H1N1 Swine Flu - Swine Flu News Feed from MedWorm

Authors: Greene SK, Rett M, Weintraub ES, Li L, Yin R, Amato AA, Ho DT, Sheikh SI, Fireman BH, Daley MF, Belongia EA, Jacobsen SJ, Baxter R, Lieu TA, Kulldorff M, Vellozzi C, Lee GM Abstract An increased risk of Guillain-Barré syndrome (GBS) following administration of the 1976 swine influenza vaccine led to a heightened focus on GBS when monovalent vaccines against a novel influenza A (H1N1) virus of swine origin were introduced in 2009. GBS cases following receipt of monovalent inactivated (MIV) and seasonal trivalent inactivated (TIV) influenza vaccines in the Vaccine Safety Datalink Project in 2009-2010 were identified in electronic data and confirmed by medical record review. Within 1-42 days following vaccination, 9 cases were confirmed in MIV recipients (1.48 million doses)...

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Authors: Nelson KE Abstract After a new reassortant swine influenza A H1N1 virus caused outbreaks in Mexico and the United States in 2009, a vaccine was prepared from this virus to immunize the entire US population. Surveillance for Guillain-Barré syndrome (GBS) after receipt of this vaccine was carried out in 3 populations: the Vaccine Safety Datalink Project, the 10 Centers for Disease Control and Prevention Emerging Infections Program sites, and a network of large insurance companies. These studies found a small increase of approximately 1 case of GBS per million vaccinees above the baseline rate, which is similar to that observed after administration of seasonal influenza vaccines over the past several years. Enhanced surveillance for GBS was conducted in 2009-2010 because of ...

Publication of bird flu study was delayed after warnings that the information could be exploited by terroristsControversial research on a hybrid strain of bird flu that could potentially spread between humans was published on Wednesday in Nature after security restrictions on the work were lifted.Scientists created the virus by merging a mutated strain of bird flu with the "swine flu" virus that sparked a human pandemic in 2009. The hybrid strain spread easily between ferrets – the best proxy that flu researchers have for people – but was not lethal and could be controlled with antiviral drugs and bird flu vaccines.The work by Yoshihiro Kawaoka at the University of Wisconsin-Madison was submitted last year to the journal, but was delayed after the US government's biosecurity advisers s...

Conclusion: It is an important task to protect oncohematological and organ transplant patients. Orv. Hetil., 2012, 153, 649-654. PMID: 22543220 [PubMed - in process] (Source: Orvosi Hetilap)

Authors: Lindstrom S, Garten R, Balish A, Shu B, Emery S, Berman L, Barnes N, Sleeman K, Gubareva L, Villanueva J, Klimov A Abstract During July-December 2011, a variant virus, influenza A(H3N2)v, caused 12 human cases of influenza. The virus contained genes originating from swine, avian, and human viruses, including the M gene from influenza A(H1N1)pdm09 virus. Influenza A(H3N2)v viruses were antigenically distinct from seasonal influenza viruses and similar to proposed vaccine virus A/Minnesota/11/2010. PMID: 22516540 [PubMed - in process] (Source: Emerging Infectious Diseases)

Conclusions  Retinoic acid promoted ciliogenesis, whereas epidermal growth factor controlled the thickness of the pseudoepithelium. The optimal concentrations for differentiated swine cell cultures were 1·5 ng/ml epidermal growth factor and 100 nm retinoic acid. Influenza A viruses infected and productively replicated in these cultures in the absence of exogenous trypsin, suggesting that the cultures express a protease capable of activating influenza virus hemagglutinin. Differences in virus infection and replication characteristics found previously in pigs in vivo were recapitulated in the swine cultures. This system could be a useful tool for a range of applications, including investigating influenza virus species specificity, defining cell tropism of influenza viruses in the swin...

