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Frontiers in Virology

○ Frontiers Media SA

Preprints posted in the last 30 days, ranked by how well they match Frontiers in Virology's content profile, based on 15 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.

1
Rhinovirus Infection of Human Airway Epithelial Cells Stimulates Neutrophil Superoxide

Wilson, J. L.; Schneider, R. B.; Juang, T.; Kennedy, G. A.; Devries, M.; Bochkov, Y. A.; Gern, J. E.

2026-10-08 immunology 10.64898/2026.10.05.756757 medRxiv
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Background: Neutrophils migrate to the respiratory epithelium during rhinovirus (RV) infection, but whether RV directly activates neutrophils or whether activation arises from epithelial responses remains unclear. Objective: To determine whether RV directly activates human neutrophils or indirectly activates them through RV infected airway epithelial cells. Methods: Human neutrophils were exposed to purified RV, and activation was assessed by myeloperoxidase activity, CD11b/CD66b expression, and reactive oxygen species (ROS) production. Neutrophils were co-cultured with RV-infected air liquid interface (ALI) bronchial epithelium evaluated for effects on epithelial integrity. At 48 to 72 hours post-infection, we used live-cell imaging to measure ROS responses and neutrophil-tracking assays to measure migration velocity and ROS responses to basolateral supernatants, clarified apical washes, and apical debris from RV-infected epithelial cells. Plaque assays were used to assess for RV infectivity after incubation with apical neutrophils. Results: RV did not directly activate neutrophils. Adding neutrophils to the apical surface of airway epithelial cells increased neutrophil ROS production at 48 to 72 hrs post-infection but did not alter epithelial cytotoxicity. Conversely, basolateral supernatants from infected cells enhanced neutrophil migration but not ROS, consistent with cytokine-mediated priming. Clarified apical washes had no effect on migration or ROS. By contrast, apical debris from infected cultures triggered a robust ROS response. Basolateral fractions from medium control or RV infected cultures did not induce ROS. Infectivity is not impacted by apical neutrophil presence. Conclusion: RV does not directly activate neutrophils. Instead, RV infected epithelial cells release basolateral factors that enhance neutrophil migration, while apical debris from infected cells drives ROS activation. These findings indicate that epithelial injury, not RV itself, is the dominant trigger of neutrophil activation during infection.

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Wastewater is Not a Reliable Proxy for Clinical Carbapenem Resistance Prevalence in E. coli

Berglund, B.; Shridar, V. D.; Wrande, M.; Jerlström-Hultqvist, J.; Engblom, S.; Sandegren, L.; Koskiniemi, S.

2026-10-06 public and global health 10.64898/2026.10.02.26364587 medRxiv
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Antimicrobial resistance (AMR) is a major threat to modern medicine and an emerging environmental pollutant. Wastewater-based monitoring offers a scalable alternative to traditional surveillance by enabling population-level monitoring across One Health compartments. However, it remains unclear how well bacterial variants detected in wastewater reflect those causing clinical infections. Here, we assessed the prevalence of carbapenem-resistant Escherichia coli (CREC) in wastewater from Uppsala, Sweden, and compared wastewater isolates with clinical isolates from the same region and period. We observed partial overlap between wastewater and clinical CREC populations, but several common clinical variants were not detected in wastewater and vice versa. CREC prevalence was an order of magnitude higher in wastewater receiving hospital effluent, yet this did not improve concordance with clinical isolates, suggesting that hospital wastewater may artificially inflate CREC prevalence estimates. These findings indicate that wastewater CREC prevalence does not necessarily reflect the regional clinical burden. Furthermore, metagenomic sequencing of wastewater-derived E. coli populations rarely detected CREC resistance genes, suggesting that CREC abundance is below the detection limit of this approach and that targeted enrichment is required for reliable monitoring. Together, our results show that while wastewater-based monitoring can complement AMR surveillance, it should be interpreted cautiously when used as an indicator of clinical risk.

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Four Years of Continuous Weekly Wastewater Analysis Reveals Sequencing as a Robust Alternative to PCR for Respiratory Virome Surveillance.

Prakash, H.; Avadhanula, V.; Tisza, M. J.; Cormier, J.; Ross, M. C.; Perez, R. K.; Chang, J. D.; Mazurek, C. R.; Deegan, J.; Petrosino, J. F.; Piedra, P.; Clark, J. R.; Boerwinkle, E.; Maresso, A. W.

