Viruses

18 pages, 1003 KiB

Open AccessArticle

Single-Dose Intranasal or Intramuscular Administration of Simian Adenovirus-Based H1N1 Vaccine Induces a Robust Humoral Response and Complete Protection in Mice

by Daria V. Voronina, Irina V. Vavilova, Olga V. Zubkova, Tatiana A. Ozharovskaia, Olga Popova, Anastasia S. Chugunova, Polina P. Goldovskaya, Denis I. Zrelkin, Daria M. Savina, Irina A. Favorskaya, Dmitry V. Shcheblyakov, Denis Y. Logunov and Alexandr L. Gintsburg

Viruses 2025, 17(8), 1085; https://doi.org/10.3390/v17081085 - 5 Aug 2025

Abstract

Despite the widespread accessibility of vaccines and antivirals, seasonal influenza virus epidemics continue to pose a threat to public health. In this study, we constructed a recombinant replication-deficient simian adenovirus type 25 vector carrying the full-length hemagglutinin (HA) of the H1N1 influenza virus, [...] Read more.

Despite the widespread accessibility of vaccines and antivirals, seasonal influenza virus epidemics continue to pose a threat to public health. In this study, we constructed a recombinant replication-deficient simian adenovirus type 25 vector carrying the full-length hemagglutinin (HA) of the H1N1 influenza virus, named rSAd25-H1. Both systemic and mucosal humoral immune responses, as well as the protective efficacy, were assessed in mice immunized via the intramuscular (IM) or intranasal (IN) route. A single-dose IM or IN administration of rSAd25-H1 elicited a robust systemic IgG antibody response, including hemagglutination inhibition antibodies. As expected, only IN immunization was able to induce IgA production in serum and respiratory mucosa. Notably, a single dose of rSAd25-H1 at the highest dose (10¹⁰ viral particles) conferred complete protection against lethal homologous H1N1 challenge in mice despite the route of administration. These findings demonstrate the potential of simian adenovirus type 25-based vectors as a promising candidate for intranasal vaccine development targeting respiratory pathogens. Full article

(This article belongs to the Special Issue Influenza, SARS-CoV-2, RSV and Other Vaccines: Immunogenicity Parameters and Protection, 3rd Edition)

14 pages, 1669 KiB

Open AccessArticle

Guinea Pig X Virus Is a Gammaherpesvirus

by Vy Ngoc Yen Truong, Robert Ellis and Brent A. Stanfield

Viruses 2025, 17(8), 1084; https://doi.org/10.3390/v17081084 - 5 Aug 2025

Abstract

The Guinea Pig X Virus (GPXV), a newly identified gammaherpesvirus, provides an opportunity to study viral evolution and host–virus dynamics. This study characterizes the GPXV genome and investigates its phylogenetic relationships and divergence from related viruses through comparative genomic and phylogenetic analyses. Virus [...] Read more.

The Guinea Pig X Virus (GPXV), a newly identified gammaherpesvirus, provides an opportunity to study viral evolution and host–virus dynamics. This study characterizes the GPXV genome and investigates its phylogenetic relationships and divergence from related viruses through comparative genomic and phylogenetic analyses. Virus propagation was conducted in Vero cells, followed by genomic DNA extraction and pan-herpesvirus nested PCR. Sanger sequencing filled gaps in the initial genome assembly, and whole-genome sequencing was performed using the Illumina MiSeq platform. Phylogenetic analyses focused on ORF8 (glycoprotein B), ORF9 (DNA polymerase catalytic subunit), ORF50 (RTA: replication and transcription activator), and ORF73 (LANA: latency-associated nuclear antigen). Results showed that GPXV ORFs showed variable evolutionary relationships with other gammaherpesviruses, including divergence from primate-associated viruses and clustering with bovine and rodent viruses. In addition to phylogenetics, a comprehensive comparative analysis of protein-coding genes between GPXV and the previously described Guinea Pig Herpes-Like Virus (GPHLV) revealed divergence. Twenty-four non-ORF genomic features were unique to GPXV, while 62 shared ORFs exhibited low to high sequence divergence. These findings highlight GPXV’s distinct evolutionary trajectory and its potential role as a model for studying host-specific adaptations and gammaherpesvirus diversity. Full article

(This article belongs to the Special Issue Animal Herpesvirus 2025)

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16 pages, 4746 KiB

Open AccessArticle

SARS-CoV-2 Nsp1 Is a Major Suppressor of HLA Class I and Class II Expression

by Ivo Schirmeister, Nicolas Eckert, Sebastian Weigang, Jonas Fuchs, Lisa Kern, Georg Kochs and Anne Halenius

Viruses 2025, 17(8), 1083; https://doi.org/10.3390/v17081083 - 5 Aug 2025

Abstract

Human leukocyte antigen class I (HLA-I) molecules present intracellular peptides on the cell surface to enable CD8+ T cells to effectively control viral infections. Many viruses disrupt this antigen presentation pathway to evade immune detection. In this study, we demonstrate that SARS-CoV-2 Nsp1 [...] Read more.

