| [distribution and circulation of influenza viruses in nature]. | all of the known subtypes of influenza a viruses are circulating in ducks, providing the reservoir for the emergence of influenza viruses in all other species including humans. each of the pandemic influenza virus strains that emerged in 20th century is a reassortant generated in pig co-infected with avian viruses and the preceding human strains. none of the 15 ha and 9 na subtypes can be ruled out as potential candidates for future pandemics since avian viruses of any subtype can contribute gen ... | 2003 | 14619423 |
| prediction of tyrosine sulfation sites in animal viruses. | post-translational modification of proteins by tyrosine sulfation enhances the affinity of extracellular ligand-receptor interactions important in the immune response and other biological processes in animals. for example, sulfated tyrosines in polyomavirus and varicella-zoster virus may help modulate host cell recognition and facilitate viral attachment and entry. using a position-specific-scoring-matrix with an accuracy of 96.43%, we analyzed the possibility of tyrosine sulfation in all 1517 a ... | 2003 | 14651993 |
| structural differences among hemagglutinins of influenza a virus subtypes are reflected in their antigenic architecture: analysis of h9 escape mutants. | we used a panel of monoclonal antibodies to h9 hemagglutinin to select 18 escape mutants of mouse-adapted influenza a/swine/hong kong/9/98 (h9n2) virus. cross-reactions of the mutants with the antibodies and the sequencing of hemagglutinin genes revealed two minimally overlapping epitopes. we mapped the amino acid changes to two areas of the recently reported three-dimensional structure of a/swine/hong kong/9/98 hemagglutinin. the grouping of the antigenically relevant amino acid positions in h9 ... | 2004 | 14671105 |
| interactions of influenza a virus with sialic acids present on porcine surfactant protein d. | pigs can be infected with both human and avian influenza a virus (iav) strains and are therefore considered to be important intermediates in the emergence of new iav strains due to mixing of viral genes derived from human, avian, or porcine influenza viruses. these reassortant strains may have potential to cause pandemic influenza outbreaks in humans. the innate immune response against iav plays a significant role in containment of iav in the airways. we studied the interactions of iav with porc ... | 2004 | 14672916 |
| nucleic acid sequence-based amplification methods to detect avian influenza virus. | infection of poultry with highly pathogenic avian influenza virus (aiv) can be devastating in terms of flock morbidity and mortality, economic loss, and social disruption. the causative agent is confined to certain isolates of influenza a virus subtypes h5 and h7. due to the potential of direct transfer of avian influenza to humans, continued research into rapid diagnostic tests for influenza is therefore necessary. a nucleic acid sequence-based amplification (nasba) method was developed to dete ... | 2004 | 14684165 |
| porcine circovirus-2 and concurrent infections in the field. | porcine circovirus-2 (pcv-2) is the necessary cause of post-weaning multisystemic wasting syndrome (pmws) in swine; however, a variety of co-factors, including other infectious agents, are thought to be necessary in the full expression of disease. porcine parvovirus (ppv) was found in the inoculum used in the first experiments to reproduce pmws in gnotobiotic swine. retrospective and prospective studies in the field and laboratory have demonstrated pcv-2 can act synergistically with ppv to enhan ... | 2004 | 14741128 |
| the structure and receptor binding properties of the 1918 influenza hemagglutinin. | the 1918 influenza pandemic resulted in about 20 million deaths. this enormous impact, coupled with renewed interest in emerging infections, makes characterization of the virus involved a priority. receptor binding, the initial event in virus infection, is a major determinant of virus transmissibility that, for influenza viruses, is mediated by the hemagglutinin (ha) membrane glycoprotein. we have determined the crystal structures of the ha from the 1918 virus and two closely related has in comp ... | 2004 | 14764886 |
| pathogenicity and immunogenicity of influenza viruses with genes from the 1918 pandemic virus. | the 1918 influenza a h1n1 virus caused the worst pandemic of influenza ever recorded. to better understand the pathogenesis and immunity to the 1918 pandemic virus, we generated recombinant influenza viruses possessing two to five genes of the 1918 influenza virus. recombinant influenza viruses possessing the hemagglutinin (ha), neuraminidase (na), matrix (m), nonstructural (ns), and nucleoprotein (np) genes or any recombinant virus possessing both the ha and na genes of the 1918 influenza virus ... | 2004 | 14963236 |
| comparison of a commercial enzyme-linked immunosorbent assay with hemagglutination inhibition assay for serodiagnosis of swine influenza virus (h1n1) infection. | a commercial indirect swine influenza virus (siv) h1n1 enzyme-linked immunosorbent assay (elisa) was compared with the hemagglutination inhibition (hi) assay by testing 72 samples from experimentally infected pigs and 780 field samples of undefined siv status. the hi assay was performed using siv isolates a/swine/ia/73 for h1n1 and a/swine/ia/8548-1/98 for h3n2. the elisa used an siv isolated in 1988. the results showed that hi and elisa detected an antibody in 11 and 6, respectively, of 72 seru ... | 2004 | 14974854 |
| evaluation of transmission of swine influenza type a subtype h1n2 virus in seropositive pigs. | to examine clinical signs, virus infection and shedding, and transmission of swine influenza virus (siv) subtype h1n2 among seropositive pigs. | 2004 | 15027676 |
| changes in in vitro susceptibility of influenza a h3n2 viruses to a neuraminidase inhibitor drug during evolution in the human host. | influenza a h3n2 viruses isolated recently have characteristic receptor binding properties that may decrease susceptibility to neuraminidase inhibitor drugs. a panel of clinical isolates and recombinant viruses generated by reverse genetics were characterized and tested for susceptibility to zanamivir. | 2004 | 15028666 |
| antiviral effect of saccharomyces cerevisiae beta-glucan to swine influenza virus by increased production of interferon-gamma and nitric oxide. | the aim of these experiments was to investigate the potential antiviral effect of saccharomyces cerevisiae beta-glucan on the pneumonia induced by swine influenza virus (siv). forty colostrum-deprived 5-day-old piglets were randomly divided into four groups of 10. the 20 pigs in groups 1 and 2 were administered saccharomyces cerevisiae beta-glucan orally (50 mg/day/pig; en-bio technology co., ltd) for 3 days before siv infection and those in groups 3 and 4 were given culture medium/diluent alone ... | 2004 | 15030604 |
