| [the use of internal protein of equine influenza virus in fluorescence antibody test for rapid diagnosis of influenza (author's transl)]. | | 1982 | 6809272 |
| mouse neurotropic recombinants of influenza a viruses. | recombinants with known gene constellations between fowl plague virus (fpv) and various prototype influenza virus strains have been examined for neurovirulence in suckling mice. strongly neurotropic recombinants were obtained from crosses between fpv and the strains virus n, hong kong, and pr8, but not between fpv and equi 2 or swine viruses. all highly neurotropic recombinants had rna segment 4 (ha) derived from fpv and rna segment 2 (ptra gene) from the other prototype strain. the derivation o ... | 1983 | 6838380 |
| prevalence of influenza viruses a-h1n1 and a-h3n2 in swine in the netherlands. | in the period december 1979-may 1980 a respiratory disease spread rapidly through pig herds in the netherlands. surveillance of 12 pig farms resulted in isolation of 22 influenza a-swine-h1n1 (hsw1n1) strains from 9 pig herds. the morbidity rate was high but the mortality rate was nil. retardation in growth was observed. sera collected from affected pig herds showed a fourfold increase in haemagglutination inhibition (hi) titre against a-swine-h1n1 virus. sera collected on five farms showed a ge ... | 1983 | 6851479 |
| auto-antibody dependent activation of the autologous classical complement pathway by guinea-pig red cells treated with influenza virus or neuraminidase: in vitro and in vivo study. | guinea-pig erythrocytes that had been exposed to influenza a virus or vibrio cholerae neuraminidase activated the classical complement pathway in autologous serum. because all viral particles were eluted from the treated cells, activation was not dependent on anti-viral antibodies or on the particles themselves. after a threshold of 45-55% desialation, had been reached, the relative capacity of treated cells to activate complement increased very rapidly with desialation. desialation unmasked sit ... | 1983 | 6852870 |
| [biological properties of live and inactivated influenza vaccines under experimental conditions]. | biological properties of influenza vaccines were studied on experimental animals inoculated intraperitoneally with regard to the vaccine effect on peritoneal exudate cells. the development of neutrophilia and inhibition of acid phosphatase activity in macrophages within the first 24 hours after intraperitoneal inoculation of influenza viruses or influenza vaccines were used for determination of the toxic effect of the inoculum. the values of subsequent later activation of acid phosphatase in mac ... | 1983 | 6868558 |
| adjustment of rates of guillain-barré syndrome among recipients of swine flu vaccine, 1976-1977. | | 1983 | 6876058 |
| evidence for the natural transmission of influenza a virus from wild ducts to swine and its potential importance for man. | in 1979, epidemics of influenza occurred in pigs in belgium from which were isolated strains of influenza a (hsw1n1) virus antigenically closely related to hsw1n1 strains previously isolated from ducks in north america and the federal republic of germany. this finding is considered as the first supportive evidence that an influenza a virus in an avian species might have been transmitted to mammals. | 1981 | 6973418 |
| the ecology of influenza viruses: a who memorandum. | influenza a viruses continue to be isolated from man, pigs, horses, and a wide range of avian species, especially ducks. the recent isolation of an influenza a virus from seals has added an additional mammal to the list of natural hosts for these viruses. in contrast, influenza b viruses have been isolated only from man.the haemagglutinin of a virus isolated from gulls in the united states of america could not be identified with reference antisera and may constitute a new haemagglutinin subtype. ... | 1981 | 6978194 |
| [search for antibodies against human influenza virus in swine]. | | 1982 | 6985408 |
| [testing of influenza virus vaccines--an international comparison]. | | 1980 | 7003931 |
| joseph e. smadel memorial lecture. strategy for development of respiratory and gastrointestinal tract viral vaccines in the 1980s. | | 1981 | 7014728 |
| the binding of staphylococcal protein a by the sera of different animal species. | the capacity of purified immunoglobulin or serum to bind (125i)-labeled staphylococcal protein a (spa) was measured by means of an immunofiltration assay that facilitated the examination of large numbers of sera and required only a minute quantity of each. sera from 80 species, including humans, laboratory animals, domestic animals, and a variety of african mammals were examined. a wide interspecies variation in the spa-binding capacity of serum immunoglobulins was confirmed. only small variatio ... | 1982 | 7061862 |
| further genetic evidence for maintenance of early hong kong-like influenza a(h3n2) strains in swine until 1976. | | 1982 | 7064347 |
| isolation of an influenza h1n1 virus from a pig. | | 1982 | 7064356 |
| prevalence of hemagglutination inhibition antibody to current strains of the h3n2 and h1n1 subtypes of influenza a virus in sera collected from the elderly in 1976. | sera were collected in 1976 from 182 individuals born between 1876-1935, who included patients in a large local nursing home in orange county, california, and patients and staff at the university of california, irvine medical center. sera were treated with receptor-destroying enzyme and assayed for hemagglutination inhibition (hi) antibody to recent strains of influenza a virus. the antigens tested were: a/victoria/3/76 and a/texas/1/77 for subtype h3n2; a/new jersey/8/76, a/x53 and a/swine/1976 ... | 1982 | 7072705 |
| statistical analysis of results of a survey on antibody against swine influenza virus in pigs by single radial hemolysis and hemagglutination-inhibition tests. | | 1982 | 7078660 |
| swine-influenza vaccine. | | 1982 | 7092000 |