Human leukocyte antigen class I (HLA-I) molecules present intracellular peptides on the cell surface to enable CD8+ T cells to effectively control viral infections. Many viruses disrupt this antigen presentation pathway to evade immune detection. In this study, we demonstrate that SARS-CoV-2 Nsp1 impairs both the constitutive and interferon-γ (IFN-γ)-induced upregulation of HLA-I. Moreover, Nsp1 also blocks IFN-γ-induced expression of HLA-II. We found that, contrary to previously published work, the early SARS-CoV-2 B 1.1.7 Alpha variant lacking the accessory protein ORF8 retained full capacity to downregulate HLA-I, comparable to an ORF8-expressing wild-type isolate. While ectopic overexpression of ORF8 could reduce HLA-I surface levels, this effect was only observed at high expression levels. In contrast, moderate expression of the viral protein Nsp1 was sufficient to potently suppress both basal and IFN-γ-induced HLA-I, as well as HLA-II expression. To probe the underlying mechanism, we analyzed HLA-I-associated genes in previously published RNA-sequencing datasets and confirmed that Nsp1 reduces expression of components required for HLA-I biosynthesis and antigen processing. These findings identify Nsp1 as a key factor that impairs antigen presentation pathways, potentially contributing to the ability of SARS-CoV-2 to modulate immune recognition. Full article

(This article belongs to the Section Coronaviruses)

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18 pages, 3120 KiB

Open AccessArticle

Měnglà Virus VP40 Localizes to the Nucleus and Impedes the RIG-I Signaling Pathway

by Joyce Sweeney Gibbons, Naveen Thakur, Emma Komers, Olivia A. Vogel, Poushali Chakraborty, JoAnn M. Tufariello and Christopher F. Basler

Viruses 2025, 17(8), 1082; https://doi.org/10.3390/v17081082 - 5 Aug 2025

Abstract

Měnglà virus (MLAV) is a member of the genus Dianlovirus in the family Filoviridae, which also includes Ebola virus (EBOV) and Marburg virus (MARV). Whether MLAV poses a threat to human health is uncertain. However, the MLAV VP35 and VP40 proteins can impair [...] Read more.

Měnglà virus (MLAV) is a member of the genus Dianlovirus in the family Filoviridae, which also includes Ebola virus (EBOV) and Marburg virus (MARV). Whether MLAV poses a threat to human health is uncertain. However, the MLAV VP35 and VP40 proteins can impair IFNα/β gene expression and block IFNα/β-induced Jak-STAT signaling, respectively, suggesting the capacity to counteract human innate immune defenses. In this study, MLAV VP40 is demonstrated to impair the Sendai virus (SeV)-induced activation of the IFNβ promoter. Inhibition is independent of the MLAV VP40 PPPY late-domain motif that interacts with host proteins possessing WW-domains to promote viral budding. Similar IFNβ promoter inhibition was not detected for EBOV or MARV VP40. MLAV VP40 exhibited lesser capacity to inhibit TNFα activation of an NF-κB reporter gene. MLAV VP40 impaired IFNβ promoter activation by an over-expressed, constitutively active form of RIG-I and by the over-expressed IRF3 kinases TBK1 and IKKε. However, MLAV VP40 did not inhibit IFNβ promoter activation by constitutively active IRF3 5D. Consistent with these findings, MLAV VP40 inhibited SeV-induced IRF3 phosphorylation. Although IRF3 phosphorylation occurs in the cytoplasm, MLAV VP40 exhibits substantial nuclear localization, accumulating in foci in HeLa cell nuclei. In contrast, the VP40 of EBOV and MARV exhibited lower degrees of nuclear localization and did not accumulate in foci. MLAV VP40 interacts with importin alpha-1 (IMPα1), suggesting entry via the IMPα/IMPβ nuclear import pathway. Cumulatively, these data identify novel features that distinguish MLAV VP40 from its homologues in EBOV and MARV. Full article

(This article belongs to the Section Animal Viruses)

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14 pages, 2266 KiB

Open AccessArticle

PCV2 Infection Upregulates SOCS3 Expression to Facilitate Viral Replication in PK-15 Cells

by Yiting Li, Hongmei Liu, Yi Wu, Xiaomei Zhang, Juan Geng, Xin Wu, Wengui Li, Zhenxing Zhang, Jianling Song, Yifang Zhang and Jun Chai

Viruses 2025, 17(8), 1081; https://doi.org/10.3390/v17081081 - 5 Aug 2025

Abstract

Porcine circovirus type 2 (PCV2) is a globally prevalent swine pathogen that induces immunosuppression, predisposing pigs to subclinical infections. In intensive farming systems, PCV2 persistently impairs growth performance and vaccine efficacy, leading to substantial economic losses in the swine industry. Emerging evidence suggests [...] Read more.

