instruction:
In this task, you're given a paragraph and title from the research paper. Your task is to classify whether the given title is suitable or not for the research paper based on the given paragraph. Return "True" if title is proper according to paragraph else "False".
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Paragraph: Estimating the case-fatality risk (CFR)-the probability that a person dies from an infection given that they are a case-is a high priority in epidemiologic investigation of newly emerging infectious diseases and sometimes in new outbreaks of known infectious diseases. The data available to estimate the overall CFR are often gathered for other purposes (e.g., surveillance) in challenging circumstances. We describe two forms of bias that may affect the estimation of the overall CFR-preferential ascertainment of severe cases and bias from reporting delays-and review solutions that have been proposed and implemented in past epidemics. Also of interest is the estimation of the causal impact of specific interventions (e.g., hospitalization, or hospitalization at a particular hospital) on survival, which can be estimated as a relative CFR for two or more groups. When observational data are used for this purpose, three more sources of bias may arise: confounding, survivorship bias, and selection due to preferential inclusion in surveillance datasets of those who are hospitalized and/or die. We illustrate these biases and caution against causal interpretation of differential CFR among those receiving different interventions in observational datasets. Again, we discuss ways to reduce these biases, particularly by estimating outcomes in smaller but more systematically defined cohorts ascertained before the onset of symptoms, such as those identified by forward contact tracing. Finally, we discuss the circumstances in which these biases may affect non-causal interpretation of risk factors for death among cases. PLOS Neglected Tropical Diseases | 
 Title: Potential Biases in Estimating Absolute and Relative Case-Fatality Risks during Outbreaks
answer:
False


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Paragraph: The majority of human emerging infectious diseases (EIDs) are zoonotic, with viruses originating in wild mammals of particular concern (e.g. HIV, Ebola, SARS) 1-3 . Understanding patterns of viral diversity in wildlife and determinants of successful cross-species transmission, or spillover, are therefore key goals for pandemic surveillance programs 4 . However, few analytical tools exist to identify which host species likely harbor the next human virus, or which viruses can cross species boundaries 5-7 . Here we conduct the most comprehensive analysis yet of mammalian hostvirus relationships and show that both the total number of viruses that infect a given species, and the proportion likely to be zoonotic are predictable. After controlling for research effort, the proportion of zoonotic viruses per species is predicted by phylogenetic relatedness to humans, host taxonomy, and human population within a species range -which may reflect human-wildlife contact. We demonstrate for the first time that bats harbor a significantly higher proportion of zoonotic viruses than all other mammalian orders. We identify the taxa and geographic regions with the largest estimated number of 'missing viruses' and 'missing zoonoses' and therefore of highest value for future surveillance. We then show that phylogenetic host breadth and other viral traits are significant predictors of zoonotic potential, providing a novel framework to assess if a newly discovered mammalian virus could infect people. Viral zoonoses are a serious threat to public health and global security, and have caused the majority of recent pandemics in people 4 , yet our understanding of the factors driving viral diversity in mammals, viral host range, and cross-species transmission to humans remain nascent. Recent studies have described broad patterns of pathogen host range 1,3 and various host or microbial factors that facilitate cross-species transmission 5,7,8 , or have focused on Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use: http://www.nature. All datasets (host traits, viral traits, full list of host-virus associations and associated references, phylogenetic trees, and phylogenetic distance matrices) along with the R code and R package dependencies needed to fully replicate and evaluate these analyses are provided at http://doi.org/10.5281/zenodo.569079. The top-level README.txt file in the directory details the file structure and metadata provided. 
 Title: Host and viral traits predict zoonotic spillover from mammals HHS Public Access
answer:
False


