| generation of candidate human influenza vaccine strains in cell culture - rehearsing the european response to an h7n1 pandemic threat. | although h5n1 avian influenza viruses pose the most obvious imminent pandemic threat, there have been several recent zoonotic incidents involving transmission of h7 viruses to humans. vaccines are the primary public health defense against pandemics, but reliance on embryonated chickens eggs to propagate vaccine and logistic problems posed by the use of new technology may slow our ability to respond rapidly in a pandemic situation. | 2007 | 19432631 |
| infection with human h1n1 influenza virus affects the expression of sialic acids of metaplastic mucous cells in the ferret airways. | glycans terminating in sialic acids serve as receptors for influenza viruses. in this study ferrets were infected with influenza virus a/new caledonia/20/99, and the in situ localization of sialic acids linked alpha2-3 and alpha2-6 in the airways was investigated in infected and non-infected animals by use of sialic acid detecting lectins and a monoclonal antibody towards the sialyl-tn antigen. the goblet cells in the bronchi from non-infected ferrets expressed sialyl alpha 2-6gal glycans, while ... | 2009 | 19447147 |
| chloroquine is effective against influenza a virus in vitro but not in vivo. | chloroquine is an inexpensive and widely available 9-aminoquinolone used in the management of malaria. recently, in vitro assays suggest that chloroquine may have utility in the treatment of several viral infections including influenza. | 2007 | 19453426 |
| a plant-produced influenza subunit vaccine protects ferrets against virus challenge. | influenza a viruses are of major concern for public health, causing worldwide epidemics associated with high morbidity and mortality. vaccines are critical for protection against influenza, but given the recent emergence of new strains with pandemic potential, and some limitations of the current production systems, there is a need for new approaches for vaccine development. | 2008 | 19453491 |
| evaluation of vaccines for h5n1 influenza virus in ferrets reveals the potential for protective single-shot immunization. | as part of influenza pandemic preparedness, policy decisions need to be made about how best to utilize vaccines once they are manufactured. since h5n1 avian influenza virus has the potential to initiate the next human pandemic, isolates of this subtype have been used for the production and testing of prepandemic vaccines. clinical trials of such vaccines indicate that two injections of preparations containing adjuvant will be required to induce protective immunity. however, this is a working ass ... | 2009 | 19457991 |
| lipid vesicle size of an oral influenza vaccine delivery vehicle influences the th1/th2 bias in the immune response and protection against infection. | previous studies, using parenteral administration of antigen in lipid vesicles, have indicated a possible role for vesicle size in determining the th1/th2 bias of the resulting immune response. we have also demonstrated that the incorporation of bile salts into lipid vesicles (bilosomes) allows successful induction of mucosal and systemic immunity via the oral route. the following study was therefore carried out to determine whether size could also influence the th1/th2 bias in the immune respon ... | 2009 | 19464545 |
| zoonotic potential of highly pathogenic avian h7n3 influenza viruses from pakistan. | h5 and h7 avian influenza viruses can become highly pathogenic in chickens after interspecies transmission. these viruses have transmitted directly to humans from birds in eurasia and africa (h5n1), the netherlands (h7n7), and canada (h7n3). here we report antigenic, sequence, and phylogenetic analyses of h7n3 viruses isolated from chickens in pakistan from 1995 to 2002. we compared the pathogenic and zoonotic potential of the pakistani viruses in avian and mammalian hosts. in chickens, all of t ... | 2009 | 19535120 |
| a trivalent virus-like particle vaccine elicits protective immune responses against seasonal influenza strains in mice and ferrets. | there is need for improved human influenza vaccines, particularly for older adults who are at greatest risk for severe disease, as well as to address the continuous antigenic drift within circulating human subtypes of influenza virus. we have engineered an influenza virus-like particle (vlp) as a new generation vaccine candidate purified from the supernatants of sf9 insect cells following infection by recombinant baculoviruses to express three influenza virus proteins, hemagglutinin (ha), neuram ... | 2009 | 19554101 |
| naturally occurring influenza infection in a ferret (mustela putorius furo) colony. | tissue samples from 2 juvenile ferrets (mustela putorius furo) from a colony that was undergoing an outbreak of respiratory disease were submitted to the iowa state university veterinary diagnostic laboratory. microscopic examination of lung samples revealed bronchointerstitial pneumonia with necrotizing bronchiolitis. influenza a virus was detected in sections of formalin-fixed lung by immunohistochemistry and reverse transcription polymerase chain reaction assay. a field investigation of the p ... | 2009 | 19564504 |
| the pig as a mixing vessel for influenza viruses: human and veterinary implications. | influenza a viruses are highly infectious respiratory pathogens that can infect many species. birds are the reservoir for all known influenza a subtypes; and novel influenza viruses can emerge from birds and infect mammalian species including humans. because swine are susceptible to infection with both avian and human influenza viruses, novel reassortant influenza viruses can be generated in this mammalian species by reassortment of influenza viral segments leading to the "mixing vessel" theory. ... | 2008 | 19565018 |
| das181 inhibits h5n1 influenza virus infection of human lung tissues. | das181 is a novel candidate therapeutic agent against influenza virus which functions via the mechanism of removing the virus receptor, sialic acid (sia), from the adjacent glycan structures. das181 and its analogues have previously been shown to be potently active against multiple strains of seasonal and avian influenza virus strains in several experimental models, including cell lines, mice, and ferrets. here we demonstrate that das181 treatment leads to desialylation of both alpha2-6-linked a ... | 2009 | 19596886 |
| zanamivir-resistant influenza viruses with a novel neuraminidase mutation. | the neuraminidase inhibitors zanamivir and oseltamivir are marketed for the treatment and prophylaxis of influenza and have been stockpiled by many countries for use in a pandemic. although recent surveillance has identified a striking increase in the frequency of oseltamivir-resistant seasonal influenza a (h1n1) viruses in europe, the united states, oceania, and south africa, to date there have been no reports of significant zanamivir resistance among influenza a (h1n1) viruses or any other hum ... | 2009 | 19641000 |
| in vitro and in vivo characterization of new swine-origin h1n1 influenza viruses. | influenza a viruses cause recurrent outbreaks at local or global scale with potentially severe consequences for human health and the global economy. recently, a new strain of influenza a virus was detected that causes disease in and transmits among humans, probably owing to little or no pre-existing immunity to the new strain. on 11 june 2009 the world health organization declared that the infections caused by the new strain had reached pandemic proportion. characterized as an influenza a virus ... | 2009 | 19672242 |