| guillain-barré syndrome in the united states, 1979-1980 and 1980-1981. lack of an association with influenza vaccination. | an ongoing surveillance program was intensified during the 1979-1980 and the 1980-1981 influenza seasons to determine whether an increased risk of acquiring guillain-barré syndrome (gbs) within eight weeks after influenza vaccination existed for adults in the united states who received influenza vaccine, when compared with adult who had not been vaccinated recently. five hundred twenty-eight cases of gbs with onset between sept 1 and march 31, including seven following recent vaccination, were r ... | 1982 | 7097920 |
| bilateral optic nerve atrophy and blindness following swine influenza vaccination. | | 1982 | 7103325 |
| equine influenza virus enhances responsiveness of guinea-pig tracheal muscle to isoprenaline. | groups of guinea-pigs were vaccinated with equine influenza a-1 virus and helically-cut tracheal strips were subsequently contracted to carbachol (ec50) and relaxed to isoprenaline at 3, 5 and 10 days post-vaccination. tracheas from another group were contracted to phenylephrine in the presence of propranolol. compared to controls, responses to isoprenaline in virus-infected tracheas were significantly potentiated at days 3 and 10. virus infection significantly inhibited tracheal responsiveness ... | 1982 | 7123002 |
| isolation of ortho- and paramyxoviruses from migrating feral ducks in hokkaido. brief report. | a total of 18 hemagglutinating agents were isolated from 14 of 278 migrating feral ducks in hokkaido during the surveillance studies conducted from 1978 to 1981. seven of the 18 isolates belonged to paramyxovirus and the rest to influenza a virus. five isolates of paramyxovirus reacted specifically with antiserum to duck/hk/199/77 and 7 isolates of influenza a virus possessed the antigenic configuration of h10n3. three of the isolates possessed an hemagglutinin that has no antigenic relation to ... | 1982 | 7165509 |
| detection of influenza a viruses and influenza epidemics in wild pelagic birds by sentinels and population studies. | field experiments with domestic ducks as sentinels and virological and serological population observations on wild pelagic birds on a seabird-breeding island in the baltic sea and on rivers and lakes near berlin were conducted to detect the influenza a virus circulation and epidemics in wild pelagic bird populations. influenza a virus isolates were detected in tracheal and cloacal swabs from sentinel ducks and from healthy pelagic birds. influenza a virus epidemics with different subtypes in an ... | 1982 | 7170852 |
| [rapid preparation of inhibitor-resistant clones of the influenza a viruses for diagnostic purposes]. | | 1982 | 7187558 |
| guillain-barré syndrome and the 1978-1979 influenza vaccine. | an ongoing surveillance program was intensified to determine whether an increased risk of acquiring vaccine-related guillain-barré syndrome (gbs) (similar to that observed after vaccination with the a/new jersey swine-influenza vaccine in 1976) existed for the approximately 12.5 million adults (greater than or equal to 18 years old) vaccinated in the 1978-1979 influenza campaign. in the contiguous united states (excluding maryland) 544 cases of gbs with onset between september 1, 1978, and march ... | 1981 | 7231501 |
| registration is not informed consent: the swine flu program revisited. | | 1981 | 7232692 |
| ["standard" and "defective" populations of a/swine/1976/31 influenza virus and their role in the development of persistent infection in tissue culture]. | | 1981 | 7253975 |
| [grouping of influenza a virus np proteins]. | a comparative study of influenza a virus np proteins was carried out using peptide mapping. thirty-five strains of all main serotypes of human and animal viruses were tested. the greatest diversity was found in np proteins of human influenza viruses belonging to different serotypes, while within serotypes the variability is less pronounced. four main groups of np proteins were distinguished and designated np0, np1, np2, and np3. the np0 group includes proteins of viruses of hon1 serotype, np pro ... | 1981 | 7257320 |
| the interaction of influenza virus haemagglutinin with phospholipid vesicles - morphological and immunological studies. | ha-lipid spheres or "virosomes' were prepared using neutral or negatively charged, but not positively charged, phospholipids. virosomes were similar in size and shape to native virus particles although the ha subunites were at least twofold less numerous on the virosomes. the ha subunites were attached by their narrow end to the lipid bilayer, and could be removed by digestion with bromelain. however, ha subunits released from intact virus by digestion with bromelain, which removed the hydrophob ... | 1981 | 7288397 |
| intrinsic interference between swine influenza and fowl plague virus. | multiplication of swine influenza (sw) virus is inhibited by fowl plaque virus (fpv) at the level of rna synthesis when host cells are infected with both viruses at a high multiplicity of infection. under these conditions reassortment between the two viruses cannot be detected. the inhibitory effect of fpv is highly reduced and recombinants between the two viruses could be obtained when the cells were superinfected with fpv 1--2 hours after infection with sw virus, or after simultaneous infectio ... | 1981 | 7295037 |
| [effect of influenza virus on the lung tissue in the immune complex in vitro]. | | 1981 | 7300509 |
| replication of avian influenza a viruses in mammals. | the recent appearance of an avian influenza a virus in seals suggests that viruses are transmitted from birds to mammals in nature. to examine this possibility, avian viruses of different antigenic subtypes were evaluated for their ability to replicate in three mammals-pigs, ferrets, and cats. in each of these mammals, avian strains replicated to high titers in the respiratory tract (10(5) to 10(7) 50% egg infective doses per ml of nasal wash), with peak titers at 2 to 4 days post-inoculation, s ... | 1981 | 7309229 |
| [on the immunoserological modification of the human type a influenza virus in animals (author's transl)]. | | 1981 | 7309835 |
