Results 801-825 of about 1,000
  1. Since 2014, an Asian lineage of Zika virus has caused outbreaks, and it has been associated with neurological disorders in adults and congenital defects in newborns. The resulting threat of the Zika virus to human health has prompted the development of new vaccines, which have yet to be approved for human use. Vaccines based on the attenuated or chemically inactivated virus will require large-scale production of the intact virus to meet potential global demands. Intact viruses are produced by infecting cultures of susceptible cells, a dynamic process that spans from hours to days and has yet to be optimized. Here, we infected Vero cells adhesively cultured in well-plates with two Zika virus strains: a recently isolated strain from the Asian lineage, and a cell-culture-adapted strain from the African lineage. At different time points post-infection, virus particles in the supernatant were quantified; further, microscopy images were used to quantify cell density and the proportion of cells expressing viral protein. These measurements were performed across multiple replicate samples of one-step infections every four hours over 60 hours and for multi-step infections every four to 24 hours over 144 hours, generating a rich dataset. For each set of data, mathematical models were developed to estimate parameters associated with cell infection and virus production. The African-lineage strain was found to produce a 14-fold higher yield than the Asian-lineage strain in one-step growth and a 7-fold higher titer in multi-step growth, suggesting a benefit of cell-culture adaptation for developing a vaccine strain. We found that image-based measurements were critical for discriminating among different models, and different parameters for the two strains could account for the experimentally observed differences. An exponential-distributed delay model performed best in accounting for multi-step infection of the Asian strain, and it highlighted the significant sensitivity of virus titer to the rate of viral degradation, with implications for optimization of vaccine production. More broadly, this work highlights how image-based measurements can contribute to discrimination of virus-culture models for the optimal production of inactivated and attenuated whole-virus vaccines.
    Date: 2021-05-01
    Authors: Shi H, Yin J.
    Ref: Authorea Preprints
  2. The rapid spread of COVID-19 has already affected human lives throughout the globe. Governments of different countries have taken various measures, but how they affected people lives is not clear. In this study, a rule-based and a machine-learning based models are applied to answer the above question using public tweets from Japan, USA, UK, and Australia. Two polarity timeseries (meanPol and pnRatio) and two events, namely "lockdown or emergency (LED)" and "the economic support package (ESP)", are considered in this study. Statistical testing on the sub-series around LED and ESP events showed their positive impacts to the people of (UK and Australia) and (USA and UK), respectively unlike Japanese people that showed opposite effects. Manual validation with the relevant tweets showed an agreement with the statistical results. A case study with Japanese tweets using supervised logistic regression classifies tweets into heath-worry, economy-worry and other classes with 83.11% accuracy. Predicted tweets around events re-confirm the statistical outcomes.
    Date: 2021-04-30
    Authors: Bashar MK.
    Ref: arXiv
  3. The baculovirus-insect cell expression system is readily utilized to produce viral glycoproteins for research as well as for subunit vaccines and vaccine candidates, for instance against SARS-CoV-2 infections. However, the glycoforms of recombinant proteins derived from this expression system are inherently different from mammalian cell-derived glycoforms with mainly complex-type N -glycans attached, and the impact of these differences in protein glycosylation on the immunogenicity is severely underinvestigated. This applies also to the SARS-CoV-2 spike glycoprotein, which is the antigen target of all licensed vaccines and vaccine candidates including virus like particles and subunit vaccines that are variants of the spike protein. Here, we expressed the transmembrane-deleted human β-1,2 N-acetlyglucosamintransferases I and II (MGAT1∆TM and MGAT2∆TM) and the β-1,4-galactosyltransferase (GalT∆TM) in E. coli to in-vitro remodel the N -glycans of a recombinant SARS-CoV-2 spike glycoprotein derived from insect cells. In a cell-free sequential one-pot reaction, fucosylated and afucosylated paucimannose-type N -glycans were converted to complex-type galactosylated N -glycans. In the future, this in-vitro glycoengineering approach can be used to efficiently generate a wide range of N -glycans on antigens considered as vaccine candidates for animal trials and preclinical testing to better characterize the impact of N -glycosylation on immunity and to improve the efficacy of protein subunit vaccines.
    Date: 2021-04-30
    Authors: Ruhnau J, Grote V, Juarez-Osorio M, Bruder D, Rapp E, Rexer TFT, Reichl U.