2026-10-15 infectious diseases 10.64898/2026.10.13.26364774 medRxiv
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Wastewater-based epidemiology uses both targeted and non-targeted bioanalytical approaches to detect and track disease-causing microbes in wastewater. Targeted approaches such as quantitative polymerase chain reaction (qPCR) remain widely used while sequencing-based approaches have slowly gained popularity. However, concordance between established targeted molecular assays and sequencing approaches remains incompletely characterized. To assess the validity of sequencing as an alternative to qPCR, we compared outcomes of both methods targeting five respiratory viruses in wastewater samples collected across 16 Texas cities over 4 years (May 2022-July 2026) of continuous sampling. We found positive correlations between qPCR and sequencing measurements, with both methods independently correlating with statewide clinical emergency department visits. qPCR positivity also increased with genomic sequencing coverage, and sequencing demonstrated greater potential than qPCR as an early respiratory virus outbreak detection method. Our findings support metagenomic sequencing as a sensitive and highly specific alternative to targeted qPCR for wastewater surveillance, and reinforce its utility towards long-term longitudinal monitoring of respiratory viruses.

4
Detecting measles virus in hospital air during a local outbreak

Barbian, H. J.; Funk, M.; Black, S. R.; Hayden, M. K.; Zelencik, S.; Borah, B. F.; Zhang, D.; Bartlett, A. H.; Kociolek, L. K.; Rosenthal, A.; Farhat, N.; McSorley, V. E.; Kittner, A.

2026-09-27 infectious diseases 10.64898/2026.09.25.26363929 medRxiv
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In 2024, Chicago experienced a measles virus outbreak. Air samples collected as part of routine respiratory virus surveillance from three hospitals that received measles patients were retrospectively analyzed. Measles virus was detected in air samples from one emergency department across five weeks when measles patients were present and another when no known cases were present. Two of three viral sequences derived from air samples were identical to measles patients. The source of one diverging sequence could not be identified and may represent a case not identified by traditional surveillance methods. Air sampling may supplement measles investigation, surveillance and response.

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Opposing roles of ACE2 and TMPRSS2 in IBV Beaudette infection

Cao, Y.; Long, Y.; Schleibinger, S.; von Heyl, T.; de Wit, J. J.; Kaufer, B.; Schusser, B.; Sid, H.

2026-10-08 microbiology 10.64898/2026.10.06.753779 medRxiv
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Infectious bronchitis virus (IBV) is an economically important avian gammacoronavirus. IBV uses sialic acids and heparan sulfate for cellular attachment, but the host proteins governing its infection remain poorly defined. Here, we investigated the roles of angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TMPRSS2) during IBV Beaudette (IBV BD) infection. ACE2 knockout impaired IBV replication in DF-1 cells, whereas ACE2 reconstitution restored infection. Furthermore, ACE2 overexpression enhanced infection of DF-1 and primary chicken embryo kidney cells, supporting the role of chicken ACE2 as a proviral host factor. In contrast, TMPRSS2 exerted a restrictive function on IBV BD infection as demonstrated in TMPRSS2 KO DF-1 cells and upon pharmacological inhibition, which significantly increased IBV BD infection in DF-1 and Vero cells. RNA sequencing revealed significant changes in lipid metabolism and membrane-related processes following TMPRSS2 knockout and pharmacological inhibition. These findings highlight the opposing roles of ACE2 and TMPRSS2 in IBV BD infection, emphasizing the combined impact of proviral host factors, protease activity, and the cellular membrane environment during gammacoronavirus infections.

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A versatile and stable reporter platform for human rhinovirus and other enteroviruses

Okada, K.; Hirano, J.; Adachi, T.; Noguchi, T.; Uemura, K.; Ono, C.; Nagata, S.; Yamamoto, Y.; Nagamoto, T.; Taguwa, S.; Yeh, M. T.; Matsuura, Y.

