scholarly journals Influenza Virus Aerosols in the Air and Their Infectiousness

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Nikolai Nikitin ◽  
Ekaterina Petrova ◽  
Ekaterina Trifonova ◽  
Olga Karpova
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Hospital Admissions ◽  
Influenza Infection ◽  
Human Infection ◽  
Virus Concentration ◽  
Virus Particles ◽  
Viral Particles ◽  
Transmission And Distribution ◽  
The Relationship

Influenza is one of the most contagious and rapidly spreading infectious diseases and an important global cause of hospital admissions and mortality. There are some amounts of the virus in the air constantly. These amounts is generally not enough to cause disease in people, due to infection prevention by healthy immune systems. However, at a higher concentration of the airborne virus, the risk of human infection increases dramatically. Early detection of the threshold virus concentration is essential for prevention of the spread of influenza infection. This review discusses different approaches for measuring the amount of influenza A virus particles in the air and assessing their infectiousness. Here we also discuss the data describing the relationship between the influenza virus subtypes and virus air transmission, and distribution of viral particles in aerosol drops of different sizes.

scholarly journals Routine blood parameters are helpful for early identification of influenza infection in children

2020 ◽  
Author(s):  
Ronghe Zhu ◽  
Cuie Chen ◽  
Qiu Wang ◽  
Xixi Zhang ◽  
Chaosheng Lu ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Influenza A Virus ◽  
Early Identification ◽  
Influenza A ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
Cutoff Value ◽  
Routine Blood ◽  
Influenza A Virus Infection

Abstract Purpose Routine blood parameters, such as the lymphocyte (LYM) count, platelet (PLT) count, lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), LYM*PLT and mean platelet volume-to-platelet ratio (MPV/PLT), are widely used to predict the prognosis of infectious diseases. We aimed to explore the value of these parameters in the early identification of influenza virus infection in children.Methods We conducted a single-center, retrospective, observational study of fever with influenza-like symptoms in pediatric outpatients from different age groups and evaluated the predictive value of various routine blood parameters measured within 48 hours of the onset of fever for influenza virus infection.Results The LYM count, PLT count, LMR and LYM*PLT were lower, and the NLR and MPV/PLT were higher in children with an influenza infection (PCR-confirmed and symptomatic). The LYM count, LMR and LYM*PLT in the influenza infection group were lower in the 1- to 6-year-old subgroup, and the LMR and LYM*PLT in the influenza infection group were lower in the >6-year-old subgroup. In the 1- to 6-year-old subgroup, the cutoff value of the LMR for predicting influenza A virus infection was 3.75, the sensitivity was 81.87%, the specificity was 84.31%, and the area under the curve (AUC) was 0.886; the cutoff value of the LMR for predicting influenza B virus infection was 3.71, the sensitivity was 73.58%, the specificity was 84.31%, and the AUC was 0.843. In the >6-year-old subgroup, the cutoff value of the LMR for predicting influenza A virus infection was 3.05, the sensitivity was 89.27%, the specificity was 89.61%, and the AUC was 0.949; the cutoff value of the LMR for predicting influenza B virus infection was 2.88, the sensitivity was 83.19%, the specificity was 92.21%, and the AUC was 0.924.Conclusions Routine blood tests are simple, inexpensive and easy to perform, and they are useful for the early identification of influenza virus infection in children. The LMR had the strongest predictive value for influenza virus infection in children older than 1 year, particularly influenza A virus infection.

Evaluation of cytokine production by J774.G8 macrophages after treatment with biotherapics

2021 ◽  
Vol 10 (36) ◽  
pp. 167-169
Author(s):  
Camila Siqueira ◽  
Diogo Kuczera ◽  
Eneida Da Lozzo ◽  
Dorly Buchi ◽  
José Nelson Couceiro ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Viral Infection ◽  
Influenza A ◽  
Control Groups ◽  
Viral Particles ◽  
Significant Difference ◽  
Infected Cells ◽  
H3n2 Influenza ◽  
Aseptic Conditions ◽  
H3n2 Influenza Virus