| experimental dual infection of pigs with an h1n1 swine influenza virus (a/sw/hok/2/81) and mycoplasma hyopneumoniae. | dual infection of pigs with swine influenza virus (siv) and mycoplasma hyopneumoniae was carried out to compare the clinical and pathological effects of dual infection in caesarian derived and colostrums deprived (cdcd) pigs, with that of a single infection with m. hyopneumoniae. in experiment 1, 40-day-old cdcd pigs were inoculated only with siv (a/sw/hok/2/81, h1n1). the virus was isolated from nasal swabs for 5-6 days. none of these pigs showed clinical signs of infection throughout the exper ... | 2004 | 15036530 |
| detection and isolation of h1n1 influenza virus from pigs in korea. | | 2004 | 15043001 |
| [avian flu, what are the risks of inter-human transmission?]. | | 2004 | 15105776 |
| clinical effects of experimental dual infections with porcine reproductive and respiratory syndrome virus followed by swine influenza virus in conventional and colostrum-deprived pigs. | previous studies demonstrated that experimental dual infections of pigs with porcine reproductive and respiratory syndrome virus (prrsv) followed by h1n1 influenza virus cause more severe disease and growth retardation than the respective single virus infections. here three experiments were undertaken to better define the clinical impact of combined prrsv-h1n1 infections in conventional and caesarean-derived colostrum-deprived (cdcd) pigs. groups of pigs were inoculated by aerosol with prrsv fol ... | 2001 | 15129583 |
| comparison of a commercial h1n1 enzyme-linked immunosorbent assay and hemagglutination inhibition test in detecting serum antibody against swine influenza viruses. | recently a commercial enzyme-linked immunosorbent assay (elisa) kit for detecting antibody against h1n1 swine influenza virus (siv) has been made available to diagnosticians and veterinary practitioners. because the hemagglutination inhibition (hi) test has been considered the standard test for siv serology, diagnostic performance of the new elisa was evaluated using positive (n = 60) and negative (n = 188) serum samples from young pigs with known status of siv infection and compared with that o ... | 2004 | 15152833 |
| multiple lineages of antigenically and genetically diverse influenza a virus co-circulate in the united states swine population. | before the isolation of h3n2 viruses in 1998, swine influenza in the united states was an endemic disease caused exclusively by classical-swine h1n1 viruses. in this study we determined the antigenic and phylogenetic composition of a selection of currently circulating strains and revealed that, in contrast to the situation pre-1998, the swine population in the united states is now a dynamic viral reservoir containing multiple viral lineages. h3n2 viruses still circulate and representatives of ea ... | 2004 | 15163491 |
| the ns1 gene of h5n1 influenza viruses circumvents the host anti-viral cytokine responses. | the h5n1 influenza viruses transmitted to humans in 1997 were highly virulent, but the mechanism of their virulence in humans is largely unknown. here we show that lethal h5n1 influenza viruses, unlike other human, avian, and swine influenza viruses, are resistant to the anti-viral effects of interferons and tumor necrosis factor alpha the nonstructural (ns) gene of h5n1 viruses is associated with this resistance. pigs infected with recombinant human h1n1 influenza virus that carried the h5n1 ns ... | 2004 | 15163498 |
| genetic relationships, serological cross-reaction and cross-protection between h1n2 and other influenza a virus subtypes endemic in european pigs. | this study examines the genetic relationships between the recently emerged h1n2 swine influenza virus and viruses of h1n1 and h3n2 subtypes, and the extent of protection against h1n2 challenge in pigs immune after infection or vaccination with the other subtypes. there was low amino acid homology (70.4-71.9%) in the haemagglutinin (ha) gene between h1n1 viruses used for primary infection or vaccination and the h1n2 challenge strain, with 94-99 amino acid changes between these viruses involving a ... | 2004 | 15163499 |
| in vitro and in vivo inhibitory effects of disodium cromoglycate on influenza virus infection. | disodium cromoglycate (dscg) is one of the safest drugs for the prevention of bronchial asthma and allergic rhinitis attacks. the effect of dscg on acute upper respiratory tract viral infection is still controversial. here we investigated dscg inhibition of influenza virus infection in vivo and in vitro. in vivo effects of dscg on viral infection were assessed using a murine model of respiratory tract infection. intranasal administration of dscg protected mice from death induced by infection wit ... | 2004 | 15187427 |
| molecular epidemiology of porcine h3n2 influenza a viruses isolated in germany between 1982 and 2001. | we examined influenza virus strains of the subtype h3n2 from outbreaks of respiratory diseases in swine herds in germany. four different clusters can be distinguished when comparing parts of the ha1 gene from porcine h3n2 isolates analyzed between 1982 and 2001. comparison between these clusters reveals a bp homology of less than 90%. in contrast, the homology within the clusters is between 93.7 and 100%. each of these clusters was confined to a specific time period. for the na gene an additiona ... | 2004 | 15192270 |
| phylogenetic analysis of an h1n2 influenza a virus isolated from a pig in korea. brief report. | an influenza h1n2 virus was isolated from a pig during an severe outbreak of respiratory disease in a korean herd. the neuraminidase (na) and pb1 genes of the h1n2 isolate were of human origin, while the hemagglutinin (ha), matrix (m), nucleoprotein (np), and non-structural (ns) genes were of swine origin and pa and pb2 gene were of avian origin. phylogenetic results indicate that the korean h1n2 isolate was closely related to h1n2 viruses isolated recently from pigs in the united states. | 2004 | 15221541 |
| influenza a viruses in feral canadian ducks: extensive reassortment in nature. | the current dogma of influenza accepts that feral aquatic birds are the reservoir for influenza a viruses. although the genomic information of human influenza a viruses is increasing, little of this type of data is available for viruses circulating in feral waterfowl. this study presents the genetic characterization of 35 viruses isolated from wild canadian ducks from 1983 to 2000, as the first attempt at a comprehensive genotypic analysis of influenza viruses isolated from feral ducks. this stu ... | 2004 | 15269374 |