2026-10-05 microbiology 10.64898/2026.10.02.756346 medRxiv
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Human rhinovirus (HRV), a major cause of upper respiratory infections, has increasingly been associated with lower respiratory tract disease. Although tools to investigate HRV pathogenesis are needed, they remain limited. Reporter viruses expressing fluorescent or luminescent proteins are powerful tools for analyzing viral distribution and replication; however, insertion of a reporter gene often impairs viral replication, and the inserted gene is readily lost during serial passage. To address these problems, we established a versatile and stable strategy for generating reporter HRV and other enteroviruses. The gene encoding mScarlet3, a red fluorescent protein, was inserted between the 5'UTR and VP4 gene, a site previously used in other enteroviruses but not in HRV. Optimizing the 2A cleavage sequence between mScarlet3 and VP4 yielded a reporter HRV with growth kinetics comparable to those of the wild-type virus. To improve the genetic stability of the reporter insert, we evaluated GC-content optimization of the reporter gene and relocation of the cis-acting replication element (CRE). GC-content optimization substantially improved reporter stability in both HRV-B14 and EV-A71, whereas CRE relocation provided additional stabilization in EV-A71 but not in HRV-B14, demonstrating the potential applicability of this strategy to other enteroviruses. This strategy for constructing stable reporter HRV and other enteroviruses will facilitate studies of enterovirus pathogenesis.

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Efficient primer design for broad-range virus detection: A semi-automated workflow using sequence clustering and varVAMP

Johnston, C. M.; Mingoli, A.; Hoegh, A. M.; Lohse, L.; Rasmussen, T. B.

2026-09-24 microbiology 10.64898/2026.09.21.753121 medRxiv
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Broad-range RT-qPCR assays are essential for detecting highly diverse viruses within virus families, but designing suitable primers remains challenging because of extensive sequence diversity and biases in public sequence databases. Here, we present a semi-automated workflow that combines sequence clustering and varVAMP to streamline pan-RT-qPCR primer design. The workflow reduces sequence redundancy, improves the representation of viral diversity, and facilitates the identification of broadly reactive primer candidates. We demonstrate the workflow using the arboviral genera Orthoflavivirus and Alphavirus as proof-of-concept datasets, showing its applicability to large and genetically diverse viral sequence collections. The workflow provides a practical, scalable, and reproducible framework for developing broad-range primer candidates and may support surveillance, diagnostics, and preparedness for emerging or divergent viruses.

8
Zika virus sequence and secondary structure analysis using VADR

Dickinson, E. B.; Nawrocki, E. P.

2026-09-24 bioinformatics 10.64898/2026.09.21.753218 medRxiv
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Zika virus is a mosquito-borne flavivirus that caused a major epidemic in the Americas in 2015 and 2016 and is associated with congenital birth defects and neurological disease. Like other flaviviruses, it depends on conserved sequence and RNA structural elements that carry out essential steps in its life cycle and in evading host immune defenses. Public sequence databases and annotation tools give free access to Zika sequence data, but comparable structural information is sparse. We built a computational model of Zika sequence and secondary structure for use with the VADR software package, which validates and annotates Zika sequences for GenBank submission and assigns each sequence to a genetic lineage following a published classification scheme. On a test set of 1254 Zika sequences, 97.2% passed validation, and the model's annotations agreed with those of an existing annotation tool (VIGOR4) for 99.3% of the sequences compared. We also extended VADR to draw secondary structure diagrams of each sequence's structural elements in its linear and circular conformations using R2DT, and we submitted a newly characterized Zika pseudoknotted RNA element to the Rfam database. Together these freely available resources provide secondary structure information for every Zika sequence.

9
Human Infection with Avian Influenza A(H7N7) Virus, Taiwan, 2026

Li, Y.-T.; Lin, Y.-T.; Chen, B.-S.; Kuo, C.-Y.; Huang, H.-Y.; Ko, H.-Y.; Huang, P.-Y.; Smith, G. J.; Lin, Y.-L.; Liu, M.-T.

2026-10-11 infectious diseases 10.64898/2026.10.09.26365013 medRxiv
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Low pathogenic avian influenza A(H7N7) virus detected in a poultry worker in Taiwan, 2026 was related to viruses circulating in Asian wild birds and possessed PB2 E627K, a mammalian adaptation marker. Enhanced surveillance for H7 viruses in poultry and rapid characterization of human cases are essential to assess pandemic potential.

10
Reverse genetics system for emerging tick-borne orthonairovirus highlights dispensable N-terminal region of Gn associated with replication in tick vectors

Mimura, Y.; Hiono, T.; Arakawa, H.; Go, S.; Shigeno, A.; Ito, M.; Fujii, E.; Mizuma, K.; Nakao, R.; Orba, Y.; Kaji, H.; Matsuno, K.