    Ref: bioRxiv
  4. An effective response to the ongoing coronavirus disease (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) will involve a range of complementary preventive modalities. The current studies were conducted to evaluate the in vitro SARS-CoV-2 antiviral and virucidal (irreversible) activity of astodrimer sodium, a dendrimer with broad spectrum antimicrobial activity, including against enveloped viruses in in vitro and in vivo models, that is marketed for antiviral and antibacterial applications. We report that astodrimer sodium inhibits replication of SARS-CoV-2 in Vero E6 and Calu-3 cells, with 50% effective concentrations (EC50) for i) reducing virus-induced cytopathic effect of 0.002-0.012 mg/mL in Vero E6 cells, and ii) infectious virus release by plaque assay of 0.019-0.032 mg/mL in Vero E6 cells and 0.030-0.037 mg/mL in Calu-3 cells. The selectivity index (SI) in these assays was as high as 2197. Astodrimer sodium was also virucidal, reducing SARS-CoV-2 infectivity by >99.9% (>3 log10) within 1 minute of exposure, and up to >99.999% (>5 log10) shown at astodrimer sodium concentrations of 10 to 30 mg/mL in Vero E6 and Calu-3 cell lines. Astodrimer sodium also inhibited infection in a primary human airway epithelial cell line. The data were similar for all investigations and were consistent with the potent antiviral and virucidal activity of astodrimer sodium being due to irreversible inhibition of virus-host cell interactions, as previously demonstrated for other viruses. Further studies will confirm if astodrimer sodium binds to SARS-CoV-2 spike protein and physically blocks initial attachment of the virus to the host cell. Given the in vitro effectiveness and significantly high SI, astodrimer sodium warrants further investigation for potential as a topically administered agent for SARS-CoV-2 therapeutic applications.
    Date: 2021-04-28
    Authors: Paull J, Heery G, Bobardt M, Castellarnau A, Luscombe C, Fairley J, Gallay P.
    Ref: SSRN
  5. ABSTRACT Emerging microbe infections such as Zika virus (ZIKV) pose an increasing threat to human health. Current investigations on ZIKV replication have revealed the construction of replication compartments (RCs) and the utilization of host cellular endomembranes, without careful examination of the cytoskeletal network. Here, we investigated the function of vimentin, one of the intermediate filaments (IFs) that play a central role in basic cellular functions and diseases, in the life cycle of ZIKV infection. Using advanced imaging techniques, we uncovered that vimentin filaments have drastic reorganization upon viral protein synthesis, to form a perinuclear cage-like structure that embraces and concentrates RCs. Genetically removal of vimentin markedly reduced viral genome replication, viral protein production and infectious virions release, without interrupting viral binding and entry. Furthermore, proteomics and transcriptome screens by mass spectrometry and RNA sequencing identified intense interaction and regulation between vimentin and hundreds of endoplasmic reticulum (ER)-resident RNA-binding proteins. Among them, the cytoplasmic-region of ribosome receptor binding protein 1 (RRBP1), an ER transmembrane protein directly binds viral RNA, can interact with vimentin, resulting in modulation of ZIKV replication. Together, our work discovered a dual role for vimentin as being not only a structural element for RCs but also an RNA-binding-regulating hub in the ZIKV infection model, unveiling another layer of the complexity between host and virus interaction.
    Date: 2021-04-26
    Authors: Zhang Y, Zhao S, Li M, Li Y, Feng F, Cui J, Xue Y, Jin X, Jiu Y.
    Ref: bioRxiv
  6. RNA viruses including SARS-CoV-2, Ebola virus (EBOV), and Zika virus (ZIKV) constitute a major threat to global public health and society. The interactions between viral genomes and host proteins are essential in the life cycle of RNA viruses and thus provide targets for drug development. However, viral RNA-host protein interactions have remained poorly characterized. Here we applied ChIRP-MS to profile the interactomes of human proteins and the RNA genomes of SARS-CoV-2, EBOV, and ZIKV in infected cells. Integrated interactome analyses revealed interaction patterns that reflect both common and virus-specific host responses, and enabled rapid drug screening to target the vulnerable host factors. We identified Enasidenib as a SARS-CoV-2 specific antiviral agent, and Trifluoperazine and Cepharanthine as broad spectrum antivirals against all three RNA viruses. One Sentence Summary Interactome analyses of host proteins and the SARS-CoV-2, EBOV, and ZIKV RNA genomes unveil viral biology and drug targets.
    Date: 2021-04-26
    Authors: Zhang S, Huang W, Ren L, Ju X, Gong M, Rao J, Sun L, Li P, Ding Q, Wang J, Zhang QC.