Introduction: Strains of macrophages, such as murine J774.G8 macrophages, are susceptible to influenza A infection [1]. One of the responses to viral infection involves the production of various types of immunostimulatory cytokines by infected cells [2]. Methods: In the present study, the macrophage strain J774.G8, maintained in RPMI medium, was submitted to treatment with 10% V/V of two different biotherapics prepared from influenza H3N2, both at 30x. Additionally, two control groups were analyzed: macrophages stimulated with water 30x and macrophages without any treatment. Biotherapics were prepared from intact H3N2 influenza virus and H3N2 inactivated by alcohol 70%. The compounding of both biotherapics followed this procedure: one part of viral particles was diluted in 9 parts of sterile distilled water. The 1:10 sample was submitted to 100 mechanical succussions using Autic® Brazilian machine, originating the first dilution, named decimal (1x). 1 ml of this solution was diluted in 9 ml of solvent and was submitted to 100 succussions, generating biotherapic 2x. This procedure was successively repeated, according to Brazilian Homeopathic Pharmacopoeia, to obtain the biotherapic 30x. By the same technique, water vehicle was prepared in the potency of 30x to be used as control. All samples were prepared under sterile and aseptic conditions, using laminar flow cabinet, class II, and were stored in the refrigerator (8ºC), to avoid microbiological contamination. J774.G8 macrophages were stimulated for 2 days, in a total of six stimuli. Immediately before infection with 25 µl of H3N2 influenza virus, the supernatants were collected and frozen at -20 ºC for later analysis. Next, 24 hours after the virus infection, the supernatants were aliquoted and frozen under the same conditions. Three independent experiments were done in triplicate. Analysis of supernatants was performed by flow cytometry using the Mouse Inflammation Kit. The cytokines detected in this experiment were IL-10, IL 12, TNF-α and MCP1. Results: In all cases, there were no significant differences compared to control groups. However, the production of TNF-α detected in macrophages treated by intact and inactivated biotherapics presented a tendency to increase after infection. In fact, similar results were previously detected in other experiments conducted only with the intact biotherapic [3]. The release of the cytokine MCP1 in all experimental situations presented a tendency to decrease after the viral infection when compared to untreated macrophages. No statistically significant difference was detected in the production of IL 12 and IL 10. These experiments will be repeated to confirm the data obtained.

scholarly journals Influenza PB1-F2 Inhibits Avian MAVS Signaling

Viruses ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 409
Author(s):  
Yanna Xiao ◽  
Danyel Evseev ◽  
Chase A. Stevens ◽  
Adam Moghrabi ◽  
Domingo Miranzo-Navarro ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A Virus ◽  
Virus Strain ◽  
Species Interactions ◽  
Influenza A ◽  
Promoter Activity ◽  
Interferon Beta ◽  
Influenza Infection ◽  
Adaptor Protein ◽  
Human Cells

RIG-I plays an essential role in the duck innate immune response to influenza infection. RIG-I engages the critical adaptor protein mitochondrial antiviral signaling (MAVS) to activate the downstream signaling pathway. The influenza A virus non-structural protein PB1-F2 interacts with MAVS in human cells to inhibit interferon production. As duck and human MAVS share only 28% amino acid similarity, it is not known whether the influenza virus can similarly inhibit MAVS signaling in avian cells. Using confocal microscopy we show that MAVS and the constitutively active N-terminal end of duck RIG-I (2CARD) co-localize in DF-1 cells, and duck MAVS is pulled down with GST-2CARD. We establish that either GST-2CARD, or duck MAVS can initiate innate signaling in chicken cells and their co-transfection augments interferon-beta promoter activity. Demonstrating the limits of cross-species interactions, duck RIG-I 2CARD initiates MAVS signaling in chicken cells, but works poorly in human cells. The D122A mutation of human 2CARD abrogates signaling by affecting MAVS engagement, and the reciprocal A120D mutation in duck 2CARD improves signaling in human cells. We show mitochondrial localization of PB1-F2 from influenza A virus strain A/Puerto Rico/8/1934 (H1N1; PR8), and its co-localization and co-immunoprecipitation with duck MAVS. PB1-F2 inhibits interferon-beta promoter activity induced by overexpression of either duck RIG-I 2CARD, full-length duck RIG-I, or duck MAVS. Finally, we show that the effect of PB1-F2 on mitochondria abrogates TRIM25-mediated ubiquitination of RIG-I CARD in both human and avian cells, while an NS1 variant from the PR8 influenza virus strain does not.