| continuing evolution of h9n2 influenza viruses in southeastern china. | h9n2 influenza viruses are panzootic in domestic poultry in eurasia and since 1999 have caused transient infections in humans and pigs. to investigate the zoonotic potential of h9n2 viruses, we studied the evolution of the viruses in live-poultry markets in hong kong in 2003. h9n2 was the most prevalent influenza virus subtype in the live-poultry markets between 2001 and 2003. antigenic and phylogenetic analysis of hemagglutinin (ha) showed that all of the 19 isolates found except one belonged t ... | 2004 | 15280470 |
| binding of the hemagglutinin from human or equine influenza h3 viruses to the receptor is altered by substitutions at residue 193. | interactions of the hemagglutinin (ha) of influenza viruses with sialic acids (sa) are important for host range restriction. most human h3s have a ser193, while avian and equine h3s usually have an asn or a lys, respectively. to investigate the role of residue 193 in the recognition of sa, substitutions were introduced by mutagenesis within a human h3 and an equine h3. hemadsorption assays performed on cos-1 cells expressing wt or mutated has, showed that a k193s substitution in the context of a ... | 2004 | 15290389 |
| adaptation and limitations of established hemagglutination inhibition assays for the detection of porcine anti-swine influenza virus h1n2 antibodies. | hemagglutination inhibition (hi) has been a reliable method for determining porcine antibody levels to the well-characterized swine influenza virus (siv) h1n1 and h3n2 subtypes. however, the recent emergence of the novel h1n2 serotype of siv and the persistence of 2 other serotypes (h1n1 and h3n2) in the united states swine population represents a significant challenge to diagnostics. both standardized and modified hi protocols were used in a blinded study to examine a collection of 50 control s ... | 2004 | 15305735 |
| influenza as a model system for studying the cross-species transfer and evolution of the sars coronavirus. | severe acute respiratory syndrome coronavirus (sars-cov) moved into humans from a reservoir species and subsequently caused an epidemic in its new host. we know little about the processes that allowed the cross-species transfer of this previously unknown virus. i discuss what we have learned about the movement of viruses into humans from studies of influenza a, both how it crossed from birds to humans and how it subsequently evolved within the human population. starting with a brief review of se ... | 2004 | 15306391 |
| protection of weaned pigs by vaccination with human adenovirus 5 recombinant viruses expressing the hemagglutinin and the nucleoprotein of h3n2 swine influenza virus. | swine influenza virus (siv), subtype h3n2, is a recent reassortant virus that emerged in 1998 in north american swine causing severe respiratory and reproductive disease. in this study, two replication-defective adenovirus recombinants were developed as potential vaccines against h3n2 influenza viruses. three groups of 3-week-old pigs (10 pigs per group) were vaccinated intramuscularly (im) with the recombinants; one group was vaccinated with the recombinant adenovirus expressing the influenza v ... | 2004 | 15308368 |
| isolation and identification of swine influenza recombinant a/swine/shandong/1/2003(h9n2) virus. | ten influenza virus isolates were obtained from infected pigs from different places in shandong province showing clinical symptoms from october 2002 to january 2003. all 10 isolates were identified in china's national influenza research center as influenza a virus of h9n2 subtype. the complete genome of one isolate, designated a/swine/shandong/1/2003(h9n2), was sequenced and compared with sequences available in genbank. the results of analyses indicated that the sequence of a/swine/shandong/1/20 ... | 2004 | 15310468 |
| bird flu data languish in chinese journals. | | 2004 | 15329683 |
| [characterization of ha and na genes of swine influenza a (h9n2) viruses]. | to understand the origin of ha and na genes of swine influenza a (h9n2) viruses isolated from pigs in the mainland of china and on basis of these to reveal the pathogenicity of them in pigs. | 2004 | 15340516 |
| [origin of hemagglutinin and neuraminidase gene of swine influenza a h1n1 viruses]. | to understand the origin of hemagglutinin (ha), and neuraminidase (na) gene of swine influenza a (h1n1) viruses isolated in pigs in mainland china in 2002 and reveal the reason of pathogenesis of them in pigs. | 2003 | 15340540 |
| exposure of sero-positive gilts to swine influenza virus may cause a few stillbirths per litter. | six pregnant gilts were purchased from a high health herd and were found to be serologically positive for swine influenza virus (siv) subtype h3n2. three of the gilts, at 80 to 82 days of gestation, were experimentally exposed a second time to the same siv subtype--h3n2. no clinical signs resulted from the second exposure to siv and hemagglutination-inhibition (hi) titers for siv at 4 weeks postexposure were unchanged suggesting that the gilts had not been reinfected. however, the second exposur ... | 2004 | 15352547 |
| virology. avian flu finds new mammal hosts. | | 2004 | 15353766 |
| characterization of avian h3n3 and h1n1 influenza a viruses isolated from pigs in canada. | h3n3 and h1n1 influenza a viruses were isolated from canadian pigs in 2001 and 2002. these viruses are phylogenetically related to waterfowl viruses and antigenically distinct from reference swine influenza viruses. the isolation of these viruses reemphasizes the potential for interspecies transmission of influenza viruses from waterfowl to pigs in north america. | 2004 | 15365042 |
| real-time reverse transcription-polymerase chain reaction assays for the detection and differentiation of north american swine influenza viruses. | swine influenza is an acute respiratory disease of swine caused by type a influenza viruses. before 1998, mainly "classical" hin1 swine influenza viruses (sivs) were isolated from swine in the united states. since then, antigenically distinct reassortant h3 and h1 sivs have been identified as causative agents of respiratory disease in pigs on us farms. improvement in siv diagnostics is needed in light of the recently observed rapid evolution of h1 and h3 sivs and their zoonotic potential. to add ... | 2004 | 15460317 |