| isolation and serological characterization of influenza a virus from a pig in thailand. | a hemagglutinating agent was isolated from a pig in thailand in 1978 during the early febrile stage of an influenza-like illness and identified as influenza a virus. the isolate contained hemagglutinin and neuraminidase antigens that were antigenically indistinguishable from those of a/tokyo/6/73 (h3n2), a port chalmers-like strain isolated in japan. serological tests also indicated that prevalence of h3n2 virus in the swine population in thailand. | 1981 | 7311111 |
| [role of animals in the epidemiology of hunan type a influenza]. | | 1981 | 7313131 |
| serological evidence of infection with h1n1 subtype of influenza virus at dibrugarh, assam. | | 1981 | 7348722 |
| further studies in man of hsw1n1 influenza viruses. | two subpopulations of antigenically different hsw1n1 influenza viruses, cloned from 'swine' new jersey virus 1976, were individually inoculated into antibody-free volunteers. one clone contained a haemagglutinin so far seen only in swine viruses prevalent in 1971 and after, the other a haemagglutinin of earlier strains dating back to a least 1957. each of the viruses was infectious for man and intermediate in human virulence between a wild human virus and swine pathogens of 1966 and 1967, which ... | 1980 | 7381437 |
| two forms of influenza virus nucleoprotein in infected cells and virions. | | 1981 | 7467131 |
| [surveillance of influenza virus in healthy pigs (author's transl)]. | | 1980 | 7471705 |
| [serological survey of human influenza antibodies in domestic animals, poultry and wild birds (author's transl)]. | | 1980 | 7472052 |
| synthesis of substituted 1-norbornylamines with antiviral activity. | the reaction of (+/-)-camphor (7) with triflic anhydride (tf2o) yields the bridgehead triflate 8. the nametkin rearrangement of 8 to 3 was realized by treatment with triflic acid (tfoh). the solvolysis of the bridgehead triflates 3 and 8 in acetonitrile affords the n-acetyl-1-norbornylamines 4 and 9. the pd(0)-catalyzed hydrogenation of 4 and 9 gives the amides 5 and 10. the corresponding 1-norbornylamines 2 and 13 and the n-ethyl derivatives 1, 6, 11, and 12 were obtained by basic hydrolysis or ... | 1995 | 7473574 |
| the effect of cell density on influenza virus replication in cv-1 cells. | the number of hemadsorbing cells in cv-1 cell monolayers infected with influenza a virus was higher in semi-confluent cultures than in dense contact-inhibited monolayers. the level of virus-specific protein synthesis as well as the accumulation of virus progeny were also inversely correlated with cell density. at a high multiplicity of infection the majority of these cells in dense monolayers did not express ha on the cell surface, did not synthesize virus-specific proteins and survived at least ... | 1995 | 7477030 |
| immunogenicity of recombinant influenza virus haemagglutinin carrying peptides from the envelope protein of human immunodeficiency virus type 1. | haemagglutinin (ha), the major surface glycoprotein of influenza virus, is a potent immunogen against which viral neutralizing antibodies are directed. studies of the three-dimensional structure of ha have identified major antigenic sites on the molecule. we have exploited ha as a carrier for small antigenic regions (epitopes) of the hiv-1 envelope (env) glycoprotein. using recombinant dna techniques, the epitopes were inserted in-frame into a known antigenic site of ha to produce ha-epitope chi ... | 1994 | 7522383 |
| disease outbreaks in pigs in great britain due to an influenza a virus of h1n2 subtype. | | 1995 | 7541591 |
| genetic variation in swine influenza virus a isolate associated with proliferative and necrotizing pneumonia in pigs. | a new antigenic variant of h1n1 swine influenza virus a (sw/qc/5393/91 [qc/91]) has been found to be associated with porcine proliferative and necrotizing pneumonia. analysis of its genomic rna by t1 oligonucleotide mapping revealed that considerable genomic divergence exists between qc/91 and the swine influenza viruses currently circulating in north american swine herds. analysis of the nucleotide sequence of the ha1 region of the hemagglutinin rna of qc/91, in comparison with those of most co ... | 1994 | 7545918 |
| interspecies transmission of influenza viruses. | in this report we examine the hypothesis that aquatic birds are the primordial source of all influenza viruses in other species. two partly overlapping reservoirs of influenza a viruses exist in migrating water-fowl and shorebirds throughout the world. these species harbor influenza viruses of all the known hemagglutinin and neuraminidase subtypes. in contrast to the rapid, progressive changes in both the nucleotide and amino acid sequences of mammalian virus gene lineages, avian virus genes sho ... | 1995 | 7551408 |
| european swine virus as a possible source for the next influenza pandemic? | according to phylogenetic data, about 100 years ago an avian influenza virus passed the species barrier (possibly first) to pigs and (possibly from there) to humans. in 1979 an avian influenza a virus (as a whole, without reassortment) again entered the pig population in northern europe, forming a stable lineage. here it is shown that the early north european swine viruses exhibit higher than normal evolutionary rates and are highly variable with respect to plaque morphology and neutralizability ... | 1995 | 7571425 |
| persistence of a 1930 swine influenza a (h1n1) virus in quebec. | two antigenically distinct h1n1 influenza a viruses were isolated during an outbreak of respiratory disease in quebec swine in 1990/91. analysis of haemagglutinin and partial nucleoprotein sequences indicated that one was a variant of the swine h1n1 influenza virus circulating in the american midwest whereas the other was very similar to virus isolated from swine in 1930. the existence of this latter isolate supports the concept that influenza viruses can be maintained for long periods in swine, ... | 1995 | 7595357 |
