| structural variation occurring in the hemagglutinin of influenza virus a/turkey/oregon/71 during adaptation to different cell types. | the influenza virus a/turkey/oregon/71 (h7n3) has been adapted to grow in mdck or chicken embryo cells (cec) in the absence of trypsin. changes occurred in the biological properties of the virus variants selected, depending on the cell type used for adaptation. they coincided with enhanced hemagglutinin (ha) activation by intracellular proteolytic cleavage. in the case of mdck cell selected variants growth, plaque formation, and ha cleavability were restricted to this cell type, whereas the cec- ... | 1990 | 2345964 |
| isolation of influenza a viruses from migratory waterfowls in san-in district, western japan in winters of 1980-1982. | in the two winters of 1980-1982, we surveyed migratory waterfowl of some species staying in san-in district, western japan for influenza virus at a few stations. from november 1980 to april 1981, only two strains of influenza virus, h13n1 and h11n6 subtypes, were isolated from 465 fecal samples from pintails but none from 255 samples from whistling swans nor from 625 black-tailed gulls. from november 1981 to march 1982, 17 viruses were isolated from 1156 fecal samples. fourteen viruses, 10 h7n3, ... | 1987 | 3673333 |
| studies on the temperature sensitivity of influenza a virus reassortants nonpathogenic for chicken. | influenza a virus reassortants which are nonpathogenic for chickens are like mammalian influenza a viruses in that they are temperature sensitive for growth at 41 degrees c. we have investigated the mechanism of this temperature sensitivity using reassortants between the two highly pathogenic strains a/fpv/rostock/34 (fpv, h7n1) and a/turkey/england/63 (te, h7n3). these reassortants show a strict correlation between the pathogenicity for chickens and the constellation of the genes coding for the ... | 1986 | 3751286 |
| perpetuation of influenza a viruses in alaskan waterfowl reservoirs. | to provide information on the mechanism of perpetuation of influenza viruses among waterfowl reservoirs in nature, virological surveillance was carried out in alaska during their breeding season in summer from 1991 to 1994. influenza viruses were isolated mainly from fecal samples of dabbling ducks in their nesting places in central alaska. the numbers of subtypes of 108 influenza virus isolates were 1 h2n3, 37 h3n8, 55 h4n6, 1 h7n3, 1 h8n2, 1 h10n2, 11 h10n7, and h10n9. influenza viruses were a ... | 1995 | 7646350 |
| consistent occurrence of hemagglutinin variants among avian influenza virus isolates of the h7 subtype. | several field isolates of avian influenza virus of the h7 subtype were analyzed for the presence of hemagglutinin variants by labeling proteins in cells infected with virus clones, and reacting with monoclonal antibodies. each strain was shown to contain two distinct electrophoretic variants of the uncleaved hemagglutinin. in the a/tk/ore/71 (h7n3) isolate, two variants remained in the population through 35 laboratory passages, indicating both are stable and may be important to expression of the ... | 1994 | 7831962 |
| observations on the relationship in chickens between the virulence of some avian influenza viruses and their pathogenicity for various organs. | comparative histological and immunocytochemical studies were conducted on formalin-fixed tissues from chickens infected with avian influenza viruses of varying virulence. results showed a distinct pattern of disease that depended on the virulence of the virus and the susceptibility of the birds. at 3 days post-intranasal inoculation with a highly virulent h7n7 virus, all 6-to-8-week-old specific-pathogen-free (spf) birds were affected, and all developed pancreatic necrosis and encephalitis assoc ... | 1995 | 8561728 |
| identification and characterisation of an h7n3 influenza a virus from an outbreak of virulent avian influenza in victoria. | | 1997 | 9140656 |
| development of a diva (differentiating infected from vaccinated animals) strategy using a vaccine containing a heterologous neuraminidase for the control of avian influenza. | the present paper reports of the development and validation of a control strategy for avian influenza infections in poultry. the "diva" (differentiating infected from vaccinated animals) strategy is based on the use of an inactivated oil emulsion vaccine containing the same haemagglutinin (h) subtype as the challenge virus, but a different neuraminidase (n). the possibility of using the heterologous n subtype, to differentiate between vaccinated and naturally infected birds, was investigated thr ... | 2003 | 12745380 |
| 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 ... | 2003 | 14575082 |
| development and preliminary validation of an ad hoc n1-n3 discriminatory test for the control of avian influenza in italy. | the development of a discriminatory test, based on the differentiation between n1 and n3 antibodies, to be used in the framework of a vaccination program, based on vaccination with a heterologous h7n3 inactivated vaccine against the italian h7n1 field virus, is reported. the indirect immunofluorescence antibody (iifa) assay was based on the expression of the n1 protein in a baculovirus system. highfive insect cells were transfected with the recombinant virus and used as an antigen in the iifa te ... | 2003 | 14575111 |
| eradication of low pathogenicity avian influenza of the h7n3 subtype from italy. | | 2004 | 15180403 |
| recombination resulting in virulence shift in avian influenza outbreak, chile. | influenza a viruses occur worldwide in wild birds and are occasionally associated with outbreaks in commercial chickens and turkeys. however, avian influenza viruses have not been isolated from wild birds or poultry in south america. a recent outbreak in chickens of h7n3 low pathogenic avian influenza (lpai) occurred in chile. one month later, after a sudden increase in deaths, h7n3 highly pathogenic avian influenza (hpai) virus was isolated. sequence analysis of all eight genes of the lpai viru ... | 2004 | 15200862 |
| microbial adaptation and change: avian influenza. | the evolution of influenza is a continuing process involving viral and host factors. the increasing frequency of emergence of the highly pathogenic h5n1, h7n3 and h7n7 influenza viruses and the panzootic spread of h9n2 influenza virus, all of which can be potentially transmitted to humans, are of great concern to both veterinary and human public health officials. the question is how soon the next pandemic will emerge. a convergence of factors, including the population densities of poultry, pigs ... | 2004 | 15702713 |
| serological analysis of serum samples from humans exposed to avian h7 influenza viruses in italy between 1999 and 2003. | we evaluated the potential for avian-to-human transmission of low pathogenic avian influenza (lpai) and highly pathogenic avian influenza (hpai) h7n1 and lpai h7n3 viruses that were responsible for several outbreaks of influenza in poultry in italy between 1999 and 2003. a serological survey of poultry workers was conducted by use of a combination of methods. evidence of anti-h7 antibodies was observed in 3.8% of serum samples collected from poultry workers during the period in 2003 when lpai h7 ... | 2005 | 16170747 |