| partial direct contact transmission in ferrets of a mallard h7n3 influenza virus with typical avian-like receptor specificity. | avian influenza viruses of the h7 subtype have caused multiple outbreaks in domestic poultry and represent a significant threat to public health due to their propensity to occasionally transmit directly from birds to humans. in order to better understand the cross species transmission potential of h7 viruses in nature, we performed biological and molecular characterizations of an h7n3 virus isolated from mallards in canada in 2001. | 2009 | 19682381 |
| use of animal models to understand the pandemic potential of highly pathogenic avian influenza viruses. | it has been 40 years since the last influenza pandemic and it is generally considered that another could occur at any time. recent introductions of influenza a viruses from avian sources into the human population have raised concerns that these viruses may be a source of a future pandemic strain. therefore, there is a need to better understand the pathogenicity of avian influenza viruses for mammalian species so that we may be better able to predict the pandemic potential of such viruses and dev ... | 2009 | 19695381 |
| vaccination focusing immunity on conserved antigens protects mice and ferrets against virulent h1n1 and h5n1 influenza a viruses. | immunization against conserved virus components induces broad, heterosubtypic protection against diverse influenza a viruses, providing a strategy for controlling unexpected outbreaks or pandemics until strain-matched vaccines become available. this study characterized immunization to nucleoprotein (np) and matrix 2 (m2) by dna priming followed by parenteral or mucosal boosting in mice and ferrets. dna vaccination followed by boosting with antigen-matched recombinant adenovirus (rad) or cold-ada ... | 2009 | 19729082 |
| measurement of neutralizing antibody responses against h5n1 clades in immunized mice and ferrets using pseudotypes expressing influenza hemagglutinin and neuraminidase. | neutralizing antibody is associated with the prevention and clearance of influenza virus infection. microneutralization (mn) and hemagglutination inhibition (hi) assays are currently used to evaluate neutralizing antibody responses against human and avian influenza viruses, including h5n1. the mn assay is somewhat labor intensive, while hi is a surrogate for neutralization. moreover, use of replication competent viruses in these assays requires biosafety level 3 (bsl-3) containment. therefore, a ... | 2009 | 19732860 |
| an early 'classical' swine h1n1 influenza virus shows similar pathogenicity to the 1918 pandemic virus in ferrets and mice. | the 1918 pandemic influenza virus has demonstrated significant pathogenicity in animal models and is the progenitor of 'classical' swine and modern seasonal human h1n1 lineages. here we characterize the pathogenicity of an early 'classical' swine h1n1 influenza a virus isolated in 1931 compared to the pathogenicity of the 1918 pandemic virus and a seasonal h1n1 virus in mice and ferrets. a/swine/iowa/31 (sw31) and the 1918 influenza viruses were uniformly lethal in mice at low doses and produced ... | 2009 | 19733889 |
| recent human influenza a/h3n2 virus evolution driven by novel selection factors in addition to antigenic drift. | examination of the evolutionary dynamics of complete influenza viral genomes reveals that other processes, in conjunction with antigenic drift, play important roles in viral evolution and selection, but there is little biological evidence to support these genomic data. previous work demonstrated that after the a/fujian/411/2002-like h3n2 influenza a epidemic during 2003-2004, a preexisting nondominant fujian-like viral clade gained a small number of changes in genes encoding the viral polymerase ... | 2009 | 19743921 |
| aerosol transmission of influenza a virus: a review of new studies. | over the past few years, prompted by pandemic preparedness initiatives, the debate over the modes of transmission of influenza has been rekindled and several reviews have appeared. arguments supporting an important role for aerosol transmission that were reviewed included prolonged survival of the virus in aerosol suspensions, demonstration of the low infectious dose required for aerosol transmission in human volunteers, and clinical and epidemiological observations were disentanglements of larg ... | 2009 | 19773292 |
| the influence of the multi-basic cleavage site of the h5 hemagglutinin on the attenuation, immunogenicity and efficacy of a live attenuated influenza a h5n1 cold-adapted vaccine virus. | a recombinant live attenuated influenza virus deltah5n1 vaccine with a modified hemagglutinin (ha) and intact neuraminidase genes from a/vietnam/1203/04 (h5n1) and six remaining genome segments from a/ann arbor/6/60 (h2n2) cold-adapted (aa ca) virus was previously shown to be attenuated in chickens, mice and ferrets. evaluation of the recombinant h5n1 viruses in mice indicated that three independent factors contributed to the attenuation of the deltah5n1 vaccine: the attenuating mutations specif ... | 2009 | 19833372 |
| the infection of ferrets with swine influenza virus. | the experiments described confirm the earlier observation of smith, andrewes, and laidlaw that the swine influenza virus is pathogenic for ferrets when administered intranasally. a disease that is clinically more severe and pathologically more extensive than that described by the above workers is obtained if inoculation with the virus is performed under ether anesthesia. animals infected in this way show at autopsy an edematous type of pneumonia of lobar distribution which may terminate fatally. ... | 1934 | 19870285 |
| the infection of mice with swine influenza virus. | the experiments confirm the earlier observation of andrewes, laidlaw and smith that the swine influenza virus is pathogenic for white mice when administered intranasally. two field strains of the swine influenza virus were found to differ in their initial pathogenicity for mice. one strain was apparently fully pathogenic even in its 1st mouse passage while the other required 2 or 3 mouse passages to acquire full virulence for this species. both strains, however, were initially infectious for mic ... | 1935 | 19870434 |
| immunization experiments with swine influenza virus. | 1. swine influenza virus obtained from the lungs of infected ferrets or mice, when administered intramuscularly or subcutaneously, immunizes swine to swine influenza. 2. ferrets, which have received subcutaneous injections of swine influenza virus obtained from the lungs of infected ferrets, are immune to intranasal infection with this virus. similar injections with virus from the lungs of infected mice or swine do not immunize. 3. mice can be immunized to intranasal infection with swine influen ... | 1936 | 19870522 |
| quantitative aspects of homologous and heterologous active immunity to strains of the virus of epidemic influenza. | when mice are immunized by one intraperitoneal inoculation with active or inactive influenza virus (strain pr8, w.s., and melbourne) the quantity required for protection against heterologous strains is about 10 times the homologous minimal immunizing dose. three injections increase the immunity to all strains, but the ratio between the homologous and heterologous minimal immunizing dose is not altered. swine influenza virus given intraperitoneally fails to immunize against human strains unless t ... | 1940 | 19871048 |