    Ref: bioRxiv
  7. The coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has killed millions of people worldwide. The current crisis has created an unprecedented demand for rapid test of SARS-CoV-2 infection. Reverse transcription loop-mediated isothermal amplification (RT-LAMP) is a fast and convenient method to amplify and identify the transcripts of a targeted pathogen. However, the sensitivity and specificity of RT-LAMP were generally regarded as inferior when compared with the gold standard RT-qPCR. To address this issue, we combined bioinformatic and experimental analyses to improve the assay performance for COVID-19 diagnosis. First, we developed an improved algorithm to design LAMP primers targeting the nucleocapsid (N), membrane (M), and spike (S) genes of SARS-CoV-2. Next, we rigorously validated these new assays for their efficacy and specificity. Further, we demonstrated that multiplexed RT-LAMP assays could directly detect as low as a few copies of SARS-CoV-2 RNA in saliva, without the need of RNA isolation. Importantly, further testing using saliva samples from COVID-19 patients indicated that the new RT-LAMP assays were in total agreement in sensitivity and specificity with standard RT-qPCR. In summary, our new LAMP primer design algorithm along with the validated assays provide a fast and reliable method for the diagnosis of COVID-19 cases.
    Date: 2021-04-26
    Authors: Huang X, Tang G, Ismail N, Wang X.
    Ref: medRxiv
  8. COVID 19 is an acute disease that started spreading throughout the world, beginning in December 2019. It has spread worldwide and has affected more than 7 million people, and 200 thousand people have died due to this infection as of Oct 2020. In this paper, we have forecasted the number of deaths and the confirmed cases in Los Angeles and New York of the United States using the traditional and Big Data platforms based on the Times Series: ARIMA and ETS. We also implemented a more sophisticated time-series forecast model using Facebook Prophet API. Furthermore, we developed the classification models: Logistic Regression and Random Forest regression to show that the Weather does not affect the number of the confirmed cases. The models are built and run in legacy systems (Azure ML Studio) and Big Data systems (Oracle Cloud and Databricks). Besides, we present the accuracy of the models.
    Date: 2021-04-22
    Authors: Shinde S, Joshi J, Mareedu S, Kim YP, Woo J.
    Ref: arXiv
  9. SUMMARY Many host RNA sensors are positioned in the cytosol to detect viral RNA during infection. However, most positive-strand RNA viruses replicate within a modified organelle co-opted from intracellular membranes of the endomembrane system, which shields viral products from host cell innate immune sensors. Targeting innate RNA sensors to the endomembrane system may enhance their ability to sense viral RNA generated by viruses that use these compartments for replication. Here, we reveal that an isoform of oligoadenylate synthetase 1, OAS1 p46, is prenylated and targeted to the endomembrane system. Membrane localization of OAS1 p46 confers enhanced access to viral replication sites and results in increased antiviral activity against a subset of RNA viruses including flavivirus, picornavirus, and SARS-CoV-2. Finally, our human genetic analysis shows that the OAS1 splice-site SNP responsible for production of the OAS1 p46 isoform strongly associates with COVID-19 severity. This study highlights the importance of endomembrane targeting for the antiviral specificity of OAS1 and suggests early control of SARS-CoV-2 replication through OAS1-p46 is an important determinant of COVID-19 severity.
    Date: 2021-04-22
    Authors: Soveg FW, Schwerk J, Gokhale NS, Cerosaletti K, Smith JR, Pairo-Castineira E, Kell AM, Forero A, Zaver SA, Esser-Nobis K, Roby JA, Hsiang T, Ozarkar S, Clingan JM, McAnarney ET, Stone AEL, Malhotra U, Speake C, Perez J, Balu C, Allenspach EJ, Hyde JL, Menachery VD, Sarkar SN, Woodward JJ, Stetson DB, Baillie JK, Buckner JH, Gale M, Savan R.
    Ref: bioRxiv
  10. The COVID-19 pandemic ushered in vast deprivations of liberty previously unthinkable: lockdowns, business closures, travel restrictions, and quarantines. Even witnessing China’s January 2020 lockdown of 11 million people in Wuhan, it seemed wholly implausible that London, Rome, or New York would shut down. But they did, and much more. At the initial height of the pandemic in April 2020, more than 3.9 billion people, about half the world's population, were under stay-at-home orders. That same month, 43 US states were under stay-at-home orders. What are the scientific, public health, and ethical justifications for various forms of liberty deprivations? Are they lawful? Which branch, or level, of government holds the power to deprive individuals of freedom and the right to travel? What principles and policy mechanism can we establish to do a better job of protecting both liberty and public health during future emergencies?