2026-09-29 microbiology 10.64898/2026.09.28.755240 medRxiv
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A growing number of emerging and re-emerging tick-borne orthonairoviruses belonging to the Sulina and Tamdy genogroups have recently been identified in association with febrile diseases in East Asia. Yezo virus (YEZV) is one such viruses and is genetically distinct from well-characterized Crimean-Congo hemorrhagic fever virus. Orthonairovirus glycoproteins (Gn and Gc) expressed from a single glycoprotein precursor (GPC) gene mediate interaction with host cells, yet the organization and functions of the YEZV glycoproteins remain largely undefined. To characterize YEZV glycoproteins in the context of infection, we developed a reverse genetics system that enables recovery of recombinant YEZV entirely from cloned cDNAs. The recombinant wild-type virus exhibited growth properties comparable to those of the parental isolate in vitro and maintained pathogenicity in vivo. Proteomic analysis of purified virus particles produced in mammalian cells showed that peptide coverage of GPC-derived products began at residue 69. We therefore used the reverse genetics system to examine the functional importance of the GPC subregion upstream of residue 69. A mutant with a deletion of GPC residues 28 to 68 (rYEZV GPC{Delta}28-68), which retained the predicted signal peptide, was successfully recovered, suggesting that this subregion is dispensable for producing infectious virus. rYEZV GPC{Delta}28-68 propagated at levels comparable to those of the wild-type virus in mammalian cells and exhibited similar pathogenicity in a mouse model. Interestingly, the mutant reached lower viral titers in tick-derived ISE6 cells and in ticks in vivo, suggesting that this N-terminal subregion may contribute to virus replication in ticks. Together, these findings demonstrate the utility of the newly established reverse genetics system for dissecting the functions of the YEZV glycoproteins in mammalian and tick systems.

11
Detection and characterisation of alpha- and betacoronaviruses in rodents and bats from Germany, France, Belgium and Ireland

Sgarabotto, E.; Venkat, V.; Altan, E.; Gyzels, D.; Erdin, M.; Lehtinen, V.; Niamsap, T.; Greilich, S.; Valta, A.; Galan, M.; Firozpoor, J.; Eccard, J. A.; Jacob, J.; Imholt, C.; Sluydts, V.; Colombo, V.; Leirs, H.; McManus, A.; Stuart, P.; Gryseels, S.; De Bruyn, L.; Voigt, C. C.; Hoffmeister, U.; Alburkat, H.; Bourret, V.; Smura, T.; Castel, G.; Charbonnel, N.; Sironen, T.; Dutra, L. A. L.

2026-09-24 microbiology 10.64898/2026.09.23.753110 medRxiv
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Recent zoonotic coronavirus outbreaks have sparked an interest in understanding coronaviruses circulating in animal reservoirs. While bats are recognised as major reservoirs for these viruses, coronaviruses have also been detected in a wide range of terrestrial small mammals, particularly rodents. However, coronavirus diversity in these mammals, specifically in Europe, is still poorly characterised. In this study, we detected and characterised coronaviruses in terrestrial small mammals and bats from Belgium, France, Germany, and Ireland. We screened tissue samples from rodents and shrews and environmental bat guano using pan-coronavirus real-time and conventional PCRs, with positive results confirmed by sanger sequencing. Among 2667 bat and 1152 terrestrial mammal samples, we detected 59 positive samples, 36 from bats and 23 from rodents, from which we recovered 60 coronavirus sequences, spanning both Alphacoronavirus and Betacoronavirus lineages. Through next generation sequencing we identified one Pipistrellus pygmaeus bat guano sample carrying two distinct alphacoronaviruses, representing Nyctacovirus and Pedacovirus subgenera. Among rodents, most coronavirus-positive samples originated from a zoo in Belgium, where several CoV lineages co-circulated. The identified rodent coronaviruses clustered among previously described rodent-associated lineages, some of which also include human and other mammal-derived coronavirus sequences. Consistent with previous studies, we found sarbecoviruses in horseshoe bats (particularly Rhinolophus ferrumequinum and R. hipposideros) and merbecoviruses in Plecotus auritus bats, and these viruses are distantly related to the human coronaviruses of the respective families. Similar to bat coronaviruses, some rodent coronaviruses strains seemed to be association with specific rodent species. In conclusion, our study enhances the understanding of coronaviruses in rodents and bats, revealing potential hotspots for these viruses and their implication for human and animal health. These findings underscore the necessity for continued surveillance of coronaviruses in wildlife reservoirs to mitigate future zoonotic spillover risks.