scholarly journals RNA-Sequencing-Based Transcriptomic Analysis Reveals a Role for Annexin-A1 in Classical and Influenza A Virus-Induced Autophagy

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1399 ◽  
Author(s):  
Jianzhou Cui ◽  
Dhakshayini Morgan ◽  
Dao Han Cheng ◽  
Sok Lin Foo ◽  
Gracemary L. R. Yap ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A Virus ◽  
Influenza A ◽  
Influenza Infection ◽  
Critical Role ◽  
Mtor Inhibitors ◽  
Influenza Viruses ◽  
Annexin A1 ◽  
Underlying Mechanisms

Influenza viruses have been shown to use autophagy for their survival. However, the proteins and mechanisms involved in the autophagic process triggered by the influenza virus are unclear. Annexin-A1 (ANXA1) is an immunomodulatory protein involved in the regulation of the immune response and Influenza A virus (IAV) replication. In this study, using clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 (CRISPR associated protein 9) deletion of ANXA1, combined with the next-generation sequencing, we systematically analyzed the critical role of ANXA1 in IAV infection as well as the detailed processes governing IAV infection, such as macroautophagy. A number of differentially expressed genes were uniquely expressed in influenza A virus-infected A549 parental cells and A549 ∆ANXA1 cells, which were enriched in the immune system and infection-related pathways. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway revealed the role of ANXA1 in autophagy. To validate this, the effect of mechanistic target of rapamycin (mTOR) inhibitors, starvation and influenza infection on autophagy was determined, and our results demonstrate that ANXA1 enhances autophagy induced by conventional autophagy inducers and influenza virus. These results will help us to understand the underlying mechanisms of IAV infection and provide a potential therapeutic target for restricting influenza viral replication and infection.

scholarly journals Autoimmune neutropenia associated with influenza virus infection in childhood: a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ignacio Callejas Caballero ◽  
Marta Illán Ramos ◽  
Arantxa Berzosa Sánchez ◽  
Eduardo Anguita ◽  
José Tomás Ramos Amador
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Viral Infections ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
Rapid Test ◽  
Male Infant ◽  
Severe Neutropenia ◽  
Autoimmune Neutropenia ◽  
Benign Condition

Abstract Background Although neutropenia is relatively frequent in infants and children and is mostly a benign condition with a self-limited course, it can lead to life-threatening severe infections. Autoimmune neutropenia is a relatively uncommon hematological disorder characterized by the autoantibody-induced destruction of neutrophils. It is usually triggered by viral infections with very few documented cases after influenza virus. Case presentation An 8-month-old male infant presented at the emergency room with a 5-days history of fever up to 39.7 °C, cough and runny nose. In the blood test performed, severe neutropenia was diagnosed (neutrophils 109/μL). A nasopharyngeal aspirate revealed a positive rapid test for Influenza A. Serum antineutrophil antibodies were determined with positive results. Neutropenia targeted panel showed no mutations. Despite maintenance of severe neutropenia for 9 months the course was uneventful without treatment. Conclusions When severe neutropenia is diagnosed and confirmed, it is essential to rule out some potential etiologies and underlying conditions, since the appropriate subsequent management will depend on it. Although autoimmune neutropenia triggered by viral infections has been widely reported, it has seldom been reported after influenza infection. The benign course of the disease allows a conservative management in most cases.

scholarly journals Features of immune response against influenza infection in animals vaccinated with recombinant cross-protective vaccine

2019 ◽  
Vol 9 (3-4) ◽  
pp. 485-494
Author(s):  
L. M. Tsybalova ◽  
L. A. Stepanova ◽  
A. V. Korotkov ◽  
M. A. Shuklina ◽  
M. V. Zaitseva ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Influenza Virus ◽  
Influenza A Virus ◽  
Cd4 T Cells ◽  
Influenza A ◽  
Influenza Infection ◽  
Sublethal Dose ◽  
Universal Vaccine ◽  
Toll Like Receptor 5