Porcine circovirus type 2 (PCV2) is a globally prevalent swine pathogen that induces immunosuppression, predisposing pigs to subclinical infections. In intensive farming systems, PCV2 persistently impairs growth performance and vaccine efficacy, leading to substantial economic losses in the swine industry. Emerging evidence suggests that certain viruses exploit Suppressor of Cytokine Signaling 3 (SOCS3), a key immune checkpoint protein, to subvert host innate immunity by suppressing cytokine signaling. While SOCS3 has been implicated in various viral infections, its regulatory role in PCV2 replication remains undefined. This study aims to elucidate the mechanisms underlying the interplay between SOCS3 and PCV2 during viral pathogenesis. Porcine SOCS3 was amplified using RT-PCR and stably overexpressed in PK-15 cells through lentiviral delivery. Bioinformatics analysis facilitated the design of three siRNA candidates targeting SOCS3. We systematically investigated the effects of SOCS3 overexpression and knockdown on PCV2 replication kinetics and host antiviral responses by quantifying the viral DNA load and the mRNA levels of cytokines. PCV2 infection upregulated SOCS3 expression at both transcriptional and translational levels in PK-15 cells. Functional studies revealed that SOCS3 overexpression markedly enhanced viral replication, whereas its knockdown suppressed viral proliferation. Intriguingly, SOCS3-mediated immune modulation exhibited a divergent regulation of antiviral cytokines: PCV2-infected SOCS3-overexpressing cells showed elevated IFN-β but suppressed TNF-α expressions, whereas SOCS3 silencing conversely downregulated IFN-β while amplifying TNF-α responses. This study unveils a dual role of SOCS3 during subclinical porcine circovirus type 2 (PCV2) infection: it functions as a host-derived pro-viral factor that facilitates viral replication while simultaneously reshaping the cytokine milieu to suppress overt inflammatory responses. These findings provide novel insights into the mechanisms underlying PCV2 immune evasion and persistence and establish a theoretical framework for the development of host-targeted control strategies. Although our results identify SOCS3 as a key host determinant of PCV2 persistence, the precise molecular pathways involved require rigorous experimental validation. Full article

(This article belongs to the Section Animal Viruses)

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24 pages, 1028 KiB

Open AccessReview

Biocontrol of Phage Resistance in Pseudomonas Infections: Insights into Directed Breaking of Spontaneous Evolutionary Selection in Phage Therapy

by Jumpei Fujiki, Daigo Yokoyama, Haruka Yamamoto, Nana Kimura, Manaho Shimizu, Hinatsu Kobayashi, Keisuke Nakamura and Hidetomo Iwano

Viruses 2025, 17(8), 1080; https://doi.org/10.3390/v17081080 - 4 Aug 2025

Abstract

Phage therapy, long overshadowed by antibiotics in Western medicine, has a well-established history in some Eastern European countries and is now being revitalized as a promising strategy against antimicrobial resistance (AMR). This resurgence of phage therapy is driven by the urgent need for [...] Read more.

Phage therapy, long overshadowed by antibiotics in Western medicine, has a well-established history in some Eastern European countries and is now being revitalized as a promising strategy against antimicrobial resistance (AMR). This resurgence of phage therapy is driven by the urgent need for innovative countermeasures to AMR, which will cause an estimated 10 million deaths annually by 2050. However, the emergence of phage-resistant variants presents challenges similar to AMR, thus necessitating a deeper understanding of phage resistance mechanisms and control strategies. The highest priority must be to prevent the emergence of phage resistance. Although phage cocktails targeting multiple receptors have demonstrated a certain level of phage resistance suppression, they cannot completely suppress resistance in clinical settings. This highlights the need for strategies beyond simple resistance suppression. Notably, recent studies examining fitness trade-offs associated with phage resistance have opened new avenues in phage therapy that offer the potential of restoring antibiotic susceptibility and attenuating pathogen virulence despite phage resistance. Thus, controlling phage resistance may rely on both its suppression and strategic redirection. This review summarizes key concepts in the control of phage resistance and explores evolutionary engineering as a means of optimizing phage therapy, with a particular focus on Pseudomonas infections. Harnessing evolutionary dynamics by intentionally breaking the spontaneous evolutionary trajectories of target bacterial pathogens could potentially reshape bacterial adaptation by acquisition of phage resistance, unlocking potential in the application of phage therapy. Full article

(This article belongs to the Section Bacterial Viruses)

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23 pages, 2193 KiB

Open AccessArticle

A Virome Scanning of Saffron (Crocus sativus L.) at the National Scale in Iran Using High-Throughput Sequencing Technologies

by Hajar Valouzi, Akbar Dizadji, Alireza Golnaraghi, Seyed Alireza Salami, Nuria Fontdevila Pareta, Serkan Önder, Ilhem Selmi, Johan Rollin, Chadi Berhal, Lucie Tamisier, François Maclot, Long Wang, Rui Zhang, Habibullah Bahlolzada, Pierre Lefeuvre and Sébastien Massart

Viruses 2025, 17(8), 1079; https://doi.org/10.3390/v17081079 - 4 Aug 2025

Abstract

Saffron (Crocus sativus L.) is a vegetatively propagated crop of high economic and cultural value, potentially affected by viral infections that may impact its productivity. Despite Iran’s dominance in global saffron production, knowledge of its virome remains limited. In this study, we [...] Read more.