| comparison of in vitro replication features of h7n3 influenza viruses from wild ducks and turkeys: potential implications for interspecies transmission. | in previous work, it was shown that turkey h7n3 influenza viruses, presumably derived 'in toto' from interspecies transmission of duck viruses in northern italy, had only 2 aa differences in haemagglutinin and a few amino acid differences as well as a 23 aa deletion in neuraminidase compared with duck viruses. here, the replication of these duck and turkey viruses in madin-darby canine kidney cells was investigated with respect to virus-cell fusion and viral elution from red blood cells. duck vi ... | 2006 | 16361429 |
| human illness and isolation of low-pathogenicity avian influenza virus of the h7n3 subtype in british columbia, canada. | | 2006 | 16479527 |
| quantification of the effect of vaccination on transmission of avian influenza (h7n7) in chickens. | recent outbreaks of highly pathogenic avian influenza (hpai) viruses in poultry and their threatening zoonotic consequences emphasize the need for effective control measures. although vaccination of poultry against avian influenza provides a potentially attractive control measure, little is known about the effect of vaccination on epidemiologically relevant parameters, such as transmissibility and the infectious period. we used transmission experiments to study the effect of vaccination on the t ... | 2005 | 16330777 |
| implementation of the community network of reference laboratories for human influenza in europe. | the increased need for accurate influenza laboratory surveillance data in the european union required formalisation of the existing network of collaborating national influenza reference laboratories participating in the european influenza surveillance scheme (eiss). | 2005 | 16157259 |
| field experiences in the control of avian influenza outbreaks in densely populated poultry areas. | from 1997 to 2003, italy has been affected by two epidemics of highly pathogenic avian influenza (hpai) and by several outbreaks of low pathogenic avian influenza (lpai). in 1999-2000 a severe hpai epidemic affected the country, causing 413 outbreaks: a total of about 16 million birds died or were stamped out. from august 2000 to march 2001, a h7n1 lpai strain infected 78 poultry farms. the last affected flock was stamped out on the 26th of march 2001. in october 2002, another lpai virus of the ... | 2004 | 15742627 |
| intersegmental recombination between the haemagglutinin and matrix genes was responsible for the emergence of a highly pathogenic h7n3 avian influenza virus in british columbia. | in february 2004 a highly pathogenic avian influenza (hpai) outbreak erupted in british columbia. investigations indicated that the responsible hpai h7n3 virus emerged suddenly from a low pathogenic precursor. analysis of the haemagglutinin (ha) genes of the low and high pathogenic viruses isolated from the index farm revealed the only difference to be a 21 nt insert at the ha cleavage site of the highly pathogenic avian influenza virus. it was deduced that this insert most probably arose as a r ... | 2005 | 15722533 |
| virus characterization, clinical presentation, and pathology associated with h7n3 avian influenza in british columbia broiler breeder chickens in 2004. | low-pathogenicity avian influenza (lpai) subtype h7n3 was diagnosed on a two-age broiler breeder farm in abbotsford, british columbia (bc), in early february 2004. the presenting complaint in the older index flock was feed refusal, with 0.5% mortality over 72 hr that resolved over the following week ten days after the initial complaint in the index flock, a younger flock in an adjacent barn experienced an abrupt spike in mortality (25% in 48 hr). the gross lesions of tracheal hyperemia and hilar ... | 2004 | 15666877 |
| novel avian influenza h7n3 strain outbreak, british columbia. | genome sequences of chicken (low pathogenic avian influenza [lpai] and highly pathogenic avian influenza [hpai]) and human isolates from a 2004 outbreak of h7n3 avian influenza in canada showed a novel insertion in the ha0 cleavage site of the human and hpai isolate. this insertion likely occurred by recombination between the hemagglutination and matrix genes in the lpai virus. | 2004 | 15663859 |
| comparison of three rapid detection systems for type a influenza virus on tracheal swabs of experimentally and naturally infected birds. | the present paper reports of the comparison between three rapid virus detection systems and virus isolation (vi) from pooled tracheal swabs collected from naturally and experimentally infected birds with a low pathogenicity avian influenza virus of the h7n3 subtype. the relative sensitivity, specificity and agreement (k value) were calculated for a commercial antigen capture enzyme immunoassay (ac-eia) and for two nucleic acid detection tests, a one-step reverse transcriptase-polymerase chain re ... | 2004 | 15370041 |
| molecular characterization of low pathogenicity h7n3 avian influenza viruses isolated in italy. | the complete coding regions of the surface glycoproteins, nucleoprotein (np), polymerase 2 (pb2), and matrix (m) of a/turkey/214845/02 and a/turkey/220158/99 (h7n3) low pathogenicity avian influenza (lpai) viruses isolated in october 2002 in italy were amplified and sequenced to determine the epidemiologic relationships with an a/turkey/italy/4603/99 (h7n1/4603/99) lpai virus isolated during the 1999-2001 epizootic in italy. the hemagglutinin (ha) of h7n3 viruses showed 97.8% nucleotide similari ... | 2004 | 15283425 |
| development and evaluation of an influenza virus subtype h7n2 vaccine candidate for pandemic preparedness. | influenza virus of the h7n2 subtype has been introduced into noncommercial poultry in the united states, and this probably resulted in incidents of transmission of h7n2 virus to humans, documented in 2002 and 2003. this virus could be considered a potential threat to public health if it acquired person-to-person transmissibility. a favored approach for global pandemic preparedness includes development of prepandemic vaccines for any potential pandemic virus. to this end, we created a high-growth ... | 2007 | 17913860 |
| increased resistance of vaccinated turkeys to experimental infection with an h7n3 low-pathogenicity avian influenza virus. | a trial was performed to establish whether turkeys vaccinated against avian influenza with a vaccine containing a strain with a heterologous neuraminidase to the challenge virus required a higher infectious dose to develop infection than naïve birds. birds were vaccinated with a commercially available, inactivated oil emulsion product containing the strain a/ty/italy/99/(h7n1) and challenged with different dilutions of a lpai isolate a/ty/italy/8000/02(h7n3) obtained during the 2002 to 2003 ital ... | 2004 | 15276982 |
| influenza in migratory birds and evidence of limited intercontinental virus exchange. | migratory waterfowl of the world are the natural reservoirs of influenza viruses of all known subtypes. however, it is unknown whether these waterfowl perpetuate highly pathogenic (hp) h5 and h7 avian influenza viruses. here we report influenza virus surveillance from 2001 to 2006 in wild ducks in alberta, canada, and in shorebirds and gulls at delaware bay (new jersey), united states, and examine the frequency of exchange of influenza viruses between the eurasian and american virus clades, or s ... | 2007 | 17997603 |
