Publications by authors named "Marina Escalera Zamudio"

Objectives: We aimed to evaluate the adaptive immune responses cross-recognition of the hypermutated SARS-CoV-2 BA.2.86 variant and identify the determinants influencing this recognition.

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During outbreaks of emerging infectious diseases, internationally connected cities often experience large and early outbreaks, while rural regions follow after some delay. This hierarchical structure of disease spread is influenced primarily by the multiscale structure of human mobility. However, during the COVID-19 epidemic, public health responses typically did not take into consideration the explicit spatial structure of human mobility when designing nonpharmaceutical interventions (NPIs).

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Background: Aedes-borne arboviruses cause both seasonal epidemics and emerging outbreaks with a significant impact on global health. These viruses share mosquito vector species, often infecting the same host population within overlapping geographic regions. Thus, comparative analyses of the virus evolutionary and epidemiological dynamics across spatial and temporal scales could reveal convergent trends.

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Over 200 different SARS-CoV-2 lineages have been observed in Mexico by November 2021. To investigate lineage replacement dynamics, we applied a phylodynamic approach and explored the evolutionary trajectories of five dominant lineages that circulated during the first year of local transmission. For most lineages, peaks in sampling frequencies coincided with different epidemiological waves of infection in Mexico.

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Comparing the evolution of distantly related viruses can provide insights into common adaptive processes related to shared ecological niches. Phylogenetic approaches, coupled with other molecular evolution tools, can help identify mutations informative on adaptation, although the structural contextualization of these to functional sites of proteins may help gain insight into their biological properties. Two zoonotic betacoronaviruses capable of sustained human-to-human transmission have caused pandemics in recent times (SARS-CoV-1 and SARS-CoV-2), although a third virus (MERS-CoV) is responsible for sporadic outbreaks linked to animal infections.

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Article Synopsis
  • Recombination among coronaviruses, including SARS-CoV-2, is documented, but previous recombinant lineages appeared to circulate minimally.
  • A detailed phylogenetic analysis of four SARS-CoV-2 lineages shows significant genetic differences, particularly in the Orf1ab region compared to the Spike protein and other sections of the genome.
  • The research identifies the B.1.628 cluster (designated lineage XB) as a product of recombination between B.1.631 and B.1.634 lineages, highlighting its geographical origins in the USA and Mexico during 2021, thus raising questions about the implications for the virus's evolutionary path.
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  • COVID-19, caused by the SARS-CoV-2 virus, presents a range of symptoms, from no symptoms to severe illness or death, with age and pre-existing conditions being key factors in severity.
  • A study in Mexico analyzed 57 complete SARS-CoV-2 genomes from patients under 60 without pre-existing conditions to explore relationships between viral genetics and disease severity.
  • The research found greater genomic diversity in the viruses compared to earlier strains and identified numerous mutations, but did not link specific mutations to disease outcomes, suggesting that severity is more influenced by patient genetics and demographics.
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  • The study investigates the genetic diversity of SARS-CoV-2 in Ecuador during 2020 to understand how the virus spread both internationally and domestically.
  • It includes the analysis of 160 whole genome sequences to identify various transmission lineages and their distribution across different provinces.
  • Findings indicate that the virus was introduced multiple times before health interventions, with notable differences in how it persisted and spread in different regions of the country.
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Comparing the evolution of distantly related viruses can provide insights into common adaptive processes related to shared ecological niches. Phylogenetic approaches, coupled with other molecular evolution tools, can help identify mutations informative on adaptation, whilst the structural contextualization of these to functional sites of proteins may help gain insight into their biological properties. Two zoonotic betacoronaviruses capable of sustained human-to-human transmission have caused pandemics in recent times (SARS-CoV-1 and SARS-CoV-2), whilst a third virus (MERS-CoV) is responsible for sporadic outbreaks linked to animal infections.

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Characterisation of SARS-CoV-2 genetic diversity through space and time can reveal trends in virus importation and domestic circulation, and permit the exploration of questions regarding the early transmission dynamics. Here we present a detailed description of SARS-CoV-2 genomic epidemiology in Ecuador, one of the hardest hit countries during the early stages of the COVID-19 pandemic. We generate and analyse 160 whole genome sequences sampled from all provinces of Ecuador in 2020.

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Parallel molecular evolution and adaptation are important phenomena commonly observed in viruses. Here, we exploit parallel molecular evolution to understand virulence evolution in avian influenza viruses (AIV). Highly-pathogenic AIVs evolve independently from low-pathogenic ancestors via acquisition of polybasic cleavage sites.