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Authors: Vinnerås B, Samuelson A, Emmoth E, Nyberg KA, Albihn A Abstract The aim of the study was to investigate the effects of formic acid addition to ground high risk animal by-products (ABP 1) in terms of stabilization and pathogen inactivation and to evaluate the biosecurity risk connected with the ABP 1 based combustion fuel Biomal. Laboratory studies were performed on the persistence of Salmonella Typhimurium, Bacillus cereus spores, porcine herpes virus, avian influenza virus, bovine viral diarrhea virus, equine rhinitis A virus and porcine parvovirus in Biomal at different storage times. It was shown that Salmonella and enveloped viruses were inactivated within 1 day (24 h). Bacillus cereus spores were not reduced during 147 days and the non-enveloped virus porcine parvovi...

Authors: Abstract Since August 2011, a total of 12 human infections with influenza A (H3N2) variant viruses with genes from avian, swine, and human viruses (i.e., A [H3N2]v) that had acquired the M gene from influenza A (H1N1)pdm09 virus have been reported to CDC. Eleven of the cases occurred in children aged <10 years. In six cases, no history of recent exposure to swine was noted, suggesting that human-to-human transmission had occurred. This new gene constellation for A (H3N2)v viruses and its temporal association with an increase in human cases of A (H3N2)v highlight the need to better understand the risk for human infection with these viruses and the extent to which current seasonal vaccines might elicit cross-reactive antibodies to them. CDC conducted a preliminary analy...

Authors: Ocaña-Macchi M, Ricklin ME, Python S, Monika GA, Stech J, Stech O, Summerfield A Abstract The 2009 influenza A virus (IAV) pandemic resulted from reassortment of avian, human and swine strains probably in pigs. To elucidate the role of viral genes in host adaptation regarding innate immune responses, we focussed on the effect of genes from an avian H5N1 and a porcine H1N1 IAV on infectivity and activation of porcine GM-CSF-induced dendritic cells (DC). The highest interferon type I responses were achieved by the porcine virus reassortant containing the avian polymerase gene PB2. This finding was not due to differential tropism since all viruses infected DC equally. All viruses equally induced MHC class II, but porcine H1N1 expressing the avian viral PB2 induced more promi...

In this study, we identify a recombinant pb1 gene, a recombinant MP segment and a recombinant PA segment. The pb1 gene is recombined from two Eurasia swine H1N1 influenza virus lineages. It belongs to a H1N1 swine clade circulating in Europe and Asia from 1999 to 2009. The mosaic MP segment descends from H7 avian and H1N1 human virus lineages and pertains to a large human H1N1 virus family circulating in Asia, Europe and America from 1918 to 2007. The recombinant PA segment originated from two swine H1N1 lineages is found in a swine H1N1 group prevailing in Asia and Europe from 1999 to 2003. These results collectively falsify the hypothesis that influenza virus do not evolve by homologous recombination. Since recombination not only leads to virus genome diversity but also can alter its hos...

This study indicates that swine influenza is disseminated throughout Minas Gerais state, Brazil. (Source: Influenza and Other Respiratory Viruses)

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CONCLUSIONSOverall, no significant safety issues were identified. The methodology and use of modern technologies to collect safety data from large numbers of patients was successful and could be used again in similar safety studies. (Source: British Journal of Clinical Pharmacology)

Researchers at the University of British Columbia have identified a number of tiny but powerful "genetic regulators" that are hijacked by avian and swine flu viruses during human infection. The discovery, published in the Journal of Virology, could reveal new targets for broad-spectrum antivirals to combat current - and perhaps future - strains of influenza A viruses... (Source: Health News from Medical News Today)

In this study, researchers found that 75% of the children analysed had been vaccinated against swine flu. There were 67 confirmed cases of narcolepsy, of which 46 vaccinated and seven unvaccinated cases were included in the primary analysis. This second study looked at cases of narcolepsy within “person years”. A person year represents one person exposed for a year and is a way of correcting for the various lengths of time the children were in the study before they were vaccinated or after vaccination. For example, one child studied for 18 months and another studied for six months would provide two person years of data altogether. The incidence of narcolepsy among the vaccinated children was 9.0 cases per 100,000 person years, compared with 0.7 cases per 100,000 person years in unvacci...