| genetic subtyping of influenza a viruses using rt-pcr with a single set of primers based on conserved sequences within the ha2 coding region. | influenza a viruses are subtyped conventionally according to the antigenic characteristics of the external glycoproteins, haemagglutinin (ha) and neuraminidase (na). to date 15 ha and 9 na subtypes have been described. there is a need to develop fast, accurate and reliable methods to identify influenza virus subtypes, which may be associated with disease outbreaks. an rt-pcr is described using a single primer pair based on a conserved region of the ha2 gene that can detect all 15 ha influenza a ... | 2004 | 15488629 |
| novel origin of the 1918 pandemic influenza virus nucleoprotein gene. | the nucleoprotein (np) gene of the 1918 pandemic influenza a virus has been amplified and sequenced from archival material. the np gene is known to be involved in many aspects of viral function and to interact with host proteins, thereby playing a role in host specificity. the 1918 np amino acid sequence differs at only six amino acids from avian consensus sequences, consistent with reassortment from an avian source shortly before 1918. however, the nucleotide sequence of the 1918 np gene has mo ... | 2004 | 15507633 |
| no apoptotic deaths and different levels of inductions of inflammatory cytokines in alveolar macrophages infected with influenza viruses. | influenza viruses are reported to infect mainly the respiratory tract epithelium of hosts. our studies in a pig model show that influenza a viruses infect alveolar macrophages that constitutively reside in the respiratory tract, without causing apoptosis. tumor necrosis factor alpha was the inflammatory cytokine most highly induced in these macrophages. in vivo, alveolar macrophages infected with human h3n2 influenza virus showed greater expression of tumor necrosis factor alpha than did alveola ... | 2004 | 15518807 |
| a hypothesis: the conjunction of soldiers, gas, pigs, ducks, geese and horses in northern france during the great war provided the conditions for the emergence of the "spanish" influenza pandemic of 1918-1919. | the great influenza pandemic of 1918-1919 was a cataclysmic outbreak of infection wherein over 50 million people died worldwide within 18 months. the question of the origin is important because most influenza surveillance at present is focussed on s.e. asia. two later pandemic viruses in 1957 and 1968 arose in this region. however we present evidence that early outbreaks of a new disease with rapid onset and spreadability, high mortality in young soldiers in the british base camp at etaples in n ... | 2005 | 15603896 |
| avian influenza viruses and their implication for human health. | widespread outbreaks of avian influenza in domestic fowl throughout eastern asia have reawakened concern that avian influenza viruses may again cross species barriers to infect the human population and thereby initiate a new influenza pandemic. simultaneous infection of humans (or swine) by avian influenza viruses in the presence of human influenza viruses could theoretically generate novel influenza viruses with pandemic potential as a result of reassortment of genome subunits between avian and ... | 2004 | 15614699 |
| [discovery of a novel reassortant h1n2 influenza virus]. | three strains of influenza a virus were isolated from patients suffering from influenza like disease in railway hygiene and anti-epidemic station of taiyuan in january 1996. the identification results by serological method indicated that the isolates were different from h1n2 subtype of influenza a virus isolated from men in 1989 and 1992 and that their ha antigenicity was similar to that of a/rp/8/34 (h1n1) virus, but distinguishable from that of influenza a (h1n1) virus circulating in mans rece ... | 1997 | 15619808 |
| a novel rt-multiplex pcr for enteroviruses, hepatitis a and e viruses and influenza a virus among infants and children with diarrhea in vietnam. | a novel reverse transcription-multiplex polymerase chain reaction (rt-multiplex pcr) assay that can detect enteroviruses, hepatitis a and e viruses and influenza a virus from various hosts (avian species, human, swine and horse) was developed. the identification of that group of viruses was performed with the mixture of four pairs of published specific primers (f1 and r1, p3 and p4, 2s and 2as, mmu42 and mmu43) for amplifying viral genomes and specifically generated four different amplicon sizes ... | 2005 | 15645373 |
| h3n2 influenza virus transmission from swine to turkeys, united states. | in 1998, a novel h3n2 reassortant virus emerged in the united states swine population. we report the interspecies transmission of this virus to turkeys in two geographically distant farms in the united states in 2003. this event is of concern, considering the reassortment capacity of this virus and the susceptibility of turkey to infection by avian influenza viruses. two h3n2 isolates, a/turkey/nc/16108/03 and a/turkey/mn/764/03, had 98.0% to 99.9% nucleotide sequence identity to each other in a ... | 2004 | 15663853 |
| avian influenza and pandemics--research needs and opportunities. | | 2005 | 15668221 |
| use of real-time reverse transcriptase polymerase chain reaction assay and cell culture methods for detection of swine influenza a viruses. | to evaluate sensitivity and specificity of a real-time reverse transcriptase polymerase chain reaction (rt-pcr) assay performed on pooled nasal swab specimens, compared with virus isolation performed on individual nasal swab specimens by use of 2 cell culture lines for detection of swine influenza a viruses. | 2005 | 15691046 |
| 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 |
| serologic evidence of human and swine influenza in mayan persons. | antibodies against influenza viruses were detected in 115 serum samples from indigenous mayan persons from kochol, yucatan. seropositivity rates were 26.9% to a/bayern/7/95, 40.8% to a/sydney/5/97, 1.7% to a/swine/wisconsin/238/97, and 79.1% to a/swine/minnesota/593/99. this report is the first in mexico of the prevalence of antibodies to swine influenza virus in humans. | 2005 | 15705345 |
| capturing a killer flu virus. | | 2005 | 15724338 |
| pathogenesis of swine influenza virus subtype h1n2 infection in pigs. | the purpose of this study was to elucidate pathogenesis and viral distribution in pigs infected with swine influenza virus subtype h1n2, over a period of 10 days, by morphometric analysis and in-situ hybridization. fifteen colostrum-deprived pigs aged 3 weeks were inoculated intranasally with virus. pneumonia was severe at 1 day post-inoculation (dpi), moderate at 3 and 5 dpi, and mild at 7 and 10 dpi. the pulmonary lesion score was correlated with the score of cells positive by in-situ hybridiz ... | 2005 | 15737344 |
| infectious diseases. experts dismiss pig flu scare as nonsense. | | 2005 | 15746398 |
| [application of gene sequence cluster in research for h3 antigenic evolution of influenza a virus]. | gene sequence data were clustered to explore evolution lineages of h3 antigen of influenza a virus. | 2004 | 15769361 |
