Journal Description
Viruses
Viruses
is a peer-reviewed, open access journal of virology, published monthly online by MDPI. The Spanish Society for Virology (SEV), Canadian Society for Virology (CSV), Italian Society for Virology (SIV-ISV), Australasian Virology Society (AVS), Brazilian Society for Virology (BSV) and Global Virus Network (GVN) are affiliated with Viruses and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), PubMed, MEDLINE, PMC, Embase, PubAg, and other databases.
- Journal Rank: JCR - Q2 (Virology) / CiteScore - Q1 (Virology/Infectious Diseases)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 17.2 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2025).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Journal Cluster of Microbiology: Acta Microbiologica Hellenica, Applied Microbiology, Bacteria, Journal of Fungi, Microorganisms, Microbiology Research, Pathogens and Viruses.
Impact Factor:
3.5 (2024);
5-Year Impact Factor:
3.7 (2024)
Latest Articles
Phage Therapy Beyond Static Pharmaceuticals: A Framework for Controlled Evolutionary Platforms
Viruses 2026, 18(5), 534; https://doi.org/10.3390/v18050534 - 1 May 2026
Abstract
Rising antimicrobial resistance has revived global interest in phage therapy, yet its transition to standard clinical practice remains slow. This challenge is not solely due to a lack of efficacy. Instead, we face a fundamental conceptual barrier caused by an “evaluation mismatch.” Traditional
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Rising antimicrobial resistance has revived global interest in phage therapy, yet its transition to standard clinical practice remains slow. This challenge is not solely due to a lack of efficacy. Instead, we face a fundamental conceptual barrier caused by an “evaluation mismatch.” Traditional regulations treat phages as static chemical molecules—like taking a “snapshot.” However, biologically, phages are dynamic, evolving populations—more like a living “movie.” In this review, we use Schrödinger’s cat metaphor to explain this reality: phage variability is not a defect, but an essential feature. To bridge this gap, we propose a Controlled Evolutionary Platform. By distinguishing between a fixed “Safety Core” and a fluctuating “Adaptive Periphery,” we can manage viral evolution rather than trying to stop it. Ultimately, to integrate phages into modern medicine, we must redefine “consistency”: shifting our focus from preserving a fixed genetic sequence to ensuring the reliable performance of population dynamics.
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Open AccessReview
Minimal Genome, Maximal Effect: How Polyomavirus Genomes Are Capable of Complex Pathogenesis
by
Michaela Lano and Barry Milavetz
Viruses 2026, 18(5), 533; https://doi.org/10.3390/v18050533 - 1 May 2026
Abstract
The Polyomaviridae family contains members known for achieving high seroprevalence within their target species despite a limited genomic economy. Minimalism, by definition, allows for the clarification and streamlining of purpose via the removal of unnecessary or distracting components. Among viruses, Simian Vacuolating Virus
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The Polyomaviridae family contains members known for achieving high seroprevalence within their target species despite a limited genomic economy. Minimalism, by definition, allows for the clarification and streamlining of purpose via the removal of unnecessary or distracting components. Among viruses, Simian Vacuolating Virus 40 (SV40) and other polyomaviruses are master minimalists, achieving efficient replication and persistence with compact genomes of approximately 5 kb in length. This review examines how polyomaviruses employ limited genetic material and simple structure to participate in complex functions and interactions, highlighting minimalism as both an evolutionary and functional advantage. Polyomaviruses make the most of their compact genomes in each stage of the viral lifecycle through the production of multifunctional early proteins and cis-regulatory elements, utilization of alternative splicing and host infrastructure, and organization of compact structural proteins. This allows for the successful replication and proliferation of virions while also reducing evolutionary pressure and promoting host immune evasion. Examination of the implications of polyomaviral minimalism illustrates that genome economy is not a constraint, but rather a driver of biological sophistication.
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(This article belongs to the Special Issue Polyomavirus)
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Open AccessArticle
Isolation and Genomic Characterization of a Lytic Bacteriophage Against Multidrug-Resistant E. coli
by
Ramesh Kumpatla, Vinaya Kruthi Vitala and Arunasree M. Kalle
Viruses 2026, 18(5), 532; https://doi.org/10.3390/v18050532 - 30 Apr 2026
Abstract
Antimicrobial resistance (AMR) has become a major concern in the treatment of bacterial infections, and bacteriophage therapy has emerged as a promising alternative to antibiotics. Bacteriophages are highly specific to their bacterial hosts; hence, isolating phages indigenous to a specific region offers a
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Antimicrobial resistance (AMR) has become a major concern in the treatment of bacterial infections, and bacteriophage therapy has emerged as a promising alternative to antibiotics. Bacteriophages are highly specific to their bacterial hosts; hence, isolating phages indigenous to a specific region offers a significant advantage against various pathogen strains. We have isolated a cocktail of bacteriophages against pathogenic E. coli from sewage water at a primary healthcare centre. Characterisation of the isolated phages demonstrated their stability across a broad pH and temperature range, strong lytic activity, and effective biofilm degradation, with no cross-reactivity with Staphylococcus aureus (S. aureus). Genomic analysis and phylogenetic studies indicated that the largest phage (by genome size) in the cocktail belongs to the genus Vequintavirus (myoviruses, rV5-like phages), and its genome sequence has been deposited in NCBI (Accession ID: PX741096). The phage genome was linear, with headful (PAC) packaging, encoded lysis proteins, and lacked antibiotic-resistant or major lysogeny-associated genes, collectively suggesting a lytic lifestyle. These findings emphasize the therapeutic potential of rV5-like phages and underscore the critical need to establish phage banks in India to improve disease management.