    Date: 2021-04-20
    Authors: Gostin LO, Chertoff M.
    Ref: SSRN
  11. Inhibition of the binding of enveloped viruses surface glycoproteins to host cell receptor(s) is a major target of vaccines and constitutes an efficient strategy to block viral entry and infection of various host cells and tissues. Cellular entry usually requires fusion of the viral envelope with host plasma membranes. Such entry mechanism is often preceded by “priming” and/or “activation” steps requiring limited proteolysis of the viral surface glycoprotein to expose a fusiogenic domain for efficient membrane juxtapositions. The 9-membered family of Proprotein Convertases related to Subtilisin/Kexin (PCSK) serine proteases (PC1, PC2, Furin, PC4, PC5, PACE4, PC7, SKI-1/S1P and PCSK9) participate in post-translational cleavages and/or regulation of multiple secretory proteins. The type-I membrane-bound Furin and SKI-1/S1P are the major convertases responsible for the processing of surface glycoproteins of enveloped viruses. Stefan Kunz has considerably contributed to define the role of SKI-1/S1P in the activation of arenaviruses causing hemorrhagic fever. Furin was recently implicated in the activation of the spike S-protein of SARS-CoV-2 and Furin-inhibitors are being tested as antivirals in COVID-19. Other members of the PCSK-family are also implicated in some viral infections such as PCSK9 in Dengue. Herein, we summarize the various functions of the PCSKs and present arguments whereby their inhibition could represent a powerful arsenal to limit viral infections causing the present and future pandemics.
    Date: 2021-04-19
    Authors: Seidah NG, Pasquato A, Andreo U.
    Ref: Preprints.org
  12. The ongoing COVID-19 pandemic has clearly established how vital rapid, widely accessible diagnostic tests are in controlling infectious diseases and how difficult and slow it is to scale existing technologies. Here, we demonstrate the use of the rapid affinity pair identification via directed selection (RAPIDS) method to discover multiple affinity pairs for SARS-CoV-2 nucleocapsid protein (N-protein), a biomarker of COVID-19, from in vitro libraries in 10 weeks. The pair with the highest biomarker sensitivity was then integrated into a 10-minute, vertical-flow cellulose paper test. Notably, the as-identified affinity proteins were compatible with a roll-to-roll printing process for large-scale manufacturing of tests. The test achieved 40 pM and 80 pM limits of detection in 1×PBS (mock swab) and saliva matrices spiked with cell-culture generated SARS-CoV-2 viruses and is also capable of detection of N-protein from characterized clinical swab samples. Hence, this work paves the way towards the mass production of cellulose paper-based assays which can address the shortages faced due to dependence on nitrocellulose and current manufacturing techniques. Further, the results reported herein indicate the promise of RAPIDS and engineered binder proteins for the timely and flexible development of clinically relevant diagnostic tests in response to emerging infectious diseases.
    Date: 2021-04-19
    Authors: Kim S, Yee EH, Miller EA, Hao Y, Tay DMY, Sung K, Jia H, Johnson JM, Saeed M, Mace CR, Yurt DY, Sikes H.
    Ref: ChemRxiv
  13. Neurological complications are common in COVID-19 patients. Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been detected in patients’ brain tissues, its entry routes and resulting consequences are not well understood. Here, we report that the blood-brain barrier (BBB) and its microenvironment show pronounced upregulation of interferon signaling pathways in fatal COVID-19. Moreover, human induced pluripotent stem cell (hiPSC)-derived brain capillary endothelial-like cells (BCECs) were susceptible to SARS-CoV-2 infection and recapitulated the transcriptional changes detected in vivo . While BCECs were not compromised in their paracellular tightness, we found SARS-CoV-2 in the basolateral compartment in transwell assays after apical infection, suggesting active transcytosis of the virus across the BBB in vitro . SARS-CoV-2 entry into BCECs could be reduced by anti-spike-, anti-ACE2- and anti-NRP1-specific antibodies or the TMPRSS2 inhibitor nafamostat. Together, our data provide direct evidence for SARS-CoV-2 brain entry across the BBB resulting in an increase in interferon signaling.
    Date: 2021-04-16
    Authors: Krasemann S, Haferkamp U, Pfefferle S, Woo MS, Heinrich F, Schweizer M, Appelt-Menzel A, Barenberg J, Leu J, Hartmann K, Thies E, Littau JL, Sepulveda-Falla D, Zhang L, Ton K, Liang Y, Matschke J, Ricklefs F, Sauvigny T, Sperhake J, Fitzek A, Gerhartl A, Brachner A, Franzenburg S, Franke A, Moese S, Müller F, Geisslinger G, Claussen C, Kannt A, Zaliani A, Gribbon P, Ondruschka B, Neuhaus W, Friese MA, Glatzel M, Pless O.