| interspecies transmission of an h7n3 influenza virus from wild birds to intensively reared domestic poultry in italy. | since the "bird flu" incident in hong kong sar in 1997, several studies have highlighted the substantial role of domestic birds, such as turkeys and chickens, in the ecology of influenza a viruses. even if recent evidence suggests that chickens can maintain several influenza serotypes, avian influenza viruses (aivs) circulating in domestic species are believed to be introduced each time from the wild bird reservoir. however, so far the direct precursor of influenza viruses from domestic birds ha ... | 2004 | 15165816 |
| comparative pathobiology of low and high pathogenicity h7n3 chilean avian influenza viruses in chickens. | chickens were intranasally inoculated with chilean h7n3 avian influenza (ai) viruses of low pathogenicity (lp) (h7n3/lp), high pathogenicity (hp) (h7n3/hp), and a laboratory derivative (02-ai-15-#9) (h7n3/14d) from the lpai virus to determine pathobiologic effects. all chickens inoculated with h7n3/hp ai virus became infected and abruptly died 2 or 3 days postinoculation, but a few showed moderate depression before death. the h7n3/hp ai virus produced focal hemorrhages of the comb, petechial hem ... | 2004 | 15077805 |
| low-pathogenicity avian influenza (lpai) in italy (2000-01): epidemiology and control. | in 1999-2000, italy was affected by the most severe avian influenza (ai) epidemic that has ever occurred in europe. the epidemic was caused by a type a influenza virus of the h7n1 subtype, which originated from the mutation of a low-pathogenicity (lp) ai virus of the same subtype. from august to november 2000, 4 months after the eradication of the highly pathogenic (hp) ai virus, the lpai strain re-emerged and infected 55 poultry farms mainly located in the southern area of verona province (vene ... | 2003 | 14575102 |
| prophylaxis and treatment of influenza encephalitis in an experimental mouse model. | a mouse model study using mouse brain-adapted influenza a virus was performed to establish the prophylaxis and treatment of influenza encephalitis and encephalopathy. all mice died after intranasal inoculation of the brain-adapted influenza a virus (h7n3), and the pathological findings indicated the presence of significant encephalitis. viral antigen was also detected in the brain, both pathologically and virologically. by contrast, infected mice immunized with inactivated vaccine of the same st ... | 2002 | 12116035 |
| origin of the 1918 spanish influenza virus: a comparative genomic analysis. | to test the avian-origin hypothesis of the 1918 spanish influenza virus we surveyed influenza sequences from a broad taxonomic distribution and collected 65 full-length genomes representing avian, human and "classic" swine h1n1 lineages in addition to numerous other swine (h1n2, h3n1, and h3n2), human (h2n2, h3n2, and h5n1), and avian (h1n1, h4n6, h5n1, h6n1, h6n6, h6n8, h7n3, h8n4, h9n2, and h13n2) subtypes. amino acids from all eight segments were concatenated, aligned, and used for phylogenet ... | 2008 | 18353690 |
| contemporary north american influenza h7 viruses possess human receptor specificity: implications for virus transmissibility. | avian h7 influenza viruses from both the eurasian and north american lineage have caused outbreaks in poultry since 2002, with confirmed human infection occurring during outbreaks in the netherlands, british columbia, and the united kingdom. the majority of h7 infections have resulted in self-limiting conjunctivitis, whereas probable human-to-human transmission has been rare. here, we used glycan microarray technology to determine the receptor-binding preference of eurasian and north american li ... | 2008 | 18508975 |
| role of the m2 protein in influenza virus membrane fusion: effects of amantadine and monensin on fusion kinetics. | we have investigated the effects of the anti-influenza drug amantadine (amt) and the proton-ionophore monensin on the membrane fusion activity of influenza virus in a liposomal model system, using a kinetic fluorescence lipid mixing assay. fusion of influenza virus a/turkey/oregon/71 (h7n3) with liposomes was slowed down in the presence of 2 microm amt. the effect of amt was not observed with an amt-resistant mutant virus. fusion inhibition by amt was reversed by the proton-ionophore monensin. i ... | 1993 | 8337846 |
| [characterization of rna polymerase activity of highly purified preparations of influenza virus a/duck/alberta/48/76]. | the influenza virus a/duck/alberta/48/76 with the antigen formula h7n3 (16) and hav1 nav2 (who nomenclature from 1971) (15), respectively, as well as a nonpathogenic virus of the subtype hav1 were purified to a high degree by ultracentrifugation in continuous sucrose gradients (15-40% w/w and 20-60% w/w, respectively). the activity of the rna polymerase of this virus preparation was determined by incorporating 3h-ump in acid insoluble material following preincubation of the virus with the nonion ... | 1984 | 6377762 |
| studies of some biological and molecular characteristics of avian influenza a/h7 (hav1) subtypes. | current isolates of the subtypes h7n3 and h7n7 from 1979 to 1981 were examined and compared with the reference strains with regard to their antigenic variability and to their pathogenicity for birds and mammals in order to establish the potentiality of influenza a/h7 virus (hav1) transmission from birds to mammals. the analysis of the electrophoretic mobility of virus-induced polypeptides and of the double-stranded rna segments after hybridization revealed equal, similar and deviating patterns. ... | 1986 | 2871730 |
| characterization of h5n1 influenza a viruses isolated from domestic green-winged teal. | two avian influenza virus strains, a/domestic green-winged teal/hunan/67/2005 (h5n1) (d-gwt/67) and a/domestic green-winged teal/hunan/79/2005 (h5n1) (d-gwt/79), were isolated from healthy domestic green-winged teals (anas crecca) in hunan province, south china. genomic analysis showed that both isolates were reassortants. the hemagglutinin (ha) genes of the two isolates were closely related to that of an h5n1 strain isolated from tree sparrow (a/tree sparrow/henan/1/04). the neuraminidase (na) ... | 2009 | 18825495 |
| protective measures and human antibody response during an avian influenza h7n3 outbreak in poultry in british columbia, canada. | in 2004 an outbreak of avian influenza of the h7n3 subtype occurred among poultry in british columbia, canada. we report compliance with recommended protective measures and associated human infections during this outbreak. | 2007 | 17200390 |
| passive immunization against highly pathogenic avian influenza virus (aiv) strain h7n3 with antiserum generated from viral polypeptides protect poultry birds from lethal viral infection. | our studies were aimed at developing a vaccination strategy that could provide protection against highly pathogenic avian influenza virus (aiv), h7n3 or its variants outbreaks. a purified viral stock of highly pathogenic h7n3 isolate was lysed to isolate viral proteins by electrophresing on 12% sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-page), followed by their elution from gel through trituration in phosphate buffered saline (pbs). overall, five isolated viral polypeptides/p ... | 2008 | 19040734 |
