Search results for "influenza virus"
showing 10 items of 29 documents
Genetic characterization of influenza viruses from influenza-related hospital admissions in the St. Petersburg and Valencia sites of the Global Influ…
2016
Abstract Background Continuous surveillance for genetic changes in circulating influenza viruses is needed to guide influenza prevention and control. Objectives To compare intra-seasonal influenza genetic diversity of hemagglutinin in influenza A strains isolated from influenza hospital admissions collected at two distinct sites during the same season. Study design Comparative phylogenetic analysis of full-length hemagglutinin genes from 77 isolated influenza A viruses from the St. Petersburg, Russian Federation and Valencia, Spain sites of the Global Influenza Hospital Surveillance Network (GIHSN) during the 2013/14 season. Results We found significant variability in A(H3N2) and A(H1N1)pdm…
Regulation of kynurenine biosynthesis during influenza virus infection.
2017
Influenza A viruses (IAVs) remain serious threats to public health because of the shortage of effective means of control. Developing more effective virus control modalities requires better understanding of virus–host interactions. It has previously been shown that IAV induces the production of kynurenine, which suppresses T-cell responses, enhances pain hypersensitivity and disturbs behaviour in infected animals. However, the regulation of kynurenine biosynthesis during IAV infection remains elusive. Here we showed that IAV infection induced expression of interferons (IFNs), which upregulated production of indoleamine-2,3-dioxygenase (IDO1), which catalysed the kynurenine biosynthesis. Furt…
The molecular epidemiology and evolutionary dynamics of influenza B virus in two Italian regions during 2010-2015: The experience of Sicily and Ligur…
2016
Molecular epidemiology of influenza B virus remained poorly studied in Italy, despite representing a major contributor to seasonal epidemics. This study aimed to reconstruct the phylogenetic relationships and genetic diversity of the hemagglutinin gene sequences of 197 influenza B strains circulating in both Southern (Sicily) and Northern (Liguria) Italy between 2010 and 2015. Upper respiratory tract specimens of patients displaying symptoms of influenza-like illness were screened by real-time RT-PCR assay for the presence of influenza B virus. PCR-positive influenza B samples were further analyzed by sequencing. Neighbor-joining phylogenetic trees were constructed and the amino-acid alignm…
Clinical effectiveness of influenza vaccination after allogeneic hematopoietic stem cell transplantation: A cross-sectional prospective observational…
2018
Abstract Background Vaccination is the primary method for preventing influenza respiratory virus infection (RVI). Although the influenza vaccine is able to achieve serological responses in some allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients, its clinical benefits are still uncertain. Methods In this prospective, cross-sectional study, we retrospectively analyzed the effect of inactivated trivalent influenza vaccination on the prevalence of influenza RVI in a consecutive cohort of 136 allo-HSCT adult recipients who developed 161 RVI over 5 flu seasons (from 2013 to 2018). Respiratory viruses in upper– and/or lower–respiratory tract specimens were tested using multi…
Direct Visualization of the Conformational Dynamics of Single Influenza Hemagglutinin Trimers
2018
Influenza hemagglutinin (HA) is the canonical type I viral envelope glycoprotein and provides a template for the membrane-fusion mechanisms of numerous viruses. The current model of HA-mediated membrane fusion describes a static "spring-loaded" fusion domain (HA2) at neutral pH. Acidic pH triggers a singular irreversible conformational rearrangement in HA2 that fuses viral and cellular membranes. Here, using single-molecule Förster resonance energy transfer (smFRET)-imaging, we directly visualized pH-triggered conformational changes of HA trimers on the viral surface. Our analyses reveal reversible exchange between the pre-fusion and two intermediate conformations of HA2. Acidification of p…
Human CD8(+) T Cells Damage Noninfected Epithelial Cells during Influenza Virus Infection In Vitro
2017
During severe influenza A virus (IAV) infections, a large amount of damage to the pulmonary epithelium is the result of the antiviral immune response. Specifically, whilst CD8+ T cells are important for killing IAV-infected cells, during a severe IAV infection, they can damage uninfected epithelial cells. At present, the mechanisms by which this occurs are unclear. Here, we used a novel in vitro coculture model of human NCl-H441 cells and CD8+ T cells to provide a new insight into how CD8+ T cells may affect uninfected epithelial cells during severe IAV infections. Using this model, we show that human IAV-specific CD8+ T cells produce soluble factors that reduce the barrier integrity of non…
A risk-adapted approach to treating respiratory syncytial virus and human parainfluenza virus in allogeneic stem cell transplantation recipients with…
2017
Here we report the applicability of a protocol based on clinical conditions and risk factors (RFs) for managing 35 allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients who developed a total of 52 episodes of respiratory viral infections (RVIs) caused by respiratory syncytial virus (RSV; n=19), human parainfluenza virus (HPIV; n=29), or both (n=4) over a 2-year study period. Risk categories were classified as high risk (cat-1) when the immunodeficiency scoring index was >= 3 and/or >= 3 RFs and/or >= 1 co-infective virus(es) were present; the remaining cases were classified as low risk (cat-0). The presence of two or more signs or symptoms including fever (T>38 degrees C…
Influenza vaccination of primary healthcare physicians may be associated with vaccination in their patients: a vaccination coverage study
2015
Background: To assess the contribution of physician-related factors, especially their influenza vaccine status, in the vaccination coverage of their patients. Methods: A study of vaccination coverage was carried out in Spain in 2011–12. The dependent variable (vaccination coverage in patients aged ≥65 years) was obtained from regional records. Information was gathered on the vaccination of physicians through an anonymous web survey. We compared the vaccination coverage of patients with the vaccination of their physicians using the Student t test. Associations were determined using a multilevel regression model. Results: The coverage in patients aged ≥ 65 years was 56.3% and was higher (57.3…
Pandemic influenza A (H1N1) infection in pregnant and nonpregnant women in Spain (2009-2010)
2014
The present study aimed to compare the main features of infection with pandemic influenza A virus in pregnant and nonpregnant women admitted to hospitals in Spain during the first waves of the 2009-2010 influenza pandemic. This was a prospective (November 2009 to June 2010), multicenter observational study. All cases were women of reproductive age who had not been vaccinated against seasonal or pandemic influenza A. Influenza infection was confirmed by reverse transcription-polymerase chain reaction (RT-PCR). The sociodemographic and clinical data of all cases were reviewed. A total of 219 inpatients, including 49 pregnant women and 170 nonpregnant women, were enrolled in the study upon adm…
H-2-linked murine cytotoxic T cell responses specific for sendai virus-infected cells
1978
CBA (H-2k) mouse-derived lymphochoriomeningitis virus and herpes simplex virus-specific cytotoxic T lymphocytes lyse virus-infected target cells compatible on either the H-2k or H-2D region. In contrast, CBA, C3H and AKR (H-2k) mouse-derived sendai virus-specific cytotoxic T lymphocytes (CTL) fail to lyse H-2D-compatible virus-infected cells. A similar lack of H-2D region-associated lytic activity was found with C57BL/6 and C57BL/10 (H-2b) mice as well as with the recombinants B10.A (2R) [Kb-Db] and B10.A (4R) [Kk-Db]. On the other hand, BALB/c (H-2d) mice and A/J (H-2a) mice do generate H-2Dd-associated sendai virus-specific CTL. These results are in contrast to those obtained with (CBA X …