Full article
(This article belongs to the Special Issue Phage Cocktails: Promising Approaches Against Infections)
Open AccessSystematic Review
Methodological Approaches to Dengue Virus Detection in Wastewater: A Systematic Review and Meta-Analysis of Positivity Rate
by
Siti Aishah Rashid, Sakshaleni Rajendiran, Nurul Farehah Shahrir, Nurul Athirah Naserrudin, Terence Tan Yew Chin, Janice Chan Sue Wen, Imanul Hassan Abdul Shukor and Nurul Amalina Khairul Hasni
Viruses 2026, 18(5), 531; https://doi.org/10.3390/v18050531 - 30 Apr 2026
Abstract
Dengue fever, with a high proportion of asymptomatic infections, poses a major global public health challenge that traditional surveillance systems frequently underestimate. Wastewater-based epidemiology (WBE) has emerged as a promising approach to monitoring infectious diseases beyond enteric viruses. Dengue virus is shed in
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Dengue fever, with a high proportion of asymptomatic infections, poses a major global public health challenge that traditional surveillance systems frequently underestimate. Wastewater-based epidemiology (WBE) has emerged as a promising approach to monitoring infectious diseases beyond enteric viruses. Dengue virus is shed in urine, feces, and saliva, providing a biological basis for wastewater detection alongside clinical surveillance. This systematic review and meta-analysis synthesize current evidence on dengue virus (DENV) detection in wastewater and evaluate methodological factors influencing detection success in WBE. A systematic literature search using selected databases and predetermined keywords, followed by eligibility screening, resulted in ten studies being included, covering community surveillance and experimental trials. DENV ribonucleic acids (RNA) were most consistently detected and enriched in wastewater solids, indicating this matrix as the most reliable for surveillance. Among concentration methods, ultrafiltration achieved the highest viral recovery efficiency, while reverse transcription digital polymerase chain reaction (RT-dPCR) demonstrated superior sensitivity and precision compared to those of reverse transcription quantitative polymerase chain reaction (RT-qPCR), particularly at low viral concentrations. Storage at −80 °C was critical for preserving RNA integrity. The meta-analysis yielded a pooled DENV positivity rate of 24% (95% CI: 20–28%) after exclusion of outliers. Overall, solid-phase analysis combined with RT-dPCR represents the most sensitive methodological approach across the included studies. Harmonized protocols are needed to support future translation of dengue WBE into community surveillance as current evidence mainly demonstrates methodological feasibility and provides a technical foundation for future public health integration. Therefore, further longitudinal and multi-site validation is required to establish its broader applicability for dengue surveillance.
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(This article belongs to the Special Issue Viral Dynamics in Aquatic Environments: Pathogens, Transmission and Impacts)
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Open AccessArticle
Respiratory Syncytial Virus-Associated Severe Acute Respiratory Infections in Hospitalized Patients at a University Hospital Center in Rabat, Morocco: An Epidemiological Overview
by
Ghizlane El-Amin, Naima El Hafidi, Soumia Benchekroun, Mahraoui Chafiq, Amal Zouaki, Nora Touyar, Najat Bouihat, Salma Ech-Cherif El Kettani, Saad Harrak, Larbi Ed-Dafali, Aziza Bentalha, Mustapha Alilou, Hamza El Hamzaoui, Amina Barkat, Ilham Elouardighi, Tarek Dendane, Khalid Abidi, Jihane Bel Ayachi, Naoufal Madani, Redouane Abouqal, Hicham Harmouche, Mouna Maamar, Rachid El Jaoudi, Mourad Feindiri, Myriam Seffar, Mohamed Bouskraoui and Hakima Kabbajadd
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Viruses 2026, 18(5), 530; https://doi.org/10.3390/v18050530 - 30 Apr 2026
Abstract
Respiratory syncytial virus (RSV) imposes a substantial burden of severe acute respiratory infection (SARI), especially in young children and the elderly. Methods: We describe RSV epidemiology among hospitalized SARI patients at the Ibn Sina University Hospital Center (Rabat, Morocco) from 1 January 2021,
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Respiratory syncytial virus (RSV) imposes a substantial burden of severe acute respiratory infection (SARI), especially in young children and the elderly. Methods: We describe RSV epidemiology among hospitalized SARI patients at the Ibn Sina University Hospital Center (Rabat, Morocco) from 1 January 2021, to 31 December 2025, using multiplex PCR (BioFire® RP2.1plus or Xpert® SARS-CoV-2/Flu/RSV). Results: Among 4604SARI samples, RSV prevalence was 16.1% (739/4604), predominantly pediatric (88.6%, p < 0.001), with peak burden in infants <6 months (70.4% of cases, p < 0.001). Pediatric prevalence was 28.3% (655/2316) vs. 3.8% (84/2204) in adults (p < 0.001), with predominance in the elderly ≥60 years (51/1041, 4.9%). Co-infections occurred in 46.7% (310/665) of FilmArray-tested positives (total = 665), led by rhinovirus/enterovirus (198/310, 63.9%), and were significantly higher in children (48.5%, p < 0.001). RSV peaked in winter (51.6%), except for summer dominance in 2021 (52.5%), reflecting COVID-19 non-pharmaceutical intervention effects. Conclusions: These data establish Morocco’s first comprehensive RSV surveillance baseline, highlighting post-pandemic epidemiological shifts. As maternal vaccines and monoclonal antibodies emerge, these data inform optimal implementation in low- and middle-income countries (LMICs).