Saffron (Crocus sativus L.) is a vegetatively propagated crop of high economic and cultural value, potentially affected by viral infections that may impact its productivity. Despite Iran’s dominance in global saffron production, knowledge of its virome remains limited. In this study, we conducted the first nationwide virome survey of saffron in Iran employing a high-throughput sequencing (HTS) approach on pooled samples obtained from eleven provinces in Iran and one location in Afghanistan. Members of three virus families were detected—Potyviridae (Potyvirus), Solemoviridae (Polerovirus), and Geminiviridae (Mastrevirus)—as well as one satellite from the family Alphasatellitidae (Clecrusatellite). A novel Potyvirus, tentatively named saffron Iran virus (SaIRV) and detected in three provinces, shares less than 68% nucleotide identity with known Potyvirus species, thus meeting the ICTV criteria for designation as a new species. Genetic diversity analyses revealed substantial intrapopulation SNP variation but no clear geographical clustering. Among the two wild Crocus species sampled, only Crocus speciosus harbored turnip mosaic virus. Virome network and phylogenetic analyses confirmed widespread viral circulation likely driven by corm-mediated propagation. Our findings highlight the need for targeted certification programs and biological characterization of key viruses to mitigate potential impacts on saffron yield and quality. Full article

(This article belongs to the Special Issue Emerging and Reemerging Plant Viruses in a Changing World)

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21 pages, 1330 KiB

Open AccessArticle

Global Circulation Dynamics and Its Determinants of Dengue Virus: A Network Evolution and Model Study from 1990 to 2019

by Haoyu Long, Jinfeng Zeng, Yilin Chen, Kang Tang, Chi Zhang, Qianru Sun, Lei Gao, Yuhui Lin, Junting He, Chunhui Yang, Xiaoying Lin, Wenzhe Su, Kuibiao Li, Biao Di, Min Kang, Chongguang Yang and Xiangjun Du

Viruses 2025, 17(8), 1078; https://doi.org/10.3390/v17081078 - 4 Aug 2025

Abstract

As dengue is an increasing global health threat, a better understanding of the global circulation dynamics and its determinants would be helpful for precise prevention and control of dengue. The dynamics of global circulation of the four dengue virus serotypes were explored utilizing [...] Read more.

As dengue is an increasing global health threat, a better understanding of the global circulation dynamics and its determinants would be helpful for precise prevention and control of dengue. The dynamics of global circulation of the four dengue virus serotypes were explored utilizing genetic sequences through a network-based method. Four new circulation indicators, including local intensity, betweenness centrality, tip frequency, and persistence time, were defined. Three circulation roles, including source, hub, and destination, were proposed on the basis of new indicators. Spatial and temporal changes of the three circulation roles, along with the persistence time, were explored. Important determinants were also evaluated by machine learning models. Thailand, Indonesia, and Vietnam in Asia and Venezuela and Colombia in Americas were the sources for all four serotypes in different decades. Destinations were observed mostly in island regions. Over the decades, the number of regions with different circulation roles and persistence of DENV-1 increased significantly. Climate and airline factors were involved in the important determinants to circulation roles and persistence of dengue. The roles identified in the global circulation of dengue and important determinants, including climate and airline factors, provide new insights into global dynamics and are beneficial for controlling dengue. Full article

(This article belongs to the Section Human Virology and Viral Diseases)

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26 pages, 3619 KiB

Open AccessReview

Baculovirus-Based Biocontrol: Synergistic and Antagonistic Interactions of PxGV, PxNPV, SeMNPV, and SfMNPV in Integrative Pest Management

by Alberto Margarito García-Munguía, Carlos Alberto García-Munguía, Paloma Lucía Guerra-Ávila, Estefany Alejandra Sánchez-Mendoza, Fabián Alejandro Rubalcava-Castillo, Argelia García-Munguía, María Reyna Robles-López, Luis Fernando Cisneros-Guzmán, María Guadalupe Martínez-Alba, Ernesto Olvera-Gonzalez, Raúl René Robles-de la Torre and Otilio García-Munguía

Viruses 2025, 17(8), 1077; https://doi.org/10.3390/v17081077 - 2 Aug 2025

Abstract

The use of chemical pesticides in agriculture has led to the development of resistant pest populations, posing a challenge to long-term pest management. This review aims to evaluate the scientific literature on the individual and combined use of baculoviruses with conventional chemical and [...] Read more.

The use of chemical pesticides in agriculture has led to the development of resistant pest populations, posing a challenge to long-term pest management. This review aims to evaluate the scientific literature on the individual and combined use of baculoviruses with conventional chemical and biological insecticides to combat Plutella xylostella, Spodoptera exigua, and Spodoptera frugiperda in broccoli, tomato, and maize crops. Notable findings include that both individual Plutella xylostella nucleopolyhedrovirus (PxNPV) and the combination of Plutella xylostella granulovirus (PxGV) and azadirachtin at a low dose effectively control Plutella xylostella; both combinations of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) with emamectin benzoate and chlorfenapyr reduced resistance in Spodoptera exigua and increased the efficacy of the insecticides; and the combination of Spodoptera frugiperda nucleopolyhedrovirus (SfMNPV) and spinetoram is effective against Spodoptera frugiperda. Integrating baculoviruses into pest management strategies offers a promising approach to mitigate the adverse effects of chemical pesticides, such as resistance development, health risks, and environmental damage. However, there remains a broad spectrum of research opportunities regarding the use of baculoviruses in agriculture. Full article

(This article belongs to the Special Issue Applications of Baculoviruses: Expression Factories, Vaccines and VLPs, Gene Delivery Vectors, and Virus Genetics Models)