| sequence comparison between the extracellular domain of m2 protein human and avian influenza a virus provides new information for bivalent influenza vaccine design. | to prevent the human and economic losses caused by human and avian influenza viruses, it is necessary to prepare safe bivalent influenza vaccines. recent studies found that human influenza vaccines based on the extracellular domain of influenza m2 protein (m2e) induced broad-spectrum protective immunity in various antigen constructs. a prerequisite for using the m2e protein as a bivalent influenza vaccine component was to find out the sequence differences between human and non-human (avian or sw ... | 2004 | 15777646 |
| receptor specificity of influenza viruses from birds and mammals: new data on involvement of the inner fragments of the carbohydrate chain. | we studied receptor-binding properties of influenza virus isolates from birds and mammals using polymeric conjugates of sialooligosaccharides terminated with common neu5ac alpha2-3gal beta fragment but differing by the structure of the inner part of carbohydrate chain. viruses isolated from distinct avian species differed by their recognition of the inner part of oligosaccharide receptor. duck viruses displayed high affinity for receptors having beta1-3 rather than beta1-4 linkage between neu5ac ... | 2005 | 15780877 |
| detection of influenza a virus by rt-pcr and standard methods in experimental infection of ducks. | cloacal swabs collected from mallard ducks (anas platyrhynchos) experimentally infected with a h7n1 avian influenza strain were examined by reverse transcription polymerase chain reaction to detect the influenza a virus. reverse transcription polymerase chain reaction was compared with standard methods: inoculation of embryonated chicken eggs and inoculation of three established cell lines: newborn swine kidney cells, newborn pig trachea cells and madine darby canine kidney cells. reverse transc ... | 2005 | 15782624 |
| pathogenesis of hong kong h5n1 influenza virus ns gene reassortants in mice: the role of cytokines and b- and t-cell responses. | the severity of disease caused in humans by h5n1 influenza viruses remains unexplained. the ns gene of hong kong h5n1/97 viruses was shown to contribute to high pathogenicity of reassortants in a pig model. however, the molecular pathogenesis and host immune response underlying this phenomenon remain unclear. here, in a mouse model, h1n1 a/puerto rico/8/34 (pr/8) reassortants that contained the h5n1/97 ns gene, the h5n1/01 ns gene, or an altered h5n1/97 ns gene encoding a glu92-->asp substitutio ... | 2005 | 15784906 |
| first outbreak of respiratory disease associated with swine influenza h1n2 virus in pigs in korea. | this report describes the first diagnosis of swine influenza h1n2 virus infection in growing pigs in korea by virus isolation, reverse transcription-polymerase chain reaction (rt-pcr), histopathology, and in situ hybridization. the subtype of swine influenza virus isolates was determined to be h1n2 by rt-pcr. the most consistent and predominant histological feature was bronchointerstitial pneumonia. lung tissues from these pigs were hybridized with the nonradioactive digoxigenin-labeled compleme ... | 2005 | 15825500 |
| probable tiger-to-tiger transmission of avian influenza h5n1. | during the second outbreak of avian influenza h5n1 in thailand, probable horizontal transmission among tigers was demonstrated in the tiger zoo. sequencing and phylogenetic analysis of those viruses showed no differences from the first isolate obtained in january 2004. this finding has implications for influenza virus epidemiology and pathogenicity in mammals. | 2005 | 15890122 |
| risk factors for the introduction of high pathogenicity avian influenza virus into poultry farms during the epidemic in the netherlands in 2003. | an epidemic of high pathogenicity avian influenza (hpai) occurred in the netherlands in 2003. a census survey of 173 infected and 401 uninfected commercial poultry farms was carried out to identify factors associated with the introduction of the hpai virus into poultry farms. data on farm size, production characteristics, type of housing, presence of cattle and pigs were gathered by the national inspection service for livestock and meat from all farms included in this study. for each risk factor ... | 2005 | 15899292 |
| evidence of the concurrent circulation of h1n2, h1n1 and h3n2 influenza a viruses in densely populated pig areas in spain. | this paper reports on a serological and virological survey for swine influenza virus (siv) in densely populated pig areas in spain. the survey was undertaken to examine whether the h1n2 siv subtype circulates in pigs in these areas, as in other european regions. six hundred sow sera from 100 unvaccinated breeding herds across northern and eastern spain were examined using haemagglutination inhibition (hi) tests against h1n1, h3n2 and h1n2 siv subtypes. additionally, 225 lung samples from pigs wi ... | 2006 | 15914047 |
| mutations in the ns1 protein of swine influenza virus impair anti-interferon activity and confer attenuation in pigs. | it has been shown previously that the nonstructural protein ns1 of influenza virus is an alpha/beta interferon (ifn-alpha/beta) antagonist, both in vitro and in experimental animal model systems. however, evidence of this function in a natural host has not yet been obtained. here we investigated the role of the ns1 protein in the virulence of a swine influenza virus (siv) isolate in pigs by using reverse genetics. the virulent wild-type a/swine/texas/4199-2/98 (tx/98) virus and various mutants e ... | 2005 | 15919908 |
| birds, migration and emerging zoonoses: west nile virus, lyme disease, influenza a and enteropathogens. | wild birds are important to public health because they carry emerging zoonotic pathogens, either as a reservoir host or by dispersing infected arthropod vectors. in addition, bird migration provides a mechanism for the establishment of new endemic foci of disease at great distances from where an infection was acquired. birds are central to the epidemiology of west nile virus (wnv) because they are the main amplifying host of the virus in nature. the initial spread of wnv in the u.s. along the ea ... | 2003 | 15931279 |
| receptor-binding properties of swine influenza viruses isolated and propagated in mdck cells. | to study the receptor specificities of h1 and h3 influenza viruses isolated recently from pigs, we employed the analogues of natural receptors, namely sialyloligosaccharides conjugated with polyacrylamide in biotinylated and label free forms. all madin-darby canine kidney (mdck) cell-propagated viruses with human h3 or classical swine h1 hemagglutinins bound only to neu5acalpha2-6galbeta1-bearing polymers, and not to neu5acalpha2-3galbeta1-bearing polymers. this receptor-binding pattern is typic ... | 2005 | 15996787 |