| studies on influenza virus : the complement-fixing antigen of influenza a and swine influenza viruses. | influenza complement fixation tests designed for use with ferret serum are described. complement-fixing antigens derived from influenza ferret lungs were unsatisfactory due to their low content of soluble antigen; those prepared from mouse lungs or developing chick embryo membranes proved to be better antigenically and were reliable when the various reagents in the test were properly adjusted to eliminate non-specific fixation of complement. the results of cross complement fixation tests indicat ... | 1941 | 19871098 |
| the quantitative determination of influenza virus and antibodies by means of red cell agglutination. | 1. the agglutination titer for chicken red cells of freshly prepared or carefully stored suspensions of pr8 influenza virus, that is to say virus of maximum pathogenicity, was found to be proportional to the mouse lethal titer of the same preparations. 2. the agglutination titer of infected allantoic fluid procured in a standard way is relatively constant, regardless of the influenza strain used and its pathogenicity for mice. 3. virus preparations inactivated by heat or storage may retain their ... | 1942 | 19871167 |
| antigenic relationship of british swine influenza strains to standard human and swine influenza viruses : the use of chicken and ferret antisera in red cell agglutination. | the antigenic relationships of type a (pr 8, ws) and type b (lee) human strains and the shope and british (cambridge, north ireland) swine strains were studied by specific antiserum inhibition of chicken red cell agglutination by the influenza virus. the cambridge and north ireland strains were found to be closely related to the type a strains and differentiated from the shope virus. the distinctive antigenicity of the lee strain of type b was confirmed. specific antibodies were developed in chi ... | 1943 | 19871297 |
| studies of antigenic differences among strains of influenza a by means of red cell agglutination. | a study of cross inhibition tests among strains of influenza a virus and their antisera showed that the results obtained were subject to a certain amount of variation due to the red cells, the virus suspensions, and the ferret antisera employed. methods have been demonstrated for handling the data obtained from such tests, so that these variables were corrected or avoided, making it possible to use the agglutination technique for antigenic comparisons. the antigenic pattern of eighteen strains o ... | 1943 | 19871338 |
| qualitative differences in the antigenic composition of influenza a virus strains. | a study of the pr8, christie, talmey, w.s., and swine strains of influenza a virus by means of antibody absorption tests revealed the following findings: 1. serum antibody could be specifically absorbed with allantoic fluid containing influenza virus or, more effectively, with concentrated suspensions of virus obtained from allantoic fluid by high-speed centrifugation or by the red cell adsorption and elution technique. normal allantoic fluid, or the centrifugalized sediment therefrom, failed to ... | 1944 | 19871392 |
| development of a new candidate h5n1 avian influenza virus for pre-pandemic vaccine production. | highly pathogenic h5n1 avian influenza viruses currently circulating in birds have caused hundreds of human infections, and pose a significant pandemic threat. vaccines are a major component of the public health preparedness for this likely event. the rapid evolution of h5n1 viruses has resulted in the emergence of multiple clades with distinct antigenic characteristics that require clade-specific vaccines. a variant h5n1 virus termed clade 2.3.4 emerged in 2005 and has caused multiple fatal inf ... | 2009 | 19903211 |
| detection of influenza a and b neutralizing antibodies in vaccinated ferrets and macaques using specific biotin-streptavidin conjugated antibodies. | several critical factors of an influenza microneutralization assay, utilizing a rapid biotin-streptavidin conjugated system for detecting influenza virus subtypes a and b, are addressed within this manuscript. factors such as incubation times, amount of virus, cell seeding, sonication, and tpck trypsin were evaluated for their ability to affect influenza virus neutralization in a microplate-based neutralization assay using madin-darby canine kidney (mdck) cells. it is apparent that the amount of ... | 2010 | 19913054 |
| efficient transmission of swine-adapted but not wholly avian influenza viruses among pigs and from pigs to ferrets. | pigs are considered to be intermediate hosts for the transmission of avian influenza viruses (aivs) between birds and humans, but the transmissibility of aivs among pigs and from pigs to other mammals remains largely unexplored. | 2009 | 19919303 |
| influenza b virus causes milder pathogenesis and weaker inflammatory responses in ferrets than influenza a virus. | abstract it is unknown why the influenza b virus causes less severe clinical signs than the influenza a virus in humans. here we show that influenza b virus induces a lower levels of inflammatory cytokines in the lungs of infected ferrets, and causes less pathological damage to their lung tissues than does influenza a virus. the copy numbers of inflammatory cytokine genes, such as tnf-alpha and ifn-alpha, was significantly lower in the lungs of ferrets infected with influenza b virus than in tho ... | 2009 | 19951179 |
| [study on evolutionary origin of influenza a virus (h1n1) based on ha gene]. | to determine the evolutionary rate and divergence time of influenza a virus ha gene isolated recently worldwide pandemic and explore the origin and its transmission. | 2009 | 19954063 |
| animal models for the preclinical evaluation of candidate influenza vaccines. | at present, new influenza a (h1n1)2009 viruses of swine origin are responsible for the first influenza pandemic of the 21st century. in addition, highly pathogenic avian influenza a/h5n1 viruses continue to cause outbreaks in poultry and, after zoonotic transmission, cause an ever-increasing number of human cases, of which 59% have a fatal clinical outcome. it is also feared that these viruses adapt to replication in humans and become transmissible from human to human. the development of effecti ... | 2010 | 20021306 |
| fitness of pandemic h1n1 and seasonal influenza a viruses during co-infection: evidence of competitive advantage of pandemic h1n1 influenza versus seasonal influenza. | on june 11, 2009 the world health organization (who) declared a new h1n1 influenza pandemic. this pandemic strain is as transmissible as seasonal h1n1 and h3n2 influenza a viruses. major concerns facing this pandemic are whether the new virus will replace, co-circulate and/or reassort with seasonal h1n1 and/or h3n2 human strains. using the ferret model, we investigated which of these three possibilities were most likely favored. our studies showed that the current pandemic virus is more transmis ... | 2009 | 20029606 |
| [hemagglutination inhibition test for retrospective diagnosis of avian influenza in mammals]. | to compare usage of native and formalinized erythrocytes from different animal species in hemagglutination inhibition (hi) test for detection of level of specific antibodies to h5n1 influenza virus in sera of mammals. | 2009 | 20063797 |
| effect of the neuraminidase mutation h274y conferring resistance to oseltamivir on the replicative capacity and virulence of old and recent human influenza a(h1n1) viruses. | the viral fitness of neuraminidase inhibitor (nai)-resistant influenza viruses is believed to be impaired. unexpectedly, an oseltamivir-resistant a(h1n1) variant containing the h274y neuraminidase (na) mutation recently disseminated worldwide, suggesting that the replication and virulence properties of this mutant virus were not compromised. | 2010 | 20100088 |