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16 pages, 2285 KiB

Open AccessArticle

Pegiviruses and Coronavirus: Biomolecular Prevalence and Phylogenetic Analysis of Strains Detected in Italian Horse Populations

by Ida Ricci, Francesca Rosone, Giulia Pacchiarotti, Giuseppe Manna, Antonella Cersini, Andrea Carvelli, Davide La Rocca, Elisa Cammalleri, Roberta Giordani, Silvia Tofani, Raffaella Conti, Pasquale Rombolà, Roberto Nardini, Carlo Alberto Minniti, Reno Caforio, Boris Linardi and Maria Teresa Scicluna

Viruses 2025, 17(8), 1076; https://doi.org/10.3390/v17081076 - 2 Aug 2025

Abstract

Equestrian sports play a significant economic role in the horse industry. In recent years, numerous equine viruses have emerged, among which are equine Pegiviruses and the re-emerging Equine coronavirus (ECoV). These viruses are distributed globally and primarily cause subclinical infections with unknown morbidity, [...] Read more.

Equestrian sports play a significant economic role in the horse industry. In recent years, numerous equine viruses have emerged, among which are equine Pegiviruses and the re-emerging Equine coronavirus (ECoV). These viruses are distributed globally and primarily cause subclinical infections with unknown morbidity, even if ECoV can occasionally induce febrile and diarrheic episodes. To broaden the data on the Italian equine population, a study was conducted to assess their prevalence in two distinct horse populations belonging to the Carabinieri Corps (CC) and the Italian Army (IA) of the Italian Armed Forces (IAF). Samples consisted of blood serum and rectal swabs of 436 horses collected within the national surveillance program for equine infectious anemia and gastrointestinal parasite monitoring and analyzed for Pegivirus (caballi and equi) and ECoV by Real-Time RT PCR. The prevalence detected were 6.56% and 3.53%, respectively, for Pegivirus caballi and equi for the IA, while for the CC, they were 10.13% and 0.84%. Only one sample tested positive for ECoV belonging to a horse of the CC. Phylogenetic analyses were carried out on the PCR-positive samples that were sequenced using Sanger protocols. Understanding the epidemiology of these viruses is essential for evaluating the implementation of effective prevention strategies. Full article

(This article belongs to the Section Animal Viruses)

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23 pages, 2284 KiB

Open AccessArticle

The Replication Function of Rabies Virus P Protein Is Regulated by a Novel Phosphorylation Site in the N-Terminal N Protein-Binding Region

by Ericka Tudhope, Camilla M. Donnelly, Ashish Sethi, Cassandra David, Nicholas Williamson, Murray Stewart, Jade K. Forwood, Paul R. Gooley and Gregory W. Moseley

Viruses 2025, 17(8), 1075; https://doi.org/10.3390/v17081075 - 1 Aug 2025

Abstract

The rabies virus (RABV) phosphoprotein (P protein) has multiple functions, including acting as the essential non-catalytic cofactor of the viral polymerase (L protein) for genome replication and transcription; the principal viral antagonist of the interferon (IFN)-mediated innate immune response; and the chaperone for [...] Read more.

The rabies virus (RABV) phosphoprotein (P protein) has multiple functions, including acting as the essential non-catalytic cofactor of the viral polymerase (L protein) for genome replication and transcription; the principal viral antagonist of the interferon (IFN)-mediated innate immune response; and the chaperone for the viral nucleoprotein (N protein). Although P protein is known to undergo phosphorylation by cellular kinases, the location and functions of the phosphorylation sites remains poorly defined. Here, we report the identification by mass-spectrometry (MS) of residues of P protein that are modified by phosphorylation in mammalian cells, including several novel sites. Analysis of P protein with phospho-mimetic and phospho-inhibitory mutations of three novel residues/clusters that were commonly identified by MS (Ser48, Ser183/187, Ser217/219/220) indicate that phosphorylation at each of these sites does not have a major influence on nuclear trafficking or antagonistic functions toward IFN signalling pathways. However, phosphorylation of Ser48 in the N-terminus of P protein impaired function in transcription/replication and in the formation of replication structures that contain complexes of P and N proteins, suggestive of altered interactions of these proteins. The crystal structure of P protein containing the S48E phospho-mimetic mutation indicates that Ser48 phosphorylation facilitates the binding of residues 41–52 of P protein into the RNA-binding groove of non-RNA-bound N protein (N⁰), primarily through the formation of a salt bridge with Arg434 of N protein. These data indicate that Ser48 modification regulates the cycling of P-N⁰ chaperone complexes that deliver N protein to RNA to enable transcription/replication, such that enhanced interaction due to S48E phospho-mimetic mutation reduces N protein delivery to the RNA, inhibiting subsequent transcription/replication processes. These data are, to our knowledge, the first to implicate phosphorylation of RABV P protein in conserved replication functions of the P gene. Full article

(This article belongs to the Section Animal Viruses)

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13 pages, 1085 KiB

Open AccessArticle

Comparative Endosymbiont Community Structures of Nonviruliferous and Rice Stripe Virus-Viruliferous Laodelphax striatellus (Hemiptera: Delphacidae) in Korea

by Jiho Jeon, Minhyeok Kwon, Bong Choon Lee and Eui-Joon Kil

Viruses 2025, 17(8), 1074; https://doi.org/10.3390/v17081074 - 1 Aug 2025

Abstract

Insects and their bacterial endosymbionts form intricate ecological relationships, yet their role in host–pathogen interactions are not fully elucidated. The small brown planthopper (Laodelphax striatellus), a polyphagous pest of cereal crops, acts as a key vector for rice stripe virus (RSV), [...] Read more.

