic within the poultry population. it may be successfully eradicated by human intervention, or the virus may fail to successfully spread on its own. in the last 5 yr, influenza virus has been isolated from poultry in the united states on numerous occasions, and, with the use of molecular epidemiology, the r ...200314575082
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
influenza virus circulation in wild aquatic birds in italy during h5n2 and h7n1 poultry epidemic periods (1998 to 2000).two epidemics of avian influenza due to h5 and h7 highly pathogenic viruses occurred in poultry in italy in 1997/98 and 1999/2000, respectively. the circulation of these serotypes in wild aquatic birds was investigated examining 638 cloacal swabs and 621 sera collected from 150 gulls, 162 coots, and 326 ducks trapped in italian wetlands from 1998 to 2000. seroprevalences against influenza a viruses, detected by a double-antibody sandwich-blocking enzyme-linked immunosorbent assay (elisa), were 1 ...200516537162
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
avian influenza virus screening in wild waterfowl in norway, 2005.the prevalence of influenza a virus infection, and the distribution of different subtypes of the virus, were studied in 604 geese and ducks shot during ordinary hunting 2005. the study was based upon molecular screening of cloacal swabs taken by the hunters. the sampling included the following species: greylag (anser anser), mallard (anas platyrhynchos), wigeon (anas penelope), teal (anas crecca), goosander (mergus merganser), tufted duck (aythya fuligula), common scoter (melanitta nigra), golde ...200717494599
relationship between h5n2 avian influenza viruses isolated from wild and domestic ducks in british columbia, canada.in the summer of 2005 a canadian national surveillance program for influenza a viruses in wild aquatic birds was initiated. the program involved collaboration between federal and provincial levels of government and was coordinated by the canadian cooperative wildlife health centre. the surveillance plan targeted young-of-the-year mallards along with other duck species at six sampling locations along the major migratory flyways across canada. beginning in early august, cloacal swabs were taken fr ...200717494600
detection of a north american lineage h5 avian influenza virus in a south african wild duck.an h5-coinfection of a sample from wild ducks from which an h3n8 virus was isolated in 2004 was detected by reverse transcription polymerase chain reaction (rt-pcr). sequence analysis of the partial h5 gene revealed that the strain was of low pathogenicity according to the amino acid sequence pqrtglf at the ho cleavage site. phylogenetic analysis demonstrated that the partial h5 gene sequence fell within the american h5 lineage and shared 99.6% nucleotide sequence identity with the a/mallard duc ...200717883204
evidence of infection by h5n2 highly pathogenic avian influenza viruses in healthy wild waterfowl.the potential existence of a wild bird reservoir for highly pathogenic avian influenza (hpai) has been recently questioned by the spread and the persisting circulation of h5n1 hpai viruses, responsible for concurrent outbreaks in migratory and domestic birds over asia, europe, and africa. during a large-scale surveillance programme over eastern europe, the middle east, and africa, we detected avian influenza viruses of h5n2 subtype with a highly pathogenic (hp) viral genotype in healthy birds of ...200818704172
transmission of highly pathogenic avian influenza h5n1 virus in pekin ducks is significantly reduced by a genetically distant h5n2 vaccine.domestic ducks play an important role in the epidemiology of h5n1 avian influenza. although it is known that vaccines that have a high homology with the challenge virus are able to prevent infection in ducks, little is yet known about the ability of genetically more distant vaccines in preventing infection, disease, and transmission. here we study the effect of a widely used h5n2 vaccine (a/chicken/mexico/232/94/cpa) on the transmission of h5n1 virus (a/chicken/china/1204/04) in ducks. the quant ...200818848343
[distribution of avian influenza virus subtypes among domestic ducks in eastern china].to identify the distribution of avian influenza virus subtypes among domestic ducks in eastern china.200819160806