Full article
(This article belongs to the Special Issue RSV Epidemiological Surveillance: 3rd Edition)
Open AccessArticle
Changing Patterns of HCV Genotype Distribution in a Migration-Affected Region of Turkey: A Retrospective Hospital-Based Study (2014–2021)
by
Yasemin Ay Altintop and Esma Saatçi
Viruses 2026, 18(5), 529; https://doi.org/10.3390/v18050529 - 30 Apr 2026
Abstract
Hepatitis C virus (HCV) infection is still a major worldwide health concern. It is distinguished by a high degree of genetic variation that affects the course of the illness and the effectiveness of treatment. The epidemiological profile of HCV is prone to rapid
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Hepatitis C virus (HCV) infection is still a major worldwide health concern. It is distinguished by a high degree of genetic variation that affects the course of the illness and the effectiveness of treatment. The epidemiological profile of HCV is prone to rapid change in areas where there is significant human migration, like Turkey. The purpose of this study was to evaluate the impact of long-term migration on local viral diversity by analyzing the distribution and temporal trends of HCV genotypes among Turkish citizens and asylum seekers in Kayseri, Turkey, over an eight-year period. From January 2014 to December 2021. 1173 HCV RNA-positive patients at Kayseri City Training and Research Hospital were the subject of a retrospective analysis. Genotypes were determined using the Abbott RealTime HCV Genotype II assay and Montania 4896 assay (Anatolia Geneworks, Türkiye). The most prevalent genotypes were Genotype 1b (48.3%, 95% CI: 45.5–51.2%), Genotype 4 (25.0%, 95% CI: 22.5–27.5%), and Genotype 1a (10.3%, 95% CI: 8.6–12.1%). Turkish patients exhibited the highest prevalence of Genotype 1b (98.2%), while asylum seekers demonstrated greater relative burdens of Genotype 4 (8.5% of total GT4) and Genotype 5 (83.3% of total GT5). Genotype 3a emerged in 2018, with a predominance in males (73.9%). The Cochran–Armitage trend test revealed statistically significant increasing trends for Genotype 3 (Z = 3.572, p = 0.0004) and Genotype 3a (Z = 2.600, p = 0.009). This eight-year retrospective study demonstrates that the HCV genotype distribution in Kayseri has undergone significant changes in the context of migration and demographic shifts. The statistically significant increasing trends of Genotypes 3 and 3a, particularly among younger male populations, suggest evolving transmission dynamics. These findings underscore the necessity of demographically targeted and culturally appropriate screening and treatment strategies for both resident and migrant populations to achieve HCV elimination goals.
Full article
(This article belongs to the Special Issue Hepatitis Virus Genetic Heterogeneity: Impact in Epidemiology and Clinical Pathology)
Open AccessArticle
Association of Initial Chest CT Findings, CT Severity Score and Clinical Parameters with ICU Admission in Hospitalized COVID-19 Patients
by
Aleksandra Milenkovic, Simon Nikolic, Jelena Aritonovic Pribakovic, Branislava Radovic, Aleksandra Ilic, Milica Stevanovic, Sara Kovacevic, Kristina Bulatovic, Jelena Milovanovic, Arijeta Kostic and Aleksandra Janicevic
Viruses 2026, 18(5), 528; https://doi.org/10.3390/v18050528 - 30 Apr 2026
Abstract
The aim of this study was to evaluate the association between baseline clinical and CT characteristics and to identify factors associated with intensive care unit (ICU) admission in hospitalized COVID-19 patients. This retrospective study included 176 adult patients with laboratory-confirmed SARS-CoV-2 infection hospitalized
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The aim of this study was to evaluate the association between baseline clinical and CT characteristics and to identify factors associated with intensive care unit (ICU) admission in hospitalized COVID-19 patients. This retrospective study included 176 adult patients with laboratory-confirmed SARS-CoV-2 infection hospitalized at the COVID Hospital of the Clinical Hospital Center Kosovska Mitrovica during 2021–2022 (Delta and Omicron variants). Patients were divided into two groups according to intensive care unit requirement: those treated in a general inpatient ward (No ICU) and those requiring ICU admission (ICU group). Demographic and clinical characteristics, lifestyle factors, CT findings, CT severity score (CTSS) values, and therapeutic interventions were compared between groups. Of the total cohort, 113 patients (64%) were hospitalized in a general inpatient ward, while 63 (36%) required intensive care unit admission. Independent predictors of ICU admission identified in the multivariate logistic regression analysis were obesity (B = 2.96, p < 0.001), dyspnea (B = 1.51, p = 0.041), higher CT severity score (B = 0.68, p < 0.001), and lower glucose levels (B = −0.27, p = 0.014). Furthermore, for each one-point increase in the CTSS, the odds of ICU admission nearly doubled (OR = 1.97). Total CT score values above the cut-off point (15.0) demonstrated significant reliability in discriminating the need for ICU transfer in patients with COVID-19. These findings suggest that combined clinical and radiological assessment at hospital admission may facilitate early identification of patients at high risk of requiring ICU care, with the CT severity score representing the strongest radiological predictor.