| severity of pneumonia due to new h1n1 influenza virus in ferrets is intermediate between that due to seasonal h1n1 virus and highly pathogenic avian influenza h5n1 virus. | the newly emerged influenza a(h1n1) virus (new h1n1 virus) is causing the first influenza pandemic of this century. three influenza pandemics of the previous century caused variable mortality, which largely depended on the development of severe pneumonia. however, the ability of the new h1n1 virus to cause pneumonia is poorly understood. | 2010 | 20187747 |
| influenza h1n1 a/solomon island/3/06 virus receptor binding specificity correlates with virus pathogenicity, antigenicity, and immunogenicity in ferrets. | influenza viruses attach to cells via a sialic acid moiety (sialic acid receptor) that is alpha2-3 linked or alpha2-6 linked to galactose (alpha2-3sal or alpha2-6sal); sialic acid acts as a receptor for the virus. using lectin staining, we demonstrated that the alpha2-6sal configuration is predominant in the respiratory tract of ferrets, including trachea, bronchus, and lung alveolus tissues. recombinant wild-type (rwt) influenza a/solomon island/3/06 (si06) (h1n1) viruses were constructed to as ... | 2010 | 20200248 |
| mutations in the ns1 c-terminal tail do not enhance replication or virulence of the 2009 pandemic h1n1 influenza a virus. | the 'classical' swine h1n1 influenza a virus lineage was established after the devastating 1918 human pandemic virus entered domestic pig herds. a descendent of this lineage recently re-emerged in humans as the 2009 pandemic h1n1 virus. adaptation in pigs has led to several changes in the multifunctional viral ns1 protein as compared with the parental 1918 virus, most notably a k217e substitution that abolishes binding to host crk/crkl signalling adapters, and an 11 aa c-terminal truncation. usi ... | 2010 | 20237225 |
| significance of antigenic differences among strains of influenza a virus in reinfection of ferrets. | | 1946 | 20274239 |
| modeling host responses in ferrets during a/california/07/2009 influenza infection. | immune responses during infection with pandemic h1n1 2009 influenza a virus (2009-h1n1) are still poorly understood. using an experimental infection model in ferrets, we examined the pathological features and characterized the host immune responses by using microarray analysis, during infection with 2009-h1n1 a/california/07/2009 and seasonal a/brisbane/59/2007. chemokines ccl2, ccl8, cxcl7 and cxcl10 along with the majority of interferon-stimulated genes were expressed early, correlated to lung ... | 2010 | 20334888 |
| rapid selection of a transmissible multidrug-resistant influenza a/h3n2 virus in an immunocompromised host. | the overall impact of influenza virus infection in immunocompromised patients is largely unknown. antigenic drift and genetic variations during prolonged influenza infection have been demonstrated. in this report we describe a multidrug-resistant h3n2 influenza virus isolated from an immunocompromised patient after 5 days of therapy. | 2010 | 20350163 |
| comparative efficacy of hemagglutinin, nucleoprotein, and matrix 2 protein gene-based vaccination against h5n1 influenza in mouse and ferret. | efforts to develop a broadly protective vaccine against the highly pathogenic avian influenza a (hpai) h5n1 virus have focused on highly conserved influenza gene products. the viral nucleoprotein (np) and ion channel matrix protein (m2) are highly conserved among different strains and various influenza a subtypes. here, we investigate the relative efficacy of np and m2 compared to ha in protecting against hpai h5n1 virus. in mice, previous studies have shown that vaccination with np and m2 in re ... | 2010 | 20352112 |
| in vitro assessment of attachment pattern and replication efficiency of h5n1 influenza a viruses with altered receptor specificity. | the continuous circulation of the highly pathogenic avian influenza (hpai) h5n1 virus has been a cause of great concern. the possibility of this virus acquiring specificity for the human influenza a virus receptor, alpha2,6-linked sialic acids (sa), and being able to transmit efficiently among humans is a constant threat to human health. different studies have described amino acid substitutions in hemagglutinin (ha) of clinical hpai h5n1 isolates or that were introduced experimentally that resul ... | 2010 | 20392847 |
| the impact of key amino acid substitutions in the hemagglutinin of influenza a (h3n2) viruses on vaccine production and antibody response. | influenza h3n2 viruses have recently drifted from a/wisconsin/67/05-like to a/brisbane/10/07-like viruses. the effect of key amino acid substitutions in the hemagglutinin (ha) protein on the replication, antigenicity and immunogenicity of cold-adapted, live attenuated vaccine strains was examined. a/brisbane/10/07 egg isolate contained a unique combination of g186 and p194 which were required for efficient virus growth in madin-darby canine kidney (mdck) cells and embryonated chicken eggs, but t ... | 2010 | 20399830 |
| neuraminidase receptor binding variants of human influenza a(h3n2) viruses resulting from substitution of aspartic acid 151 in the catalytic site: a role in virus attachment? | changes in the receptor binding characteristics of human h3n2 viruses have been evident from changes in the agglutination of different red blood cells (rbcs) and the reduced growth capacity of recently isolated viruses, particularly in embryonated eggs. an additional peculiarity of viruses circulating in 2005 to 2009 has been the poor inhibition of hemagglutination by postinfection ferret antisera for many viruses isolated in mdck cells, including homologous reference viruses. this was shown not ... | 2010 | 20410266 |
| glycosylation at 158n of the hemagglutinin protein and receptor binding specificity synergistically affect the antigenicity and immunogenicity of a live attenuated h5n1 a/vietnam/1203/2004 vaccine virus in ferrets. | a live attenuated influenza a/vietnam/1203/2004 (h5n1) vaccine virus (vn04 ca) has receptor binding specificity to alpha2,3-linked sialosides (alpha2,3sal), and a single dose induces a minimal serum antibody response in mice and ferrets. in contrast, a/hong kong/213/2003 (h5n1) vaccine virus (hk03 ca) binds to both alpha2,6sal and alpha2,3sal and generates a stronger serum antibody response in animals. among the 9 amino acids that differed between the two h5 ha1 proteins, several hk03-specific r ... | 2010 | 20427525 |
| inefficient control of host gene expression by the 2009 pandemic h1n1 influenza a virus ns1 protein. | in 2009, a novel swine-origin h1n1 influenza a virus emerged. here, we characterize the multifunctional ns1 protein of this human pandemic virus in order to understand factors that may contribute to replication efficiency or pathogenicity. although the 2009 h1n1 virus ns1 protein (2009/ns1) is an effective interferon antagonist, we found that this ns1 (unlike those of previous human-adapted influenza a viruses) is unable to block general host gene expression in human or swine cells. this propert ... | 2010 | 20444891 |
| recombinant h1n1 virus-like particle vaccine elicits protective immunity in ferrets against the 2009 pandemic h1n1 influenza virus. | the pandemic virus of 2009 (2009 h1n1) continues to cause illness worldwide, especially in younger age groups. the widespread h1n1 virus infection further emphasizes the need for vaccine strategies that are effective against emerging pandemic viruses and are not dependent on the limitations of traditional egg-based technology. this report describes a recombinant influenza virus-like particle (vlp) vaccine consisting of hemagglutinin (ha), neuraminidase (na), and matrix (m1) proteins of influenza ... | 2010 | 20470801 |
