Search Results (4,816)

Despite serological evidence of tick-borne encephalitis virus (TBEV) circulation in Belgian animals since 2007, confirmed autochthonous human infection was only first documented in 2020. We review the current national epidemiologic situation and investigate a household cluster of confirmed autochthonous cases identified in 2025. A cohabiting couple experienced a near-simultaneous onset of meningoencephalitis and tested positive for TBEV-specific IgM and IgG, with confirmation by PRNT90. One patient reported a recent tick bite, and both patients reported consumption of unpasteurized milk and goat cheese, suggesting possible alimentary transmission. The identification of Case 2, who lacked neurological symptoms at presentation and was only tested due to the index case, illustrates the risk of missed diagnoses and supports the notion that human TBEV infection is likely underdiagnosed in Belgium. These findings underscore the need to increase clinical awareness, strengthen surveillance, and reinforce prevention strategies. TBE should be considered in the differential diagnosis of patients presenting with non-specific fever or neurological syndromes such as meningoencephalitis, particularly during the spring-to-autumn tick activity season. Full article

Background/Objectives: Tunisia lacks recent national data on hepatitis B virus (HBV) prevalence, particularly following the introduction of universal HBV vaccination in 1995. A national HBV seroprevalence study is essential to guide prevention strategies. This study aimed to estimate the national seroprevalence of HBV infection and identify its determinants 20 years after vaccine introduction. Methods: We conducted a nationwide, household-based, cross-sectional sero-epidemiological survey among a representative sample of the Tunisian general population using a two-stage cluster sampling method. The study was conducted by the National Observatory of New and Emerging Diseases (ONMNE) between December 2014 and June 2015. Data were collected using standardized questionnaires, and blood samples were tested using electrochemiluminescence (ECLIA) to detect HBV biomarkers (HBsAg, anti-HBc, anti-HBs). HBV infection was defined as the presence of HBsAg and/or anti-HBc with the absence of anti-HBs. Associations between HBV infection and explanatory variables (socio-demographics, vaccination status, intrafamilial transmission, and hospital exposures) were assessed using multivariate logistic regression, reporting adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Results: Among 21,720 participants, 19,155 (88.2%) were tested. The national prevalence of HBsAg was 1.7% (95% CI: 1.55–1.85%), higher among males (2.1%; 95% CI: 1.9–2.4%) than females (1.4%; 95% CI: 1.3–1.6%) (p < 0.001; M/F ratio = 1.48). The mean age of HBsAg-positive participants was 48 ± 15.7 years. Prevalence was highest in the Central (2.3%; 95% CI: 2.0–2.7%) and Southern regions (2.2%; 95% CI: 1.8–2.8%) (p < 0.001). In multivariate analysis, independent risk factors for HBV infection included age >20 years (aOR = 15.10; 95% CI: 4.79–47.64; p < 0.001), having a family member with HBV infection (aOR = 2.82; 95% CI: 2.09–3.79; p < 0.001), residing in the Southern (aOR = 2.51; 95% CI: 1.76–2.71; p < 0.001) or Central region (aOR = 2.18; 95% CI: 1.76–2.71; p < 0.001), male gender (aOR = 1.69; 95% CI: 1.39–2.05; p < 0.001), and hospital follow-up (aOR = 1.23; 95% CI: 1.01–1.51; p = 0.039). HBV vaccination was strongly protective (aOR = 0.36; 95% CI: 0.20–0.62; p < 0.001). Conclusions: The national HBsAg seroprevalence in Tunisia was 1.7%, reflecting a low-endemic status. Vaccination programs should prioritize high-risk groups, including males, adults over 20 years, household contacts of HBV carriers, and residents of the Central and Southern regions. Strengthening infection prevention and control in healthcare settings and adopting intrafamilial precautions among high-risk populations are essential for long-term HBV control. Full article

Pathogen manipulation of host behavior is a widespread evolutionary strategy to enhance its transmission, yet whether different pathogens elicit distinct behavioral and molecular responses in the same host remains poorly understood. We performed parallel behavioral assays and comparative transcriptomic analyses on third-instar Lymantria dispar larvae infected with Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV, virus), Staphylococcus aureus (bacterium) and Metarhizium anisopliae (fungus). Climbing height was recorded over 72 h post-infection, and gene expression pattern was profiled using RNA-seq at 72 h. Only LdMNPV infection induced significant, sustained upward climbing behavior among the three pathogen infection groups. All three pathogens activated Toll and IMD immune pathways, but LdMNPV triggered substantially broader transcriptomic reprogramming. Notably, the virus specifically upregulated multiple energy metabolism pathways (nicotinate/nicotinamide metabolism, pyruvate metabolism, TCA cycle and oxidative phosphorylation) and the neuroactive ligand-receptor interaction pathway—a pattern absent in bacterial and fungal infections. LdMNPV drove tree-top disease through a virus-specific, multi-system manipulation strategy that couples metabolic activation with neural signaling modulation. This comparative study reveals fundamental differences in behavioral manipulation across pathogen kingdoms and provides candidate pathways for functional validation. Full article