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(This article belongs to the Special Issue Emerging Concepts in SARS-CoV-2 Biology and Pathology, 3rd Edition)
Open AccessArticle
Enterovirus Testing in Hand, Foot, and Mouth Disease and Herpangina: A Highly Sensitive Single-Round VP4–VP2 Reverse-Transcription Polymerase Chain Reaction Assay with a Redesigned Reverse Primer
by
Tsuguto Fujimoto, Miki Ogi, Kazuhiro Kitakawa, Takako Sano, Yorihiro Nishimura, Kouichi Kitamura, Minami Kikuchi Ueno and Minetaro Arita
Viruses 2026, 18(5), 527; https://doi.org/10.3390/v18050527 - 30 Apr 2026
Abstract
Molecular typing of enteroviruses (EVs) is essential for surveillance of hand, foot, and mouth disease (HFMD). Conventional reverse-transcription polymerase chain reaction (RT-PCR) targeting the VP4–VP2 region can be insufficiently sensitive, reducing the detectability of Enterovirus A (EV-A). We developed a single-round RT-PCR assay
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Molecular typing of enteroviruses (EVs) is essential for surveillance of hand, foot, and mouth disease (HFMD). Conventional reverse-transcription polymerase chain reaction (RT-PCR) targeting the VP4–VP2 region can be insufficiently sensitive, reducing the detectability of Enterovirus A (EV-A). We developed a single-round RT-PCR assay using a modified reverse primer design (C3R) for rapid EV detection and genotyping. Sensitivity was evaluated using EV-A71 and poliovirus type 1 reference strains, across 60 EV-positive clinical specimens. The C3R-based assay showed ~1000-fold higher sensitivity for EV-A71 than for conventional assays (limit of detection: 6.6 copies/reaction). The assay detected 98.3% (59/60) of clinical specimens in a single-round format, whereas the conventional assay detected only 45.0% (27/60) and showed a marked decline in detection at higher Ct values. The C3R-based assay maintained complete detection for clinical specimens with Ct values below 40. The majority of the amplified products yielded high-quality sequences suitable for genotyping. This C3R-based RT-PCR overcomes sensitivity limitations of existing protocols and provides reliable genotyping from low-viral-load specimens, supporting its use in routine diagnostics and large-scale HFMD surveillance.
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(This article belongs to the Special Issue An Update on Enterovirus Research, 2nd Edition)
Open AccessArticle
Isolation of Bacteriophages with Lytic Activity from Biological Samples of Left Ventricular Assist Device Patients: An In Vitro Study
by
Balazs Sax, Adam Koppanyi, Katalin Kristof, Akos Kiraly, Gyula Prinz, Istvan Hartyanszky, Gergely Gyorgy Nagy, Istvan Nemet, Fanni Temesvari-Kis, Balazs Kiss and Bela Merkely
Viruses 2026, 18(5), 526; https://doi.org/10.3390/v18050526 - 30 Apr 2026
Abstract
Percutaneous cable infection of left ventricular assist device (LVAD) patients is a significant source of morbidity, often caused by biofilm-producing or multidrug-resistant bacteria. We hypothesized that bacteriophage viruses can be identified from biological samples of patients with active driveline infection. Six patients with
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Percutaneous cable infection of left ventricular assist device (LVAD) patients is a significant source of morbidity, often caused by biofilm-producing or multidrug-resistant bacteria. We hypothesized that bacteriophage viruses can be identified from biological samples of patients with active driveline infection. Six patients with local percutaneous lead infections were enrolled. Microbiological samples were collected from the infected wound and other skin regions. The isolated viral strains and phages from wastewater samples were then tested against the pathogen bacterial cultures in vitro. Biofilm disruption assay and genetic analysis of the strains were also performed. Bacteriophages with lytic activity could be identified from samples of two patients. One patient contained four strains showing strong efficacy against his own Staphylococcus epidermidis. Furthermore, this bacterium was susceptible to phages identified from another patient and strains from wastewater samples. Genomic analysis suggested lysogenic lifestyle of the phages. However, none of them have shown any microbiological signs of lysogeny. In conclusion, we have been able to prove in vitro lytic activity of bacteriophages originating from the same LVAD patient. We also found effective phages in biological samples of other patients and wastewater samples, suggesting that patients implanted in the same center may share bacteriophage flora.
Full article
(This article belongs to the Special Issue Bacteriophages and Biofilms 2026)
Open AccessBrief Report
Emergence and Evolution of Triple Reassortant Highly Pathogenic Avian Influenza A(H5N1) Virus, Argentina, 2025
by
Estefania Benedetti, Maria Carolina Artuso, Alex Byrne, Maria de Belen Garibotto, Martín Avaro, Luana Piccini, Ariana Chamorro, Marcelo Sciorra, Vanina Marchione, Mara Russo, Maria Elena Dattero, Erika Macias Machicado, Monica Galiano, Nicola Lewis and Andrea Pontoriero
Viruses 2026, 18(5), 525; https://doi.org/10.3390/v18050525 - 30 Apr 2026
Abstract
The H5N1 subtype of highly pathogenic avian influenza (HPAI) poses a major zoonotic threat due to its high fatality rate and capacity for cross species transmission. In early 2025, Argentina detected a novel triple reassortant A(H5N1) virus in Chaco Province, combining Eurasian, North
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The H5N1 subtype of highly pathogenic avian influenza (HPAI) poses a major zoonotic threat due to its high fatality rate and capacity for cross species transmission. In early 2025, Argentina detected a novel triple reassortant A(H5N1) virus in Chaco Province, combining Eurasian, North American, and South American lineage segments. Genomic analyses of subsequent outbreaks in Buenos Aires and Entre Ríos confirmed persistence of this reassortant and additional HA substitutions (T204K, P251S) potentially linked to increased mammalian receptor affinity. Although PB2 sequences lacked canonical mammalian-adaptive markers (E627K, Q591K, D701N), all contained I292M, a mutation associated with human adaptation. Phylogenetic analyses revealed distinct genotypes and increasing divergence. These findings indicate ongoing viral evolution and adaptation within Argentina, emphasizing the urgent need for sustained genomic surveillance, timely data sharing, and integrated One Health strategies to mitigate zoonotic and socioeconomic risks associated with H5N1 spread in South America.