| sialidase of swine influenza a viruses: variation of the recognition specificities for sialyl linkages and for the molecular species of sialic acid with the year of isolation. | the sialidase of swine influenza a viruses of n1 and n2 subtypes, isolated from 1930 to 1992, was studied for substrate specificity with ganglio-series, lacto-series type ii and gm3 gangliosides containing neu5ac alpha 2-3gal, neu5gc alpha 2-3gal and neu5ac alpha 2-6gal linkages. all viral sialidases tested showed that the activity for hydrolysing substrates with neu5ac alpha 2-3gal was higher than the activities with neu5gc alpha 2-3gal and neu5ac alpha 2-6gal linkages. when gm1b, gm3 and sialy ... | 1995 | 7620333 |
| alpha 2-macroglobulin is the major neutralizing inhibitor of influenza a virus in pig serum. | horse, pig, and rabbit sera contain distinct glycoprotein inhibitors of influenza a viruses that inhibit hemagglutinating activity and neutralize viral infectivity. although alpha 2-macroglobulin has been identified as the inhibitor in horse serum, the inhibitors in pig and rabbit sera have not been identified. as an initial step in elucidating the structural differences among inhibitor molecules, we sought to isolate the inhibitor in pig serum. the purified inhibitor decreased the hemagglutinat ... | 1993 | 7681613 |
| ion channel activity of influenza a virus m2 protein: characterization of the amantadine block. | the influenza a virus m2 integral membrane protein has ion channel activity which can be blocked by the antiviral drug amantadine. the m2 protein transmembrane domain is highly conserved in amino acid sequence for all the human, swine, equine, and avian strains of influenza a virus, and thus, known amino acid differences could lead to altered properties of the m2 ion channel. we have expressed in oocytes of xenopus laevis the m2 protein of human influenza virus a/udorn/72 and the avian virus a/c ... | 1993 | 7688826 |
| type- and subtype-specific detection of influenza viruses in clinical specimens by rapid culture assay. | a rapid culture assay which allows for the simultaneous typing and subtyping of currently circulating influenza a(h1n1), a(h3n2), and b viruses in clinical specimens was developed. pools of monoclonal antibodies (mabs) against influenza a and b viruses and mabs ha1-71 and ha2-76, obtained by immunizing mice with the denatured hemagglutinin subfragments ha1 and ha2 of influenza virus a/victoria/3/75, were used for immunoperoxidase staining of antigens in infected mdck cells. mab ha1-71 reacted ex ... | 1995 | 7714186 |
| [pseudosuspended cultured cells for obtaining influenza a and b viral antigens]. | conditions for pseudosuspension culturing of continuous cells of the kidneys of dogs (mdck), green marmosets (cv-1), and swine (spev) on two types of microcarriers (cytogel-3 and cytolar-2) under semiproduction conditions (50 liter bioreactor) were developed on a model of reassortants of influenza viruses a and b. to standardize the conditions, native sera were replaced by growth-stimulating proteins isolated from the sera of various animals (cattle, northern deer, swine). a better adhesive capa ... | 1994 | 7716923 |
| antigenic and genetic characteristics of h1n1 human influenza virus isolated from pigs in japan. | two strains of influenza a virus were isolated from pigs in northern japan in 1992. serological tests showed that the haemagglutinin (ha) and neuraminidase (na) antigens were more closely related to those of recent human h1n1 viruses than to those of swine h1n1 viruses. the ha and na genes of isolate a/sw/obihiro/5/92 were shown to be closely related to those of current human h1n1 viruses. evolutionary trees constructed from nucleotide sequences showed that the ha and na genes of a/sw/obihiro/5/ ... | 1995 | 7730809 |
| class specific antibody response to influenza a h1n1 infection in swine. | early detection of swine influenza a outbreaks is essential to understand the true cause and effect relationship that exists between this disease and other serious respiratory or herd health problems. enzyme-linked immunosorbent assays (elisas) for the early detection of h1n1 subtype specific serum igm, igg and secretory iga were compared to direct virus detection in in embryonated eggs. elevated levels of h1 hemagglutinin (ha) specific igm and igg were detected as early as 3 days post experimen ... | 1995 | 7740762 |
| porcine respiratory coronavirus-mediated interference against influenza virus replication in the respiratory tract of feeder pigs. | effect of prior porcine respiratory coronavirus (prcv) infection on replication of h1n1-influenza virus in the respiratory tract of swine was studied. in an initial experiment, 3 groups of 5 feeder pigs were studied. pigs of 2 groups were inoculated sequentially with prcv, followed by h1n1-influenza virus at 2- and 3-day intervals. pigs of the other group were inoculated with h1n1-influenza virus only. pigs were monitored clinically and examined for nasal excretion of influenza virus. in the sin ... | 1994 | 7802396 |
| serological studies in austrian fattening pigs with respiratory disorders. | serum samples of 253 fattening pigs out of 44 different herds with respiratory signs were examined for antibodies to aujeszky's disease virus by elisa, swine influenza virus (hi test), porcine respiratory coronavirus (elisa) and porcine reproductive and respiratory syndrome virus (ipma). one single case of aujeszky's disease was detected at slaughter. on the other hand 24.5% of the animals proved to be positive for swine influenza, although no vaccine is licensed in austria, and 63.6% reacted po ... | 1994 | 7810433 |
| source for influenza pandemics. | there are three ways how influenza a viruses can escape the immune response in the human population: (1) by antigenic drift. this means by mutation and selection of variants under the selection pressure of the immune system. these variants have amino acid replacements mainly in the epitopes of the hemagglutinin. (2) by antigenic shift. this means replacement of at least the hemagglutinin gene of the prevailing human strain by the allelic gene of an avian influenza virus by reassortment. (3) as a ... | 1994 | 7843354 |