| amelioration of influenza virus pathogenesis in chickens attributed to the enhanced interferon-inducing capacity of a virus with a truncated ns1 gene. | avian influenza virus (aiv) a/turkey/oregon/71-seprl (tk/or/71-seprl) (h7n3) encodes a full-length ns1 protein and is a weak inducer of interferon (ifn). a variant, tk/or/71-delns1 (h7n3), produces a truncated ns1 protein and is a strong inducer of ifn. these otherwise genetically related variants differ 20-fold in their capacities to induce ifn in primary chicken embryo cells but are similar in their sensitivities to the action of ifn. furthermore, the weak ifn-inducing strain actively suppress ... | 2007 | 17121796 |
| outbreak of avian influenza h7n3 on a turkey farm in the netherlands. | this case report describes the course of an outbreak of avian influenza on a dutch turkey farm. when clinical signs were observed their cause remained unclear. however, serum samples taken for the monitoring campaign launched during the epidemic of highly pathogenic avian influenza in 2003, showed that all the remaining turkeys were seropositive against an h7 strain of avian influenza virus, and the virus was subsequently isolated from stored carcases. the results of a reverse-transcriptase pcr ... | 2006 | 16997995 |
| h7n3 avian influenza virus found in a south american wild duck is related to the chilean 2002 poultry outbreak, contains genes from equine and north american wild bird lineages, and is adapted to domestic turkeys. | an h7n3 avian influenza virus (aiv) was isolated from a cinnamon teal (anas cyanoptera) (a/cinnamonteal/bolivia/4537/01) during a survey of wild waterfowl in bolivia in 2001. the na and m genes had the greatest identity with north american wild bird isolates, the ns was most closely related to an equine virus, and the remaining genes were most closely related to isolates from an outbreak of h7n3 in commercial poultry in chile in 2002. the ha protein cleavage site and the results of pathogenesis ... | 2006 | 16840356 |
| use of strategic vaccination for the control of avian influenza in pakistan. | the first outbreak of highly pathogenic avian influenza (hpai) virus caused by subtype h7n3 appeared in pakistan in 1995. a homologous aqueous-based vaccine prepared from the field isolate employed as ring vaccination around the epicentre of the outbreak helped in controlling the disease. later, in 1998, an outbreak of avian influenza virus (aiv) subtype h9n2, particularly affecting the broilers and broiler-breeders, was dealt with using the same vaccination approach. however, this time, the vir ... | 2006 | 16447505 |
| control of avian influenza in italy: from stamping out to emergency and prophylactic vaccination. | since 1997, north-eastern italy has been repeatedly challenged by avian influenza (ai) infections caused by viruses of the h5 and h7 subtypes. the penetration of such infections in the industrial circuit in densely populated poultry areas (dppas) resulted in massive spread, and early attempts to control ai only by stamping-out and restriction policies resulted in death or culling of millions of birds. the re-emergence or the introduction of ai viruses in the same dppa resulted in the development ... | 2006 | 16447501 |
| avian influenza viruses and human health. | influenza a viruses cause natural infections of humans, some other mammals and birds. few of the 16 haemagglutinin and nine neuraminidase subtype combinations have been isolated from mammals, but all subtypes have been isolated from birds. in the 20th century, there were four pandemics of influenza as a result of the emergence of antigenically different strains in humans: 1918 (h1n1), 1957 (h2n2), 1968 (h3n2) and 1977 (h1n1). influenza a viruses contain eight distinct rna genes and reassortment ... | 2006 | 16447497 |
| zoonotic potential of highly pathogenic avian h7n3 influenza viruses from pakistan. | h5 and h7 avian influenza viruses can become highly pathogenic in chickens after interspecies transmission. these viruses have transmitted directly to humans from birds in eurasia and africa (h5n1), the netherlands (h7n7), and canada (h7n3). here we report antigenic, sequence, and phylogenetic analyses of h7n3 viruses isolated from chickens in pakistan from 1995 to 2002. we compared the pathogenic and zoonotic potential of the pakistani viruses in avian and mammalian hosts. in chickens, all of t ... | 2009 | 19535120 |
| recent epidemiology and ecology of influenza a viruses in avian species in europe and the middle east. | there have been at least ten distinct outbreaks of lpai or hpai in poultry caused by h5 or h7 viruses in the last eight years in europe and the middle east. there appears to be an increased occurrence of such episodes consistent with global trends. as a result, surveillance systems have been enhanced to facilitate early detection of infection in poultry, together with active surveillance of wild bird populations. these complementary activities have resulted in the detection of a number of viruse ... | 2006 | 16447493 |
| ecology and epidemiology of avian influenza in north and south america. | wild waterfowl and shorebirds are known to be the natural reservoir for influenza a viruses. surveillance studies in waterfowl and shorebirds in north america show that influenza a viruses are repeatedly recovered from these birds. however, the virus recovery is influenced by geography, season, age and species of birds. in addition to the natural reservoir, the live-bird marketing system (lbms) in certain regions of the united states has been recognized as a man-made reservoir of influenza virus ... | 2006 | 16447492 |
| the use of vaccination to combat multiple introductions of notifiable avian influenza viruses of the h5 and h7 subtypes between 2000 and 2006 in italy. | since 1999, italy has been challenged by several epidemics of notifiable avian influenza (nai) of the h5 and h7 subtypes, occurring in the densely populated poultry areas of northern part of the country. vaccination with a conventional vaccine containing a seed strain with a different neuraminidase subtype to the field virus was used to complement biosecurity and restriction measures as part of an overall eradication strategy. this vaccination technique, known as the "diva-differentiating infect ... | 2007 | 17418460 |
| the feasibility of using high resolution genome sequencing of influenza a viruses to detect mixed infections and quasispecies. | the rapidly expanding availability of de novo sequencing technologies can greatly facilitate efforts to monitor the relatively high mutation rates of influenza a viruses and the detection of quasispecies. both the mutation rates and the lineages of influenza a viruses are likely to play an important role in the natural history of these viruses and the emergence of phenotypically and antigenically distinct strains. | 2009 | 19771155 |
| highly pathogenic avian influenza virus a (h7n3) in domestic poultry, saskatchewan, canada, 2007. | epidemiologic, serologic, and molecular phylogenetic methods were used to investigate an outbreak of highly pathogenic avian influenza on a broiler breeding farm in saskatchewan, canada. results, coupled with data from influenza a virus surveillance of migratory waterfowl in canada, implicated wild birds as the most probable source of the low pathogenicity precursor virus. | 2009 | 19788823 |