| establishment and characterization of a madin-darby canine kidney reporter cell line for influenza a virus assays. | influenza virus diagnosis has traditionally relied on virus isolation in chicken embryo or cell cultures. many laboratories have adopted rapid molecular methods for detection of influenza viruses and discontinued routine utilization of the relatively slow viral culture methods. we describe an influenza a virus reporter cell line that contributes to more efficient viral detection in cell culture. madin-darby canine kidney (mdck) cells were engineered to constitutively produce an influenza virus g ... | 2010 | 20504984 |
| a single immunization with covaccine ht-adjuvanted h5n1 influenza virus vaccine induces protective cellular and humoral immune responses in ferrets. | highly pathogenic avian influenza a viruses of the h5n1 subtype continue to circulate in poultry, and zoonotic transmissions are reported frequently. since a pandemic caused by these highly pathogenic viruses is still feared, there is interest in the development of influenza a/h5n1 virus vaccines that can protect humans against infection, preferably after a single vaccination with a low dose of antigen. here we describe the induction of humoral and cellular immune responses in ferrets after vacc ... | 2010 | 20519384 |
| assessing the development of oseltamivir and zanamivir resistance in a(h5n1) influenza viruses using a ferret model. | using an in vivo ferret model, we investigated the development of resistance to oseltamivir and zanamivir for two different influenza a(h5n1) viruses (a/vietnam/1203/2004, haemagglutinin phylogenetic clade 1, and a/chicken/laos/26/2006, haemagglutinin phylogenetic clade 2.3) by treating the animals with doses equivalent either to the recommended human treatment dose or a range of sub-optimal drug doses. no resistance was observed in oseltamivir-treated ferrets, but analysis of nasal washes from ... | 2010 | 20603155 |
| course of seasonal influenza a/brisbane/59/07 h1n1 infection in the ferret. | every year, influenza viruses infect approximately 5-20% of the population in the united states leading to over 200,000 hospitalizations and 36,000 deaths from flu-related complications. in this study, we characterized the immune and pathological progression of a seasonal strain of h1n1 influenza virus, a/brisbane/59/2007 in a ferret model. the immune response of the animals showed a dose-dependent increase with increased virus challenge, as indicated by the presence of virus specific igg, igm, ... | 2010 | 20618974 |
| an influenza a/h1n1/2009 hemagglutinin vaccine produced in escherichia coli. | the a/h1n1/2009 influenza pandemic made evident the need for faster and higher-yield methods for the production of influenza vaccines. platforms based on virus culture in mammalian or insect cells are currently under investigation. alternatively, expression of fragments of the hemagglutinin (ha) protein in prokaryotic systems can potentially be the most efficacious strategy for the manufacture of large quantities of influenza vaccine in a short period of time. despite experimental evidence on th ... | 2010 | 20661476 |
| comparative pathology of select agent influenza a virus infections. | influenza a virus infections may spread rapidly in human populations and cause variable mortality. two of these influenza viruses have been designated as select agents: 1918 h1n1 virus and highly pathogenic avian influenza (hpai) virus. knowledge of the pathology of these virus infections in humans, other naturally infected species, and experimental animals is important to understand the pathogenesis of influenza, to design appropriate models for evaluation of medical countermeasures, and to mak ... | 2010 | 20682805 |
| recombinant soluble, multimeric ha and na exhibit distinctive types of protection against pandemic swine-origin 2009 a(h1n1) influenza virus infection in ferrets. | the emergence and subsequent swift and global spread of the swine-origin influenza virus a(h1n1) in 2009 once again emphasizes the strong need for effective vaccines that can be developed rapidly and applied safely. with this aim, we produced soluble, multimeric forms of the 2009 a(h1n1) ha (sha(3)) and na (sna(4)) surface glycoproteins using a virus-free mammalian expression system and evaluated their efficacy as vaccines in ferrets. immunization twice with 3.75-microg doses of these antigens e ... | 2010 | 20686020 |
| multiple infections with seasonal influenza a virus induce cross-protective immunity against a(h1n1) pandemic influenza virus in a ferret model. | an age bias toward children and young adults has been reported for infection and hospitalizations with pandemic h1n1 influenza (a[h1n1]pdm) in the 2009 and 2010 influenza seasons in the southern and northern hemispheres. serological analysis of prepandemic samples has shown a higher incidence of cross-reactive antibodies to a(h1n1)pdm virus in older populations; conserved t cell epitopes between viruses have been identified. the contribution of preexisting immunity to seasonal influenza to prote ... | 2010 | 20715930 |
| evaluation of a modified vaccinia virus ankara (mva)-based candidate pandemic influenza a/h1n1 vaccine in the ferret model. | the zoonotic transmissions of highly pathogenic avian influenza viruses of the h5n1 subtype that have occurred since 1997 have sparked the development of novel influenza vaccines. the advent of reverse genetics technology, cell-culture production techniques and novel adjuvants has improved the vaccine strain preparation, production process and immunogenicity of the vaccines, respectively, and has accelerated the availability of pandemic influenza vaccines. however, there is still room for improv ... | 2010 | 20719991 |
| oseltamivir-resistant variants of the 2009 pandemic h1n1 influenza a virus are not attenuated in the guinea pig and ferret transmission models. | oseltamivir is routinely used worldwide for the treatment of severe influenza a virus infection, and should drug-resistant pandemic 2009 h1n1 viruses become widespread, this potent defense strategy might fail. oseltamivir-resistant variants of the pandemic 2009 h1n1 influenza a virus have been detected in a substantial number of patients, but to date, the mutant viruses have not moved into circulation in the general population. it is not known whether the resistance mutations in viral neuraminid ... | 2010 | 20739532 |
| natural cases of 2009 pandemic h1n1 influenza a virus in pet ferrets. | respiratory swab samples were collected from 5 pet ferrets (mustela putorius furo) exhibiting influenza-like illness. the ferrets represented 3 households in 2 states. in each case, the owners reported influenza-like illness in themselves or family members prior to the onset of a similar illness in the ferrets. real-time reverse transcription polymerase chain reaction assays designed for the detection of the 2009 h1n1 influenza a virus were conducted in the state animal health laboratories. the ... | 2010 | 20807944 |
| ferrets develop fatal influenza after inhaling small particle aerosols of highly pathogenic avian influenza virus a/vietnam/1203/2004 (h5n1). | there is limited knowledge about the potential routes for h5n1 influenza virus transmission to and between humans, and it is not clear whether humans can be infected through inhalation of aerosolized h5n1 virus particles. ferrets are often used as a animal model for humans in influenza pathogenicity and transmissibility studies. in this manuscript, a nose-only bioaerosol inhalation exposure system that was recently developed and validated was used in an inhalation exposure study of aerosolized a ... | 2010 | 20843329 |