Insects and their bacterial endosymbionts form intricate ecological relationships, yet their role in host–pathogen interactions are not fully elucidated. The small brown planthopper (Laodelphax striatellus), a polyphagous pest of cereal crops, acts as a key vector for rice stripe virus (RSV), a significant threat to rice production. This study aimed to compare the endosymbiont community structures of nonviruliferous and RSV-viruliferous L. striatellus populations using 16S rRNA gene sequencing with high-throughput sequencing technology. Wolbachia was highly dominant in both groups; however, the prevalence of other endosymbionts, specifically Rickettsia and Burkholderia, differed markedly depending on RSV infection. Comprehensive microbial diversity and composition analyses revealed distinct community structures between nonviruliferous and RSV-viruliferous populations, highlighting potential interactions and implications for vector competence and virus transmission dynamics. These findings contribute to understanding virus-insect-endosymbiont dynamics and could inform strategies to mitigate viral spread by targeting symbiotic bacteria. Full article

(This article belongs to the Special Issue Plant Viruses and Their Vectors: Epidemiology and Control)

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19 pages, 633 KiB

Open AccessReview

Predictive Factors and Clinical Markers of Recurrent Wheezing and Asthma After RSV Infection

by Luca Buttarelli, Elisa Caselli, Sofia Gerevini, Pietro Leuratti, Antonella Gambadauro, Sara Manti and Susanna Esposito

Viruses 2025, 17(8), 1073; https://doi.org/10.3390/v17081073 - 31 Jul 2025

Abstract

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory infections (ALRIs) in young children, especially bronchiolitis, with significant global health and economic impact. Increasing evidence links early-life RSV infection to long-term respiratory complications, notably recurrent wheezing and asthma. This narrative [...] Read more.

Respiratory syncytial virus (RSV) is a major cause of acute lower respiratory infections (ALRIs) in young children, especially bronchiolitis, with significant global health and economic impact. Increasing evidence links early-life RSV infection to long-term respiratory complications, notably recurrent wheezing and asthma. This narrative review examines these associations, emphasizing predictive factors and emerging biomarkers for risk stratification. Early RSV infection can trigger persistent airway inflammation and immune dysregulation, increasing the likelihood of chronic respiratory outcomes. Risk factors include severity of the initial infection, age at exposure, genetic susceptibility, prematurity, air pollution, and tobacco smoke. Biomarkers such as cytokines and chemokines are showing promise in identifying children at higher risk, potentially guiding early interventions. RSV-related bronchiolitis may also induce airway remodeling and promote Th2/Th17-skewed immune responses, mechanisms closely linked to asthma development. Advances in molecular profiling are shedding light on these pathways, suggesting novel targets for early therapeutic strategies. Furthermore, passive immunization and maternal vaccination offer promising approaches to reducing both acute and long-term RSV-related morbidity. A deeper understanding of RSV’s prolonged impact is essential to develop targeted prevention, enhance risk prediction, and improve long-term respiratory health in children. Future studies should aim to validate biomarkers and refine immunoprophylactic strategies. Full article

(This article belongs to the Special Issue RSV Epidemiological Surveillance: 2nd Edition)

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16 pages, 1622 KiB

Open AccessArticle

Simian Foamy Virus Prevalence and Evolutionary Relationships in Two Free-Living Lion Tamarin Populations from Rio de Janeiro, Brazil

by Déa Luiza Girardi, Thamiris Santos Miranda, Matheus Augusto Calvano Cosentino, Caroline Carvalho de Sá, Talitha Mayumi Francisco, Bianca Cardozo Afonso, Flávio Landim Soffiati, Suelen Sanches Ferreira, Silvia Bahadian Moreira, Alcides Pissinatti, Carlos Ramon Ruiz-Miranda, Valéria Romano, Marcelo Alves Soares, Mirela D’arc and André Felipe Santos

Viruses 2025, 17(8), 1072; https://doi.org/10.3390/v17081072 - 31 Jul 2025

Abstract

Simian foamy virus (SFV) is a retrovirus that infects primates. However, epidemiological studies of SFV are often limited to captive populations. The southeastern Brazilian Atlantic Forest is home to both an endemic, endangered species, Leontopithecus rosalia, and an introduced species, Leontopithecus chrysomelas [...] Read more.

Simian foamy virus (SFV) is a retrovirus that infects primates. However, epidemiological studies of SFV are often limited to captive populations. The southeastern Brazilian Atlantic Forest is home to both an endemic, endangered species, Leontopithecus rosalia, and an introduced species, Leontopithecus chrysomelas, to which no data on SFV exist. In this study, we assessed the molecular prevalence of SFV, their viral load, and their phylogenetic relationship in these two species of primates. Genomic DNA was extracted from 48 oral swab samples of L. chrysomelas and 102 of L. rosalia. Quantitative PCR (qPCR) was performed to diagnose SFV infection and quantify viral load. SFV prevalence was found to be 23% in L. chrysomelas and 33% in L. rosalia. No age-related differences in prevalence were observed; however, L. rosalia showed a higher mean viral load (3.27 log10/10⁶ cells) compared to L. chrysomelas (3.03 log10/10⁶ cells). The polymerase gene sequence (213 pb) of L. rosalia (SFVlro) was clustered within a distinct SFV lineage found in L. chrysomelas. The estimated origin of SFVlro dated back approximately 0.0836 million years ago. Our study provides the first molecular prevalence data for SFV in free-living Leontopithecus populations while offering insights into the complex evolutionary history of SFV in American primates. Full article