avian influenza: the canadian experience.reports of sporadic avian influenza outbreaks involving domestic poultry date back to the 1960s. with the exception of a/turkey/ontario/7732/1966 (h5n9), which was isolated from a turkey breeding establishment, all viruses characterised prior to 2004 fit the criteria of low pathogenic avian influenza (lpai). only in retrospect was a/turkey/ontario/7732/1966 shown to meet the criteria of a highly pathogenic avian influenza (hpai). in 2004, canada reported its first case of hpai to the world organ ...200919618638
an evaluation of avian influenza diagnostic methods with domestic duck specimens.monitoring of poultry, including domestic ducks, for avian influenza (ai) virus has increased considerably in recent years. however, the current methods validated for the diagnosis and detection of ai virus infection in chickens and turkeys have not been evaluated for performance with samples collected from domestic ducks. in order to ensure that methods for the detection of ai virus or ai virus antibody will perform acceptably well with these specimens, samples collected from domestic ducks exp ...200919630236
influenza virus in a natural host, the mallard: experimental infection data.wild waterfowl, particularly dabbling ducks such as mallards (anas platyrhynchos), are considered the main reservoir of low-pathogenic avian influenza viruses (lpaivs). they carry viruses that may evolve and become highly pathogenic for poultry or zoonotic. understanding the ecology of lpaivs in these natural hosts is therefore essential. we assessed the clinical response, viral shedding and antibody production of juvenile mallards after intra-esophageal inoculation of two lpaiv subtypes previou ...201020126617
characterization of h5n2 influenza viruses isolated in south korea and their influence on the emergence of a novel h9n2 influenza virus.we characterized low pathogenic avian influenza (lpai) h5n2 and h9n2 viruses isolated in south korea from 2008 to 2009. genetic analysis of the h5n2 viruses isolated from wild birds and domestic ducks demonstrated that they were related to the recently isolated southern chinese lpai h5 viruses and various influenza viruses circulating in eurasia. three h9n2 viruses obtained at live bird markets and duck farms were reassortant viruses generated from the h5n2 viruses of domestic ducks and the h9n2 ...201020392898
phylogenetic analysis of influenza a viruses (h6n8, h1n8, h4n2, h9n2, h10n7) isolated from wild birds, ducks, and ostriches in south africa from 2007 to 2009.influenza a strains emerging from wild birds are a constant threat to south africa's valuable ostrich industry. in 2004 and again in 2006, low pathogenicity avian influenza h5n2 strains introduced from a wild bird reservoir mutated in ostriches to high pathogenicity avian influenza (hpai), with serious economic consequences and export bans imposed by the european union. although no outbreaks of notifiable avian influenza have occurred in south africa since 2006, the h9n2 virus caused a localized ...201020521652
low pathogenicity avian influenza subtypes isolated from wild birds in the united states, 2006-2008.due to concerns that high pathogenicity avian influenza would enter into the united states, an interagency strategic plan was developed to conduct surveillance in wild birds in order to address one of the possible pathways of entry. the usda and state wildlife agencies participated in this effort by collecting samples from 145,055 wild birds from april 2006 through march 2008 in all 50 states. the majority (59%) of all wild bird samples was collected from dabbling ducks, and 91% of h5 detections ...201020521670
the effect of age on avian influenza viral shedding in mallards (anas platyrhynchos).avian influenza virus (aiv) prevalence in wild aquatic bird populations varies with season, geographic location, host species, and age. it is not clear how age at infection affects the extent of viral shedding. to better understand the influence of age at infection on viral shedding of wild bird-origin low pathogenicity avian influenza (lpai) viruses, mallards (anas platyrhynchos) of increasing age (2 wk, 1 mo, 2 mo, 3 mo, and 4 mo) were experimentally inoculated via choanal cleft with a 10(6) m ...201020521698
surveillance and identification of influenza a viruses in wild aquatic birds in the crimea, ukraine (2006-2008).the ecology of avian influenza (ai) viruses in wild aquatic birds of asia is poorly understood, especially for the h5n1 high pathogenicity ai (hpai) viruses. from march 2006 through november 2008, 20 ai viruses were isolated in the crimea region of ukraine with an overall frequency of virus recovery of 3.3%. all the viruses were isolated from three species of dabbling ducks: mallard (anas platyrhynchos), wigeon (anas penelope), and garganey (anas querquedula), making the frequency of virus recov ...201020945793