| virulence-associated substitution d222g in the hemagglutinin of 2009 pandemic influenza a(h1n1) virus affects receptor binding. | the clinical impact of the 2009 pandemic influenza a(h1n1) virus (pdmh1n1) has been relatively low. however, amino acid substitution d222g in the hemagglutinin of pdmh1n1 has been associated with cases of severe disease and fatalities. d222g was introduced in a prototype pdmh1n1 by reverse genetics, and the effect on virus receptor binding, replication, antigenic properties, and pathogenesis and transmission in animal models was investigated. pdmh1n1 with d222g caused ocular disease in mice with ... | 2010 | 20844044 |
| the ha and ns genes of human h5n1 influenza a virus contribute to high virulence in ferrets. | highly pathogenic h5n1 influenza a viruses have spread across asia, europe, and africa. more than 500 cases of h5n1 virus infection in humans, with a high lethality rate, have been reported. to understand the molecular basis for the high virulence of h5n1 viruses in mammals, we tested the virulence in ferrets of several h5n1 viruses isolated from humans and found a/vietnam/ut3062/04 (ut3062) to be the most virulent and a/vietnam/ut3028/03 (ut3028) to be avirulent in this animal model. we then ge ... | 2010 | 20862325 |
| characterization of oseltamivir-resistant 2009 h1n1 pandemic influenza a viruses. | influenza viruses resistant to antiviral drugs emerge frequently. not surprisingly, the widespread treatment in many countries of patients infected with 2009 pandemic influenza a (h1n1) viruses with the neuraminidase (na) inhibitors oseltamivir and zanamivir has led to the emergence of pandemic strains resistant to these drugs. sporadic cases of pandemic influenza have been associated with mutant viruses possessing a histidine-to-tyrosine substitution at position 274 (h274y) in the na, a mutatio ... | 2010 | 20865125 |
| classical swine h1n1 influenza viruses confer cross protection from swine-origin 2009 pandemic h1n1 influenza virus infection in mice and ferrets. | the hemagglutinin of the 2009 pandemic h1n1 influenza virus is a derivative of and is antigenically related to classical swine but not to seasonal human h1n1 viruses. we compared the a/california/7/2009 (ca/7/09) virus recommended by the who as the reference virus for vaccine development, with two classical swine influenza viruses a/swine/iowa/31 (sw/ia/31) and a/new jersey/8/1976 (nj/76) to establish the extent of immunologic cross-reactivity and cross-protection in animal models. primary infec ... | 2010 | 20926110 |
| ns-based live attenuated h1n1 pandemic vaccines protect mice and ferrets. | although vaccines against influenza a virus are the most effective method to combat infection, it is clear that their production needs to be accelerated and their efficacy improved. we generated live attenuated human influenza a vaccines (laivs) by rationally engineering mutations directly into the genome of a pandemic-h1n1 virus. two laivs (ns1-73 and ns1-126) were based on the success of laivs for animal influenza a viruses. a third candidate (nsδ5) is a unique ns-mutant that has never been us ... | 2010 | 20934458 |
| rapid detection of the pandemic 2009 h1n1 virus m gene by real-time and gel-based rt-pcr assays. | since the first pandemic 2009 h1n1 (ph1n1) virus was isolated from humans, it has also been detected in other mammalian (pigs, cats, dogs, ferrets) and avian (turkey) species, most likely because of cross-species transmission from humans. the ph1n1 contains six genes derived from swine influenza viruses (sivs) currently circulating in north america of human- (pb1), avian- (pb2, pa), and swine- (ha, np, and ns) origin and two genes (na and m) derived from eurasian sivs. the novel genetic composit ... | 2010 | 20958934 |
| contemporary seasonal influenza a (h1n1) virus infection primes for a more robust response to split inactivated pandemic influenza a (h1n1) virus vaccination in ferrets. | human influenza pandemics occur when influenza viruses to which the population has little or no immunity emerge and acquire the ability to achieve human-to-human transmission. in april 2009, cases of a novel h1n1 influenza virus in children in the southwestern united states were reported. it was retrospectively shown that these cases represented the spread of this virus from an ongoing outbreak in mexico. the emergence of the pandemic led to a number of national vaccination programs. surprisingl ... | 2010 | 20962210 |
| antibody responses induced by japanese whole inactivated vaccines against equine influenza virus (h3n8) belonging to florida sublineage clade2. | in 2010, the world organisation for animal health recommended the inclusion of a florida sublineage clade2 strain of equine influenza virus (h3n8), which is represented by a/equine/richmond/1/07 (richmond07), in equine influenza vaccines. here, we evaluate the antigenic differences between japanese vaccine strains and richmond07 by performing hemagglutination inhibition (hi) assays. ferret antiserum raised to a/equine/la plata/93 (la plata93), which is a japanese vaccine strain, reacted with ric ... | 2010 | 21099188 |
| immunogenicity and protective efficacy of a live attenuated vaccine against the 2009 pandemic a h1n1 in mice and ferrets. | a novel 2009 influenza a (h1n1) virus was transmitted from humans to humans worldwide. the live attenuated monovalent a h1n1 vaccine (lamv) for intranasal administration has shown promising immunogenicity and safety in clinical trials and for human use, but the experimental data based on lamv is incomplete. in this study, using reverse genetic technology, we produced a cold-adapted (ca), live attenuated bj/aa ca that contained hemagglutinin (ha) and neuraminidase (na) genes from a 2009 pandemic ... | 2010 | 21111782 |
| genetic immunization in the lung induces potent local and systemic immune responses. | successful vaccination against respiratory infections requires elicitation of high levels of potent and durable humoral and cellular responses in the lower airways. to accomplish this goal, we used a fine aerosol that targets the entire lung surface through normal respiration to deliver replication-incompetent recombinant adenoviral vectors expressing gene products from several infectious pathogens. we show that this regimen induced remarkably high and stable lung t-cell responses in nonhuman pr ... | 2010 | 21135247 |
| seasonal influenza vaccination and the risk of infection with pandemic influenza: a possible illustration of non-specific temporary immunity following infection. | four canadian studies have suggested that receipt of seasonal influenza vaccine increased the risk of laboratory-confirmed infection with 2009 pandemic influenza a(h1n1). during the influenza season of 2009 in victoria, australia, this virus comprised 97% of all circulating influenza viruses for which sub-typing was available. we found no evidence that seasonal influenza vaccine increased the risk of, or provided protection against, infection with the pandemic virus. ferret experiments have sugg ... | 2010 | 21144441 |
| preclinical and clinical development of plant-made virus-like particle vaccine against avian h5n1 influenza. | the recent swine h1n1 influenza outbreak demonstrated that egg-based vaccine manufacturing has an achille's heel: its inability to provide a large number of doses quickly. using a novel manufacturing platform based on transient expression of influenza surface glycoproteins in nicotiana benthamiana, we have recently demonstrated that a candidate virus-like particle (vlp) vaccine can be generated within 3 weeks of release of sequence information. herein we report that alum-adjuvanted plant-made vl ... | 2010 | 21203523 |
