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Virus Research

○ Elsevier BV

Preprints posted in the last 30 days, ranked by how well they match Virus Research's content profile, based on 37 papers previously published here. The average preprint has a 0.03% match score for this journal, so anything above that is already an above-average fit.

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Discovery of two potential new species and two novel bat-coronavirus subgenera (Phyllacovirus and Phyllobecovirus) in the Neotropics

Correa, L.; Dezordi, F.; da Silva, A. c.; Melo, J.; Dias, Y.; Resende, P. C.; Appolinario, L.; Siqueira, M.; Ogrzewalska, M.; Wallau, G. d. L.

2026-09-24 genomics 10.64898/2026.09.23.753618 medRxiv
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Bats are major natural reservoirs for coronaviruses, yet complete viral genomes from South America remain scarce, limiting evolutionary and taxonomic understanding. Here, we conducted metatranscriptomic sequencing of coronavirus-positive bat samples collected across two ecologically distinct Brazilian biomes: the Atlantic Forest and the semi-arid Caatinga. We recovered seven complete or near-complete genomes belonging to Alphacoronavirus and Betacoronavirus. Phylogenetic and comparative similarity analyses of conserved replicase domains (3CLpro, NiRAN, RdRp, ZBD, HEL1), following International Committee on Taxonomy of Viruses (ICTV) demarcation criteria, revealed significant viral diversity. Within Alphacoronavirus, two genomes from Atlantic Forest phyllostomid bats (Artibeus lituratus and Carollia perspicillata) formed a deeply divergent sister lineage to Amalacovirus, exhibiting a mean amino acid similarity of 76.7% with the reference genome. Within Betacoronavirus, one genome from a Caatinga phyllostomid bat (Artibeus planirostris) clustered within the recently described Ambecovirus clade, displaying 75.9% mean amino acid similarity with mormoopid-associated reference sequences. Based on these divergence levels and non-recombinant genomic architectures, we propose two novel candidate subgenera, Phyllacovirus and Phyllobecovirus, alongside potential novel viral species. Furthermore, our findings demonstrate strong host-associated structuring and biogeographical partitioning of viral lineages across Neotropical biomes. Overall, this study expands the genomic landscape of South American bat coronaviruses and underscores the importance of continuous genomic surveillance at human-wildlife interfaces.

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Interferon gamma-induced MX1 and IFITM1 inhibit Varicella-Zoster Virus Replication

Kim, S.; Shakya, A. K.; Guo, H.

2026-09-28 microbiology 10.64898/2026.09.28.754940 medRxiv
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Interferon gamma (IFN-{gamma}) is a potent cytokine secreted following primary varicella-zoster virus (VZV) infection. Our previous studies demonstrated that pretreatment with IFN-{gamma} completely inhibited VZV replication in lung fibroblast MRC-5 and retinal epithelial ARPE-19 but not in melanoma MeWo cells, suggesting that IFN-{gamma}-stimulated protein(s) inhibit viral replication. Our microarray analysis revealed that 34 interferon-stimulated genes (ISGs) were upregulated by greater than 2.5-fold at 8 h post-treatment in both ARPE-19 and MRC-5 cells compared to those of MeWo cells. The depletion of CTSS, GBP4, MX1, IFIT1, IFITM1 and IRF1 by siRNA in IFN-{gamma}-treated cells significantly increased VZV yields. Ectopic overexpression of interferon-induced myxovirus resistance 1 (MX1) or transmembrane protein 1 (IFITM1) significantly reduced VZV yield both in ARPE-19 and MeWo cells. IFITM1 abrogated viral major immediate-early IE62 protein-mediated trans-activation. IFITM1 reduced the level of VZV immediate-early IE62 protein, but not the IE62 mRNA, suggesting that IFITM1 expression reduces the expression level of IE62 by post-transcriptional regulation. Cell-free VZV failed to infect human primary epidermal keratinocytes, in which the basal level of endogenous MX1 gene expression is very high. Pharmacologic inhibition of JAK signaling reduced MX1 expression and enhanced VZV replication in calcium chloride-induced differentiated keratinocytes. Collectively, these findings identify MX1 and IFITM1 as key IFN-{gamma}-induced restriction factors that inhibit VZV replication and suggest that suppression of JAK-STAT signaling can promote VZV replication in differentiated keratinocytes.

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Isolation and characterisation of Lytic Jumbo Klebsiella phage BMPCR_005026

Lloyd-Evans, I.; Ford, M.; Hazzard, J.; Bartis, C.; Patel, F.; Roemer, N.; Wright, K.; Porter, K.; Coleman, M.; Galyov, E.; Megremis, S.; Clokie, M. R.; Millard, A. D.; Michniewski, S.; Wilkinson, R. C.