transmission of avian influenza a viruses among species in an artificial barnyard.waterfowl and shorebirds harbor and shed all hemagglutinin and neuraminidase subtypes of influenza a viruses and interact in nature with a broad range of other avian and mammalian species to which they might transmit such viruses. estimating the efficiency and importance of such cross-species transmission using epidemiological approaches is difficult. we therefore addressed this question by studying transmission of low pathogenic h5 and h7 viruses from infected ducks to other common animals in a ...201121483843
avian influenza virus wild bird surveillance in the azov and black sea regions of ukraine (2010-2011).the azov and black sea basins are part of the transcontinental wild bird migration routes from northern asia and europe to the mediterranean, africa, and southwest asia. these regions constitute an area of transit, stops during migration, and nesting for many different bird species. from september 2010 to september 2011, a wild bird surveillance study was conducted in these regions to identify avian influenza viruses. biological samples consisting of cloacal and tracheal swabs and fecal samples ...201223402128
effect of different routes of inoculation on infectivity and viral shedding of lpai viruses in mallards.we studied the effect of different routes of inoculation on the infectivity and duration of viral shedding in mallards (anas platyrhynchos) infected with wild bird-origin low pathogenic avian influenza viruses (lpaivs). one-month-old mallards were inoculated with 10(6) median embryo infectious doses of either a/mallard/mn/199106/99 (h3n8) or a/mallard/mn/355779/00 (h5n2) via 1 of 5 different routes: intranasal (in), intratracheal (it), intraocular (io), intracloacal (ic), or intra-ingluvial (ii) ...201223402123
genome sequence of a natural reassortant h5n2 avian influenza virus from domestic mallard ducks in eastern china.here, we report the genomic sequence of a chinese reassortant h5n2 avian influenza virus which possessed the polybasic motif plrekrrk-r/gl at the hemagglutinin cleavage site. phylogenetic analysis showed that all eight genes were of the eurasian lineage, five of which were highly homologous to the endemic clade 2.3.4 h5n1 viruses and their h5n5 reassortant descendants. these data suggested that novel multisubtypic na reassortants bearing the h5n1 backbone could be generated through genetic reass ...201223087121
novel reassortant highly pathogenic h5n2 avian influenza viruses in poultry in china.there has been multiple evidence that domestic poultry may act as a vessel for the generation of novel influenza a viruses. in this study, we have analyzed the evolution and pathogenicity of 4 h5n2 avian influenza viruses isolated from apparently healthy poultry from h5n1 virus endemic areas in china. phylogenetic analysis revealed that two of these viruses, a/duck/eastern china/1111/2011 (dk/ec/1111/11) and a/goose/eastern china/1112/2011 (gs/ec/1112/11) were derived from reassortment events in ...201223049973
migration strategy affects avian influenza dynamics in mallards (anas platyrhynchos).studies of pathogen transmission typically overlook that wildlife hosts can include both migrant and resident populations when attempting to model circulation. through the application of stable isotopes in flight feathers, we estimated the migration strategy of mallards (anas platyrhynchos) occurring on california wintering grounds. our study demonstrates that mallards- a principal host of avian influenza virus (aiv) in nature, contribute differently to virus gene flow depending on migration str ...201222971007
effect of oseltamivir carboxylate consumption on emergence of drug-resistant h5n2 avian influenza virus in mallard ducks.oseltamivir carboxylate (oc) has been detected in environmental waters at various levels during recent influenza seasons in humans, reflecting levels of usage and stability of this drug. in consideration of the role of waterfowl as hosts for influenza viruses that may contribute to human infections, we evaluated the effect of consumption of low doses of oc on development of oseltamivir-resistant influenza virus mutants in mallard ducks (anas platyrhynchos) infected with two different low-pathoge ...201323459475
