avian influenza viruses from migratory and resident ducks of coastal louisiana.cloacal and tracheal swabs were collected from 1389 hunter-killed ducks in cameron parish, louisiana, during the 1986 and 1987 waterfowl seasons. twenty-eight avian influenza viruses (aivs) were isolated from 605 blue-winged teal (anas discors), 75 mottled ducks (a. fulvigula), 375 gadwalls (a. stepera) and 334 green-winged teal (a. crecca). prevalence estimates of aiv in ducks sampled during september, november, and december through january were 3.1%, 2.0%, and 0.4%, respectively. differences i ...19902369380
avian influenza viruses and paramyxoviruses in wintering and resident ducks in texas.cloacal swabs were collected from teal (anas crecca, anas cyanoptera, anas discors), mottled duck (anas fulvigula) and northern pintail (anas acuta) in brazoria county, texas, usa, during february 2001, mottled ducks during august 2001, and blue-winged teal (a. discors) during february 2002. prevalence of avian influenza virus (aiv) infections during each sampling period were 11, 0, and 15%, respectively. the hemagglutinin (h) subtypes h2 and h7 were detected in both years, while the h8 subtype ...200516244076
avian influenza a viruses in birds --an ecological, ornithological and virological view.avian influenza a viruses (aiv) are the causative agents of the presently most important poultry disease. ten countries in asia and several other countries in eastern europe suffer high losses from the lethal effects of these viruses of the h5n1 subtype. aiv of other subtypes cause in additional countries severe losses. the threat to health and well-being of the avifauna, domestic poultry and possibly mammals including humans are worldwide of major concern. the european union reacted with a comp ...200516425630
avian influenza surveillance in hunter-harvested waterfowl from the gulf coast of texas (november 2005-january 2006).the objectives of our study were to determine prevalence of avian influenza viruses (aiv) on wintering grounds on the texas gulf coast, usa, and to compare real-time reverse-transcriptase polymerase chain reaction (rrt-pcr) and virus isolation for detection of aiv in cloacal swabs from wild waterfowl. cloacal swabs were collected from hunter-harvested waterfowl from november 2005 to january 2006 at four wildlife management areas. seven aiv were isolated from four species of ducks: green-winged t ...200818436675
influenza a viruses from wild birds in guatemala belong to the north american lineage.the role wild bird species play in the transmission and ecology of avian influenza virus (aiv) is well established; however, there are significant gaps in our understanding of the worldwide distribution of these viruses, specifically about the prevalence and/or significance of aiv in central and south america. as part of an assessment of the ecology of aiv in guatemala, we conducted active surveillance in wild birds on the pacific and atlantic coasts. cloacal and tracheal swab samples taken from ...201222427902
a single dose of an avian h3n8 influenza virus vaccine is highly immunogenic and efficacious against a recently emerged seal influenza virus in mice and ferrets.h3n8 influenza viruses are a commonly found subtype in wild birds, usually causing mild or no disease in infected birds. however, they have crossed the species barrier and have been associated with outbreaks in dogs, pigs, donkeys, and seals and therefore pose a threat to humans. a live attenuated, cold-adapted (ca) h3n8 vaccine virus was generated by reverse genetics using the wild-type (wt) hemagglutinin (ha) and neuraminidase (na) genes from the a/blue-winged teal/texas/sg-00079/2007 (h3n8) ( ...201525903333
the influenza a virus protein ns1 displays structural polymorphism.ns1 of influenza a virus is a potent antagonist of host antiviral interferon responses. this multifunctional protein with two distinctive domains, an rna-binding domain (rbd) and an effector domain (ed) separated by a linker region (lr), is implicated in replication, pathogenesis, and host range. although the structures of individual domains of ns1 from different strains of influenza viruses have been reported, the only structure of full-length ns1 available to date is from an h5n1 strain (a/vie ...201424478439
prevalence and diversity of low pathogenicity avian influenza viruses in wild birds in guatemala, 2010-2013.waterfowl species are known to harbor the greatest diversity of low pathogenicity influenza a virus (lpaiv) subtypes and are recognized as their main natural reservoir. in guatemala there is evidence of circulation of lpaiv in wild ducks; however, the bird species contributing to viral diversity during the winter migration in central america are unknown. in this study, samples obtained from 1250 hunter-killed birds from 22 different species were collected on the pacific coast of guatemala during ...201627309080
