| comparative serological evaluation of avian influenza vaccine in turkeys. | four- and six-week-old turkeys were vaccinated subcutaneously using avian influenza virus (aiv) a/duck/613/mn/79 (h4n2) killed oil-emulsion vaccine. sequential serological tests using agar gel precipitin (agp), hemagglutination inhibition (hi), and enzyme-linked immunosorbent assay (elisa) for measuring antibodies to aiv were performed up to 4 weeks postvaccination, when birds were challenged intranasally using a/turkey/mn/80 (h4n2) live aiv. the elisa was 25 to 1600 times more sensitive than th ... | 1988 | 3060086 |
| catalytic and framework mutations in the neuraminidase active site of influenza viruses that are resistant to 4-guanidino-neu5ac2en. | here we report the isolation of influenza virus a/turkey/minnesota/833/80 (h4n2) with a mutation at the catalytic residue of the neuraminidase (na) active site, rendering it resistant to the novel na inhibitor 4-guanidino-neu5ac2en (gg167). the resistance of the mutant stems from replacement of one of three invariant arginines (arg 292-->lys) that are conserved among all viral and bacterial nas and participate in the conformational change of sialic acid moiety necessary for substrate catalysis. ... | 1997 | 9094607 |
| in vitro antiviral activity of favipiravir (t-705) against drug-resistant influenza and 2009 a(h1n1) viruses. | favipiravir (t-705) has previously been shown to have a potent antiviral effect against influenza virus and some other rna viruses in both cell culture and in animal models. currently, favipiravir is undergoing clinical evaluation for the treatment of influenza a and b virus infections. in this study, favipiravir was evaluated in vitro for its ability to inhibit the replication of a representative panel of seasonal influenza viruses, the 2009 a(h1n1) strains, and animal viruses with pandemic (pd ... | 2010 | 20350949 |
| 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 ... | 2010 | 20521652 |
| surveillance of avian influenza virus in migratory water birds in eastern hokkaido, japan. | the epidemiological information has obtained on avian influenza virus (aiv) in eastern hokkaido, japan, where aiv surveillance has not been performed. cloacal or fecal samples obtained from migratory water birds were screened for aiv both by real-time reverse transcriptase polymerase chain reaction to detect the influenza a virus matrix (m) gene and by egg inoculation. between 2007 and 2009, a total of 2,488 samples were collected from various avian species in abashiri, kushiro, nemuro and tokac ... | 2010 | 20948168 |
| Characterization of an H4N2 avian influenza virus isolated from domestic duck in Dongting Lake wetland in 2009. | In January 2009, an H4N2 subtype of avian influenza virus [A/duck/Hunan/8-19/2009 (H4N2)] was isolated from domestic ducks in Dongting Lake wetland. The whole genome of the virus was sequenced and the results indicated that multiple gene segments of the virus had a high homology with viruses isolated from wild waterfowl, which indicated that the virus was probably transmitted from wild waterfowl to domestic ducks. Phylogenetic analysis revealed that the each gene belonged to the Eurasian lineage ... | 2011 | 21853331 |
| genetically diverse low pathogenicity avian influenza a virus subtypes co-circulate among poultry in bangladesh. | influenza virus surveillance, poultry outbreak investigations and genomic sequencing were assessed to understand the ecology and evolution of low pathogenicity avian influenza (lpai) a viruses in bangladesh from 2007 to 2013. we analyzed 506 avian specimens collected from poultry in live bird markets and backyard flocks to identify influenza a viruses. virus isolation-positive specimens (n = 50) were subtyped and their coding-complete genomes were sequenced. the most frequently identified subtyp ... | 2016 | 27010791 |
| complete genome sequences of a novel reassortant h4n2 avian influenza virus isolated from a live poultry market in eastern china. | a/duck/shanghai/28-1/2009(h4n2) (dk28) was isolated from a live poultry market in shanghai, china. using pcr and sequencing analysis, we obtained the complete genome sequences of the dk28 virus. the sequence analysis demonstrated that this h4n2 virus was a novel multiple-gene reassortant avian influenza virus (aiv) whose genes originated from h1n1, h1n3, h3n3, h4n2, and h4n6. knowledge regarding the complete genome sequences of the dk28 virus will be useful for epidemiological surveillance. | 2012 | 23043180 |
| characterizations of h4 avian influenza viruses isolated from ducks in live poultry markets and farm in shanghai. | h4 avian influenza virus is one of the most prevalent influenza virus subtypes in birds. the evolution and pathogenicity of h4 aiv in domestic birds of china remain largely unclear. in the present study, a total of eight h4 aiv strains isolated in duck farm and live poultry markets (lpm) were characterized. phylogenetic analysis indicated that these strains are divided into two groups in the eurasian lineage. eight genes of mh-2/h4n6 isolated from a duck farm were closely related to three h4n6 v ... | 2016 | 27897216 |
| genetic characterization of natural reassortant h4 subtype avian influenza viruses isolated from domestic ducks in zhejiang province in china from 2013 to 2014. | the h4 subtype of the influenza virus was first isolated in 1999 from pigs with pneumonia in canada. h4 avian influenza viruses (aivs) are able to cross the species barrier to infect humans. in order to better understand the genetic relationships between h4 aiv strains circulating in eastern china and other aiv strains from asia, a survey of domestic ducks in live poultry markets was undertaken in zhejiang province from 2013 to 2014. in this study, 23 h4n2 (n = 14) and h4n6 (n = 9) strains were ... | 2015 | 26350888 |