    Ref: SSRN
  14. The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome virus 2 (SARS-CoV-2), has led to a global crisis that included collapsing healthcare systems and shut-down communities, producing considerable economic burden. Despite the number of effective vaccines quickly implemented, the emergence of new variants is a primary concern. The scientific community undertook a rapid response to better study this new virus. However, critical questions about viral protein-protein interactions and mechanisms of its physiopathology are still unclear. Although severe COVID-19 was associated with hematological dysfunctions, scarce experimental data were produced about iron dysmetabolism and the viral proteins’ possible interaction with hemoglobin (Hb) chains. This work demonstrates the binding of SARS-CoV-2 proteins to hemin and Hb using a multimethodological approach. In silico analysis indicated binding motifs between a cavity in the viral nucleoprotein and hemoglobin’s porphyrin coordination region. Different hemin binding capacities of mock and SARS-CoV-2-infected culture extracts were noticed using gel electrophoresis and TMB staining. Hemin-binding proteins were isolated from SARS-CoV-2-infected cells by affinity chromatography and identified by shotgun proteomics, indicating that structural (nucleoprotein, spike, and membrane protein) and non-structural (Nsp3 and Nsp7) viral proteins interact with hemin. In vitro analyses of virus adsorption to host cells and viral replication studies in Vero cells demonstrated inhibitory activities - at different levels - by hemin, protoporphyrin IX (PpIX) Hb. Strikingly, free Hb at 1μM suppressed viral replication (99 %), and its interaction with SARS-CoV-2 was localized to the RBD region of the Spike protein. The findings showed clear evidence of new avenues to disrupt viral replication and understand virus physiopathology that warrants further investigation.
    Date: 2021-04-16
    Authors: Lechuga GC, Souza-Silva F, de Queiroz Sacramento C, de Oliveira Trugilho MR, Valente RH, Napoleão-Pêgo P, da Silva Gomes Dias S, Fintelman-Rodrigues N, Temerozzo JR, Carels N, Alves CR, de Souza Pereira MC, Provance DW, Lopez Souza TM, De-Simone SG.
    Ref: bioRxiv
  15. Background: The COVID-19 outbreak has left many people isolated within their homes; these people are turning to social media for news and social connection, which leaves them vulnerable to believing and sharing misinformation. Health-related misinformation threatens adherence to public health messaging, and monitoring its spread on social media is critical to understanding the evolution of ideas that have potentially negative public health impacts. Results: Analysis using model-labeled data was beneficial for increasing the proportion of data matching misinformation indicators. Random forest classifier metrics varied across the four conspiracy theories considered (F1 scores between 0.347 and 0.857); this performance increased as the given conspiracy theory was more narrowly defined. We showed that misinformation tweets demonstrate more negative sentiment when compared to nonmisinformation tweets and that theories evolve over time, incorporating details from unrelated conspiracy theories as well as real-world events. Conclusions: Although we focus here on health-related misinformation, this combination of approaches is not specific to public health and is valuable for characterizing misinformation in general, which is an important first step in creating targeted messaging to counteract its spread. Initial messaging should aim to preempt generalized misinformation before it becomes widespread, while later messaging will need to target evolving conspiracy theories and the new facets of each as they become incorporated.
    Date: 2021-04-15
    Authors: Gerts D, Shelley CD, Parikh N, Pitts T, Ross CW, Fairchild G, Chavez NYV, Daughton AR.
    Ref: arXiv
  16. We examine the impact of COVID-19 on changes in firm value, and the moderating role of firm-level sustainability performance on this relationship. We find that firms domiciled in countries where the COVID-19 impact is more devastating experience greater decline in firm value. The negative impact of COVID-19 on firm value is less pronounced for firms with better sustainability performance. Firms domiciled in countries with a higher level of environmental- and stakeholder-value-oriented culture experience less decline in firm value from the impact of COVID-19. Findings suggest a firm’s stakeholder-value orientation contributes to preserving a firm’s value when general stakeholder value declines.
    Date: 2021-04-14
    Authors: Bose S, Shams S, Ali MJ, Mihret D.