| multidrug-resistant 2009 pandemic influenza a(h1n1) viruses maintain fitness and transmissibility in ferrets. | the 2009 influenza a(h1n1) pandemic called attention to the limited influenza treatment options available, especially in individuals at high risk of severe disease. neuraminidase inhibitor-resistant seasonal h1n1 viruses have demonstrated the ability to transmit well despite early data indicating that resistance reduces viral fitness. 2009 h1n1 pandemic viruses have sporadically appeared containing resistance to neuraminidase inhibitors and the adamantanes, but the ability of these viruses to re ... | 2010 | 21208927 |
| cellular immune response in the presence of protective antibody levels correlates with protection against 1918 influenza in ferrets. | the identification of immune correlates of protection against highly pathogenic human-adapted influenza is instrumental in the development of the next generation of vaccines. towards this, ferrets received either one dose of a conventionally produced vaccine, two inoculations of a hemagglutinin (ha)-expressing dna vaccine, or a prime-boost regimen of the dna vaccine followed by injection of a ha-expressing adenoviral vector. in addition to the antibody response, ferret-specific interferon-gamma ... | 2011 | 21211587 |
| vaccination against seasonal influenza a/h3n2 virus reduces the induction of heterosubtypic immunity against influenza a/h5n1 virus infection in ferrets. | infection with seasonal influenza viruses induces a certain extent of protective immunity against potentially pandemic viruses of novel subtypes, also known as heterosubtypic immunity. here we demonstrate that infection with a recent influenza a/h3n2 virus strain induces robust protection in ferrets against infection with a highly pathogenic avian influenza virus of the h5n1 subtype. prior h3n2 virus infection reduced h5n1 virus replication in the upper respiratory tract, as well as clinical sig ... | 2011 | 21228239 |
| vaccination with different m2e epitope densities confers partial protection against h5n1 influenza a virus challenge in chickens. | objective: currently, research is focused on universal influenza vaccines based on various ectodomains of the influenza matrix protein 2 (m2e). such vaccines are tested mostly using mouse-adapted influenza viruses and in mouse or ferret models. the aim of this study was to investigate in a chicken model the protective efficacy of vaccines based on avian-type m2e at different epitope densities. methods: on the basis of the optimized avian-type m2e gene, recombinant plasmids that contained tandem ... | 2011 | 21228535 |
| comparison of a live attenuated 2009 h1n1 vaccine with seasonal influenza vaccines against 2009 pandemic h1n1 virus infection in mice and ferrets. | the role of seasonal influenza vaccination in pandemic influenza a h1n1 disease is important to address, because a large segment of the population is vaccinated annually. we administered 1 or 2 doses of pandemic h1n1 vaccine (ca/7 ca), a seasonal trivalent inactivated (s-tiv), or live attenuated influenza vaccine (s-laiv) to mice and ferrets and subsequently challenged them with a pandemic h1n1 virus. in both species, ca/7 ca was immunogenic and conferred complete protection against challenge. s ... | 2011 | 21257740 |
| a nonlethal young domesticated ferret (mustela putorius furo) model for studying pandemic influenza virus a/california/04/2009 (h1n1). | recent events have heightened the need for the rapid development of vaccines directed against pandemic influenza h1n1 viruses circulating during 2009 to 2010. the current study was conducted to establish a virus challenge dose for a subsequent ca/04 vaccine efficacy study in 3-mo-old domesticated ferrets. an additional consideration in using ca/04 in ferrets is the selection of endpoints on which to base the challenge dose, given the potential nonlethality of this particular model. four doses ra ... | 2010 | 21262121 |
| the contribution of animal models to the understanding of the host range and virulence of influenza a viruses. | since ferrets were first used in 1933 during the initial isolation of influenza a viruses, animal models have been critical for influenza research. the following review discusses the contribution of mice, ferrets, and non-human primates to the study of influenza virus host range and pathogenicity. | 2011 | 21276869 |
| possible increased pathogenicity of pandemic (h1n1) 2009 influenza virus upon reassortment. | since emergence of the pandemic (h1n1) 2009 virus in april 2009, three influenza a viruses-seasonal (h3n2), seasonal (h1n1), and pandemic (h1n1) 2009-have circulated in humans. genetic reassortment between these viruses could result in enhanced pathogenicity. we compared 4 reassortant viruses with favorable in vitro replication properties with the wild-type pandemic (h1n1) 2009 virus with respect to replication kinetics in vitro and pathogenicity and transmission in ferrets. pandemic (h1n1) 2009 ... | 2011 | 21291589 |
| monoclonal antibodies to the haemagglutinin ha1 subunit of the pandemic influenza a/h1n1 2009 virus and potential application to serodiagnosis. | in order to provide specific serological reagents for pandemic influenza a/h1n1 2009 virus, monoclonal antibodies (mabs) to recombinant haemagglutinin component ha1 (rha1) were generated after fusing spleen cells from a mouse immunized with rha1 protein derived from influenza strain a/california/06/09 h1n1 with a mouse myeloma cell line. five hybridoma clones secreting mabs specific for the rha1 protein derived from pandemic influenza a/h1n1 2009 and not for rha1 from seasonal h1n1 influenza str ... | 2011 | 21328368 |
| avian and human influenza a virus receptors in trachea and lung of animals. | influenza a viruses are capable of crossing the specific barrier between human beings and animals resulting in interspecies transmission. the important factor of potential infectivity of influenza a viruses is the suitability of the receptor binding site of the host and viruses. the affinities of avian and human influenza virus to bind with the receptors and the distributions of receptors in animals are different. | 2010 | 21337915 |
| efficacy of seasonal live attenuated influenza vaccine against virus replication and transmission of a pandemic 2009 h1n1 virus in ferrets. | in march 2009, a swine origin influenza a (2009 h1n1) virus was introduced into the human population and quickly spread from north america to multiple continents. human serologic studies suggest that seasonal influenza virus vaccination or infection would provide little cross-reactive serologic immunity to the pandemic 2009 h1n1 virus. however, the efficacy of seasonal influenza infection or vaccination against 2009 h1n1 virus replication and transmission has not been adequately evaluated in viv ... | 2011 | 21338676 |
| insertion of a multibasic cleavage site in the haemagglutinin of human influenza h3n2 virus does not increase pathogenicity in ferrets. | a multibasic cleavage site (mbcs) in the haemagglutinin (ha) protein of influenza a virus is a key determinant of pathogenicity in chickens, and distinguishes highly pathogenic avian influenza (hpai) viruses from low pathogenic avian influenza viruses (lpai). an mbcs has only been detected in viruses of the h5 and h7 subtypes. here we investigated the phenotype of a human h3n2 virus with an mbcs in ha. insertion of an mbcs in the h3n2 virus resulted in cleavage of ha and efficient replication in ... | 2011 | 21346026 |