Generating cross-reactive vaccines aimed at targeting all human influenza A virus subtypes is among high priority tasks in contemporary vaccinology. Such vaccines will be primarily demanded during pre-pandemic period as well as used to prime some population cohorts prior to vaccination with standard vaccines containing area-relevant epidemic virus. Unlike routine approach universal vaccines do not induce a sterilizing immunity, but significantly ameliorate overt infection and probable complications. Our study was aimed at evaluating characteristics of immune response in experimental animals primed with a candidate universal vaccine challenged with sublethal influenza A virus infection. Mice were immunized intranasally with the recombinant protein FlgH2-2-4M2e containing conservative peptides derived from two influenza A virus proteins: M2 protein ectodomain and 76–130 amino acid sequence from the second hemagglutinin (HA2) subunit genetically linked to bacterial flagellin protein, which is a ligand for Toll-like receptor 5 (TLR5). Control mice received saline. Two weeks after immunization, mice from both groups were infected with a sublethal dose of A/Aichi/2/68 AN3N2 influenza virus strain. Level of immunoglobulins G and A in the blood sera and bronchoalveolar lavages (BAL) were determined two weeks after immunization and 1 month post infection. Percentage of lung CD4+ T and CD4+ Tem (CD44+CD62L–) cells secreting cytokines TNFα, IFNγ, IL-2 was determined. Immunized vs. control mice responded to sublethal infection with the influenza virus by insignificant weight loss and more pronounced production of vaccine peptide-specific (M2e and aa76–130 HA2) and pan-influenza A/Aichi/2/68 virus IgG and A in the blood sera and BAL. After challenge the number of CD4+ T cells secreting cytokines TNFα and/or IL-2 in immunized mice significantly exceeded counterpart T cells in unimmunized animals that was true for both CD4+T and CD4+ Tem cells. Memory CD4+ T cells were previously shown to play a key role in the prime-boost event and heterosubtypic immune response. Thus, we were able to demonstrate a priming effect for recombinant cross-protective vaccine used in our experiment.

scholarly journals Comparison of a New Neuraminidase Detection Assay with an Enzyme Immunoassay, Immunofluorescence, and Culture for Rapid Detection of Influenza A and B Viruses in Nasal Wash Specimens

2000 ◽  
Vol 38 (3) ◽  
pp. 1161-1165 ◽  
Author(s):  
Daniel E. Noyola ◽  
Bruce Clark ◽  
Frederick T. O'Donnell ◽  
Robert L. Atmar ◽  
Jewel Greer ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Enzyme Immunoassay ◽  
Indirect Immunofluorescence ◽  
Predictive Value ◽  
Influenza A ◽  
Influenza Infection ◽  
Influenza B Virus ◽  
Influenza B ◽  
Strong Response ◽  
Nasal Wash

The performance of a new, rapid, easy-to-perform assay based on neuraminidase enzyme activity for detection of influenza virus types A and B was compared to detection by culture, indirect immunofluorescence, and enzyme immunoassay in 479 nasal wash specimens from children with respiratory infections. Compared to isolation of influenza virus by culture, the neuraminidase assay had a sensitivity of 70.1%, specificity of 92.4%, positive predictive value of 76.3%, and negative predictive value of 89.9%. There was a higher sensitivity for the detection of influenza A virus (76.4%) than for influenza B virus (40.9%). Indirect immunofluorescence showed a sensitivity of 59.8% and specificity of 97% compared to culture isolation for detection of influenza A and B viruses. Enzyme immunoassay showed a sensitivity of 89.7% and specificity of 98.1% for the detection of influenza A alone. The quality of the nasal wash specimen had a significant effect on the detection of influenza virus by all of the assays. A strong response of the neuraminidase assay was more likely to represent a culture-confirmed influenza infection. This new rapid neuraminidase assay was useful for the detection of influenza A and B viruses in nasal wash specimens.

scholarly journals A Novel Sulfonated Derivative of β-Cyclodextrin Effectively Inhibits Influenza A Virus Infection in vitro and in vivo

Acta Naturae ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 20-30 ◽  
Author(s):  
E. P. Goncharova ◽  
Y. A. Kostyro ◽  
A. V. Ivanov ◽  
M. A. Zenkova
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
High Efficiency ◽  
Influenza Infection ◽  
Lethal Infection ◽  
Novel Drugs ◽  
Infected Cells ◽  
Low Toxicity