genome sequence of a novel h14n7 subtype influenza a virus isolated from a blue-winged teal (anas discors) harvested in texas, usa.we report here the complete genome sequence of a novel h14n7 subtype influenza a virus (iav) isolated from a blue-winged teal (anas discors) harvested in texas, usa. the genomic characteristics of this iav strain with a previously undetected subtype combination suggest recent viral evolution within the new world wild-bird iav reservoir.201627284136
ecological determinants of avian influenza virus, west nile virus, and avian paramyxovirus infection and antibody status in blue-winged teal (anas discors) in the canadian prairies.the canadian prairies are one of the most important breeding and staging areas for migratory waterfowl in north america. hundreds of thousands of waterfowl of numerous species from multiple flyways converge in and disperse from this region annually; therefore this region may be a key area for potential intra- and interspecific spread of infectious pathogens among migratory waterfowl in the americas. using blue-winged teal (anas discors, bwte), which have the most extensive migratory range among ...201626540179
avian influenza virus prevalence in migratory waterfowl in the united states, 2007-2009.we analyzed 155,535 samples collected for surveillance of avian influenza viruses (aivs), in the united states from 2007 to 2009, from migratory waterfowl (ducks, geese, and swans). the goal was to elucidate patterns of prevalence by flyway and functional groups to determine targets for future surveillance. apparent prevalence of aiv was highest in the pacific flyway in 2007-2008 (14.2% and 14.1%, respectively), in the mississippi flyway in 2009 (16.8%), and lowest each year in the atlantic flyw ...201425618997
demographic and spatiotemporal patterns of avian influenza infection at the continental scale, and in relation to annual life cycle of a migratory host.since the spread of highly pathogenic avian influenza (hpai) h5n1 in the eastern hemisphere, numerous surveillance programs and studies have been undertaken to detect the occurrence, distribution, or spread of avian influenza viruses (aiv) in wild bird populations worldwide. to identify demographic determinants and spatiotemporal patterns of aiv infection in long distance migratory waterfowl in north america, we fitted generalized linear models with binominal distribution to analyze results from ...201526110538
optimizing surveillance for south american origin influenza a viruses along the united states gulf coast through genomic characterization of isolates from blue-winged teal (anas discors).relative to research focused on inter-continental viral exchange between eurasia and north america, less attention has been directed towards understanding the redistribution of influenza a viruses (iavs) by wild birds between north america and south america. in this study, we genomically characterized 45 viruses isolated from blue-winged teal (anas discors) along the texas and louisiana gulf coast during march of 2012 and 2013, coincident with northward migration of this species from neotropical ...201625056712
evidence for seasonal patterns in the relative abundance of avian influenza virus subtypes in blue-winged teal (anas discors).seasonal dynamics of influenza a viruses (iavs) are driven by host density and population immunity. through an analysis of subtypic data for iavs isolated from blue-winged teal (anas discors), we present evidence for seasonal patterns in the relative abundance of viral subtypes in spring and summer/autumn.201424949926
genomic characterization of h14 subtype influenza a viruses in new world waterfowl and experimental infectivity in mallards (anas platyrhynchos).recent repeated isolation of h14 hemagglutinin subtype influenza a viruses (iavs) in the new world waterfowl provides evidence to suggest that host and/or geographic ranges for viruses of this subtype may be expanding. in this study, we used genomic analyses to gain inference on the origin and evolution of h14 viruses in new world waterfowl and conducted an experimental challenge study in mallards (anas platyrhynchos) to evaluate pathogenicity, viral replication, and transmissibility of a repres ...201424788792
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