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(This article belongs to the Special Issue Molecular Epidemiology, Evolution, and Transmission of Avian Influenza Viruses)
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Open AccessArticle
Dual Aspect of the Pandemic on the African Continent: Viral Distribution and Shifting Demographic Susceptibility to SARS-CoV-2
by
Julia Cyrielle Andeko, Sonia Etenna Lekana-Douki, Gabriel Falque, Nadine N’dilimabaka and Jean-Bernard Lekana-Douki
Viruses 2026, 18(5), 524; https://doi.org/10.3390/v18050524 - 30 Apr 2026
Abstract
SARS-CoV-2, the causative agent of COVID-19, emerged in late 2019 and rapidly developed into a global health crisis. In this study, we analysed 173,194 SARS-CoV-2 genomes from the GISAID database to explore the intra-continental dynamics and distribution of variants across Africa between 2020
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SARS-CoV-2, the causative agent of COVID-19, emerged in late 2019 and rapidly developed into a global health crisis. In this study, we analysed 173,194 SARS-CoV-2 genomes from the GISAID database to explore the intra-continental dynamics and distribution of variants across Africa between 2020 and 2024. We have identified 1377 distinct lineages, which were classified by clade to assess associations with infection and mortality rate. So, we conducted a Shannon entropy analysis to confirm the diversity and we applied a Correspondence Analysis (CA). Our findings revealed that one of the deadliest in Africa during the Delta wave, lineage AY.45 predominated in the South Africa cluster, whereas AY.34.1 drove transmission in the Atlantic West Africa cluster, underscoring regional heterogeneity. Furthermore, early in the pandemic, men exhibited a 39% higher risk of infection compared to women (aOR: 1.39, 95% CI [1.34–1.45]), particularly in association with clade G. By contrast, later stages were dominated by clade GRA, which disproportionately affected the elderly (≥70 years; aOR: 1.39, 95% CI [1.33–1.45]) and children (0–9 years; aOR: 1.26, 95% CI [1.20–1.33]). Our analysis highlighted that the pandemic on the African continent unfolded as a mosaic of epidemics shaped by diverse variants and regional epidemiological contexts. These findings emphasize the importance of genomic surveillance to capture local epidemic signatures and inform region-specific public health strategies.
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(This article belongs to the Special Issue Emerging Variants of SARS-CoV-2)
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Open AccessReview
A Review of Human Immunodeficiency Virus and Hepatitis B Virus Co-Infection in Botswana
by
Linda Mpofu-Dobo, Kebaneilwe Lebani, Jason T. Blackard, Sikhulile Moyo, Motswedi Anderson and Simani Gaseitsiwe
Viruses 2026, 18(5), 523; https://doi.org/10.3390/v18050523 - 30 Apr 2026
Abstract
Hepatitis B virus (HBV) remains a leading cause of chronic liver disease worldwide, contributing to cirrhosis and hepatocellular carcinoma. Sub-Saharan Africa accounts for an estimated 68% of incident HBV infections, where co-infection with human immunodeficiency virus (HIV) is common and associated with poorer
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Hepatitis B virus (HBV) remains a leading cause of chronic liver disease worldwide, contributing to cirrhosis and hepatocellular carcinoma. Sub-Saharan Africa accounts for an estimated 68% of incident HBV infections, where co-infection with human immunodeficiency virus (HIV) is common and associated with poorer clinical outcomes. In Botswana, limited HBV screening and the absence of established HBV management guidelines persist despite reported HIV-HBV co-infection rates ranging from 1.1% to 10.6%. This scoping review aimed to summarise existing research on HBV and HIV-HBV co-infection in Botswana and assess clinical and policy implications. Following PRISMA methodology, searches were conducted across PubMed, Google Scholar, Semantic Scholar, and Consensus databases. Thirty eligible peer-reviewed studies were identified and evaluated for prevalence data, virological characteristics, genotypes, mutations, treatment outcomes, vaccination programs, and the availability of guidelines. Findings indicate intermediate-to-high HBV and HIV-HBV disease burden, substantial occult HBV infection, and gaps in diagnostic and preventive practices. The lack of routine screening, deficient infant birth-dose and adult vaccination, and established treatment pathways likely increase the risk of HBV-associated morbidity and mortality. Strengthened public health interventions, including expanded testing, enhanced vaccination coverage, and prevention of mother-to-child transmission strategies, are recommended to improve disease control and clinical outcomes in Botswana.