| [do pigs play a role in human infection with avian influenza a h9n2 viruses]. | to understand whether pigs play a role in human infection with avian influenza a h9n2 viruses. | 2005 | 16027771 |
| studies of h5n1 influenza virus infection of pigs by using viruses isolated in vietnam and thailand in 2004. | to determine whether avian h5n1 influenza viruses associated with human infections in vietnam had transmitted to pigs, we investigated serologic evidence of exposure to h5n1 influenza virus in vietnamese pigs in 2004. of the 3,175 pig sera tested, 8 (0.25%) were positive for avian h5n1 influenza viruses isolated in 2004 by virus neutralization assay and western blot analysis. experimental studies of replication and transmissibility of the 2004 asian h5n1 viruses in pigs revealed that all viruses ... | 2005 | 16051873 |
| isolation and characterization of h3n2 influenza a virus from turkeys. | five 34-wk-old turkey breeder layer flocks in separate houses of 2550 birds each in a single farm in ohio experienced a drop in egg production from late january to early february 2004. tracheal swabs (n = 60), cloacal swabs (n = 50), and convalescent sera (n = 110) from the flocks were submitted to the laboratory for diagnostics. virus isolation was attempted in specific-pathogen free embryonating chicken eggs and vero and mdck cells. virus characterization was performed using agar gel immunodif ... | 2005 | 16094824 |
| characterization of the humoral immune response of experimentally infected and vaccinated pigs to swine influenza viral proteins. | the value of serologic tests for diagnosis of swine influenza virus (siv) infection has been diminished by the emergence of new subtypes and by antigenic drift within subtype. the intensive use of vaccination also has complicated interpretation of serology results. serologic assays are needed that can detect infection regardless of subtype or antigenic variation and that can differentiate antibody induced by infection from that induced by vaccination. in this study, the antibody responses to spe ... | 2006 | 16132180 |
| substitution of the transmembrane domain of vpu in simian-human immunodeficiency virus (shivku1bmc33) with that of m2 of influenza a results in a virus that is sensitive to inhibitors of the m2 ion channel and is pathogenic for pig-tailed macaques. | the vpu protein of human immunodeficiency virus type 1 has been shown to shunt the cd4 receptor molecule to the proteasome for degradation and to enhance virus release from infected cells. the exact mechanism by which the vpu protein enhances virus release is currently unknown but some investigators have shown that this function is associated with the transmembrane domain and potential ion channel properties. in this study, we determined if the transmembrane domain of vpu could be functionally s ... | 2006 | 16199074 |
| [chronicle of an announced pandemic?]. | in the last years our country has been affected by several outbreaks of infectious diseases such as cholera and hanta virus and recently, by pathogens associated to red tide. chile was able to manage those emergencies using the local health system. the new threat that may emerge and could eventually overcome that capacity, is the possible h5n1 influenza virus outbreak. influenza is responsible for the most destructive pandemic, the spanish influenza, that killed over 40 million individuals in 19 ... | 2005 | 16311690 |
| are swine workers in the united states at increased risk of infection with zoonotic influenza virus? | pandemic influenza strains originate in nonhuman species. pigs have an important role in interspecies transmission of the virus. we examined multiple swine-exposed human populations in the nation's number 1 swine-producing state for evidence of previous swine influenza virus infection. | 2006 | 16323086 |
| quail carry sialic acid receptors compatible with binding of avian and human influenza viruses. | there is growing evidence that some terrestrial avian species may play a role in the genesis of influenza viruses with pandemic potential. in the present investigation, we examined whether quail, a widespread-farmed poultry, possess the proper characteristics for serving as an intermediate host for the zoonotic transmission of influenza viruses. using a lectin-based staining based on specific agglutinins, we found that, in addition to the presence of sialic acid alpha2,3-galactose (saalpha2,3-ga ... | 2006 | 16325879 |
| [how dangerous is avian flu for mankind?]. | avian influenza, an infectious disease of birds, is caused by type a strain of the influenza virus. the disease, which was first identified in italy more than 100 years ago, occurs worldwide. avian influenza viruses are mainly distributed by migratory birds. various animals like birds, pigs, horses, sea mammals and, finally, humans are susceptible to influenza a viruses. the high possibility of genomic changes like gene shift and drift are caused by the segmented rna genome. | 2005 | 16328178 |
| evaluation of a recombinant human adenovirus-5 vaccine administered via needle-free device and intramuscular injection for vaccination of pigs against swine influenza virus. | to evaluate the safety and efficacy of a human adenovirus-5 vaccine for protecting weaned pigs against swine influenza virus subtype h3n2 infection when administered via 2 injection methods. | 2005 | 16334954 |
| evaluation of the espline influenza a&b-n kit for the diagnosis of avian and swine influenza. | the espline influenza a&b-n kit was evaluated for its applicability to the rapid diagnosis of influenza in chickens and pigs. the kit specifically detected viral antigens in tracheal swabs and tissue homogenates of the trachea, liver, spleen, and colon of chickens inoculated with a highly pathogenic avian influenza virus strain, a/chicken/yamaguchi/7/04 (h5n1), at 48 hr post-inoculation (p.i.) as well as in the tracheal and cloacal swabs and tissue homogenates of dead chickens. for those infecte ... | 2005 | 16365531 |
| avian flu to human influenza. | influenza a viral infection causes substantial annual morbidity and mortality worldwide, particularly for infants, the elderly, and the immunocompromised. the virus mainly replicates in the respiratory tract and is spread by respiratory secretions. a growing concern is the recent identification of h5n1 strains of avian influenza a in asia that were previously thought to infect only wild birds and poultry, but have now infected humans, cats, pigs, and other mammals, often with fatal results, in a ... | 2006 | 16409141 |