2026-10-01 microbiology 10.64898/2026.09.30.755614 medRxiv
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Background: Klebsiella pneumoniae is a key causative agent of multidrug resistant nosocomial infections. Bacteriophages offer a promising alternative treatment, but the diversity of Klebsiella species requires the characterisation of a broad range of phages, particularly the poorly characterised jumbo phages. Materials and Methods: Phage BMCPR_005026 was isolated from sewage against Klebsiella pneumoniae. Whole genome sequencing, transmission electron microscopy and host range analysis against a diverse set of 40 clinically relevant Klebsiella strains were used to characterise the phage. Results: The virion had a myovirus morphology and genomic analysis placed it within an undefined family in Caudoviricetes where it forms a new species within the genus Alcyoneusvirus. BMCPR_005026 could form plaques on 3 of the 40 Klebsiella strains tested (7.5%) and formed halos. Conclusion: BMCPR_005026 represents a new species of phage within the genus Alcyoneusvirus with activity against 3 Klebsiella KL-types.

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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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Constitutively-active Positive Transcription Factor b (P-TEFb) prevents viral latency.

Huang, F.; Nishiura, K.; Fujinaga, K.

2026-09-28 microbiology 10.64898/2026.09.26.754700 medRxiv
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While many cellular and viral mechanisms are associated with proviral latency, the positive transcription factor b (P-TEFb), a cellular co-factor of the nuclear factor kappa B and viral transactiator proteins, plays a critical role in low viral transcription levels in resting infected cells. P-TEFb, comprised of CDK9 and Cyclin T1 (CycT1), is absent in quiescent CD4+T cells that represent the bulk of the viral latent reservoir. In these cells, the CycT1 subunit is dephosphorylated and dissociated from CDK9, leading to its rapid proteasomal degradation. Based on the knowledge of CycT1 phosphorylation and proteolysis, we designed a mutant CycT1 protein [constitutively active (CA)-CycT1] that is resistant to protein degradation and is stably expressed in resting CD4+ T cells. Interestingly, the expression of CA-CycT1 significantly delayed the establishment of viral latency in CD4+ T cells. This is the first example of expressing a high level of CycT1 proteins in resting CD4+ T cells, which modulates viral latency and T cell functions. This finding presents a significant therapeutic potential for the development of effective therapies for latent viral infections.

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Post-outbreak surveillance reveals contrasting circulation dynamics of West Nile, Usutu and Bagaza viruses in southern Portugal, 2021 - 2023

Fontoura-Goncalves, C.; Goncalves, D.; Pascoal, L.; Llorente, F.; Moraga-Fernandez, A.; Contreras, M.; Silva, T.; Almeida, T.; Pinho, C.; Minayo-Martin, S.; Valencia, V.; Fasanelo, M.; Lopes, A.; Abrantes, J.; Mello, G.; Costa, J. B.; Alves, P. C.; Ramirez, E. P.; Roiz, D.; Jimenez-Clavero, M.; Hofle, U.; Queiros, J.

2026-09-24 genetics 10.64898/2026.09.21.752589 medRxiv
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Mosquito-borne orthoflaviviruses pose a significant threat to human and animal health worldwide. In Europe, West Nile (WNV), Usutu (USUV) and Bagaza (BAGV) viruses have expanded their geographic distribution and are detected with increasing frequency. Following the emergence of BAGV in 2021, we investigated the circulation dynamics and genomic diversity of orthoflaviviruses in southern Portugal, where their epidemiology remains poorly understood. Active Orthoflavivirus surveillance was conducted in birds and mosquitoes during 2021-2023 using serological and molecular assays, complemented by viral genome sequencing and phylogenomic analyses. Viral RNA was detected in 3.5% (41/1,171) of birds, while seroneutralization assays identified an overall seroprevalence of 55.3% (503/910). WNV RNA (lineage-1, strains WMed-1.2 and WMed-1.3) was detected annually in resident birds, including Alectoris rufa, Cyanopica cooki and Garrulus glandarius (1.5%, 18/1,171), and in Culex univittatus mosquitoes (0.8%, 2/255). Together with a WNV-specific seroprevalence of 28.5% (259/910) in birds, these findings support sustained local circulation. USUV RNA (Africa 3.1 sub-lineage) was detected in A. rufa in 2021 and 2023 (0.2%, 2/1,171), but seroprevalence was low (1.3%, 8/623), consistent with intermittent circulation. BAGV RNA (genotype-2) was detected only during the 2021 outbreak in A. rufa and Emberiza calandra (1.8%, 21/1,171), although BAGV-specific antibodies (6.6%, 60/910) were detected for up to two years after the outbreak, suggesting continued exposure or low-level circulation. Overall, our findings reveal contrasting circulation dynamics of orthoflaviviruses in southern Portugal. Sustained WNV circulation implies the need to strengthen avian and human surveillance in Portugal to better assess its public health risk, while the sporadic detection of USUV and BAGV underscores the value of long-term, integrated One Health surveillance for improving early warning and preparedness for emerging mosquito-borne diseases.