Future Virology , April 2012, Vol. 7, No. 4, Pages 403-412. (Source: Future Virology)

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Authors: Rickert JD, Herpy TA, Zhong H, Lu G Abstract The adaptive evolution of the hemagglutinin (HA) segment of the human influenza H1N1 and H3N2 viruses is not well understood due to antigenic mutations under selection pressures. This paper identified significant antigenic selection sites and discussed the structural relevance of these mutations. We discovered four positively selected sites for H1N1 (position 206 for the 1A lineage - 2009 swine influenza, and positions 144, 190, and 192 for the 1B lineage), and eight positively selected sites for H3N2 with the loop regions near residues 157 and 225 as the latest antigenic mutations, which may be targeted for vaccine development. PMID: 22450272 [PubMed - in process] (Source: International Journal of Bioinformatics Research an...

Surprisingly little is known about the interaction of human blood mononuclear cells with viruses. Here, we show that monocytes are the predominant cell type infected when peripheral blood mononuclear cells are exposed to viruses ex vivo. Remarkably, infection with vesicular stomatitis virus, vaccinia virus, and a variety of influenza A viruses (including circulating swine-origin virus) induces monocytes to differentiate within 18 hours into CD16–CD83+ mature dendritic cells with enhanced capacity to activate T cells. Differentiation into dendritic cells does not require cell division and occurs despite the synthesis of viral proteins, which demonstrates that monocytes counteract the capacity of these highly lytic viruses to hijack host cell biosynthetic capacity. Indeed, differentiat...

Conclusion This research suggests that a family of proteins has a protective role against flu infection. The mouse study indicates that when these proteins are not produced, the flu virus replicates at higher levels and can lead to more severe forms of the flu. The case-control study strengthens these findings, and indicates that there is an association between severe flu and the presence of a mutated IFITM gene in humans. However, it is important to note several limitations to the study: The animal study can suggest mechanisms through which the genetic mutation may influence the development of severe flu, but the results cannot be generalised as applying to humans. The case-control study was small, with only 53 patients with severe flu included. Larger studies will be needed to con...

Authors: Rudneva I, Ignatieva A, Timofeeva T, Shilov A, Kushch A, Masalova O, Klimova R, Bovin N, Mochalova L, Kaverin N Abstract A panel of 6 neutralizing monoclonal antibodies (MAbs) raised against A/Moscow/IIV01/2009 (H1N1) virus isolated during the 2009 pandemic was used for the selection of 26 escape mutants. The mutants were characterized in immune cross-reactions with the panel of MAbs. The sequencing of the mutant HA genes revealed 5 amino acid positions recognized by monoclonal antibodies: 129, 156, 158, 159, and 190 (H3 numbering). The amino acid positions were distributed in two epitopes belonging to antigenic sites Sa and Sb. The mutant HAs exhibited variations in the affinity to synthetic high molecular mass sialic acid-containing receptor analogues. Results are discus...

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Authors: Xia Z, Huynh T, Kang SG, Zhou R Abstract Antibodies binding to conserved epitopes can provide a broad range of neutralization to existing influenza subtypes and may also prevent the propagation of potential pandemic viruses by fighting against emerging strands. Here we propose a computational framework to study structural binding patterns and detailed molecular mechanisms of viral surface glycoprotein hemagglutinin (HA) binding with a broad spectrum of neutralizing monoclonal antibody fragments (Fab). We used rigorous free-energy perturbation (FEP) methods to calculate the antigen-antibody binding affinities, with an aggregate underlying molecular-dynamics simulation time of several microseconds (∼2 μs) using all-atom, explicit-solvent models. We achieved a high accurac...