| [origin of internal genes of two strains of swine influenza a (h1n1) virus]. | through the analysis of internal genes of viruses to understand whether the internal genes of two strains of swine influenza a(h1n1) virus contain the gene segment deriving from avian influenza a viruses, and whether the reassortment of the internal genes occurred between swine h1n1 and swine h9n2 viruses. | 2005 | 16415995 |
| architecture of ribonucleoprotein complexes in influenza a virus particles. | in viruses, as in eukaryotes, elaborate mechanisms have evolved to protect the genome and to ensure its timely replication and reliable transmission to progeny. influenza a viruses are enveloped, spherical or filamentous structures, ranging from 80 to 120 nm in diameter. inside each envelope is a viral genome consisting of eight single-stranded negative-sense rna segments of 890 to 2,341 nucleotides each. these segments are associated with nucleoprotein and three polymerase subunits, designated ... | 2006 | 16437116 |
| restricted infectivity of a human-lineage h3n2 influenza a virus in pigs is hemagglutinin and neuraminidase gene dependent. | influenza a viruses cause pandemics at sporadic intervals. pandemic viruses can potentially be introduced into the human population through in toto transfer of an avian influenza virus or through reassortment between avian and human strains. pigs are believed to play a central role in the creation of pandemic viruses through reassortment because of their susceptibility to infection with both avian and human influenza viruses. however, we recently found that a human-lineage h3n2 influenza virus w ... | 2006 | 16455873 |
| a single amino acid substitution within the transmembrane domain of the human immunodeficiency virus type 1 vpu protein renders simian-human immunodeficiency virus (shiv(ku-1bmc33)) susceptible to rimantadine. | previous studies from our laboratory have shown that the transmembrane domain (tm) of the vpu protein of human immunodeficiency virus type 1 (hiv-1) contributes to the pathogenesis of shiv(ku-1bmc33) in macaques and that the tm domain of vpu could be replaced with the m2 protein viroporin from influenza a virus. recently, we showed that the replacement of the tm domain of vpu with that of the m2 protein of influenza a virus resulted in a virus (shiv(m2)) that was sensitive to rimantadine [hout, ... | 2006 | 16458946 |
| a serological survey of selected pathogens in wild boar in slovenia. | serum samples collected from 178 shot wild boars (sus scrofa) were tested for the presence of antibodies against classical swine fever virus, aujeszky's disease virus (adv), porcine reproductive and respiratory syndrome virus, porcine respiratory coronavirus (prcv), transmissible gastroenteritis virus, swine influenza virus, porcine parvovirus (ppv), swine vesicular disease virus, actinobacillus pleuropneumoniae (app), mycoplasma hyopneumoniae, salmonella spp., brucella spp. and haemophilus para ... | 2006 | 16460352 |
| defra outlines its plans for implementing the european avian influenza directive. | | 2006 | 16489150 |
| influenza pandemics of the 20th century. | three worldwide (pandemic) outbreaks of influenza occurred in the 20th century: in 1918, 1957, and 1968. the latter 2 were in the era of modern virology and most thoroughly characterized. all 3 have been informally identified by their presumed sites of origin as spanish, asian, and hong kong influenza, respectively. they are now known to represent 3 different antigenic subtypes of influenza a virus: h1n1, h2n2, and h3n2, respectively. not classified as true pandemics are 3 notable epidemics: a p ... | 2006 | 16494710 |
| swine influenza a outbreak, fort dix, new jersey, 1976. | in early 1976, the novel a/new jersey/76 (hsw1n1) influenza virus caused severe respiratory illness in 13 soldiers with 1 death at fort dix, new jersey. since a/new jersey was similar to the 1918-1919 pandemic virus, rapid outbreak assessment and enhanced surveillance were initiated. a/new jersey virus was detected only from january 19 to february 9 and did not spread beyond fort dix. a/victoria/75 (h3n2) spread simultaneously, also caused illness, and persisted until march. up to 230 soldiers w ... | 2006 | 16494712 |
| reflections on the 1976 swine flu vaccination program. | in 1976, 2 recruits at fort dix, new jersey, had an influenza like illness. isolates of virus taken from them included a/new jersey/76 (hsw1n1), a strain similar to the virus believed at the time to be the cause of the 1918 pandemic, commonly known as swine flu. serologic studies at fort dix suggested that >200 soldiers had been infected and that person-to-person transmission had occurred. we review the process by which these events led to the public health decision to mass-vaccinate the america ... | 2006 | 16494713 |
| influenza pandemic periodicity, virus recycling, and the art of risk assessment. | influenza pandemic risk assessment is an uncertain art. the theory that influenza a virus pandemics occur every 10 to 11 years and seroarcheologic evidence of virus recycling set the stage in early 1976 for risk assessment and risk management of the fort dix, new jersey, swine influenza outbreak. additional data and passage of time proved the theory untenable. much has been learned about influenza a virus and its natural history since 1976, but the exact conditions that lead to the emergence of ... | 2006 | 16494714 |
| the swine flu episode and the fog of epidemics. | the 1918 influenza pandemic has shaped research and public health for nearly a century. in 1976, the specter of 1918 loomed large when a pandemic threatened the country again. public health officials initiated a mass vaccination campaign, but the anticipated pandemic failed to occur. an examination of the available data in 1976 and the decision to vaccinate, as well as lessons learned from the hiv/aids epidemic in the early 1980s, may help shape an appropriate public health response to future th ... | 2006 | 16494715 |
| pathogenicity of a highly pathogenic avian influenza virus, a/chicken/yamaguchi/7/04 (h5n1) in different species of birds and mammals. | outbreaks of highly pathogenic avian influenza (hpai) have been occurring in domestic poultry in asia since 1996. in the beginning of 2004, hpai outbreaks were caused by h5n1 virus in two farms and a group of pet chickens in different areas of japan. in the present study, the pathogenicity of a/chicken/yamaguchi/7/04 (h5n1), which had been isolated from a dead chicken during the first outbreak in japan, was assessed in chickens, quails, budgerigars, ducklings, mice, and miniature pigs by experim ... | 2006 | 16502281 |