The development of novel drugs against the influenza virus with high efficiency and low toxicity is an urgent and important task. Previous reports have demonstrated that compounds based on sulfo derivatives of oligo- and polysaccharides possess high antiviral activity. In this study, we have examined the ability of a novel sulfonated derivative of -cyclodextrin (KS-6469) to inhibit the influenza virus A/WSN/33 (H1N1) infection in vitro and in vivo. The antiviral potential of KS-6469 against the influenza virus was evaluated in Madin-Darby Canine Kidney epithelial cells treated with serially diluted KS-6469. We found out that KS-6469 completely inhibited viral reproduction after treatment of the infected cells with the compound for 48 h. Our data show that double intranasal treatment of mice with KS-6469 fully protected the animals from a lethal infection and significantly decreased the viral titers in the lungs of the infected animals. Thus, the novel sulfonated -cyclodextrin derivative KS-6469 is a promising candidate for the development of antiviral drugs for preventing and treating the influenza infection.

scholarly journals Universal protection against influenza infection by a multidomain antibody to influenza hemagglutinin

Science ◽  
2018 ◽  
Vol 362 (6414) ◽  
pp. 598-602 ◽  
Author(s):  
Nick S. Laursen ◽  
Robert H. E. Friesen ◽  
Xueyong Zhu ◽  
Mandy Jongeneelen ◽  
Sven Blokland ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Neutralizing Antibodies ◽  
Influenza A ◽  
Influenza Infection ◽  
Cross Reactivity ◽  
Broadly Neutralizing Antibodies ◽  
Adeno Associated Virus ◽  
Influenza Hemagglutinin ◽  
Influenza Virus Hemagglutinin ◽  
Single Domain Antibodies

Broadly neutralizing antibodies against highly variable pathogens have stimulated the design of vaccines and therapeutics. We report the use of diverse camelid single-domain antibodies to influenza virus hemagglutinin to generate multidomain antibodies with impressive breadth and potency. Multidomain antibody MD3606 protects mice against influenza A and B infection when administered intravenously or expressed locally from a recombinant adeno-associated virus vector. Crystal and single-particle electron microscopy structures of these antibodies with hemagglutinins from influenza A and B viruses reveal binding to highly conserved epitopes. Collectively, our findings demonstrate that multidomain antibodies targeting multiple epitopes exhibit enhanced virus cross-reactivity and potency. In combination with adeno-associated virus–mediated gene delivery, they may provide an effective strategy to prevent infection with influenza virus and other highly variable pathogens.

scholarly journals Association Between the Respiratory Microbiome and Susceptibility to Influenza Virus Infection

2019 ◽  
Vol 71 (5) ◽  
pp. 1195-1203 ◽  
Author(s):  
Tim K Tsang ◽  
Kyu Han Lee ◽  
Betsy Foxman ◽  
Angel Balmaseda ◽  
Lionel Gresh ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Influenza A ◽  
Influenza Infection ◽  
Influenza Virus Infection ◽  
Fold Increase ◽  
Transmission Model ◽  
Influenza B ◽  
Household Contacts ◽  
Index Cases

Abstract Background Previous studies suggest that the nose/throat microbiome may play an important role in shaping host immunity and modifying the risk of respiratory infection. Our aim is to quantify the association between the nose/throat microbiome and susceptibility to influenza virus infection. Methods In this household transmission study, index cases with confirmed influenza virus infection and their household contacts were followed for 9–12 days to identify secondary influenza infections. Respiratory swabs were collected at enrollment to identify and quantify bacterial species via high-performance sequencing. Data were analyzed by an individual hazard-based transmission model that was adjusted for age, vaccination, and household size. Results We recruited 115 index cases with influenza A(H3N2) or B infection and 436 household contacts. We estimated that a 10-fold increase in the abundance in Streptococcus spp. and Prevotella salivae was associated with 48% (95% credible interval [CrI], 9–69%) and 25% (95% CrI, 0.5–42%) lower susceptibility to influenza A(H3N2) infection, respectively. In contrast, for influenza B infection, a 10-fold increase in the abundance in Streptococcus vestibularis and Prevotella spp. was associated with 63% (95% CrI, 17–83%) lower and 83% (95% CrI, 15–210%) higher susceptibility, respectively. Conclusions Susceptibility to influenza infection is associated with the nose/throat microbiome at the time of exposure. The effects of oligotypes on susceptibility differ between influenza A(H3N2) and B viruses. Our results suggest that microbiome may be a useful predictor of susceptibility, with the implication that microbiome could be modulated to reduce influenza infection risk, should these associations be causal.

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