(This article belongs to the Special Issue Spumaretroviruses: Research and Applications)

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10 pages, 1037 KiB

Open AccessConference Report

Thirteenth International Foamy Virus Conference—Meeting Report

by Arifa S. Khan, Martin Löchelt, Florence Buseyne, Ottmar Herchenröder, Dirk Lindemann, William M. Switzer, André F. A. Santos and Marcelo A. Soares

Viruses 2025, 17(8), 1071; https://doi.org/10.3390/v17081071 - 31 Jul 2025

Abstract

The 13th International Foamy Virus (FV) Conference was held from 8 to 10 November 2023 at the BioParque/Zoological Garden in Rio de Janeiro, Brazil. This was the first conference on spumaretroviruses to be held in the Southern Hemisphere and in the unique environment [...] Read more.

The 13th International Foamy Virus (FV) Conference was held from 8 to 10 November 2023 at the BioParque/Zoological Garden in Rio de Janeiro, Brazil. This was the first conference on spumaretroviruses to be held in the Southern Hemisphere and in the unique environment of the rainforest. New developments and current perspectives in FV research were presented. Highlights of the conference included the structural biology of the envelope protein (Env) and insights into its function and evolution, epidemiologic identification of Amazonian indigenous people with a high prevalence of simian FV (SFV) infections, investigations of virus biology and genomics using synthetic FV DNAs, studies of humoral immune response, and development and applications of SFV vectors. The last day of the meeting was a special tour of the Centro de Primatologia do Rio de Janeiro, located northeast of Rio de Janeiro amidst the protected rainforest, where New World primate hosts of spumaretroviruses are rescued and studied. Our report summarizes the meeting highlights and outcomes for future discussions. Full article

(This article belongs to the Special Issue Spumaretroviruses: Research and Applications)

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19 pages, 8583 KiB

Open AccessArticle

Development and Immunogenic Evaluation of a Recombinant Vesicular Stomatitis Virus Expressing Nipah Virus F and G Glycoproteins

by Huijuan Guo, Renqiang Liu, Dan Pan, Yijing Dang, Shuhuai Meng, Dan Shan, Xijun Wang, Jinying Ge, Zhigao Bu and Zhiyuan Wen

Viruses 2025, 17(8), 1070; https://doi.org/10.3390/v17081070 - 31 Jul 2025

Abstract

Nipah virus (NiV) is a highly pathogenic bat-borne zoonotic pathogen that poses a significant threat to human and animal health, with fatality rates exceeding 70% in some outbreaks. Despite its significant public health impact, there are currently no licensed vaccines or specific therapeutics [...] Read more.

Nipah virus (NiV) is a highly pathogenic bat-borne zoonotic pathogen that poses a significant threat to human and animal health, with fatality rates exceeding 70% in some outbreaks. Despite its significant public health impact, there are currently no licensed vaccines or specific therapeutics available. Various virological tools—such as reverse genetics systems, replicon particles, VSV-based pseudoviruses, and recombinant Cedar virus chimeras—have been widely used to study the molecular mechanisms of NiV and to support vaccine development. Building upon these platforms, we developed a replication-competent recombinant vesicular stomatitis virus (rVSVΔG-eGFP-NiV_BD F/G) expressing NiV attachment (G) and fusion (F) glycoproteins. This recombinant virus serves as a valuable tool for investigating NiV entry mechanisms, cellular tropism, and immunogenicity. The virus was generated by replacing the VSV G protein with NiV F/G through reverse genetics, and protein incorporation was confirmed via immunofluorescence and electron microscopy. In vitro, the virus exhibited robust replication, characteristic cell tropism, and high viral titers in multiple cell lines. Neutralization assays showed that monoclonal antibodies HENV-26 and HENV-32 effectively neutralized the recombinant virus. Furthermore, immunization of golden hamsters with inactivated rVSVΔG-eGFP-NiV_BD F/G induced potent neutralizing antibody responses, demonstrating its robust immunogenicity. These findings highlight rVSVΔG-eGFP-NiV_BD F/G as an effective platform for NiV research and vaccine development. Full article

(This article belongs to the Section Animal Viruses)

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31 pages, 1537 KiB

Open AccessReview

Hepatitis C Virus: Epidemiological Challenges and Global Strategies for Elimination

by Daniela Toma, Lucreția Anghel, Diana Patraș and Anamaria Ciubară

Viruses 2025, 17(8), 1069; https://doi.org/10.3390/v17081069 - 31 Jul 2025

Abstract

The global elimination of hepatitis C virus (HCV) has been prioritized by the World Health Organization (WHO) as a key public health target, with a deadline set for 2030. This initiative aims to significantly reduce both new infection rates and HCV-associated mortality. A [...] Read more.