| the appearance of h3 influenza viruses in seals. | surveillance for influenza a virus infection of seals has continued following the association of influenza a virus with epizootics of pneumonia in seals off the new england coast in 1979-1980 and 1982-1983. in january 1991 and january to february 1992, influenza a viruses were isolated from seals that died of pneumonia along the cape cod peninsula of massachusetts. antigenic characterization identified two h4n6 and three h3n3 viruses. this was the first isolation of h3 influenza viruses from sea ... | 1995 | 7844533 |
| antigenic characterization of an h3n2 swine influenza virus isolated from pigs with proliferative and necrotizing pneumonia in quebec. | a new strain of swine influenza a virus, designated a/swine/saint-hyacinthe/150/90 has been isolated from pigs with severe proliferative and necrotizing pneumonia in quebec. the antigenic characterization of the hemagglutinin was performed by hemagglutination inhibition test, immunoblot and indirect immunoprecipitation using polyclonal antisera. only the last test was able to detect an antigenic relationship between the hemagglutinin of this isolate and an h3 subtype influenza virus. the immunop ... | 1994 | 7889461 |
| genetic analysis of porcine h3n2 viruses originating in southern china. | from immunological and phylogenetic analyses of h3 influenza viruses isolated from pigs and ducks in the people's republic of china (china), hong kong, taiwan and japan, between 1968 and 1982, we arrived at the following conclusions. the h3 haemagglutinin and n2 neuraminidase genes from swine isolates can be segregated into four mammalian lineages, including: (i) the earliest human strains; (ii) early swine strains including hong kong isolates from 1976-1977; (iii) an intermediate strain between ... | 1995 | 7897351 |
| recent h3n2 swine influenza virus with haemagglutinin and nucleoprotein genes similar to 1975 human strains. | of the four pandemic strains of human influenza a virus observed this century, the 1977 virus strain was very similar in all genes to a 1950 isolate. since mammalian influenza a viruses change annually by genetic drift, this reappearance could only be attributed at that time to conservation of the virus in a frozen state. we report here the isolation of swine influenza a viruses with haemagglutinin and nucleoprotein genes which are virtually identical to those of the human virus that circulated ... | 1995 | 7897358 |
| prevalence of infections with enzootic respiratory and enteric viruses in feeder pigs entering fattening herds. | the prevalence of infections with h1n1- and h3n2-influenza viruses, porcine respiratory coronavirus (prcv), transmissible gastroenteritis virus (tgev) and porcine epidemic diarrhoea virus (pedv) in feeder pigs shortly after their entry into fattening units was examined. ten groups of pigs with acute respiratory disease during the months september to october 1991 and seven groups of pigs with acute diarrhoea during the months february to march 1992 were investigated. on arrival in the fattening h ... | 1994 | 7900243 |
| [factors associated with the occurrence of influenza a virus infections in fattening swine]. | in august of 1989 sera from 2115 finishing pigs out of 214 herds in the north of schleswig- holstein (germany) were tested for antibodies against three strains of influenza a viruses by using the haemagglutination inhibition test. seroprevalences of a/swine/nederland/25/80 (h1n1), a/philippines/2/82 (h3n2), and a/port chalmers/1/73 (h3n2) on herd level were 23.4%, 20.6% and 5.1% respectively. the mean within herd prevalences were 9.6%, 14.7% and 0.6%, respectively. antibodies against h1n1 and h3 ... | 1994 | 7945181 |
| immunohistochemical detection of swine influenza virus and porcine reproductive and respiratory syndrome virus in porcine proliferative and necrotizing pneumonia cases from québec. | | 1994 | 7954227 |
| safety and immunogenicity of recombinants based on the genetically-engineered vaccinia strain, nyvac. | nyvac-based recombinants expressing pertinent immunogens from equine influenza virus (eiv), pseudorabies virus (prv), japanese encephalitis virus (jev) and human immunodeficiency virus (hiv) were used to evaluate the safety and immunogenicity of this vector. administration of either nyvac recombinants or parenteral virus to mice, horses and swine was well tolerated with no notable local or systemic reactivities. further, despite a highly attenuated phenotype, nyvac was found to function effectiv ... | 1994 | 7958466 |
| use of polymerase chain reaction to detect swine influenza virus in nasal swab specimens. | rapid and accurate detection of a virus in a population is a critical factor in the eventual treatment and/or control of the virus. in this study, we examined use of the polymerase chain reaction (pcr) to detect swine influenza virus in nasal swab specimens from infected pigs. this approach was first standardized, using viral rna purified by guanidinium/phenol-chloroform extraction and placed in the same transport medium as the swabs. by using highly conserved primers for the swine h1 hemaggluti ... | 1994 | 7978634 |
| isolation of two h1n2 influenza viruses from swine in france. | samples collected in 1987 and 1988 in brittany from influenza-infected swine made it possible to isolate and antigenically characterize two h1n2 recombinant viruses (sw/france/5027/87 and sw/france/5550/88). the former virus was cloned and reinoculated to swine to allow reproduction of the disease and reisolation of a strain similar to the original one. the serodiagnostic tests carried out on both the original sera and those from the experimentally infected animals confirmed that the virus was a ... | 1994 | 7979974 |
| while awaiting the next pandemic of influenza a. | | 1994 | 7987139 |
| recent influenza a (h1n1) infections of pigs and turkeys in northern europe. | the most recent introduction of an avian influenza a virus without reassortment into mammals occurred in 1979 when h1n1 strains could be isolated from diseased pigs in northern europe. this newly introduced avian virus formed a stable lineage in pigs and, in the meantime, spread all over europe. in 1991 highly pathogenic h1n1 strains closely related to a contemporary swine virus were isolated from turkeys of a breeding farm near bremen, germany. outbreaks in several farms in germany, france, and ... | 1994 | 8009840 |