| molecular characterization of an influenza a virus (h4n2) isolated from waterfowl habitats in the state of mexico. | wild waterfowl and their habitats are the main reservoirs of influenza a virus (iav) mainly during the breeding season and prior to migration. this study describes the molecular characterization of an iav isolated from 240 water samples of a small wetland during non-breeding season of migratory wild ducks in the state of mexico, mexico. the results showed that the virus belongs to the h4n2 subtype and each of its eight segments of the viral genome has similarity to iav isolated from ducks in nor ... | 2015 | 25482497 |
| full-genome sequence analysis of a natural reassortant h4n2 avian influenza virus isolated from a domestic duck in southern china. | we report here the complete genome sequence of a novel reassortant h4n2 avian influenza virus strain, a/duck/guangxi/125d17/2012(h4n2) (gx125d17), isolated from a duck in guangxi province, china in 2012. we obtained the complete genome sequence of the gx125d17 virus isolation by pcr, cloning, and sequencing. sequence analysis revealed that this h4n2 virus strain was a novel reassortant avian influenza virus (aiv). information about the complete genome sequence of the gx125d17 virus strain will be ... | 2014 | 25212619 |
| characterization of an h4n2 influenza virus from quails with a multibasic motif in the hemagglutinin cleavage site. | the cleavage motif in the hemagglutinin (ha) protein of highly pathogenic h5 and h7 subtypes of avian influenza viruses is characterized by a peptide insertion or a multibasic cleavage site (mbcs). here, we isolated an h4n2 virus from quails (quail/ca12) with two additional arginines in the ha cleavage site, pekrrtr/g, forming an mbcs-like motif. quail/ca12 is a reassortant virus with the ha and neuraminidase (na) gene most similar to a duck-isolated h4n2 virus, pd/ca06 with a monobasic ha cleav ... | 2014 | 25151061 |
| 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. | 2013 | 23516214 |
| genetic and antigenic characteristics of h4 subtype avian influenza viruses in korea and their pathogenicity in quails, domestic ducks and mice. | in korea, a nationwide surveillance programme was implemented in 2003 to identify highly pathogenic avian influenza viruses (aivs). aivs belonging to one of the most common haemagglutinin subtypes, h4, were isolated from two domestic ducks and 52 wild birds between 2004 and 2010. these h4 aivs could be further classified into three neuraminidase subtypes: h4n6 (94.4%), h4n2 (3.7%) and h4n3 (1.9%). phylogenetic analysis revealed that the h4 aivs had a variety of genetic constellations, with at le ... | 2013 | 23015746 |
| genetic characterisation of novel, highly pathogenic avian influenza (hpai) h5n6 viruses isolated in birds, south korea, november 2016. | a novel genotype of h5n6 influenza viruses was isolated from migratory birds in south korea during november 2016. domestic outbreaks of this virus were associated with die-offs of wild birds near reported poultry cases in chungbuk province, central south korea. genetic analysis and animal studies demonstrated that the korean h5n6 viruses are highly pathogenic avian influenza (hpai) viruses and that these viruses are novel reassortants of at least three different subtypes (h5n6, h4n2 and h1n1). | 2017 | 28079520 |
| live bird markets of bangladesh: h9n2 viruses and the near absence of highly pathogenic h5n1 influenza. | avian influenza surveillance in bangladesh has been passive, relying on poultry farmers to report suspected outbreaks of highly pathogenic h5n1 influenza. here, the results of an active surveillance effort focusing on the live-bird markets are presented. prevalence of influenza infection in the birds of the live bird markets is 23.0%, which is similar to that in poultry markets in other countries. nearly all of the isolates (94%) were of the non-pathogenic h9n2 subtype, but viruses of the h1n2, ... | 2011 | 21541296 |
| influenza infection in wild raccoons. | raccoons (procyon lotor) are common, widely distributed animals that frequently come into contact with wild waterfowl, agricultural operations, and humans. serosurveys showed that raccoons are exposed to avian influenza virus. we found antibodies to a variety of influenza virus subtypes (h10n7, h4n6, h4n2, h3, and h1) with wide geographic variation in seroprevalence. experimental infection studies showed that raccoons become infected with avian and human influenza a viruses, shed and transmit vi ... | 2008 | 19046505 |
| production and evaluation criteria of specific monoclonal antibodies to the hemagglutinin of the h7n2 subtype of avian influenza virus. | to enhance the rapidity in diagnosing the spread of avian influenza virus (aiv) in chicken layer flocks, studies were initiated to develop more sensitive and specific immunological and molecular methods for the detection of aiv. in this study, the purification of the hemagglutinin protein (h) from field isolates of h7n2, the production of monoclonal antibodies (mabs), and their evaluation as diagnostic reagents are reported. hybridomas were generated by fusion of sp2/0-ag14 myelomas and spleen c ... | 2000 | 11108449 |
| characterization of mutants of influenza a virus selected with the neuraminidase inhibitor 4-guanidino-neu5ac2en. | the development of viral resistance to the neuraminidase (na) inhibitor, 4-guanidino-neu5ac2en, of influenza viruses was studied by serial passage of a/turkey/minnesota/833/80 (h4n2) in madin-darby canine kidney cells in the presence of increasing concentrations of inhibitor. resistant mutants selected after eight passages, had a 10,000-fold reduction in sensitivity to the inhibitor in plaque assays, but their affinity (1/kd) to the inhibitor was similar to that of the parental virus. electron m ... | 1996 | 8627706 |