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Article Synopsis
  • The COVID-19 pandemic has impacted countries worldwide, necessitating the study of how the virus evolves and spreads to improve control measures.
  • Researchers analyzed the genome sequences of 17 early SARS-CoV-2 cases in Mexico, revealing two main viral lineages from North America and Europe, along with 14 distinct introduction events.
  • Findings indicated early local transmission in Mexico by mid-March 2020, featuring a genetic mutation in the Spike protein that could help track further viral spread in the region.
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Despite a small genome size, bats have comparable diversity of retroviral and non-retroviral endogenous sequences to other mammals. These include Class I and Class II retroviral sequences, foamy viruses, and deltaretroviruses, as well as filovirus, bornavirus, and parvovirus endogenous viral elements. Some of these endogenous viruses are sufficiently preserved in bat genomes to be expressed, with potential effects for host biology.

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The Amazon basin is home to numerous arthropod-borne viral pathogens that cause febrile disease in humans. Among these, (OROV) is a relatively understudied member of the genus , family , that causes periodic outbreaks in human populations in Brazil and other South American countries. Although several studies have described the genetic diversity of the virus, the evolutionary processes that shape the OROV genome remain poorly understood.

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Nipah virus (NiV) is a highly pathogenic paramyxovirus that causes frequent outbreaks of severe neurologic and respiratory disease in humans with high case fatality rates. The 2 glycoproteins displayed on the surface of the virus, NiV-G and NiV-F, mediate host-cell attachment and membrane fusion, respectively, and are targets of the host antibody response. Here, we provide a molecular basis for neutralization of NiV through antibody-mediated targeting of NiV-F.

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The Third Annual Meeting of the European Virus Bioinformatics Center (EVBC) took place in Glasgow, United Kingdom, 28-29 March 2019. Virus bioinformatics has become central to virology research, and advances in bioinformatics have led to improved approaches to investigate viral infections and outbreaks, being successfully used to detect, control, and treat infections of humans and animals. This active field of research has attracted approximately 110 experts in virology and bioinformatics/computational biology from Europe and other parts of the world to attend the two-day meeting in Glasgow to increase scientific exchange between laboratory- and computer-based researchers.

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Quantifying how the environment shapes host immune defense is important for understanding which wild populations may be more susceptible or resistant to pathogens. Spatial variation in parasite risk, food and predator abundance, and abiotic conditions can each affect immunity, and these factors can also manifest at both local and biogeographic scales. Yet identifying predictors and the spatial scale of their effects is limited by the rarity of studies that measure immunity across many populations of broadly distributed species.

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Parallel molecular evolution is the independent evolution of the same genotype or phenotype from distinct ancestors. The simple genomes and rapid evolution of many viruses mean they are useful model systems for studying parallel evolution by natural selection. Parallel adaptation occurs in the context of several viral behaviours, including cross-species transmission, drug resistance, and host immune escape, and its existence suggests that at least some aspects of virus evolution and emergence are repeatable and predictable.

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Adaptation to specialized diets often requires modifications at both genomic and microbiome levels. We applied a hologenomic approach to the common vampire bat (Desmodus rotundus), one of the only three obligate blood-feeding (sanguivorous) mammals, to study the evolution of its complex dietary adaptation. Specifically, we assembled its high-quality reference genome (scaffold N50 = 26.

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Vampire bats are the only mammals known to feed exclusively on blood from other animals, often from domestic cattle. We tested the hypothesis that the adaptation of vampire bats to hematophagy would have resulted in shared viral communities among vampire bats and cattle, as a direct result of historic spillover events occurring due to hematophagy. We analyzed the presence of different viruses in sample populations of sympatric bat and prey populations and searched for shared viruses between taxa.

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Unlabelled: Gammaherpesviruses (γHVs) are generally considered host specific and to have codiverged with their hosts over millions of years. This tenet is challenged here by broad-scale phylogenetic analysis of two viral genes using the largest sample of mammalian γHVs to date, integrating for the first time bat γHV sequences available from public repositories and newly generated viral sequences from two vampire bat species (Desmodus rotundus and Diphylla ecaudata). Bat and primate viruses frequently represented deep branches within the supported phylogenies and clustered among viruses from distantly related mammalian taxa.

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Retroviruses, as part of their replication cycle, become integrated into the genome of their host. When this occurs in the germline the integrated proviruses can become an endogenous retrovirus (ERV) which may eventually become fixed in the population. ERVs are present in the genomes of all vertebrates including humans, where more than 50 groups of human endogenous retrovirus (HERVs) have been described within the last 30 years.

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We characterized the nucleic acid-sensing Toll-like receptors (TLR) of a New World bat species, the common vampire bat (Desmodus rotundus), and through a comparative molecular evolutionary approach searched for general adaptation patterns among the nucleic acid-sensing TLRs of eight different bats species belonging to three families (Pteropodidae, Vespertilionidae and Phyllostomidae). We found that the bat TLRs are evolving slowly and mostly under purifying selection and that the divergence pattern of such receptors is overall congruent with the species tree, consistent with the evolution of many other mammalian nuclear genes. However, the chiropteran TLRs exhibited unique mutations fixed in ligand-binding sites, some of which involved nonconservative amino acid changes and/or targets of positive selection.

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