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(This article belongs to the Special Issue HIV and Viral Hepatitis Co-Infection)
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Open AccessArticle
Identification and Characterization of a Novel Bovine Adenovirus Which Represents a Distinct Evolutionary Branch
by
Jinyu Sui, Suchun Wang, Zihao Pan and Kaicheng Wang
Viruses 2026, 18(5), 522; https://doi.org/10.3390/v18050522 - 30 Apr 2026
Abstract
Bovine adenovirus (BAdV) is associated with respiratory and enteric diseases in cattle. In this study, the complete genomic sequence of a novel BAdV strain (named BAdV/LN/CHN/2023) was sequenced and annotated using the next-generation sequencing (NGS) technology. The viral genome comprises 32,391 base pairs
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Bovine adenovirus (BAdV) is associated with respiratory and enteric diseases in cattle. In this study, the complete genomic sequence of a novel BAdV strain (named BAdV/LN/CHN/2023) was sequenced and annotated using the next-generation sequencing (NGS) technology. The viral genome comprises 32,391 base pairs with a GC content of 44.93%, encoding 33 predicted open reading frames (ORFs), consistent with the genomic organization of mastadenoviruses. Comparative genomic analysis confirmed that BAdV/LN/CHN/2023 contains conserved structural and functional motifs characteristic of the genus Mastadenovirus. Phylogenetic analysis revealed that BAdV/LN/CHN/2023 shares low similarity with all currently recognized bovine mastadenoviruses classified by the International Committee on Taxonomy of Viruses (ICTV). In addition, an open reading frame (ORF) encoding the 146R protein was annotated in this strain; this feature has not been identified in any previously recognized bovine mastadenoviruses. This study presents the first full-length genomic sequence of a putative BAdV-11 strain, and based on ICTV criteria, we propose that this strain represents a novel mastadenovirus species, supported by phylogenetic distance and genomic divergence. Our findings expand the known genetic diversity of BAdVs and contribute to a better understanding of their evolutionary relationships.
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(This article belongs to the Section Animal Viruses)
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Open AccessReview
3D Single-Virus Tracking: Advances in Methodology and Labeling Strategies Towards Probing the Virus–Epithelium Interaction
by
Yuxin Lin, Haoting Lin, Donggeng Yu and Kevin Welsher
Viruses 2026, 18(5), 521; https://doi.org/10.3390/v18050521 - 30 Apr 2026
Abstract
The epithelium represents the first line of defense against viral infection, yet the precise mechanisms by which viruses penetrate this complex barrier remain incompletely understood. Single-virus tracking (SVT) has emerged as a powerful fluorescence microscopy approach to directly visualize viral dynamics with nanometer
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The epithelium represents the first line of defense against viral infection, yet the precise mechanisms by which viruses penetrate this complex barrier remain incompletely understood. Single-virus tracking (SVT) has emerged as a powerful fluorescence microscopy approach to directly visualize viral dynamics with nanometer spatial precision and millisecond temporal resolution. In this review, we survey recent progress in SVT methodologies, from image-based approaches to active feedback techniques, and assess their capacity to resolve viral behavior in physiologically relevant epithelial models. We further evaluate advances in virus labeling strategies—including fluorescent proteins, organic dyes, and nanoparticles—that enable prolonged observation while preserving infectivity. By integrating developments in optical instrumentation and molecular labeling, SVT is increasingly capable of capturing critical processes, including extracellular diffusion, receptor engagement, internalization, and trans-epithelial transport. Finally, we discuss current challenges, including limited penetration depth, photobleaching, and the complexity of 3D epithelial tissues, and outline future opportunities to extend SVT towards in situ and tissue-level studies. Together, these advances position SVT as a transformative tool to illuminate virus–epithelium interactions and guide therapeutic strategies.
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(This article belongs to the Section General Virology)
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Open AccessArticle
Shifting Epicenters: The Dynamic Regional Dispersal of SARS-CoV-2 Omicron in Poland
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Marcin Horecki, Karol Serwin and Miłosz Parczewski
Viruses 2026, 18(5), 520; https://doi.org/10.3390/v18050520 - 30 Apr 2026
Abstract
The evolution and spatial dissemination of SARS-CoV-2 Omicron subvariants have been characterized by rapid lineage replacement and complex transmission dynamics influenced by regional connectivity. This study presents a comprehensive discrete phylogeographic analysis of 90,136 SARS-CoV-2 sequences collected in Poland from 2022 to 2024
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The evolution and spatial dissemination of SARS-CoV-2 Omicron subvariants have been characterized by rapid lineage replacement and complex transmission dynamics influenced by regional connectivity. This study presents a comprehensive discrete phylogeographic analysis of 90,136 SARS-CoV-2 sequences collected in Poland from 2022 to 2024 to reconstruct the dispersal dynamics of major Omicron lineages, including BA.1, BA.2, BA.5, CH.1, XBB.1, and JN.1. Utilizing Bayesian statistical frameworks, we identified significant viral transitions between the 16 Polish voivodeships and established variant-specific dominance windows ranging from 2 to 4 months. Our findings reveal a highly dynamic epidemic landscape with shifting regional epicenters. The initial BA.1 wave was primarily driven by the Mazovian voivodeship, accounting for 36.1% of outward migration events. This pattern shifted dramatically with the rise in BA.2, which was centered in the industrial Silesian region in the south-west, a densely populated area with strong economic ties to neighboring countries, potentially reflecting a different introduction or transmission dynamic. Furthermore, the epidemic landscape continued to reconfigure during the BA.5 wave, marked by the emergence of new transmission hubs in eastern border regions such as Lublin. Subsequent lineages exhibited distinct geographic signatures: BA.5 spread broadly along the Baltic-central corridor, CH.1 was centered in the north-east, XBB.1 re-emerged in the west-central region of Greater Poland, and JN.1 was driven overwhelmingly by Lesser Poland. These transitions highlight that regional transmission hubs are transient and influenced by local factors such as population density, cross-border mobility, and socio-economic connectivity. This study underscores the critical value of dense genomic surveillance in identifying evolving dispersal routes to inform adaptive, region-specific public health interventions.