| evidence for interspecies transmission and reassortment of influenza a viruses in pigs in southern china. | the asian/57, hong kong/68, and russian/77 pandemics of this century appeared or reappeared in china. interspecies transmission and genetic reassortment of influenza viruses have been implicated in the origin of these human pandemic influenza viruses. pigs have been suspected to be the "mixing vessel" where reassortment occurs. to investigate this possibility, 104 porcine influenza viruses collected at random from southern china from 1976 to 1982, including 32 h3n2 isolates and 72 h1n1 isolates, ... | 1994 | 8030245 |
| genetic relatedness between influenza a (h1n1) viruses isolated from humans and pigs. | complete nucleotide sequences were obtained from the nucleoprotein genes of three influenza a viruses and partial nucleotide sequences were obtained from the polymerase, neuraminidase, matrix, and non-structural protein genes of four influenza a viruses that had been isolated between 1931 and 1939 from clinically sick pigs in the united states or europe. a phylogenetic analysis of the open reading frames of nine nucleoprotein genes showed that the u.s. swine influenza virus isolates from 1931 an ... | 1994 | 8046416 |
| influenza virus induces expression of antioxidant genes in human epithelial cells. | influenza infections cause airway epithelial inflammation and oxidant-mediated damage. in this setting, cellular antioxidant enzymes may protect airway epithelial cells against damage resulting from toxic oxygen radicals produced by activated leukocytes. therefore, we tested the effect of influenza virus infection, as well as exposed to human recombinant interferon-gamma (ifn-gamma), on gene expression for the antioxidant enzymes manganese superoxide dismutase (mnsod), copper/zinc superoxide dis ... | 1994 | 8070686 |
| potential for transmission of avian influenza viruses to pigs. | pandemic strains of influenza a virus arise by genetic reassortment between avian and human viruses. pigs have been suggested to generate such reassortants as intermediate hosts. in order for pigs to serve as 'mixing vessels' in genetic reassortment events, they must be susceptible to both human and avian influenza viruses. the ability of avian influenza viruses to replicate in pigs, however, has not been examined comprehensively. in this study, we assessed the growth potential of 42 strains of ... | 1994 | 8077918 |
| infection of children with avian-human reassortant influenza virus from pigs in europe. | pigs have been proposed to act as the intermediate hosts in the generation of pandemic human influenza strains by reassortment of genes from avian and human influenza virus strains. the circulation of avian-like h1n1 influenza viruses in european pigs since 1979 and the detection of human-avian reassortants in pigs raises the question of whether these viruses actually have the potential to transmit and cause disease in humans. we now report the serologic and genetic characterization of two human ... | 1994 | 8091678 |
| subtype specific elisa for the detection of antibodies against influenza a h1n1 and h3n2 in swine. | a subtype specific elisa using purified hemagglutinin (ha) from influenza a h1n1 and h3n2 was developed to detect antibodies present in swine previously exposed to either h1n1 or h3n2 influenza viruses. the ha was extracted using the detergent octylglucoside followed by ion exchange chromatography. all ha preparations were free of contaminating nucleoprotein and matrix protein contamination. monospecific swine anti-h1n1 and swine anti-h3n2 sera were used to demonstrate the subtype specificity of ... | 1993 | 8113339 |
| antigenic and sequence analysis of h3 influenza virus haemagglutinins from pigs in italy. | to investigate the possible mechanism of maintenance of old human influenza a (h3n2) viruses in pigs, the haemagglutinins (has) of seven isolates from swine were studied by analysis of nucleotide and deduced primary amino acid sequences, as well as reactivity of the ha molecule to chicken antisera and monoclonal antibodies. the swine has were closely similar to the ha of the a/victoria/3/75 human variant as regards antigenic and molecular characteristics. these findings are consistent with the h ... | 1994 | 8113758 |
| an influenza a (h1n1) virus, closely related to swine influenza virus, responsible for a fatal case of human influenza. | in july 1991, an influenza a virus, designated a/maryland/12/91 (a/md), was isolated from the bronchial secretions of a 27-year-old animal caretaker. he had been admitted to the hospital with bilateral pneumonia and died of acute respiratory distress syndrome 13 days later. antigenic analyses with postinfection ferret antisera and monoclonal antibodies to recent h1 swine hemagglutinins indicated that the hemagglutinin of this virus was antigenically related to, but distinguishable from, those of ... | 1994 | 8138990 |
| apoptosis: a mechanism of cell killing by influenza a and b viruses. | in previous studies, we observed that the virulent avian influenza a virus a/turkey/ontario/7732/66 (ty/ont) induced severe lymphoid depletion in vivo and rapidly killed an avian lymphocyte cell line (rp9) in vitro. in examining the mechanism of cell killing by this virus, we found that ty/ont induced fragmentation of the rp9 cellular dna into a 200-bp ladder and caused ultrastructural changes characteristic of apoptotic cell death by 5 h after infection. we next determined that the ability to i ... | 1994 | 8189504 |
| isolation of an influenza a virus of unusual subtype (h1n7) from pigs in england, and the subsequent experimental transmission from pig to pig. | a novel h1n7 influenza virus (a/swine/eng/191973/92) was isolated from nasal swabs collected from two pigs on a farm where there had been recent clinical disease due to infection with an h1n1 virus (a/swine/eng/195852/92). antigenically, the haemagglutinin (ha) of the h1n7 virus was related most closely to the ha of a/ussr/90/77, whilst the neuraminidase (na) appeared to be related most closely to the na of a/equine/prague/1/56 (h7n7). pigs infected experimentally with a/swine/eng/191973/92 deve ... | 1994 | 8203118 |