| summary of avian influenza activity in europe, asia, africa, and australasia, 2002-2006. | between december 2003 and january 2004 highly pathogenic avian influenza (hpai) h5n1 infections of poultry were declared in china, japan, south korea, laos, thailand, cambodia, vietnam, and indonesia. in 2004 an outbreak was reported in malaysia. in 2005 h5n1 outbreaks were recorded in poultry in russia, kazakhstan, mongolia, romania, turkey, and ukraine, and virus was isolated from swans in croatia. in 2004 hpai h5n1 virus was isolated from smuggled eagles detected at the brussels airport and i ... | 2007 | 17494548 |
| 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 |
| avian influenza in pakistan: outbreaks of low- and high-pathogenicity avian influenza in pakistan during 2003-2006. | from november 2003 to june 2004 an epidemic of high pathogenicity avian influenza (hpai) virus of subtype h7n3 affected the major layer and broiler-breeder raising areas of the country. this was accompanied by an outbreak of low pathogenicity avian influenza (lpai) virus of type h9n2 in broilers and layers, which continued during 2005. subsequently, in february 2006 avian influenza virus (aiv) subtype h5n1 was for the first time found in two isolated commercial flocks in this country. the hpai o ... | 2007 | 17494552 |
| an avian influenza virus from waterfowl in south america contains genes from north american avian and equine lineages. | apart from an outbreak in commercial poultry in chile in 2002, there have been few reports of avian influenza in south america. however, surveillance in free-flying birds has been limited. an avian influenza virus was isolated from a cinnamon teal (anas cyanoptera) in bolivia in 2001 from samples collected for an avian influenza virus and avian paramyxovirus surveillance study. this isolate was determined to be an h7n3 virus by gene sequencing. analysis of all eight genes revealed that five gene ... | 2007 | 17494565 |
| the roles of national and provincial diagnostic laboratories in the eradication of highly pathogenic h7n3 avian influenza virus from the fraser valley of british columbia, canada. | in february 2004 a highly pathogenic avian influenza outbreak erupted in the fraser valley of british columbia, canada. the index farm was a chicken broiler breeder operation comprising two flocks, 24 and 52 wk of age. birds in the older flock presented with a mild drop in egg production and a small increase in mortality. pathological specimens taken from the older flock were submitted to the provincial veterinary diagnostic laboratory from which an influenza a virus was isolated. while still un ... | 2007 | 17494572 |
| diagnostic test results and pathology associated with the 2007 canadian h7n3 highly pathogenic avian influenza outbreak. | in september 2007, an h7n3 highly pathogenic avian influenza outbreak (hpai) occurred on a multiple-age broiler breeder operation near regina beach, saskatchewan, canada. mortality was initially observed in a barn that housed 24-wk-old roosters, with later involvement of 32-wk-old breeders. all birds on the affected premises were destroyed, and surveillance of surrounding farms demonstrated no further spread. the use of water from a dugout pond during periods of high demand, and the proximity of ... | 2010 | 20521634 |
| avian influenza in chile: a successful experience. | avian influenza (ai) was diagnosed in may 2002 for the first time in chile and south america. the epidemic was caused by the highly pathogenic ai (hpai) virus subtype h7n3 that emerged from a low pathogenic virus. the index farm was a broiler breeder, located in san antonio, v region, which at the time was a densely populated poultry area. stamping of 465,000 breeders, in 27 sheds, was immediately conducted. surveillance activities detected a second outbreak, 1 wk later, at a turkey breeding far ... | 2007 | 17494584 |
| cloning of the canine rna polymerase i promoter and establishment of reverse genetics for influenza a and b in mdck cells. | recent incidents where highly pathogenic influenza a h5n1 viruses have spread from avian species into humans have prompted the development of cell-based production of influenza vaccines as an alternative to or replacement of current egg-based production. madin-darby canine kidney (mdck) cells are the primary cell-substrate candidate for influenza virus production but an efficient system for the direct rescue of influenza virus from cloned influenza cdnas in mdck cells did not exist. the objectiv ... | 2007 | 17956624 |
| a multiplex real-time rt-pcr for detection and identification of influenza virus types a and b and subtypes h5 and n1. | a multiplex real-time rt-pcr method for the simultaneous detection of influenza virus types a and b and identification of subtypes h5 and n1 in a single tube is described. the method was developed with four sets of primers and probes which were specific to influenza virus (sub)types a, b, h5, and n1, and evaluated by using a total of 40 influenza virus reference strains, including 17 avian influenza a (12 h5n1, 1 h1n1, 1 h3n2, 1 h4n6, 1 h7n3, and 1 h9n2), 18 human influenza a (11 h3n2, 6 h1n1 an ... | 2008 | 18078675 |
| avian and 1918 spanish influenza a virus ns1 proteins bind to crk/crkl src homology 3 domains to activate host cell signaling. | ns1 (nonstructural protein 1) is an important virulence factor of the influenza a virus. we observed that ns1 proteins of the 1918 pandemic virus (a/brevig mission/1/18) and many avian influenza a viruses contain a consensus src homology 3 (sh3) domain-binding motif. screening of a comprehensive human sh3 phage library revealed the n-terminal sh3 of crk and crkl as the preferred binding partners. studies with recombinant proteins confirmed avid binding of ns1 proteins of the 1918 virus and a rep ... | 2008 | 18165234 |
| sequence and phylogenetic analysis of h7n3 avian influenza viruses isolated from poultry in pakistan 1995-2004. | avian influenza virus (aiv) infections have caused heavy economic losses to the poultry industry in pakistan as well as numerous other regions worldwide. the first introduction of h7n3 aiv to pakistan occurred during 1995, since then h7n3, h9n2 and h5n1 aivs have each been sporadically isolated. this report evaluates the genetic origin of the h7n3 viruses from pakistan collected 1995-2004 and how they disseminated within the country. to accomplish this we produced whole genome sequences for 6 h7 ... | 2010 | 20576101 |
| evaluation of diagnostic applications of monoclonal antibodies against avian influenza h7 viruses. | a panel of monoclonal antibodies (mabs) was generated from mice immunized with binary ethylenimine (bei)-inactivated h7n1 (a/tk/on/18-2/00) virus. using a dot blot assay, six of seven mabs reacted with viruses of the h7 subtype, but not with any of the other 15 hemagglutinin (ha) subtypes tested. four of the seven mabs reacted with 14 different h7 isolates, indicating that the mabs binding epitopes are conserved among viruses of the h7 subtype. the binding epitopes of all seven mabs were conform ... | 2010 | 20660135 |
| rapid differentiation of influenza a virus subtypes and genetic screening for virus variants by high-resolution melting analysis. | we assessed the use of high-resolution melting (hrm) analysis for the rapid identification of influenza a virus subtypes and the detection of newly emerging virus variants. the viral matrix gene was amplified by lightcycler real-time reverse transcription-pcr (rt-pcr) in the presence of the lcgreen i fluorescent dye. upon optimization of the assay conditions, all the major influenza a virus subtypes, including h1n1, h3n2, h5n1, h7n3, and h9n2, were amplifiable by this method and had a pcr produc ... | 2008 | 18174299 |