    Ref: SSRN
  17. The novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still has serious negative effects on health, social life, and economics. Recently, vaccines from various companies have been urgently approved to control SARS-CoV-2 infections. However, any specific antiviral drug has not been confirmed so far for regular treatment. An important target is the main protease (Mpro), which plays a major role in replication of the virus. In this study, Gaussian and residue network models are employed to reveal two distinct potential allosteric sites on Mpro that can be evaluated as drug targets besides the active site. Then, FDA-approved drugs are docked to three distinct sites with flexible docking using AutoDock Vina to identify potential drug candidates. 14 best molecule hits for the active site of Mpro are determined. 6 of these also exhibit high docking scores for the potential allosteric regions. Full-atom molecular dynamics simulations with MM-GBSA method indicate that compounds docked to active and potential allosteric sites form stable interactions with high binding free energy (∆Gbind) values. ∆Gbind values reach -52.06 kcal/mol for the active site, -51.08 kcal/mol for the potential allosteric site 1, and -42.93 kcal/mol for the potential allosteric site 2. Energy decomposition calculations per residue elucidate key binding residues stabilizing the ligands that can further serve to design pharmacophores. This systematic and efficient computational analysis successfully determines ivermectine, diosmin and selinexor currently subjected to clinical trials, and further proposes bromocriptine, elbasvir as Mpro inhibitor candidates to be evaluated against SARS-CoV-2 infection
    Date: 2021-04-14
    Authors: Yuce M, Cicek E, İnan T, Dağ AB, Kürkçüoğlu Ö, Sungur FA.
    Ref: Authorea Preprints
  18. Background: Understanding seasonal human mobility at subnational scales has important implications across sciences, from urban planning efforts to disease modelling and control. Assessing how, when, and where populations move over the course of the year, however, requires spatially and temporally resolved datasets spanning large periods of time, which can be rare, contain sensitive information, or may be proprietary. Here, we aim to explore how a set of broadly available covariates can describe seasonal subnational mobility in Kenya, therefore enabling better modelling of seasonal mobility across low- and middle-income country (LMIC) settings. Methods: To do this, we used the Google Aggregated Mobility Research Dataset, containing anonymized mobility flows aggregated over users who have turned on the Location History setting, which is off by default. We combined this with socioeconomic and geospatial covariates from 2018 to 2019 to quantify seasonal changes in domestic and international mobility patterns across years. We undertook a spatiotemporal analysis within a Bayesian framework to identify relevant geospatial and socioeconomic covariates important to predicting human movement patterns, while accounting for spatial and temporal autocorrelations. Results: Mobility patterns in Kenya mostly consisted of shorter, within-county trips, followed by longer domestic travel between counties and international travel, respectively, across both years. Mobility peaked in August and December, closely corresponding to school holiday seasons, which was found to be an important predictor in our model. We further found that socioeconomic variables including urbanicity, poverty, and female education strongly predicted mobility patterns, in addition to geospatial covariates such as accessibility to major population centres and temperature. Conclusions: These findings derived from novel data sources elucidate broad spatiotemporal patterns of how populations move within and beyond Kenya, and can be easily generalized to other LMIC settings before the COVID-19 pandemic. Understanding such pre-pandemic mobility patterns provides a crucial baseline to interpret both how these patterns have changed as a result of the pandemic, as well as whether human mobility patterns have been permanently altered once the pandemic subsides. Our findings outline key correlates and predictors of mobility using broadly available covariates, alleviating the data bottlenecks of highly sensitive and proprietary mobile phone datasets, which many researchers do not have access to. These results further provide novel insight on monitoring mobility proxies in the context of disease surveillance and control efforts through LMIC settings.
    Date: 2021-04-14
    Authors: Ruktanonchai C, Lai S, Utazi C, Cunningham A, Koper P, Rogers G, Ruktanonchai N, Sadilek A, Woods D, Tatem A, Steele J, Sorichetta A.
    Ref: Research Square
  19. In Mexico, it is estimated that due to the economic system the overexploitation of natural resources, environmental impacts and health have been generated, with high rates of overweight and obesity. This review analyzes the impacts on food safety, environmental health, and the economy in Mexico before and during the COVID-19 contingency. Derived from the analysis, among the lessons learned we can include: the health contingency due to COVID-19 had negative repercussions on food security, environmental health and the economy, which require the promotion of public policies (health, environment and economy) and migrate to a health prevention system and an agroecological model, which includes multidisciplinary and intersectoral interventions (government, academia, researchers, civil society organizations, business groups and citizens themselves) to reform and enforce the right to enjoy adequate food and a healthy environment. The contingency due to COVID19 has shown us that this must go from an ideology to being a reality and the lessons learned will have to focus on promoting an innovative and ethical culture of generating an economy, with a gender balance, resilience to climate change, management transparent technology and a priority in health and this will lead to progress in the food security of the population.