12
Optimization of a Human Anti-polio Monoclonal Antibody as a Potential Therapeutic Modality

Lee, S.-M.; Siska, C.; D'Angelo, I.; Kouiavskaia, D.; Mahmood, K.

2026-09-22 biochemistry 10.64898/2026.09.20.753044 medRxiv
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Background. Vaccines have been an essential tool in bringing the world close to polio eradication, with over 99.9 percent of the global population free of poliovirus. No antiviral drugs or monoclonal antibody products, however, are currently licensed for treatment of polio. We previously isolated a human monoclonal antibody (9H2) with potent neutralizing activity against all three poliovirus serotypes. To advance 9H2 as a therapeutic candidate, we optimized its sequence to extend serum half-life and improve manufacturability. Methods. A Multi-Attribute Method under stress conditions identified post-translational modification sites, and Abacus (Trademark) ranked sequence liabilities. Six amino acid substitutions were introduced into the variable regions, generating 23 combinatorial variants. Codon-optimized genes were synthesized and engineered into a human immunoglobulin G1 backbone containing crystallizable fragment (Fc) mutations (M428L/N434S) to extend serum half-life. Constructs were transfected into CHO K1 cells to generate stable pools in 24 well plates. Protein A purified antibodies were characterized using biophysical assays and an in vitro poliovirus neutralization assay. Results. All variants retained high in vitro neutralizing activity against poliovirus. A lead candidate was selected based on integrated assessment of biophysical properties across eight assays and expression yield. Conclusions. Structure-guided engineering and experimental evaluation enabled optimization of the 9H2 antibody sequence and identification of a lead candidate suitable for clinical manufacturing as a potential anti-poliovirus immunotherapeutic agent.

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Discriminating betacoronavirus receptor usage across subgenera using protein structure prediction and molecular dynamics

Garimella, S. S.; Lauro, G.; Peddamallu, V.; Bandivadekar, P. R.; Thyagatur Kidigannappa, A.; Faller, R.; Ahn, S.-H.; Shah, P. S.

2026-09-28 biophysics 10.64898/2026.09.25.754509 medRxiv
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A critical step in the emergence of a virus is the ability of the viral protein to bind a host receptor and mediate cell entry. For many coronaviruses, this interaction occurs between the Spike S1 subunit and the human ACE2 receptor. Whether this binding interface can be computationally distinguished across unstudied viruses without experimentally resolved protein structures remains an open question. We predicted how 28 emerging coronaviruses may bind to human ACE2 using structural predictions, static interaction prediction programs, and molecular dynamics simulations. To screen the emerging coronaviruses, we predicted a library of S1 structures using AlphaFold. These predicted structures were then used to model the S1-ACE2 interaction with AlphaFold, ClusPro, and HADDOCK. We used known ACE2-binding sarbecoviruses as positive controls and coronaviruses that bind other receptors as negative controls to threshold predicted binding. Contact analysis quantified the predicted binding and revealed that these static interaction prediction methods varied in discriminative power. Less restrained static predictions separated binders from non-binders, whereas heavily restrained docking did not, potentially forcing an interaction where none should exist. This analysis highlighted an emerging coronavirus, Zhejiang2013, as a potential ACE2 binder. We used molecular dynamics simulations to further assess the static predictions and model the interaction over time. Overall, our results indicate that Zhejiang2013 exhibits dynamic interaction patterns consistent with ACE2 binding. Given that two ACE2-binding coronaviruses have caused global pandemics within the past two decades, identifying potential ACE2 binders is critical for early warning and pandemic preparedness.

14
Data Reduction in SARS-CoV-2 Amplicon Sequencing: Effects of Read Subsampling and Normalization on Consensus Quality, Lineage Assignment, and Computational Burden

Ortega, Y.; Gupta, P.; Olinares-Perdomo, O.; Oakeson, K. F.; Young, E. L.