| potential of low pathogenicity avian influenza viruses of wild bird origin to establish experimental infections in turkeys and chickens. | the potential of low pathogenicity (lp) avian influenza virus (aiv) isolates of wild bird origin to establish infection in commercial turkeys and broiler chickens was studied. isolates, representing subtypes h5n1, h7n3, h6n2, and h3n6, were recovered in 2005 and 2006 from waterfowl and shorebirds in the delmarva peninsula region of the east coast of the united states. the lp aiv isolates were not pathogenic for 2-wk-old meat-type turkeys and broiler chickens. no mortality, clinical signs, or gro ... | 2010 | 20945794 |
| molecular adaptation of an h7n3 wild duck influenza virus following experimental multiple passages in quail and turkey. | to investigate the molecular adaptation of influenza viruses during natural interspecies transmission, we performed a phenotypic and genotypic analysis of a low-pathogenic duck h7n3 influenza virus after experimental passages in turkey and quail. results obtained showed differences in the ha receptor-binding and in na enzyme activities in viruses recovered after passages in quail, compared to those obtained from passages in turkey. sequencing of the ha, na and genes of internal proteins of the v ... | 2010 | 20947115 |
| transforming growth factor-β: activation by neuraminidase and role in highly pathogenic h5n1 influenza pathogenesis. | transforming growth factor-beta (tgf-β), a multifunctional cytokine regulating several immunologic processes, is expressed by virtually all cells as a biologically inactive molecule termed latent tgf-β (ltgf-β). we have previously shown that tgf-β activity increases during influenza virus infection in mice and suggested that the neuraminidase (na) protein mediates this activation. in the current study, we determined the mechanism of activation of ltgf-β by na from the influenza virus a/gray teal ... | 2010 | 20949074 |
| development of eurasian h7n7/pr8 high growth reassortant virus for clinical evaluation as an inactivated pandemic influenza vaccine. | avian-to-human transmission of the high pathogenicity (hp) h7n7 subtype avian influenza viruses in the netherlands during 2003 caused zoonotic infections in 89 people, including a case of acute fatal respiratory distress syndrome. public health emergency preparedness against h7n7 avian influenza viruses with pandemic potential includes the development of vaccine candidate viruses. in order to develop a high growth reassortant vaccine candidate virus, low pathogenicity (lp) a/mallard/netherlands/ ... | 2008 | 18336962 |
| characterization of influenza virus variants with different sizes of the non-structural (ns) genes and their potential as a live influenza vaccine in poultry. | from a stock of a/turkey/oregon/71-delns1 (h7n3) virus, which has a 10 nucleotide deletion in the coding region of the ns1 gene, we found that several variants with different sizes of ns genes could be produced by passaging the virus in 10- and 14-day-old embryonating chicken eggs (ece), but not in 7-day-old ece or vero cells. we were able to rescue the reassortant virus that has different sizes of the ns genes and confirmed that those ns genes are genetically stable. by conducting in vivo studi ... | 2008 | 18539366 |
| phylogenetic analysis of low pathogenicity h5n1 and h7n3 influenza a virus isolates recovered from sentinel, free flying, wild mallards at one study site during 2006. | from august 2 to october 11, 2006, clusters of low pathogenicity (lp) north american lineage h5n1 and h7n3 avian influenza a viruses (aiv), and other subtypes, were recovered from free-flying, resident, wild mallards used as sentinels at one site. the antigenic subtypes, pathogenicity potential, and sanger sequencing of the isolates determined the h5n1 and h7n3 isolates were only recovered from samples collected on 8/2/2006 and 9/8/2006, respectively. however, subsequent efforts using next-gener ... | 2011 | 21658737 |
| a live attenuated cold-adapted influenza a h7n3 virus vaccine provides protection against homologous and heterologous h7 viruses in mice and ferrets. | the appearance of human infections caused by avian influenza a h7 subtype viruses underscores their pandemic potential and the need to develop vaccines to protect humans from viruses of this subtype. a live attenuated h7n3 virus vaccine was generated by reverse genetics using the ha and na genes of a low pathogenicity a/chicken/bc/cn-6/04 (h7n3) virus and the six internal protein genes of the cold-adapted a/ann arbor/6/60 ca (h2n2) virus. the reassortant h7n3 bc 04 ca vaccine virus was temperatu ... | 2008 | 18585748 |
| isolation of a highly pathogenic influenza a virus of subtype h7n3 from a peregrine falcon ( falco peregrinus ). | a peregrine falcon ( falco peregrinus ) was presented to the al safa falcon clinic in dubai, unitedarab emirates unable to stand. four hours after hospitalization, the bird died despite supportive care and calcium disodiumedetate treatment. the falcon had been on a hunting trip to syria with its owner of 2 years, prior to its death. the carcass was submitted to the central veterinary research laboratory in dubai where it was subjected to postmortem examination. investigations resulted in the iso ... | 2000 | 19184861 |
| in vitro inhibition of influenza virus infection by a crude extract from isatis indigotica root resulting in the prevention of viral attachment. | isatis indigotica root (iir) has been widely used as a chinese medicinal herb to treat regular seasonal influenza over the long history of traditional chinese medicinal practice. however, its inhibitory activities against influenza virus infections along with the associated mechanisms have not been investigated comprehensively. in this study, the chemical nature, mode of action and in vitro anti-influenza activities of a crude extract ( ... | 2011 | 22179315 |
| influenza-a viruses in ducks in northwestern minnesota: fine scale spatial and temporal variation in prevalence and subtype diversity. | waterfowl from northwestern minnesota were sampled by cloacal swabbing for avian influenza virus (aiv) from july-october in 2007 and 2008. aiv was detected in 222 (9.1%) of 2,441 ducks in 2007 and in 438 (17.9%) of 2,452 ducks in 2008. prevalence of aiv peaked in late summer. we detected 27 aiv subtypes during 2007 and 31 during 2008. ten hemagglutinin (ha) subtypes were detected each year (i.e., h1, 3-8, and 10-12 during 2007; h1-8, 10 and 11 during 2008). all neuraminidase (na) subtypes were d ... | 2011 | 21931636 |
| protection of chickens against avian influenza with nonreplicating adenovirus-vectored vaccine. | protective immunity against avian influenza (ai) virus has been elicited in chickens by single-dose in ovo or i.m. vaccination with a replication-competent adenovirus (ad)-free human ad vector encoding the ai virus a/turkey/wisconsin/68 h5 (adtw68. h5) or the a/chicken/new york/94 h7 (adchny94. h7) hemagglutinin (ha). the adtw68.h5-vaccinated chickens were protected against both h5n1 and h5n2 highly pathogenic ai virus challenges. the adchny94. h7-vaccinated chickens were protected against an h7 ... | 2009 | 19276437 |