    Date: 2021-04-14
    Authors: Monroy-Torres R, Carcaño-Valencia E, Hernández-Luna M, Caldera-Ortega A, Serafín- Muñoz A, Linares- Segovia B, Medina- Jiménez K, Castillo-Chávez A, Jiménez-Garza O, Méndez- Pérez M, López-Briones S.
    Ref: Preprints.org
  20. ABSTRACT The mechanisms by which flaviviruses use non-canonical translation to support their replication in host cells are largely unknown. Here we investigated how the integrated stress response (ISR), which promotes translational arrest by eIF2ɑ phosphorylation (p‒eIF2ɑ), regulates flavivirus replication. During Dengue virus (DENV) and Zika virus (ZIKV) infection, eIF2ɑ phosphorylation peaked at 24 hours post infection and was dependent on PKR but not type I interferon. The ISR is activated downstream of p-eIF2α during infection with either virus, but translation arrest only occurred following DENV4 infection. Despite this difference, both DENV4 and ZIKV replication was impaired in cells lacking PKR, independent of IFN-I/NF-kB signalling or cell viability. By using a ZIKV 5′ UTR reporter system as a model, we found that this region of the genome is sufficient to promote an enhancement of viral mRNA translation in the presence of an active ISR. Together we provide evidence that flaviviruses escape ISR translational arrest and co-opt this response to increase viral replication.
    Date: 2021-04-09
    Authors: Ricciardi-Jorge T, Lummertz da Rocha E, Gonzalez-Kozlova E, Rodrigues-Luiz GF, Ferguson BJ, Sweeney T, Irigoyen N, Mansur DS.
    Ref: bioRxiv
  21. Transmission of SARS-CoV-2 occurs by close contact with infected persons through droplets, the inhalation of infectious aerosols and the exposure to contaminated surface. Previously, we determined the virus stability on different types of surfaces under indoor and seasonal climatic conditions. SARS-CoV-2 survived the longest on surfaces under winter conditions, followed by spring/fall and summer conditions, suggesting the seasonal pattern of stability on surfaces. However, under natural conditions, the virus is secreted in various biological fluids from infected humans. In this respect, it remains unclear how long the virus survives in various types of biological fluids. This study explored the SARS-CoV-2 stability in human biological fluids under different environmental conditions and estimated the half-life. The virus was stable for up to 21 days in nasal mucus, sputum, saliva, tear, urine, blood, and semen; it remained infectious significantly longer under winter and spring/fall conditions than under summer conditions. In contrast, the virus was only stable up to 24 hours in feces and breast milk. These findings demonstrate the potential risk of infectious biological fluids in SARS-CoV-2 transmission and have implications for its seasonality.
    Date: 2021-04-08
    Authors: Kwon T, Gaudreault NN, Richt JA.
    Ref: bioRxiv
  22. Summary The coronavirus disease 2019 (COVID-19) pandemic, which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global public health challenge. While the efficacy of vaccines against emerging and future virus variants remains unclear, there is a need for therapeutics. Repurposing existing drugs represents a promising and potentially rapid opportunity to find novel antivirals against SARS-CoV-2. The virus encodes at least nine enzymatic activities that are potential drug targets. Here we have expressed, purified and developed enzymatic assays for SARS-CoV-2 nsp13 helicase, a viral replication protein that is essential for the coronavirus life cycle. We screened a custom chemical library of over 5000 previously characterised pharmaceuticals for nsp13 inhibitors using a FRET-based high-throughput screening (HTS) approach. From this, we have identified FPA-124 and several suramin-related compounds as novel inhibitors of nsp13 helicase activity in vitro . We describe the efficacy of these drugs using assays we developed to monitor SARS-CoV-2 growth in Vero E6 cells.
    Date: 2021-04-08
    Authors: Zeng J, Weissmann F, Bertolin AP, Posse V, Canal B, Ulferts R, Wu M, Harvey R, Hussain S, Milligan JC, Roustan C, Borg A, McCoy L, Drury LS, Kjaer S, McCauley J, Howell M, Beale R, Diffley JF.