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A Genome-Wide Association Study in the Chilean admixed population reveals four new loci for COVID-19 severity and susceptibility

Espinosa-Parrilla, Y.; Fuentes-Guajardo, M.; Carvajal-Silva, L.; Aguilar-Valdes, K.; Signore, I. A.; Arevalo, T. V.; Zapata-Contreras, D.; Donoso, G.; Zuniga-Pacheco, P.; Valenzuela-Jorquera, H.; Rosso Villanelo, S. A.; Tobar-Calfucoy, E. A.; Yanez, C. E.; Carvajal, F.; Saez Hidalgo, J. M.; Sanhueza, S.; Quiroga, R. A.; Martinez, M. F.; Cerpa, L. C.; Varela, N. M.; Cappelli, C. L.; Campillay-Veliz, C. P.; Valdebenito-Maturana, B.; Garcia-Araya, J.; Santander, R. A.; Opazo, J.; Retamales-Ortega, R.; Bocchieri, P.; Alarcon, T. A.; Plaza, A.; Moraga, M.; Munoz, C. A.; Echeverria, C. A.; Dorador,

2026-10-14 genetic and genomic medicine 10.64898/2026.10.13.26365424 medRxiv
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Background: More than five years after the COVID-19 outbreak, the infection by the SARS-CoV-2 virus should still be considered as a global threat with highly heterogeneous clinical outcomes from asymptomatic to fatal depending on existing genetic and phenotypic inter-individual and inter-population variability. Our objective is to identify risk loci associated with COVID-19 in an admixed Latin American population. Methods: We performed a genome-wide association study in the framework of the Chilean C19-GenoNet team, analyzing a cohort of 3,417 individuals recruited from the northernmost to the southernmost regions of the country, who presented variations in the severity of their COVID-19 clinical manifestations. Results: Our investigation replicated the extensively reported association of several variants at the 3p21.31 locus with COVID-19 severity and found a suggestive association for a variant within the FOXP4 gene at 6p21.1 with COVID-19 hospitalization. Both associations appear to be shared with other populations. Importantly, our study identified three previously unreported loci associated with COVID-19 severity or hospitalization at 7q21.11, 16p13.12 and 6p25.3, and one additional locus at 4p13 associated with SARS-CoV-2 positivity, a proxy for infection susceptibility. Conclusions: these new risk loci may represent population-specific effects in Chilean and, potentially, other Latin American admixed groups. Our study highlights the importance of expanding efforts to study underrepresented and genetically different populations, which may provide new clues on the genetic basis of human diseases and may help to anticipate global responses to emerging viral infections and future pandemics.

8
Shedding light on the virome of Caliothrips phaseoli, an emergent pest in peanut

bejerman, n.; de Breuil, S.; Dottori, C.; Debat, H.

2026-10-10 microbiology 10.64898/2026.10.09.758028 medRxiv
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The bean thrips, Caliothrips phaseoli, is an emergent pest affecting peanut production. Thus, gaining a deeper understanding of the naturally occurring viral populations associated with this insect is of major importance, as such knowledge could support the design of novel pest management strategies that are both ecologically responsible and sustainable over the long term. In this study, we performed the first RNA high-throughput sequencing (HTS) analysis of C. phaseoli to unravel its virome, discovering a wide number of novel RNA viruses. Our HTS analysis revealed the presence of 31 viral segments, corresponding to 18 viruses, including double-stranded RNA viruses as well as positive- and negative-sense single-stranded RNA viruses. All these are novel viruses and cover multiple viral lineages belonging to diverse families. Overall, these results indicates that C. phaseoli hides a complex virome. The findings presented here provide an important framework for subsequent studies aimed at understanding the ecological significance, evolutionary patterns, and possible use of these viruses as components of biologically based management programs for this emerging peanut pest.

9
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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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.

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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.