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(This article belongs to the Special Issue Molecular Epidemiology of SARS-CoV-2, 4th Edition)
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Open AccessArticle
Genomic Diversity of Vaginal Lactobacillus crispatus Prophages from South African Women
by
Adijat Ozohu Jimoh, Anika Chicken, Brandon Maust, Colin Feng, Seth Rakoff-Nahoum, Jo-Ann S. Passmore, Brian R. Kullin, Simona Kraberger, Fatima Aysha Hussain, Heather B. Jaspan, Arvind Varsani and Anna-Ursula Happel
Viruses 2026, 18(5), 519; https://doi.org/10.3390/v18050519 - 30 Apr 2026
Abstract
Lactobacillus crispatus is widely associated with optimal sexual and reproductive health outcomes. While L. crispatus genomes commonly harbor prophages, little is known about their genomic diversity and potential inducibility by clinically relevant compounds. We induced and characterized four bacteriophages from four L. crispatus
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Lactobacillus crispatus is widely associated with optimal sexual and reproductive health outcomes. While L. crispatus genomes commonly harbor prophages, little is known about their genomic diversity and potential inducibility by clinically relevant compounds. We induced and characterized four bacteriophages from four L. crispatus strains isolated from vaginal secretions of South African adolescents. Sequenced viral DNA from induced phages was assembled, and their respective genomes were annotated and compared to bacteriophage reference genomes. All the phage genomes range in size from 42.9 to 48.3 kbp. Of the four phages, UC101 and UC164 shared <90% pairwise intergenomic similarity to reference phages, suggesting that they represent new species. To explore factors potentially associated with prophage activation, L. crispatus strains were exposed to physiological concentrations of copper ions and tenofovir, selected based on their common use by women in Africa and reported associations with altered vaginal bacterial community composition. The presence of phage-like particles following exposure to copper ions (2.0 × 10−6 M–3.0 × 10−6 M) and tenofovir (500 ng/mL) was observed by transmission electron microscopy, suggesting possible prophage activation under these conditions. This study provides new insights into the genomic diversity of inducible L. crispatus phages and presents hypothesis-generating evidence regarding their potential inducibility using copper ions and tenofovir.
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(This article belongs to the Special Issue Viruses in the Reproductive Tract)
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Open AccessReview
Oncolytic Viruses for Cancer Therapy in Dogs
by
Daria O. Neymysheva, Galina V. Ilyinskaya, Viktoria A. Sarkisova, Elena A. Mukhina, Sofia A. Romanen-kova and Peter M. Chumakov
Viruses 2026, 18(5), 518; https://doi.org/10.3390/v18050518 - 30 Apr 2026
Abstract
Cancer remains the leading cause of death in domestic dogs. Conventional therapeutic approaches, including surgery, chemotherapy, and radiotherapy, frequently fail to achieve sustained remission or stabilization. Oncolytic virotherapy, a rapidly advancing therapeutic modality in human oncology, is emerging as a novel strategy in
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Cancer remains the leading cause of death in domestic dogs. Conventional therapeutic approaches, including surgery, chemotherapy, and radiotherapy, frequently fail to achieve sustained remission or stabilization. Oncolytic virotherapy, a rapidly advancing therapeutic modality in human oncology, is emerging as a novel strategy in veterinary medicine. This systematic review summarizes current knowledge on the application of oncolytic viruses (OVs) in canine cancer treatment, focusing on their mechanisms of action, safety profiles, and clinical efficacy. We evaluate diverse OV platforms, including myxoma virus, reovirus, vesicular stomatitis virus, canine adenoviruses, vaccinia virus, Sendai virus, and Newcastle disease virus, across preclinical and clinical studies in dogs with various malignancies. While several OVs have demonstrated favorable tolerability and modest antitumor activity, key challenges such as pre-existing immunity, optimization of dosing regimens, and rational combination strategies remain to be addressed. This review emphasizes the translational significance of canine studies for both veterinary and human oncology, underscoring the critical need for rigorously designed clinical trials to refine virotherapy protocols and expand therapeutic options for canine cancer patients.
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(This article belongs to the Section General Virology)
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Open AccessReview
Development and Evaluation of Molecular Diagnostic Tests for SARS-CoV-2 at English NHS Sites Throughout the COVID-19 Pandemic
by
Luke D. Griffith, Samir Dervisevic and Penny P. Powell
Viruses 2026, 18(5), 517; https://doi.org/10.3390/v18050517 - 30 Apr 2026
Abstract
The COVID-19 pandemic placed unprecedented pressure on diagnostic services worldwide. The first cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the UK were confirmed on 31 January 2020, prompting National Health Service (NHS) laboratories to scale diagnostic procedures. The demand for
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The COVID-19 pandemic placed unprecedented pressure on diagnostic services worldwide. The first cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the UK were confirmed on 31 January 2020, prompting National Health Service (NHS) laboratories to scale diagnostic procedures. The demand for testing rapidly exceeded historical norms for respiratory virus diagnostics, necessitating substantial government investment in consumables, assay development, and workforce expansion. This review presents a retrospective evaluation of SARS-CoV-2 diagnostic platforms deployed within the Norfolk and Norwich University Hospital (NNUH) trust and compares them with those implemented by other regional laboratories during the pandemic. It examines the molecular mechanisms, performance, scalability, and specificity of the multiple molecular testing approaches to optimise workflow based on the evolving technology. The integration of complementary platforms through a stratified testing strategy enabled high-throughput population screening while preserving diagnostic resolution for complex respiratory cases, substantially improving laboratory efficiency and resilience. The emerging diagnostic methodologies, RT-LAMP and CRISPR-based assays, are described, and we discuss their potential roles in future outbreaks. We critically evaluate the overall preparedness of UK health services for the COVID-19 pandemic and highlight key priorities for future pandemic preparedness at both local and national levels.