2026-10-07 infectious diseases 10.64898/2026.10.05.26363801 medRxiv
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Background: Amplicon-based next-generation sequencing is a cornerstone of viral genomic surveillance, but it often produces datasets with highly uneven read coverage due to PCR amplification bias. This leads to excessive data generation and substantial computational overhead for downstream bioinformatic analysis. Results: We evaluated the efficacy of two data reduction strategies on 220 SARS-CoV-2 clinical specimens and 12 wastewater samples: random subsampling with SeqKit and read depth normalization with BBNorm. FASTQ files were reduced to target depths from 10X to 10,000X to compare genome coverage, lineage assignment concordance, and computational resource usage. Both strategies markedly reduced total processing time. For clinical isolates, read depth normalization corrected for amplification bias resulting in highly concordant lineage assignments at a target depth of just 200X. Random subsampling preserved inherent bias but produced reliable assignments at depths over 500X. Reducing target depths below 500X in complex wastewater mixtures severely degraded variant deconvolution accuracy and heavily skewed lineage abundance profiles for both methods. Conclusion: Both random subsampling and read depth normalization successfully reduce computational overhead while preserving key clinical sequencing metrics at appropriate reduction settings. The optimal method depends on the analytical goal, ranging from computationally lightweight random subsampling for rapid lineage assignment, to read depth normalization for generating high-quality consensus sequences. However, aggressive data reduction should be avoided in environmental surveillance, where maintaining a high baseline sequencing depth is critical for accurate mixed-variant deconvolution.

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The actin-binding protein drebrin interacts with the respiratory syncytial virus matrix protein and promotes virus particle release.

Jaouen, T.; Marougka, K.; Feliciano, M.; Jobart-Malfait, A.; Sago, L.; Bajorek, M.; Rameix-Welti, M.-A.; Sitterlin, D.

2026-10-07 microbiology 10.64898/2026.10.05.756730 medRxiv
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Respiratory syncytial virus (RSV) is an enveloped virus that assembles and buds at the plasma membrane, producing filamentous infectious particles. Unlike many other enveloped viruses, a substantial fraction of RSV virions remains associated with the surface of infected cells, limiting our understanding of the membrane-scission mechanisms responsible for particle release. Here, we identified the actin-binding protein drebrin as a cellular interactor of the RSV matrix (M) protein, both in vitro and in infected cells. We demonstrated that RSV infection induces the relocalization of drebrin to actin-rich structures at the cell periphery associated with viral filaments. Using a Transwell-based assay to quantify infectious particles release without mechanically perturbing cells, we confirmed that RSV release is independent of the endosomal sorting complex required for transport (ESCRT) pathway and showed that drebrin depletion reduced RSV release, whereas drebrin overexpression enhanced it. Since drebrin depletion did not significantly affect overall infectious virus production, our results suggest that drebrin may act during the final step leading to membrane scission and RSV particle release. Finally, proteomics analysis identified Transmembrane 9 superfamily member 2 (TM9SF2) as a drebrin-associated protein specifically during infection. TM9SF2 depletion reduced RSV particle release and impaired the RSV-induced relocalization of drebrin to the plasma membrane. Together, these findings identify drebrin and TM9SF2 as host factors regulating RSV release and support a model in which TM9SF2 promotes the recruitment of drebrin to viral budding sites.

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Potency of nucleoside analogs against Powassan virus replication and identification of 4'-fluorouridine as a therapeutic candidate for tick-borne orthoflavivirus encephalitis

Lewis, D. S. M.; Moore, T.; Patel, R.; Cox, R.

2026-09-25 microbiology 10.64898/2026.09.24.754293 medRxiv
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Powassan virus (POWV) is an emerging tick-borne orthoflavivirus that causes severe encephalitis, long-term neurologic sequelae, and death, yet no approved antiviral therapies exist. Here, we evaluated several previously characterized nucleoside analogs as candidate countermeasures for POWV encephalitis. Favipiravir, molnupiravir, 4'-fluorouridine (4'-FlU), and GS-441524 inhibited POWV replication in vitro and demonstrated comparable activity against West Nile virus (WNV). We established C3H/HeNCrl mice as a stringent POWV disease model, showing increased susceptibility, higher day 7 brain titers, and more pronounced neurologic signs resembling severe human disease, compared with C57BL/6 mice. In prophylactic and therapeutic studies, 4'-fluorouridine was the most efficacious compound tested, significantly reducing brain viral burden even when treatment was delayed. Direct comparison with molnupiravir, favipiravir, and GS-441524 in mice confirmed superior survival benefit and antiviral activity for 4'-FlU against both POWV and WNV. These data identify 4'-fluorouridine as a promising therapeutic candidate for neurotropic flavivirus disease.