    Ref: bioRxiv
  23. Zika virus (ZIKV) infection and ZIKV epidemic have been continuously spreading silently throughout the world and its associated microcephaly and other serious congenital neurological complications poses a significant global threat to public health. ZIKV infection stimulates type I interferon response in host cells which suppresses viral replication by inducing the expression of interferon-stimulated genes (ISGs). Here, we identified ADP-ribosyltransferase PARP11 as an anti-ZIKV ISG and found that PARP11 suppressed ZIKV independently on itself PARP enzyme activity. Furthermore, PARP11 interacted with PARP12 and promoted PARP12-mediating ZIKV NS1 and NS3 protein degradation. Homo family PARP11 and PARP12 cooperated with each other on ZIKV suppression and the anti-ZIKV function of PARP11 mostly dependent on the existence of PARP12. Our findings have broadened the understanding of the anti-viral function of PARP11, and more importantly suggest a potential therapeutics target against ZIKV infection.
    Date: 2021-04-07
    Authors: Li L, Shi Y, Li S, Liu J, Zu S, Xu X, Gao M, Sun N, Pan C, Peng L, Yang H, Cheng G.
    Ref: Research Square
  24. Background: The COVID-19 pandemic has led to prolonged exposure to stress and anxiety, raising concerns about a large spectrum of psychological side effects. The primary objective of the study was to validate the COVID-19 Bullying Scale (CBS-11). The second objective was to explore factors associated with COVID-19-related bullying and evaluate the mediating effect of fear and anxiety between knowledge and COVID-19-related bullying. Methods: : A cross-sectional online survey conducted between December 20, 2020, and January 5, 2021, involved 405 Lebanese adults recruited using the snowball sampling technique. The CBS-11, an 11-item tool specially created for this study, was used to measure bullying behaviors towards COVID-19 patients. Results: : All items of CBS-11 converged over a 1-factor solution with an eigenvalue over 1, accounting for a variance of 75.16%. The scale has a high Cronbach’s alpha (0.974), indicating excellent reliability. A positive correlation was found between the COVID-19 bullying scale and fear, anxiety, and stigma discrimination. The logistic regression showed that higher fear of COVID-19 (ORa=1.04), a positive attitude toward COVID-19 preventive measures and hygiene recommendations (ORa=1.18), higher stigma discrimination scores (ORa=1.09), and having a health professional family member (ORa=2.42) were significantly associated with bullying. Conclusion: Our main findings show that CBS-11 could be an efficient tool to measure bullying behaviors toward COVID-19 patients. Stigma discrimination and fear from COVID-19 were associated with higher bullying attitudes. Future prospective studies are needed to understand better the factors related to bullying among adults during a pandemic, such as COVID-19.
    Date: 2021-04-07
    Authors: Haddad C, Sacre H, Malhab SB, Malaeb D, Saadeh D, Tayeh CA, Salameh P.
    Ref: Research Square
  25. Zika virus (ZIKV) is an arthropod-borne virus (arbovirus) and is primarily transmitted by Aedes species mosquitoes; however, ZIKV can also be sexually transmitted. During the initial epidemic and in places where ZIKV is now considered endemic, it is difficult to disentangle the risks and contributions of sexual versus vector-borne transmission to adverse pregnancy outcomes. To examine the potential impact of sexual transmission of ZIKV on pregnancy outcome, we challenged three rhesus macaques ( Macaca mulatta ) three times intravaginally with 1 × 10 7 PFU of a low passage, African lineage ZIKV isolate (ZIKV-DAK) in the first trimester (∼30 days gestational age). Samples were collected from all animals initially on days 3 through 10 post challenge, followed by twice, and then once weekly sample collection; ultrasound examinations were performed every 3-4 days then weekly as pregnancies progressed. All three dams had ZIKV RNA detectable in plasma on day 3 post-ZIKV challenge. At approximately 45 days gestation (17-18 days post-challenge), two of the three dams were found to have nonviable embryos by ultrasound. Viral RNA was detected in recovered tissues and at the maternal-fetal interface (MFI) in both cases. The remaining viable pregnancy proceeded to near term (∼155 days gestational age) and ZIKV RNA was detected at the MFI but not in fetal tissues. These results suggest that sexual transmission of ZIKV may represent an underappreciated risk of pregnancy loss during early gestation.
    Date: 2021-04-03
    Authors: Newman CM, Tarantal AF, Martinez ML, Simmons HA, Morgan TK, Zeng X, Rosinski JR, Bliss MI, Bohm EK, Dudley DM, Aliota MT, Friedrich TC, Miller CJ, O’Connor DH.
    Ref: bioRxiv
first · previous · 28 · 29 · 30 · 31 · 32 · 33 · 34 · 35 · 36 · 37 · next · last