| effect of an asparagine-to-serine mutation at position 294 in neuraminidase on the pathogenicity of highly pathogenic h5n1 influenza a virus. | like the histidine-to-tyrosine substitution at position 274 in neuraminidase (na h274y), an asparagine-to-serine mutation at position 294 in this protein (na n294s) confers oseltamivir resistance to highly pathogenic h5n1 influenza a viruses. however, unlike viruses with the na h274y mutation, the properties of viruses possessing na n294s are not well understood. here, we assessed the effect of the na n294s substitution on the replication and pathogenicity of human h5n1 viruses and on the effica ... | 2011 | 21367898 |
| development and characterization of lyophilized dna vaccine formulations. | the potential applications of using plasmid dna for immunization and other gene therapy approaches have been discussed in an increasing number of publications in the past few years. injection of mouse muscle with naked dna (plasmid dna in saline) resulted in significant episomal expression from a number of encoded reporter genes such as firefly luciferase, chloramphenicol acetyltransferase, and β-galactosidase (1). dna vaccination has been shown to induce neutralizing antibodies against the gene ... | 2000 | 21374306 |
| multiple genes contribute to the virulent phenotype observed in ferrets of an h5n1 influenza virus isolated from thailand in 2004. | human infections with highly pathogenic h5n1 avian influenza viruses continue to occur in many parts of the world and pose a considerable public health threat. with the use of animal models, the identification of virulence determinants has been instrumental in improving our understanding of how these viruses cause severe disease in humans. two genetically similar h5n1 viruses (a/thailand/16/2004 and a/thailand/sp83/2004) exhibit high or low virulence phenotypes, respectively, in multiple animal ... | 2011 | 21388650 |
| subclinical brain injury caused by h5n1 influenza virus infection. | although h5n1 influenza a viruses can cause systemic infection, their neurotropism and long-term effects on the central nervous system (cns) are not fully understood. we assessed h5n1viral invasion of the cns and its long-term effects in a ferret model. an h5n1 virus caused nonsuppurative encephalitis, which lasted for 3 months without neurologic signs. further, another h5n1 virus caused nonsuppurative vasculitis with brain hemorrhage. three-dimensional analysis of viral distribution in the brai ... | 2011 | 21389133 |
| effect of receptor binding domain mutations on receptor binding and transmissibility of avian influenza h5n1 viruses. | although h5n1 influenza viruses have been responsible for hundreds of human infections, these avian influenza viruses have not fully adapted to the human host. the lack of sustained transmission in humans may be due, in part, to their avian-like receptor preference. here, we have introduced receptor binding domain mutations within the hemagglutinin (ha) gene of two h5n1 viruses and evaluated changes in receptor binding specificity by glycan microarray analysis. the impact of these mutations on r ... | 2011 | 21397290 |
| mutations affecting the stability of the haemagglutinin molecule impair the immunogenicity of live attenuated h3n2 intranasal influenza vaccine candidates lacking ns1. | the isolation and cultivation of human influenza viruses in embryonated hen eggs or cell lines often leads to amino acid substitutions in the haemagglutinin (ha) molecule. we found that the propagation of influenza a h3n2 viruses on vero cells may trigger the appearance of ha destabilising mutations, affecting viral resistance to low ph or high temperature treatment. two δns1 reassortants, containing the ha sequences identical to the original human h3n2 influenza virus isolates were constructed. ... | 2011 | 21406268 |
| a single base-pair change in 2009 h1n1 hemagglutinin increases human receptor affinity and leads to efficient airborne viral transmission in ferrets. | the 2009 h1n1 influenza a virus continues to circulate among the human population as the predominant h1n1 subtype. epidemiological studies and airborne transmission studies using the ferret model have shown that the transmission efficiency of 2009 h1n1 viruses is lower than that of previous seasonal strains and the 1918 pandemic h1n1 strain. we recently correlated this reduced transmission efficiency to the lower binding affinity of the 2009 h1n1 hemagglutinin (ha) to a2?6 sialylated glycan rece ... | 2011 | 21407805 |
| systemic dissemination of h5n1 influenza a viruses in ferrets and hamsters after direct intragastric inoculation. | although oral exposure to h5n1 highly pathogenic avian influenza viruses is a risk factor for infection in humans, it is unclear how oral exposure to these virus results in lethal respiratory infections. to address this issue, we inoculated ferrets and hamsters with two highly pathogenic h5n1 strains. these viruses, inoculated directly into the stomach, were isolated from the large intestine and the mesenteric lymph nodes within 1 day of inoculation and subsequently spread to multiple tissues, i ... | 2011 | 21411541 |
| ns1-mediated delay of type i interferon induction contributes to influenza a virulence in ferrets. | interference of the influenza a virus non-structural protein ns1 with type i interferon (ifn) signalling has been characterized extensively in vitro. to assess the contribution of ns1 to the virulence of a specific strain, we generated recombinant ussr/90/77 viruses bearing the ns1 proteins of the attenuated strain pr/8/34 or the highly pathogenic strain 1918 'spanish flu', all belonging to the h1n1 subtype. in vitro, the extent of interference with type i ifn production exerted by the different ... | 2011 | 21411677 |
| a miniaturized assay for influenza neuraminidase-inhibiting antibodies utilizing reverse genetics-derived antigens. | antibodies to neuraminidase (na) contribute to protection during influenza virus infection, but na inhibition (ni) titers are not routinely analyzed in vaccine trials. one reason is the cumbersome nature of the conventional thiobarbituric acid (tba) ni assay, which uses chemical methods to quantify free sialic acid following incubation of na with substrate in the presence of serum. in addition, the assay is complicated by the need to use virus of a hemagglutinin (ha) subtype novel to the host to ... | 2009 | 21462400 |
| lack of transmission of a human influenza virus with avian receptor specificity between ferrets is not due to decreased virus shedding, but rather a lower infectivity in vivo. | influenza virus attaches to host cells by sialic acid (sa). human influenza viruses show preferential affinity for α2,6 linked sa whereas avian influenza viruses bind α2,3 linked sa. mutation of the haemagglutinin receptor binding site of a human h3n2 influenza a virus to switch binding to α2,3 sa did not abrogate infection of ferrets but prevented transmission even in a co-housed model. the mutant virus was shed from the noses of ferrets directly inoculated with virus in the same amounts and fo ... | 2011 | 21508186 |
| pulmonary pathology of pandemic influenza a/h1n1 virus (2009) infected ferrets upon longitudinal evaluation by computed tomography. | we investigated the development of pulmonary lesions in ferrets following infection with the 2009 pandemic a/h1n1 influenza virus by means of computed tomography (ct) and compared the scans with gross pathology, histopathology and immunohistochemistry. ground-glass opacities observed by ct-scanning in all infected lungs corresponded to areas of alveolar edema at necropsy. these areas were most pronounced on day 3 and gradually decreased from day 4 to day 7 post-infection. this pilot study shows ... | 2011 | 21543558 |