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(This article belongs to the Section Human Virology and Viral Diseases)
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Open AccessBrief Report
Hepatitis Free Hospital: Retrospective Results of an In-Hospital Project of Hepatitis C Virus Micro-Elimination
by
Federica Cerini, Loreta A. Kondili, Chiara Masellis, Agostino Cosenza, Carmelo Selvaggio and Maria Grazia Rumi
Viruses 2026, 18(5), 516; https://doi.org/10.3390/v18050516 - 30 Apr 2026
Abstract
National HCV screening, a cost-effective program in Italy, is supported by the Italian Ministry of Health. Free-of-charge screening was approved for people who use drugs, prisoners and the 1969–1989 general population birth cohort. However, the benefits of extending hospital-based screening irrespective of age,
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National HCV screening, a cost-effective program in Italy, is supported by the Italian Ministry of Health. Free-of-charge screening was approved for people who use drugs, prisoners and the 1969–1989 general population birth cohort. However, the benefits of extending hospital-based screening irrespective of age, in terms of case detection and linkage to care, remain unclear. We assessed a streamlined in-hospital pathway at San Giuseppe Hospital (Milan), between 2021 and 2024, with anti-HCV screening for all admissions and HCV-RNA confirmation when indicated. Anti-HCV seroprevalence among 18,218 screened patients was 1.9% (medical wards 3.8%, surgical 1.4%). Viremia was detected in 23/75 tested (31%); 78% linked to care and 30% initiated treatment. Notably, 91% of viremic patients were born before 1969 indicating hospital-based screening effectively identifies HCV infections in older cohorts missed by national screening programs. Systematic screening implementation across hospital wards represents a pragmatic micro-elimination strategy for Italy and similar epidemiological contexts, advancing 2030 elimination targets.
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(This article belongs to the Special Issue Cascade of Care for HIV, Hepatitis and Sexually Transmitted Infections)
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Open AccessArticle
Chronic HDV Infection Shows Higher HBsAg Isoform Levels than HBV Infection, Paralleling HDV Replicative Activity
by
Stefano D’Anna, Lorenzo Piermatteo, Alessia Magnapera, Ilaria Grossi, Caterina Tramontozzi, Antonella Olivero, Leonardo Duca, Giulia Torre, Elisabetta Teti, Andrea Di Lorenzo, Vincenzo Malagnino, Marco Iannetta, Sandro Grelli, Pierpaolo Paba, Ada Bertoli, Francesca Ceccherini-Silberstein, Leonardo Baiocchi, Simona Francioso, Ilaria Lenci, Michele Milella, Annalisa Saracino, Alessia Ciancio, Giuseppina Brancaccio, Loredana Sarmati, Pietro Lampertico, Mario Rizzetto, Gian Paolo Caviglia, Romina Salpini and Valentina Svicheradd
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Viruses 2026, 18(5), 515; https://doi.org/10.3390/v18050515 - 30 Apr 2026
Abstract
Background & Aim: The entry of Hepatitis D Virus (HDV) depends on HBV surface proteins (HBsAg) composed of three isoforms: large-, middle, and small HBsAg. Here, we investigate the levels of total HBsAg and HBsAg isoforms and their correlations with HDV-RNA, HBcrAg, and
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Background & Aim: The entry of Hepatitis D Virus (HDV) depends on HBV surface proteins (HBsAg) composed of three isoforms: large-, middle, and small HBsAg. Here, we investigate the levels of total HBsAg and HBsAg isoforms and their correlations with HDV-RNA, HBcrAg, and transaminases in the setting of untreated chronic hepatitis D (CHD). Methods: This study includes 316 HBeAg-negative patients: 192 CHD and 124 with chronic hepatitis B (CHB) as a control group. HBsAg isoforms were quantified by ad hoc-designed ELISAs. Results: The composition of HBsAg isoforms varied between the two groups of patients, with remarkably higher small HBsAg, middle-HBsAg, and large HBsAg in CHD than in CHB. This data was confirmed by multivariable analysis (p < 0.0001). Among CHD, HBsAg isoforms positively correlated with HDV-RNA (p < 0.0001) and HBcrAg (p < 0.0001) but not with HBV-DNA. The results were confirmed by stratifying patients according to HDV-RNA (< or >1000 IU/mL) and HBcrAg (< or >3 logU/mL). Furthermore, CHD patients with ALT > upper limit of normal presented significantly higher S-HBsAg and M-HBsAg levels. Conclusions: CHD is characterized by a more elevated HBsAg isoform production, paralleling HDV-RNA and HBcrAg release. This may suggest a preferential recruitment of HBsAg isoforms in HDV virions at the expense of HBV virions. The association of HBsAg isoforms with higher ALT also suggests their potential contribution in supporting HDV-induced pro-inflammatory stimuli.
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(This article belongs to the Special Issue Virology in Italy 2025—9th National Congress of the Italian Society for Virology)
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