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Evaluation of Human Norovirus Replication in Salivary Gland Cells

Harlow, J.; Briggs, S.; Pothier, E.; Pham, K.; Nasheri, N.

2026-10-01 microbiology 10.64898/2026.09.29.755260 medRxiv
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Human noroviruses (HuNoVs) are the most common cause of non-bacterial foodborne illnesses worldwide. HuNoVs are notoriously difficult to culture, and current cell culture systems, such as human intestinal enteroids have limitations in efficiency and scalability, which has limited their applications in food safety studies. Recently, it has been shown that transformed salivary gland cell lines (including NS-SV-TT-DC) allow for replication and passaging of norovirus GII.4. Herein, we examined whether we can independently observe viral replication in salivary gland cells and if other strains of human norovirus can replicate in these cells. For this purpose, we first evaluated the replication of several norovirus strains in NS-SV-TT-DC cells by either infecting them with vesicle-cloaked viruses or total viruses in stool filtrates. Low levels of viral replication was observed and vesicle isolation did not improve viral replication. Next, we screened for replication of 50 norovirus samples from 9 genotypes, and 14 isolates demonstrated over a two-fold viral replication. We observed that the initial viral load in the samples does not have a significant effect on replication efficiency. We were also able to passage several isolates. Subsequently, we examined whether interferon inhibitors such as Ruxolitinib, TPCA-1, and BX795 would improve viral replication and observed negligible effects. Finally we tested multiple supplements including MgCl2, bile salt, ceramide, and TAK-779. Most supplements had little or no effect on HuNoV replication in NS-SV-TT-DC cells. Bile salt and TAK-779 showed limited, genotype-specific benefits. Altogether these results indicate that salivary gland cells allow limited replication of certain HuNoV isolates.

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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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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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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.

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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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Hepatitis C virus NS5A is not an effective antagonist of the canonical PKR-eIF2α pathway

Gallardo Flores, C. E.; Yu, L. L.; Kertzman, E. R.; Rothhaar, P.; Lohmann, V.; Colpitts, C. C.

2026-10-08 microbiology 10.64898/2026.10.07.757322 medRxiv
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Protein kinase R (PKR) is an antiviral sensor that induces translational shutdown and stress granule (SG) formation through the phosphorylation of eIF2. Although previous studies have proposed that hepatitis C virus (HCV) non-structural protein 5A (NS5A) inhibits PKR dimerization, other studies consistently observe PKR activation and SG formation during HCV infection. To address this discrepancy, we interrogated the ability of NS5A from different genotypes and strains to regulate canonical PKR-eIF2 activation in a variety of cell culture models. Regardless of the genotype or strain tested, HCV NS5A failed to inhibit PKR dimerization or dsRNA-induced PKR activation, nor did it rescue downstream steps in the PKR-eIF2 pathway, such as translation halt and SG formation, in contrast to known viral PKR antagonists. Similarly, NS5A did not antagonise PKR activation when expressed in the context of other HCV non-structural proteins. We also tested the role of the host factor cyclophilin A (CypA), which interacts with both NS5A and PKR. However, the absence of CypA did not affect downstream PKR signaling or the activity of viral PKR antagonists or NS5A. Collectively, these findings indicate that NS5A does not effectively antagonise the PKR-eIF2 pathway and further support previous findings that HCV replication occurs in the presence of an active PKR response.

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Unnoticed high human infection incidence for West Nile virus and Usutu virus in the Netherlands: evidence from a longitudinal nationwide cohort, 2020-2023

Grobben, M.; Valle, C.; Reimerink, J.; Godeke, G.-J.; Shrestha, S.; Nellestijn, C.; Abba, H.; Franz, E.; Voordouw, B. C. G.; van der Klis, F. R. M.; Vos, E. R. A.; den Hartog, G.; Reusken, C. B. E. M.

2026-10-14 public and global health 10.64898/2026.10.13.26365405 medRxiv
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Background Ecological surveillance indicates (regional) establishment of West Nile virus (WNV) and Usutu virus (USUV) in the Netherlands. However, the incidence of human infections remains unknown. Methods We identified WNV and USUV infections in the Netherlands in 2020-2023, using a longitudinal, nationwide population-based cohort, applying a two-tiered serology approach based on protein micro-array and virus neutralization. IgG data were used to estimate overall seroprevalence and infection incidence, and to study antibody longevity. Study set-up enabled tracking of the period of seroconversion and linking of self-reported travel history. The analyses took account of the survey design and weights were incorporated to match the Dutch population distribution following census data. Findings Among 4290 participants, we identified 113 probable WNV and/or USUV cases, including 55 seroconversions. Thirty-six cases were confirmed by antibody neutralization, of which 12 seroconverted. Six confirmed seroconverters were identified as autochthonous infections. The overall weighted seroprevalence was estimated at 0.54% (0.21-0.87%) for WNV and 0.25% (0.09-0.40%) for USUV. The weighted incidence for autochthonous WNV and USUV infection was estimated as respectively 0.06% (95% CI 0-0.12%) and 0.04% (95% CI 0-0.09%). Interpretation The estimated infection incidence and seroprevalence of WNV and USUV indicate a substantial underdiagnosis of clinical cases in the Netherlands in 2020-2023. These observations highlight the need for increased awareness among physicians to identify cases and the need for continued paired syndromic-laboratory surveillance for these viruses.