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Porcine epidemic diarrhea virus Whole-Genome Diversity Reveals Divergence of Contemporary Populations in the United States

Herrera da Silva, J. P.; Rovira, A.; Vannucci, F.; Mena, J.; Pamornchainavakul, N.; Koscielny, M.; Perkins, J.; Zhang, Q.; Kikuti, M.; Yue, X.; Paploski, I.; Torremorell, M.; Corzo, C.; VanderWaal, K.

2026-10-09 microbiology 10.64898/2026.10.08.757685 medRxiv
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Porcine epidemic diarrhea virus (PEDV) was introduced into the United States (USA) in 2013 and has circulated ever since. PEDV causes significant losses in the swine industry, with the greatest impact observed during the first years following its introduction into the country. However, the evolutionary dynamics of the virus remain underexplored. Recently, analyses of the Spike protein subunit S1 suggested that the PEDV population currently circulating in the USA represents a fraction of its historical diversity and comprises only two clades restricted to specific geographic regions. These observations were based on a limited set of S1 sequences. Furthermore, our understanding of evolutionary dynamics at the genomic level is even more limited, as complete PEDV genomes have not been generated since 2017. Here, we characterized the evolutionary dynamics of PEDV populations in the USA using complete genomes and assessed the contribution of different evolutionary mechanisms to shaping population structure. We analyzed 338 complete genomes, of which 25 were obtained in this study, together with 623 Spike S1 sequences, of which 41 were obtained in this study. All sequences obtained in this study were assigned to the non-S-INDEL strain. No S-INDEL sequences were recovered in this study, although these viruses continue to circulate in the country. Our analyses revealed that most sequences sampled after 2023 formed a monophyletic clade divergent from sequences collected in previous years, suggesting an ongoing temporal population structuring. Population structure analyses further supported evidence of population differentiation over time. Recombination analyses indicated that sequences belonging to the contemporary clade shared a single recombination event, suggesting that this clade may have emerged through recombination. Time-scaled S1 phylogenies were consistent with previous findings, supporting the circulation of only two contemporary clades; however, one of these clades was detected for the first time outside its previously reported geographic range. Our findings document temporal genetic differentiation in US PEDV populations, consistent with continued viral evolution, and broaden the known geographic distribution of contemporary S1 clades. These results highlight the value of continued genomic surveillance to monitor changes in PEDV diversity and distribution and provide sequence data to inform vaccine research.

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Differential PCDH1 usage by Laguna Negra and Black Creek Canal hantaviruses

Guerra-Pilaquinga, N.; Word, C.; Lambe, U. P.; Khera, L.; Arinola, R.; Kaur, R.; Dieterle, M. E.; Jangra, R. K.

2026-10-05 microbiology 10.64898/2026.10.05.756634 medRxiv
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Laguna Negra virus and Black Creek Canal virus are hantaviruses associated with hantavirus cardiopulmonary syndrome (HCPS), but their cellular entry receptors have not been defined. We used replication-competent recombinant vesicular stomatitis viruses (rVSVs) bearing hantavirus Gn/Gc glycoprotein complexes to compare entry by these viruses, the Old World rodent-borne Dabieshan virus and Tigray virus, and the shrew-borne Cao Bang virus and Amga virus. All six Gn/Gc complexes supported infection of primary human pulmonary microvascular endothelial cells, with virus-specific efficiencies and kinetics. Genetic ablation of protocadherin-1 (PCDH1) reduced infection mediated by Laguna Negra virus and Black Creek Canal virus Gn/Gc in human osteosarcoma and endothelial cells, whereas PCDH1 re-expression restored susceptibility. Both viruses were captured by a soluble PCDH1 protein comprising the first two extracellular cadherin domains. Infection was also inhibited by a soluble decoy containing the first cadherin domain, and by an antibody specific to that domain, indicating that the first PCDH1 cadherin domain mediates viral engagement. Black Creek Canal Gn/Gc-bearing rVSVs incorporated less Gn/Gc and showed lower apparent capture by PCDH1 than Laguna Negra virus and Andes virus Gn/Gc-bearing particles, even after normalization for glycoprotein abundance. In contrast, PCDH1 depletion did not detectably alter infection mediated by the other four hantavirus Gn/Gc complexes. Thus, Laguna Negra virus and Black Creek Canal virus use PCDH1 for efficient entry but differ in apparent receptor engagement and responses to PCDH1-directed inhibitors, whereas all six viruses are potently neutralized by the broadly reactive Gn/Gc-directed antibody ADI-42898.