| determination of hemagglutination-inhibition titers to influenza a virus in porcine sera by use of an enzyme-linked immunosorbent assay. | an elisa-based method to estimate hemagglutination-inhibition (hi) titer was developed. subtype specificity was obtained by using purified h1 and h3 hemagglutinin antigens. using the linear relation that exists between elisa and hi methods, regression lines for h1n1- and h3n2-monospecific porcine antisera were constructed. approximation of actual hi titer could be obtained from insertion of elisa values into the appropriate regression line. the hi estimations were within 50% of the actual measur ... | 1993 | 8214894 |
| the hemagglutinins of duck and human h1 influenza viruses differ in sequence conservation and in glycosylation. | we determined the deduced amino acid sequences of two h1 duck influenza a virus hemagglutinins (has) and found that the consensus sequence of the ha, determined directly from virus recovered from the intestinal tract, remains unchanged through many generations of growth in mdck cells and chicken embryos. these two duck viruses differ from each other by 5 amino acids and from a/dk/alberta/35/1976 (f. j. austin, y. kawaoka, and r. g. webster, j. gen. virol. 71:2471-2474, 1990) by 9 and 12 amino ac ... | 1993 | 8230464 |
| antigenic and genetic analysis of a recently isolated h1n1 swine influenza virus. | hemagglutinins (ha) of h1n1 swine influenza viruses isolated in the united states have remained antigenically and genetically conserved for many years. in contrast to such conservation, the ha of a/swine/nebraska/1/92 (sw/neb) could readily be distinguished from those of contemporary porcine viruses. twenty-eight amino acid mutations differentiated the ha of sw/neb and a/swine/indiana/1726/88, the most recent h1n1 swine influenza virus for which ha sequence data were available. among these diffe ... | 1993 | 8250388 |
| [pneumonia diagnosis in living swine using lung lavage]. | in pigs coming from fattening units with tenacious pneumonitis problems the attempt was made to find an etiological diagnosis in living pigs by bronchoalveolar lavage (bal) and serological examinations on antibodies against mycoplasma hyopneumonia, actinobacillus pleuropneumoniae and influenza-a-virus (serotypes h1n1 and h3n2). in some cases the results of the bacteriological examinations of the bal were compared with the post mortem findings. both methods yield similar results. mycoplasma hyopn ... | 1993 | 8250824 |
| origin and evolutionary pathways of the h1 hemagglutinin gene of avian, swine and human influenza viruses: cocirculation of two distinct lineages of swine virus. | the nucleotide sequences of the ha1 domain of the h1 hemagglutinin genes of a/duck/hong kong/36/76, a/duck/hong kong/196/77, a/sw/north ireland/38, a/sw/cambridge/39 and a/yamagata/120/86 viruses were determined, and their evolutionary relationships were compared with those of previously sequenced hemagglutinin (h1) genes from avian, swine and human influenza viruses. a pairwise comparison of the nucleotide sequences revealed that the genes can be segregated into three groups, the avian, swine a ... | 1994 | 8279953 |
| effect of oxadiarrhot on some mechanisms of the immune system. | the preliminary application of the preparation oxadiarrhot has no effect on the progress and the result of bacterial and mixed (bacterial-viral) infections. in animals treated with the preparation antigen-reactive and antibody-productive cells show insignificant decrease in number. there is no essential influence of the preparation on the mononuclear phagocytes system--the alveolar macrophages and polymorphonuclears do not change their functions. | 1993 | 8285129 |
| elisa method for detection of influenza a infection in swine. | an antigen-capture enzyme-linked immunosorbent assay (elisa) was developed to monitor virus shedding associated with experimental infection with a field strain of swine influenza in pigs. the assay consisted of a monoclonal anti-nucleoprotein capture antibody and a biotinylated rabbit anti-influenza a (h1n1) sandwich antibody. the antigen-capture system was capable of detecting as little as 1 ng/ml purified virus. the elisa system surpassed egg cultivation procedures in the detection of low leve ... | 1993 | 8286447 |
| analysis of the influenza virus gene pool of avian species from southern china. | although southern china has been considered the epicenter of human influenza pandemics, little is known about the genetic composition of influenza viruses in lower mammals or birds in that region. to provide information on the molecular epidemiology of these viruses, we used dot blot hybridization and phylogenetic methods to study the internal genes (pb1, pb2, pa, np, m, and ns) of 106 avian influenza a viruses isolated from a total of 11,798 domestic ducks, chickens, and geese raised in souther ... | 1994 | 8291238 |
| [an analysis of the potential areas of recombination in the hemagglutinin genes of animal influenza viruses in relation to their adaptation to a new host--man]. | the authors tried to decode the mechanism of influenza viruses species adaptation in the process of host changing. the functionally important replacement in the surface pocket domains were revealed, particularly in the conservative region 221-241, involving fibronectin-like part. close replacements were revealed in the region 141-161. the method of construction of heteroduplexes between hemagglutinin rna of duck, pig, and human viruses was used. the method showed that all heteroduplexes formed r ... | 1993 | 8303887 |
| unravelling the ecology of influenza a virus. | for 20 years after the influenza a virus was discovered in the early 1930s, it was believed to be almost exclusively a human virus. but in the 1950s closely related viruses were discovered in diseases of horses, pigs and birds. subsequently influenza a viruses were found to occur frequently in many species of birds, particularly ducks, usually without causing disease. researchers showed that human and animal strains can hybridise thus producing new strains. such hybrids may be the cause of pande ... | 1993 | 8310117 |