| [study of biological properties of cold-adapted reassortant strain of influenza virus subtype h7n3]. | for the development of live attenuated influenza vaccine (laiv) against influenza virus strains with pandemic potential, method of classic genetic reassortment of donor of attenuation a/leningrad/134/17/57 (h2n2) [len/17] with avian apathogenic influenza viruses of different subtypes was used. strain with genome formula 6:2, which contains ha and na genes from avian apathogenic virus a/wild duck/netherlands/12/00 (h7n3) [n7n3-wt] and 6 other genes--from len/17, was studied. reassortant strain a/ ... | 2009 | 19340965 |
| ocular infection of mice with influenza a (h7) viruses: a site of primary replication and spread to the respiratory tract. | avian h7 influenza viruses have been responsible for poultry outbreaks worldwide and have resulted in numerous cases of human infection in recent years. the high rate of conjunctivitis associated with avian h7 subtype virus infections may represent a portal of entry for avian influenza viruses and highlights the need to better understand the apparent ocular tropism observed in humans. to study this, mice were inoculated by the ocular route with viruses of multiple subtypes and degrees of virulen ... | 2009 | 19458003 |
| avian influenza in north america, 2009-2011. | all reports of avian influenza virus infections in poultry and isolations from wild bird species in canada, the united states, and mexico between 2009 and 2011 involved low pathogenic avian influenza. all three countries reported outbreaks of low pathogenic notifiable avian influenza in poultry during this period. the reports involved outbreaks of h5n2 among commercial turkeys in canada in 2009 and 2010; outbreaks of h5n3 in turkeys in 2009, h5n2 in chickens in 2010, h7n3 in turkeys in 2011, and ... | 2012 | 23402102 |
| a live attenuated h7n3 influenza virus vaccine is well tolerated and immunogenic in a phase i trial in healthy adults. | live attenuated influenza vaccines (laivs) are being developed and tested against a variety of influenza viruses with pandemic potential. we describe the results of an open-label phase i trial of a live attenuated h7n3 virus vaccine. | 2009 | 19464558 |
| determining the phylogenetic and phylogeographic origin of highly pathogenic avian influenza (h7n3) in mexico. | highly pathogenic (hp) avian influenza virus (aiv) h7n3 outbreaks occurred 3 times in the americas in the past 10 years and caused severe economic loss in the affected regions. in june/july 2012, new hp h7n3 outbreaks occurred at commercial farms in jalisco, mexico. outbreaks continued to be identified in neighbouring states in mexico till august 2013. to explore the origin of this outbreak, time resolved phylogenetic trees were generated from the eight segments of full-length aiv sequences in n ... | 2014 | 25226523 |
| novel genotypes of h9n2 influenza a viruses isolated from poultry in pakistan containing ns genes similar to highly pathogenic h7n3 and h5n1 viruses. | the impact of avian influenza caused by h9n2 viruses in pakistan is now significantly more severe than in previous years. since all gene segments contribute towards the virulence of avian influenza virus, it was imperative to investigate the molecular features and genetic relationships of h9n2 viruses prevalent in this region. analysis of the gene sequences of all eight rna segments from 12 viruses isolated between 2005 and 2008 was undertaken. the hemagglutinin (ha) sequences of all isolates we ... | 2009 | 19517011 |
| vaccination as a tool to combat introductions of notifiable avian influenza viruses in europe, 2000 to 2006. | in late 2000, italy was the first country of the european union (eu) to implement an emergency vaccination programme against notifiable avian influenza. vaccination with a conventional vaccine containing a seed strain with a different neuraminidase subtype from that of the field virus was used to complement biosecurity and restriction measures as part of an overall eradication strategy. this vaccination technique, in line with the differentiating infected from vaccinated animals system (diva), w ... | 2009 | 19618629 |
| antiviral activity of isatis indigotica root-derived clemastanin b against human and avian influenza a and b viruses in vitro. | clemastanin b, 7s,8r,8'r-(-)-lariciresinol-4,4'-bis-o-β-d-glucopyranoside, is one of the major lignans extracted from isatis indigotica root (iir). in this study, the anti-influenza activities of clemastanin b were evaluated in vitro. clemastanin b was found to inhibit different subtypes of human (h1n1, including swine-origin h1n1; h3n2 and influenza b) and avian influenza viruses (h6n2, h7n3, h9n2) at different magnitudes of activity (ic50 0.087-0.72 mg/ml) while this compound was inactive agai ... | 2013 | 23403777 |
| 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 ... | 2009 | 19618638 |
| partial direct contact transmission in ferrets of a mallard h7n3 influenza virus with typical avian-like receptor specificity. | avian influenza viruses of the h7 subtype have caused multiple outbreaks in domestic poultry and represent a significant threat to public health due to their propensity to occasionally transmit directly from birds to humans. in order to better understand the cross species transmission potential of h7 viruses in nature, we performed biological and molecular characterizations of an h7n3 virus isolated from mallards in canada in 2001. | 2009 | 19682381 |
| universal influenza dna vaccine encoding conserved cd4+ t cell epitopes protects against lethal viral challenge in hla-dr transgenic mice. | the goal of the present study was to design a vaccine that would provide universal protection against infection of humans with diverse influenza a viruses. accordingly, protein sequences from influenza a virus strains currently in circulation (h1n1, h3n2), agents of past pandemics (h1n1, h2n2, h3n2) and zoonotic infections of man (h1n1, h5n1, h7n2, h7n3, h7n7, h9n2) were evaluated for the presence of amino acid sequences, motifs, that are predicted to mediate peptide epitope binding with high af ... | 2010 | 19895924 |
| multiplex polymerase chain reaction for the detection and differentiation of avian influenza viruses and other poultry respiratory pathogens. | a multiplex reverse transcription-pcr (mrt-pcr) was developed and standardized for the detection of type a influenza viruses, avian influenza virus (aiv) subtype h7, h9, and h5 hemagglutinin gene with simultaneous detection of 3 other poultry respiratory pathogens, newcastle disease virus (ndv), infectious bronchitis virus (ibv), and infectious laryngotracheitis virus (iltv). seven sets of specific oligonucleotide primers were used in this study for the m gene of aiv and hemagglutinin gene of su ... | 2009 | 19903950 |
| influenza virus inactivation for studies of antigenicity and phenotypic neuraminidase inhibitor resistance profiling. | introduction of a new influenza virus in humans urges quick analysis of its virological and immunological characteristics to determine the impact on public health and to develop protective measures for the human population. at present, however, the necessity of executing pandemic influenza virus research under biosafety level 3 (bsl-3) high-containment conditions severely hampers timely characterization of such viruses. we tested heat, formalin, triton x-100, and beta-propiolactone treatments fo ... | 2010 | 20089763 |