the impact of viral tropism and housing conditions on the transmission of three h5/h7 low pathogenic avian influenza viruses in chickens.in this study, shedding and transmission of three h5/h7 low pathogenic avian influenza viruses (lpaivs) in poultry was characterized and the impact of floor system on transmission was assessed. transmission experiments were simultaneously conducted with two groups of animals housed on either a grid or a floor covered with litter. transmission was observed for h5n2 a/ch/belgium/150vb/99 lpaiv. this virus was shed almost exclusively via the oropharynx and no impact of floor system was seen. transm ...201323398968
genome sequence of a novel reassortant h3n2 avian influenza virus from domestic mallard ducks in eastern china.the h3 subtype avian influenza virus (aiv) can provide genes for human influenza virus through gene reassortment, which raises great concerns in terms of its potential threat to human health. here, we report the complete genome sequence of a novel h3n2 aiv isolated from domestic ducks in the jiangsu province of eastern china in 2004, which is a natural recombinant virus whose genes are derived from h3n8, h5n1, h5n2, h11n2, h4n6, and h1n1 aivs. this genome will help to understand the epidemiology ...201323580713
complete genomic sequence of a novel reassortant h4n2 avian influenza virus isolated from domestic ducks in jiangsu, china.here, we report the complete genomic sequence of a novel reassortant h4n2 influenza virus isolated from domestic ducks in the jiangsu province of china in 2011. phylogenetic analysis showed that all the viral genes except for hemagglutinin (ha) were highly homologous to the clade 2.3.4 h5n2 viruses. the data suggest that genetic reassortment occurred between h4 and h5n2 avian influenza viruses, which highlights the role of domestic poultry as a reassortment vessel in china.201323516214
h5-based dna constructs derived from selected highly pathogenic h5n1 avian influenza virus induce high levels of humoral antibodies in muscovy ducks against low pathogenic viruses.h5 low pathogenic avian influenza virus (lpaiv) infection in domestic ducks is a major problem in duck producing countries. their silent circulation is an ongoing source of potential highly pathogenic or zoonotic emerging strains. to prevent such events, vaccination of domestic ducks might be attempted but remains challenging. currently licensed vector vaccines derived from h5n1 hpaiv possess clade 0, clade 2.2 or clade 2.3.4 ha sequences: selection of the best ha candidate inducing the largest ...201424762011
circulation of the low pathogenic avian influenza subtype h5n2 virus in ducks at a live bird market in ibadan, nigeria.to monitor carrier hosts of avian influenza in nigeria, we randomly collected cloaca swab specimens from 155 ducks at a live bird market (lbm) in ibadan, southwest nigeria, between july 2011 and july 2012.201425671118
lessons from the largest epidemic of avian influenza viruses in taiwan, 2015.the largest epidemic of avian influenza (ai) in history attacked poultry and wild birds throughout taiwan starting january 6, 2015. this study analyzed surveillance results, epidemiologic characteristics, and viral sequences by using government-released information, with the intention to provide recommendations to minimize future pandemic influenza. the h5 clade 2.3.4.4 highly pathogenic ai viruses (hpaivs) had not been detected in taiwan before 2015. during this epidemic, four types of etiologi ...201627309051
pathogenicity and transmission of h5 and h7 highly pathogenic avian influenza viruses in mallards.wild aquatic birds have been associated with the intercontinental spread of h5 subtype highly pathogenic avian influenza (hpai) viruses of the a/goose/guangdong/1/96 (gs/gd) lineage during 2005, 2010, and 2014, but dispersion by wild waterfowl has not been implicated with spread of other hpai viruses. to better understand why gs/gd h5 hpai viruses infect and transmit more efficiently in waterfowl than other hpai viruses, groups of mallard ducks were challenged with one of 14 different h5 and h7 ...201627558429
infectivity, transmission and pathogenicity of h5 highly pathogenic avian influenza clade 2.3.4.4 (h5n8 and h5n2) united states index viruses in pekin ducks and chinese geese.in late 2014, a h5n8 highly pathogenic avian influenza (hpai) virus, clade 2.3.4.4, spread by migratory waterfowl into north america reassorting with low pathogenicity ai viruses to produce a h5n2 hpai virus. since domestic waterfowl are common backyard poultry frequently in contact with wild waterfowl, the infectivity, transmissibility, and pathogenicity of the united states h5 hpai index viruses (h5n8 and h5n2) was investigated in domestic ducks and geese. ducks infected with the viruses had a ...201728592320
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