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Whole genome sequencing reveals a decade of human adenovirus B114 circulation in England

McClure, P. J.; Muntean, M.; Cifelli, E.; Abiodun, O. J.; Lister, M.; Lambisia, A.; Quick, J.; Astbury, S.; Houldcroft, C. J.

2026-09-23 infectious diseases 10.64898/2026.09.22.26363659 medRxiv
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BackgroundHuman Mastadenovirus B (HAdV-B) causes ocular and respiratory infections and is capable of causing outbreaks in healthcare settings. HAdV-B114, a recombinant genotype only formally recognised in 2023, has been reported predominantly from Germany, the USA, China and Japan; genomic data from UK clinical settings remain limited. This study analysed 68 HAdV-B whole genomes from ocular and respiratory-associated samples collected at a Nottingham hospital across the pre- and post-COVID-19 restriction periods (2017-2023). MethodsClinical samples typed positive for HAdV-B by partial hexon Sanger sequencing were selected for whole-genome sequencing using a novel overlapping PCR amplicon strategy, sequenced on the Oxford Nanopore Technologies PromethION platform. Phylogenetic and pairwise difference analyses were used to characterise genotype composition and genomic relatedness. SimPlot and amino-acid comparison characterised divergence between sub-lineages. ResultsWhole-genome phylogenetics confirmed that two species B genotypes were detected in Nottingham University Hospitals between 2017-23: HAdV-B114 (n=56) and HAdV-B7 (n=12). HAdV-B114 was detected before and after COVID-19 restrictions, with an increase in 2022-2023, consistent with post-restriction expansion of a pre-existing lineage. Pairwise difference analysis identified 24 genomically identical B114 sequences; associated metadata argued against a single nosocomial transmission chain interpretation, with the pattern more consistent with repeated detection of a widely circulating community strain, with the possibility of localised onward transmission. Within the B114 clade, multiple monophyletic groups were identified by whole-genome phylogenetics. ConclusionsThis study adds whole-genome resolution to the existing UK HAdV-B114 data, demonstrates the utility of WGS for clinical adenovirus surveillance and shows the benefits of combining epidemiological data with genomic analysis.

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homeRNA Just Dropped! Streamlining Remote Blood Collection and RNA Stabilization for Smaller Sample Volumes with homeRNAdrop

Eakman, M.; Stefanovic, F.; Liang, W.; Robertson, I. H.; Jindal, A.; Adams, K. N.; Berthier, E.; Haack, A. J.; Theberge, A. B.

2026-09-23 bioengineering 10.64898/2026.09.22.753625 medRxiv
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At-home sampling can address obstacles to participation in transcriptomics research. We previously developed the homeRNA and homeRNAmax platforms; these custom-designed tubes containing RNA stabilizer interface with a blood tube compatible with upper-arm blood collection devices, allowing for blood collection and RNA stabilization to occur from a participant's home. In this work we introduce homeRNAdrop, an insert for a commercially available blood tube (BD Microtainer) that divides the tube into two compartments: the top compartment holds 200 L blood and the bottom compartment holds ~590 L liquid stabilizer (RNAlater). By combining blood collection and RNA stabilization into the same tube, homeRNAdrop streamlines sample preparation for participants and allows for more compact sample storage for the lab. In a remote pilot study, n=25 participants from across the United States tested the homeRNAdrop kit. The n=23 samples successfully received by the lab show that samples collected using homeRNAdrop are of sufficient RNA quality (all RINs > 6, a common cutoff for analysis) and yield (mean yield=1.44 g) for downstream gene expression analysis. Almost all participants who successfully collected blood using the Tasso Mini device found the homeRNAdrop device easy to use (n=23/24). Overall, this work adds a simplified, user-friendly platform to the growing suite of tools for remote blood RNA stabilization.