| analysis of influenza a virus nucleoproteins for the assessment of molecular genetic mechanisms leading to new phylogenetic virus lineages. | the nucleoprotein (np) gene of influenza a viruses is decisive for separating two large individually evolving reservoirs in birds and humans. a phylogenetic analysis of the np gene revealed that all mammalian influenza viruses originated--directly or indirectly--from an avian ancestor. the stable introduction of an avian influenza a virus into a mammalian species seems to be a relatively rare event, the latest one occurred in 1979 when such an avian virus was introduced into pigs in northern eur ... | 1993 | 8347076 |
| the haemagglutinins of influenza a (h1n1) viruses in the 'o' or 'd' phases exhibit biological and antigenic differences. | influenza a (h1n1) viruses when initially isolated in mammalian cell cultures (mdck cells) had different agglutination reactions with chicken and guinea-pig erythrocytes compared to the same viruses after passage. on first isolation the virus ha resembled the 'o' phase viruses described originally by burnet and bull and agglutinated mammalian but not avian erythrocytes. after passage, the virus ha resembled a classical 'd' phase virus and agglutinated both avian and mammalian erythrocytes. monoc ... | 1993 | 8348927 |
| immunohistochemical detection of swine influenza a virus in formalin-fixed and paraffin-embedded tissues. | an avidin-biotin complex (abc) immunohistochemical method utilizing a commercially-available polyclonal antiserum to human influenza a virus was used to detect antigens of influenza a virus in formalin-fixed, paraffin-embedded tissues of swine. influenza a antigens were immunohistochemically detected in 28/30 cases in which influenza a virus was demonstrated by virus isolation and in 5/22 cases suspected to be influenza a-infected by clinical and histological criteria, but from which the virus w ... | 1993 | 8381700 |
| antigenic and genetic conservation of the haemagglutinin in h1n1 swine influenza viruses. | we examined the level of antigenic conservation amongst the haemagglutinins (has) of h1 swine influenza viruses, recently isolated from a wide geographical area, in haemagglutination inhibition assays against a panel of four monoclonal antibodies (mabs). we found a high degree of conservation with a dominant variant (52 of 54 isolates) that reacted with all mabs. only two minor variants, each failing to react with one mab, were found. using a one-step pcr technique followed by direct sequencing ... | 1993 | 8389804 |
| pathogenicity of a swine influenza h1n1 virus antigenically distinguishable from classical and european strains. | an h1n1 strain of influenza virus (a/swine/england/195852/92) isolated recently from clinical epizootics in pigs was transmitted experimentally to six-week-old specific pathogen-free pigs. between one and four days after inoculation the infected pigs developed pyrexia and showed signs of coughing, sneezing and anorexia. seroconversion was detected seven days after infection. virus was isolated from nasal swabs and tissues up to four days after infection, but was not recovered from faeces. virus ... | 1993 | 8393225 |
| influenza--a model of an emerging virus disease. | influenza a viruses continue to emerge from the aquatic avian reservoir and cause pandemics. phylogenetic analysis of the nucleotide sequence of all eight influenza a virus rna segments indicate that all of the influenza viruses in mammalian hosts originate from the avian gene pool. in contrast to the rapid progressive changes in both the nucleotide and amino acid sequences of mammalian virus gene lineages, avian virus genes show far less variation and, in most cases, appear to be in evolutionar ... | 1993 | 8407243 |
| genetic reassortment between avian and human influenza a viruses in italian pigs. | pandemic strains of influenza a virus arise by genetic reassortment between avian and human viruses. to examine the possibility that pigs serve as "mixing vessels" for such reassortment events (scholtissek et al., virology 147, 287-294, 1985), we phylogenetically analyzed the internal protein genes of classic h1n1, avian-like h1n1, and human-like h3n2 viruses circulating among italian pigs. the results show that human-like h3n2 strains isolated from 1985 to 1989 contained the internal protein ge ... | 1993 | 8438586 |
| pathogenic studies and antigenic and sequence comparisons of a/equine/alaska/1/91 (h3n8) influenza virus. | an influenza virus, a/equine/alaska/1/91 (h3n8), was isolated from horses from alaska with an acute respiratory infection. pathogenic and serologic studies revealed that this virus is similar to previously isolated equine h3n8 influenza viruses. antigenic analyses utilizing hemagglutination inhibition and neuraminidase inhibition assays indicated an antigenic drift from the prototype equine h3n8 influenza virus, a/equine/miami/1/63. partial sequence analysis of the a/equine/alaska influenza viru ... | 1993 | 8466986 |
| immune response of human volunteers and animals to vaccination with egg-grown influenza a (h1n1) virus is influenced by three amino acid substitutions in the haemagglutinin molecule. | inactivated subunit vaccines were prepared from high-growth reassortants derived from two separate egg isolates from a single clinical specimen of influenza a (h1n1) virus. one of these reassortants, nib-14, was antigenically indistinguishable from isolates made in tissue culture, while the other, nib-17, was antigenically different and typical of egg isolates. the viruses differed by three amino acid residues in the haemagglutinin (ha) molecule and the anti-ha serological response induced was s ... | 1993 | 8470424 |
| guillain-barré syndrome due to swine influenza and neurologic damage due to dtp vaccines: the touch of statistics. | | 1993 | 8506498 |
| swine influenza outbreaks in england due to a new h1n1 virus. | | 1993 | 8517008 |