The global elimination of hepatitis C virus (HCV) has been prioritized by the World Health Organization (WHO) as a key public health target, with a deadline set for 2030. This initiative aims to significantly reduce both new infection rates and HCV-associated mortality. A major breakthrough in achieving this goal has been the development of direct-acting antiviral agents (DAAs), which offer cure rates exceeding 95%, along with excellent safety and tolerability. Nevertheless, transmission via parenteral routes continues to be the dominant pathway, particularly among high-risk groups, such as individuals who inject drugs, incarcerated populations, those exposed to unsafe medical practices, and healthcare professionals. Identifying, monitoring, and delivering tailored interventions to these groups is crucial to interrupt ongoing transmission and to reduce the burden of chronic liver disease. On a global scale, several nations have demonstrated measurable progress toward HCV elimination, with some nearing the targets set by WHO. These achievements have largely resulted from context-adapted policies that enhanced diagnostic and therapeutic access while emphasizing outreach to vulnerable communities. This review synthesizes current advancements in HCV prevention and control and proposes strategic frameworks to expedite global elimination efforts. Full article

(This article belongs to the Special Issue Advancing Hepatitis Elimination: HBV, HDV, and HCV)

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20 pages, 2586 KiB

Open AccessArticle

Virome Survey of Banana Plantations and Surrounding Plants in Malawi

by Johnny Isaac Gregorio Masangwa, Coline Temple, Johan Rollin, François Maclot, Serkan Önder, Jamestone Kamwendo, Elizabeth Mwafongo, Philemon Moses, Isaac Fandika and Sebastien Massart

Viruses 2025, 17(8), 1068; https://doi.org/10.3390/v17081068 - 31 Jul 2025

Abstract

A virome survey of banana plantations and their surrounding plants was carried out at nation-wide level in Malawi using virion associated nucleic acids (VANA) high throughput sequencing (HTS) on pooled samples and appropriate alien controls. In total, 366 plants were sequenced, and 23 [...] Read more.

A virome survey of banana plantations and their surrounding plants was carried out at nation-wide level in Malawi using virion associated nucleic acids (VANA) high throughput sequencing (HTS) on pooled samples and appropriate alien controls. In total, 366 plants were sequenced, and 23 plant virus species were detected, three species on banana (275 plants) and 20 species in surrounding plants (91 plants). Two putative novel virus species; ginger tymo-like virus and pepper derived totivirus were detected and confirmed by RT-PCR on ginger and pepper. Nine known virus species and detected a host plant was identified for two of them. No viral exchange between banana and surrounding plants was observed. Results from the VANA protocol, applied to pooled banana samples, were compared with previous targeted PCR results obtained from individual banana samples. HTS test detected better BanMMV than IC-(RT)-PCR on individual samples (better inclusivity) but detected with much lower sensitivity BBTV and BSV species, often with less than 10 reads per sample. Detection of novel and known viruses and new host plants calls for strengthened sanitory and phytosanitory measures within and beyond banana production systems. Our research confirms that HTS sensitivity depends on sampling, pooling protocol and targeted virus species. Full article

(This article belongs to the Section Viruses of Plants, Fungi and Protozoa)

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Graphical abstract

18 pages, 4051 KiB

Open AccessArticle

Chimeric Vesicular Stomatitis Virus Bearing Western Equine Encephalitis Virus Envelope Proteins E2-E1 Is a Suitable Surrogate for Western Equine Encephalitis Virus in a Plaque Reduction Neutralization Test

by Kerri L. Miazgowicz, Bailey E. Maloney, Melinda A. Brindley, Mattie Cassaday, Raegan J. Petch, Paul Bates, Aaron C. Brault and Amanda E. Calvert

Viruses 2025, 17(8), 1067; https://doi.org/10.3390/v17081067 - 31 Jul 2025

Abstract

In December 2023, infections of western equine encephalitis virus (WEEV) within Argentina were reported to the World Health Organization (WHO). By April 2024, more than 250 human infections, 12 of which were fatal, and 2500 equine infections were identified in South America. Laboratory [...] Read more.

In December 2023, infections of western equine encephalitis virus (WEEV) within Argentina were reported to the World Health Organization (WHO). By April 2024, more than 250 human infections, 12 of which were fatal, and 2500 equine infections were identified in South America. Laboratory diagnosis and surveillance in affected countries were hindered by a lack of facilities equipped with BSL-3 laboratories, as confirmatory serodiagnosis for WEEV requires live virus in the plaque reduction neutralization test (PRNT). To expand serodiagnosis for WEEV in the Americas, we developed a virus chimera composed of vesicular stomatitis virus (VSV) engineered to display the E2-E1 glycoproteins of WEEV (VSV/WEEV) in place of the VSV glycoprotein (G). PRNT₉₀ and IC₉₀ values of parental WEEV and VSV/WEEV were analogous using sera collected from mice, horses, and chickens. VSV/WEEV rapidly formed plaques with clear borders and reduced the assay readout time by approximately 8 h compared to the parental virus. Overall, we demonstrate that chimeric VSV/WEEV is a suitable surrogate for WEEV in a diagnostic PRNT. Use of chimeric VSV/WEEV in place of authentic WEEV will dramatically expand testing capacity by enabling PRNTs to be performed at BSL-2 containment, while simultaneously decreasing the health risk to testing personnel. Full article

(This article belongs to the Special Issue Mosquito-Borne Encephalitis Viruses)

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