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Glycoprotein K8.1 shapes KSHV liver and bone marrow tropism in the marmoset infection model

Stahl-Hennig, C.; Roshani, B.; Grosskopf, A. K.; Schlagowski, S.; Merida Ruiz, S. A.; Vestweber, R.; Eymard, E. D.; Wood, C.; Liu, S.; Bleyer, M.; Stolte-Leeb, N.; Pöhlmann, S.; Whitby, D.; Ensser, A.; Hahn, A. S.

2026-09-28 microbiology 10.1101/2024.10.31.621273 medRxiv
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Kaposi's sarcoma-associated herpesvirus (KSHV) is a human tumor virus. Common marmosets, a potential non-human primate model for vaccine development and infection studies, have previously been shown to support KSHV infection. We established infection of marmosets with BAC-derived, recombinant KSHV to analyze the role of individual glycoproteins (GPs) in tissue tropism. Three groups of four animals were infected intravenously with BAC-derived KSHV wild type (wt), EphA2-receptor-binding-deficient KSHV gHASAELAAN, or KSHV{triangleup}K8.1, lacking glycoprotein K8.1. Viral DNA was detected in multiple tissues of all animals, with the highest loads in spleen, liver, heart, and bone marrow. In most tissues, viral DNA loads did not significantly differ between groups. However, KSHV{triangleup}K8.1-infected animals exhibited significantly lower KSHV DNA levels in liver and bone marrow. KSHV wt infection induced activation of CD4+ and CD8+ T-cells. In animals infected with KSHV wt, KSHV gHASAELAAN or KSHV{triangleup}K8.1, different B cell subpopulations expanded after infection, which suggests that the glycoproteins themselves or the cell tropism imparted by their presence or absence might shape the host response to KSHV. In summary, our findings demonstrate that neither the Eph receptor interaction nor GP K8.1 is essential for intravenous infection, but K8.1 critically contributes to KSHV tissue tropism in vivo.

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EdiProPred: Prediction of Edible Plant Tissue-Associated Proteins Using Large Language Models

Gahlot, P. S.; Shendre, A.; Raghava, G. P. S.

2026-10-06 plant biology 10.64898/2026.10.03.756411 medRxiv
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Ensuring the safety and suitability of proteins considered for food and biotechnology applications is an important challenge. Computational approaches can facilitate the prioritisation of candidate proteins for further investigation, particularly given the rapid growth of genomic and metagenomic sequence datasets. In this study, we developed computational models to distinguish edible plant tissue-associated (EPTA) proteins from non-EPTA proteins. The positive class comprised 939 proteins with experimentally validated evidence of expression in plant tissues commonly consumed by humans, hereafter referred to as EPTA proteins. The negative class comprised 939 proteins annotated in UniProt as toxic, allergenic, or antinutritional, hereafter referred to as non-EPTA proteins. Models were evaluated using five-fold cross-validation with a cluster-based partitioning strategy, ensuring that no protein in the validation set shared more than 40% sequence identity with proteins in the corresponding training set. First, composition-based sequence features were evaluated to establish a baseline for EPTA or non-EPTA classification, with the Extra Trees (ET) classifier achieving a validation AUROC of 0.848. To incorporate evolutionary information beyond amino acid composition, PSSM profiles were subsequently evaluated, yielding an AUROC of 0.842 with an SVM classifier. Finally, to capture richer sequence patterns and contextual information using protein language modelling, we evaluated ESM2-based models. The fine-tuned ESM2-T33 model achieved the highest validation AUROC of 0.925 and was selected as the final predictive model. The resulting approach was implemented as the EdiProPred web server (https://webs.iiitd.edu.in/raghava/edipropred/) and standalone software for computational classification of plant proteins. The EdiProPred framework provides a useful computational tool for prioritising candidate plant proteins and facilitating the exploration of novel protein resources for food and biotechnology applications.