| avian influenza in north and south america, the caribbean, and australia, 2006-2008. | between 2006 and 2008, only one outbreak of highly pathogenic notifiable avian influenza (ai) was reported from the americas, the caribbean, and australia. the outbreak, caused by h7n3, occurred in september 2007 in a multiage broiler breeder facility (approximately 49,000 birds) near regina beach in southern saskatchewan, canada. the disease was confined to a single farm; the farm was depopulated. all other reports of infections in poultry or wild birds involved low pathogenicity ai viruses. a ... | 2010 | 20521630 |
| rapid genome sequencing and characterization of novel avian-origin influenza a h7n9 virus directly from clinical sample by semiconductor sequencing. | recent outbreaks of severe pneumonia or acute respiratory distress syndrome have attracted much public interest. rapid and accurate diagnosis of the causative agent is key for an adequate response to suspected outbreaks. | 2015 | 26580409 |
| novel human h7n9 influenza virus in china. | outbreaks of h7n9 avian influenza in humans in 5 provinces and 2 municipalities of china have reawakened concern that avian influenza viruses may again cross species barriers to infect the human population and thereby initiate a new influenza pandemic. evolutionary analysis shows that human h7n9 influenza viruses originated from the h9n2, h7n3 and h11n9 avian viruses, and that it is as a novel reassortment influenza virus. this article reviews current knowledge on 11 subtypes of influenza a viru ... | 2014 | 24952971 |
| evaluation in mouse model of combined virus-bacterial vaccine based on attenuated influenza a(h7n3) virus and the group b streptococcus recombinant polypeptides. | secondary bacterial influenza complications are a common cause of excesses morbidity and mortality, which determines the need to develop means for specific prophylaxis. group b streptococcal infection is especially common cause of pneumonia among children and the elderly with underlying conditions. here we investigate in a mouse model the effects of combined intranasal immunization using live attenuated influenza vaccine and recombinant polypeptides based on group b streptococcus surface protein ... | 2016 | 27867430 |
| summary of avian influenza activity in europe, asia, and africa, 2006-2009. | events during the period extending from 2006 to 2009 have been overshadowed by the ongoing panzootic with h5n1 (highly pathogenic notifiable avian influenza [hpnai]), which has afflicted 63 countries and three continents (africa, asia, and europe) during the review period. two countries, indonesia and egypt, have formally declared the disease endemic to the world organisation for animal health, while others have used a variety of approaches aimed at containment, control, and eradication. these a ... | 2010 | 20521631 |
| a north american h7n3 influenza virus supports reassortment with 2009 pandemic h1n1 and induces disease in mice without prior adaptation. | reassortment between h5 or h9 subtype avian and mammalian influenza a viruses (iav) can generate a novel virus that causes disease and transmits between mammals. such information is currently not available for h7 subtype viruses. we evaluated the ability of a low-pathogenicity north american avian h7n3 virus (a/shorebird/delaware/22/2006) to reassort with mammalian or avian viruses using a plasmid-based competition assay. in addition to genome segments derived from an avian h7n9 virus, the h7n3 ... | 2016 | 26937034 |
| new approach to delist highly pathogenic avian influenza viruses from bsl3+ select agents to bsl2 non-select status for diagnostics and vaccines. | highly pathogenic avian influenza viruses (aivs) are select agents in the united states and are required to be handled in bio-containment level-3 enhanced (bsl3+) facilities. using a reverse genetics system, we attenuated a highly pathogenic virus, with the goal of making it low pathogenic and having it delisted as a select agent so that it could be handled in a bio-containment level-2 facility for diagnostic or vaccine production applications. we utilized two approaches to attenuate the target ... | 2010 | 20521650 |
| low pathogenicity avian influenza in italy during 2007 and 2008: epidemiology and control. | since 1999, the italian poultry production system has experienced several outbreaks of avian influenza (ai), mainly located in northeastern italy. this paper describes the low pathogenicity (lp) ai outbreaks detected during the surveillance activities implemented in 2007-08. from may to october 2007, ten rural and hobby poultry farms were infected by an lpai virus of the h7n3 subtype. in august-october 2007, the h7n3 lpai virus was introduced into the industrial poultry sector with the involveme ... | 2010 | 20521653 |
| phylogenetic analysis of the hemagglutinin gene of low pathogenic avian influenza virus h7n7 strains in mallards in northern europe. | the h7 subtype of avian influenza (ai) has the capability to evolve into a highly pathogenic ai (hpai) virus. in this study, we have characterized the hemagglutinin (ha) genes of three avian h7n7 influenza a viruses isolated from healthy migratory mallards in northern europe in three different years to study the natural variation of these viruses in the natural reservoir. phylogenetic analysis demonstrated that the h7 ha genes were all closely related to recent h7 isolates responsible for influe ... | 2010 | 20521678 |
| increased pathogenicity and shedding in chickens of a wild bird-origin low pathogenicity avian influenza virus of the h7n3 subtype following multiple in vivo passages in quail and turkey. | in order to investigate viral adaptation mechanisms to poultry, we performed serial in vivo passages of a wild bird low pathogenicity avian influenza isolate of the h7n3 subtype (a/mallard/italy/33/01) in three different domestic species (chicken, turkey, and japanese quail). the virus under study was administered via natural routes at the dose of 10(6) egg infective dose50/ 0.1 ml to chickens, turkeys, and quails in order to investigate the clinical susceptibility and the shedding levels after ... | 2010 | 20521693 |
| genetic stability of live attenuated vaccines against potentially pandemic influenza viruses. | ensuring genetic stability is a prerequisite for live attenuated influenza vaccine (laiv). this study describes the results of virus shedding and clinical isolates' testing of phase i clinical trials of russian laivs against potentially pandemic influenza viruses in healthy adults. | 2015 | 26432909 |
| molecular analysis of h7 avian influenza viruses from australia and new zealand: genetic diversity and relationships from 1976 to 2007. | full-genome sequencing of 11 australian and 1 new zealand avian influenza a virus isolate (all subtype h7) has enabled comparison of the sequences of each of the genome segments to those of other subtype h7 avian influenza a viruses. the inference of phylogenetic relationships for each segment has been used to develop a model of the natural history of these viruses in australia. phylogenetic analysis of the hemagglutinin segment indicates that the australian h7 isolates form a monophyletic clade ... | 2010 | 20668069 |