| expression of hemagglutinin protein from the avian influenza virus h5n1 in a baculovirus/insect cell system significantly enhanced by suspension culture. | prevention of a possible avian influenza pandemic necessitates the development of rapid diagnostic tests and the eventual production of a vaccine. | 2006 | 16504108 |
| identification of human h1n2 and human-swine reassortant h1n2 and h1n1 influenza a viruses among pigs in ontario, canada (2003 to 2005). | since 2003, three novel genotypes of h1 influenza viruses have been recovered from canadian pigs, including a wholly human h1n2 virus and human-swine reassortants. these isolates demonstrate that human-lineage h1n2 viruses are infectious for pigs and that viruses with a human pb1/swine pa/swine pb2 polymerase complex can replicate in pigs. | 2006 | 16517910 |
| activation of the intrinsic mitochondrial apoptotic pathway in swine influenza virus-mediated cell death. | the mitochondrial pathway of swine influenza virus (siv)-induced apoptosis was investigated using porcine kidney (pk-15) cells, swine testicle (st) cells, and hela cervical carcinoma cells which are known not to support viral replication. as judged by cell morphology, annexin v staining, and dna fragmentation, pk-15 and st cells infected with three different subtypes of siv (h1n1, h3n2, and h1n2) were obviously killed by apoptosis, not necrosis. siv infection in pk-15 and hela cells was shown to ... | 2006 | 16520548 |
| expression of mx protein and interferon-alpha in pigs experimentally infected with swine influenza virus. | expression of mx protein and interferon-alpha (ifn-alpha) was examined by immunohistochemistry in pigs experimentally infected with swine influenza virus. in infected pigs euthanatized at 1 day postinoculation (dpi), the lumen of bronchioles were filled with large numbers of mononuclear cells, small numbers of neutrophils, sloughing epithelial cells, and proteinaceous fluid. lesions at 3 and 5 dpi were similar but less severe. alveolar spaces were filled with neutrophils. by 7 and 10 dpi, micros ... | 2006 | 16537933 |
| influenza virus infections in mammals. | the natural reservoir of all known subtypes of influenza a viruses are aquatic birds, mainly of the orders anseriformes and charadriiformes in which the infection is asymptomatic and the viruses stay at an evolutionary equilibrium. however, mammals may occasionally contract influenza a virus infections from this pool. this article summarizes: (i) natural infections in mammals including pigs, horses, marine mammals, ferrets, minks; (ii) results from experimental infections in several animal model ... | 2006 | 16573202 |
| sialic acid is a receptor determinant for infection of cells by avian infectious bronchitis virus. | the importance of sialic acid for infection by avian infectious bronchitis virus (ibv) has been analysed. neuraminidase treatment rendered vero, baby hamster kidney and primary chicken kidney cells resistant to infection by the ibv-beaudette strain. sialic acid-dependent infection was also observed with strain m41 of ibv, which infects primary chicken kidney cells but not cells from other species. in comparison with influenza a virus and sendai virus, ibv was most sensitive to pre-treatment of c ... | 2006 | 16603523 |
| a recombinant pseudorabies virus encoding the ha gene from h3n2 subtype swine influenza virus protects mice from virulent challenge. | the hemagglutinin (ha) gene of a/swine/inner mogolian/547/2001 (h3n2) swine influenza virus (siv) was recombined into the genome of pseudorabies virus (prv) bartha-k61 vaccine strain, generating a recombinant prv expressing the ha gene, designated as rprv-ha. one group of 15 mice was inoculated intranasally (i.n.) with 10(5.0) pfu of rprv-ha, and another two control groups of mice (15 mice per group) were mock-inoculated or inoculated with bartha-k61. mice inoculated with rprv-ha developed hemag ... | 2006 | 16621018 |
| the immune response and maternal antibody interference to a heterologous h1n1 swine influenza virus infection following vaccination. | this study investigated the efficacy of a bivalent swine influenza virus (siv) vaccine in piglets challenged with a heterologous h1n1 siv isolate. the ability of maternally derived antibodies (mda) to provide protection against a heterologous challenge and the impact mda have on vaccine efficacy were also evaluated. forty-eight mda(+) pigs and 48 mda(-) pigs were assigned to 8 different groups. vaccinated pigs received two doses of a bivalent siv vaccine at 3 and 5 weeks of age. the infected pig ... | 2006 | 16621020 |
| isolation and genetic characterization of new reassortant h3n1 swine influenza virus from pigs in the midwestern united states. | since the introduction of h3n2 swine influenza viruses (sivs) into u.s. swine in 1998, h1n2 and h1n1 reassortant viruses have emerged from reassortment between classical h1n1 and h3n2 viruses. in 2004, a new reassortant h3n1 virus (a/swine/minnesota/00395/2004) was identified from coughing pigs. phylogenetic analyses revealed a hemagglutinin segment similar to those of contemporary cluster iii h3n2 sivs and a neuraminidase sequence of contemporary h1n1 origin. the internal genes were of swine, h ... | 2006 | 16641303 |
| molecular virology: was the 1918 pandemic caused by a bird flu? | taubenberger et al. have sequenced the polymerase genes of the pandemic 'spanish' influenza a virus of 1918, thereby completing the decoding of the genome of this virus. the authors conclude from these sequences that the virus jumped from birds to humans shortly before the start of the pandemic and that it was not derived from earlier viruses by gene shuffling, a process called reassortment. however, we believe that their evidence does not convincingly support these conclusions and that some of ... | 2006 | 16641948 |
| molecular virology: was the 1918 flu avian in origin? | taubenberger et al. claim that the 1918 influenza virus was derived from an avian source and adapted to humans shortly before the pandemic. however, we do not believe that this conclusion, which has been widely disseminated in the popular press and in scientific journals, is supported by their phylogenetic evidence. | 2006 | 16641950 |
| novel swine influenza virus subtype h3n1, united states. | influenza a virus infects various animal species and transmits among different hosts, especially between humans and swine. swine may serve as a mixing vessel to create new reassortants that could infect humans. thus, monitoring and characterizing influenza viruses in swine are important in preventing interspecies transmission. we report the emergence and characterization of a novel h3n1 subtype of swine influenza virus (siv) in the united states. phylogenetic analysis showed that the h3n1 sivs m ... | 2006 | 16704839 |