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Paragraph: The trimeric SARS coronavirus (SARS-CoV) surface spike (S) glycoprotein consisting of three S1-S2 heterodimers binds the cellular receptor angiotensin-converting enzyme 2 (ACE2) and mediates fusion of the viral and cellular membranes through a pre-to postfusion conformation transition. Here, we report the structure of the SARS-CoV S glycoprotein in complex with its host cell receptor ACE2 revealed by cryo-electron microscopy (cryo-EM). The complex structure shows that only one receptor-binding domain of the trimeric S glycoprotein binds ACE2 and adopts a protruding "up" conformation. In addition, we studied the structures of the SARS-CoV S glycoprotein and its complexes with ACE2 in different in vitro conditions, which may mimic different conformational states of the S glycoprotein during virus entry. Disassociation of the S1-ACE2 complex from some of the prefusion spikes was observed and characterized. We also characterized the rosette-like structures of the clustered SARS-CoV S2 trimers in the postfusion state observed on electron micrographs. Structural comparisons suggested that the SARS-CoV S glycoprotein retains a prefusion architecture after trypsin cleavage into the S1 and S2 subunits and acidic pH treatment. However, binding to the receptor opens up the receptor-binding domain of S1, which could promote the release of the S1-ACE2 complex and S1 monomers from the prefusion spike and trigger the pre-to postfusion conformational transition. The global outbreak of SARS in 2002-2003 was caused by infection by a human coronavirus, SARS-CoV. Although the virus has been extensively studied with regard to epidemiology, virology, clinical features and other aspects, there are still no approved antiviral drugs and vaccines to treat and prevent infections of SARS-CoV. The spike (S) glycoprotein of PLOS Pathogens | https://doi.Cryo-EM structure of the SARS coronavirus spike glycoprotein in complex with its host cell receptor ACE2. PLoS Pathog 14(8): e1007236. https://doi. Data Availability Statement: The coordinates and EM maps have been deposited into the Protein Data Bank and the EM Data Bank with the accession numbers: 6ACG, 6ACJ, 6ACK, 6ACD, 6ACC, EMD-9591, EMD-9593, EMD-9594, EMD-9589, EMD-9588, EMD-9598, EMD-9597, EMD-9595, EMD-9596, EMD-9585, EMD-9586, EMD-9587, EMD-9584 and EMD-9583. the coronavirus, responsible for host cell attachment and mediating host cell membrane and viral membrane fusion during infection, is key to the viral life cycle and a major target for antiviral drugs and vaccines. In this study, we report the structures of different conformational states of the SARS-CoV S glycoprotein during virus entry. Specifically, we found that the S glycoprotein retains the prefusion trimer structure after trypsin cleavage and low-pH treatment. Additionally, binding with host cell receptor ACE2 promotes the release of S1 subunits from the S trimer and triggers the pre-to postfusion conformational transition. Our results provide new insights for understanding the mechanisms involved in coronavirus S glycoprotein-mediated virus entry. Coronaviruses are a family of large, enveloped, positive-stranded RNA viruses that cause upper respiratory, gastrointestinal and central nervous system diseases in humans and other animals [1] . Human coronaviruses HCoV-OC43, HCoV-229E, HCoV-NL63 and HCoV-HKU1 circulate in humans and cause mild respiratory diseases [2] . However, the outbreak of SARS-CoV in 2002 and MERS-CoV in 2012 showed that coronaviruses can cross the species barrier and emerge as highly pathogenic viruses [3] . The high fatality rate and wide spread of these new emerging coronaviruses indicate that they are a severe threat to global health. The spike (S) glycoprotein of the coronavirus is a class I viral fusion protein located on the outer envelope of the virion that plays a critical role in viral infection by recognizing host cell receptors and mediating fusion of the viral and cellular membranes [4] . The coronavirus S glycoprotein is synthesized as a precursor protein consisting of~1,300 amino acids that is then cleaved into an amino (N)-terminal S1 subunit (~700 amino acids) and a carboxyl (C)-terminal S2 subunit (~600 amino acids). Three S1/S2 heterodimers assemble to form a trimer spike protruding from the viral envelope. The S1 subunit contains a receptor-binding domain (RBD), while the S2 subunit contains a hydrophobic fusion peptide and two heptad repeat regions. Triggered by receptor binding, proteolytic processing and/or acidic pH in the cellular compartments, the class I viral fusion protein undergoes a transition from a metastable prefusion state to a stable postfusion state during infection, in which the receptor-binding subunit is cleaved, and the fusion subunit undergoes large-scale conformational rearrangements to expose the hydrophobic fusion peptide, induce the formation of a six-helix bundle, and bring the viral and cellular membranes close for fusion [5] . Coronavirus S glycoprotein features two distinct protease cleavage sites. The S1/S2 cleavage site of the SARS-CoV S glycoprotein is located after residue 667 of the precursor protein, whereas the S2' cleavage site of the SARS-CoV S glycoprotein is on the S2 subunit and is 130 amino acids from the N terminus of the S2 subunit [6] [7] [8] . The S1/S2 cleavage site is located in a flexible loop of residues 660-675 that is completely exposed in the prefusion S1-S2 trimer spike. The S2' cleavage site of the SARS-CoV S glycoprotein is highly conserved among coronaviruses and is completely buried in the prefusion SARS-CoV S glycoprotein [6] [7] [8] . Cleavage of the S2' site by host cell proteases is required for successful infection by 9] . However, the mechanisms involved in exposure and cleavage of the S2' cleavage site are not well understood. Structural biology studies, especially recent cryo-electron microscopy (cryo-EM) studies, have advanced our understanding of the role of the coronavirus S glycoprotein in virus entry. S glycoprotein structures in the prefusion state have been reported for members from the Alphacoronavirus genus (HCoV-NL63), Betacoronavirus genus (mouse hepatitis virus (MHV), HKU1, SARS-CoV and MERS-CoV), Gammacoronavirus genus (IBV), and Deltacoronavirus genus (PdCoV) [7, [10] [11] [12] [13] [14] [15] [16] [17] . Prefusion Structure of the SARS coronavirus spike glycoprotein and ACE2 complex PLOS Pathogens | https://doi. 
 Title: Cryo-EM structure of the SARS coronavirus spike glycoprotein in complex with its host cell receptor ACE2
answer:

True