Background/Objectives: The coronavirus disease 2019 (COVID-19) pandemic profoundly disrupted global respiratory virus circulation, with sharp declines during 2020–2021, followed by a resurgence after the relaxation of public health measures. In South America, post-pandemic respiratory virus dynamics remain insufficiently characterized, particularly in ecologically diverse regions. Arequipa, a high-altitude city in southern Peru, has unique environmental conditions, including marked seasonal temperature variability, that may influence viral transmission. Methods: We performed a cross-sectional analysis of 21,784 nasopharyngeal swabs collected from symptomatic patients at four major hospitals between June 2021 and September 2023. All samples were tested for SARS-CoV-2 by RT-qPCR. Because routine screening for other respiratory viruses was implemented only in SARS-CoV-2-negative cases during the study period, a subset of SARS-CoV-2-negative samples was subsequently analyzed for influenza A virus (IAV), influenza B virus (IBV), and respiratory syncytial virus (RSV) using VIASURE assays. Viral circulation patterns were evaluated by year, month, and epidemiological week. Meteorological data were obtained from the SENAMHI–La Pampilla station. Logistic regression models were used to assess epidemiological and climatic predictors of viral detection. Results: SARS-CoV-2 positivity declined from 20.0% in 2021 to 8.8% in 2023. Conversely, detection of other respiratory viruses among SARS-CoV-2-negative samples increased from 0.8% in 2021 to 29.0% in 2023 (p < 0.01). Temporal increases in detection were observed during 2022–2023, particularly for IAV and RSV. In exploratory analyses, calendar year and relative humidity were associated with IAV and RSV detection, while age and temperature variables were associated with IBV. Conclusions: Climatic and demographic variables were associated with changes in viral detection for IAV, IBV, and RSV during the post-pandemic transition period in Arequipa. These findings describe patterns of viral detection within SARS-CoV-2-negative symptomatic patients and should be interpreted as surveillance-based observations rather than population-level estimates. Strengthened integrated epidemiological and genomic surveillance will be essential for vaccine planning and outbreak preparedness in the post-pandemic era. Full article

Nipah virus (NiV) is a highly pathogenic zoonotic paramyxovirus responsible for sporadic outbreaks of severe disease with high case fatality rates in South and Southeast Asia. Human infection occurs through spillover from natural reservoirs, primarily fruit bats, or via human-to-human transmission, and is characterized by a broad clinical spectrum ranging from asymptomatic infection to acute respiratory disease and fatal encephalitis. Following entry via ephrin-B2 and ephrin-B3 receptors, NiV exhibits marked endothelial and neuronal tropism, leading to systemic vasculitis, disruption of the blood–brain barrier, and direct infection of the central nervous system. Disease progression is driven by a complex interplay between viral replication strategies and host immune responses. NiV effectively counteracts innate immunity through multiple viral proteins that inhibit interferon signaling, while simultaneously inducing dysregulated inflammatory responses that contribute to tissue damage and multi-organ failure. Neurological involvement represents the most severe manifestation, often resulting in acute or relapsing encephalitis with long-term sequelae among survivors. Despite the severity of the disease, no licensed antiviral therapies or human vaccines are currently available. Therapeutic development has focused on neutralizing monoclonal antibodies targeting viral glycoproteins and small-molecule antivirals that inhibit viral RNA synthesis, both of which show promising results in preclinical models, but remain limited by timing and translational challenges. In parallel, several vaccine platforms—including viral vectors, mRNA-based constructs, and recombinant protein subunits—have advanced to early-phase clinical trials, demonstrating encouraging immunogenicity. Beyond biomedical interventions, effective outbreak containment relies on integrated public health strategies. The “Kerala model” highlights the importance of rapid case identification, isolation, contact tracing, and community engagement within a One Health framework to mitigate transmission and reduce mortality. This review synthesizes the current knowledge on NiV pathogenesis, immune evasion, clinical manifestations, and emerging therapeutic and vaccine strategies, while highlighting critical gaps and future directions for improving the preparedness and response to this high-consequence emerging pathogen. Full article

African swine fever (ASF), caused by African swine fever virus (ASFV), is a highly destructive transboundary disease in domestic pigs. The circulating virus in this study belonged to ASFV genotype II, commonly associated with high virulence. In endemic regions such as Thailand, limited vaccine availability and shortages of naïve breeding stock necessitate reliance on early detection, surveillance, and the retention of convalescent sows, thereby raising concerns regarding viral persistence and reproductive performance. This study evaluated the long-term reproductive performance of convalescent sows compared with naïve cohorts under co-habitation conditions, while assessing the efficacy of passive surveillance and strict biosecurity in preventing viral transmission from both internal and external sources. Convalescent sows showed reproductive performance comparable to naïve cohorts across two parities. Long-term co-habitation with naïve sentinel pigs was not associated with detectable viral transmission, although low-level viral persistence or intermittent shedding cannot be excluded. From a disease control perspective, the transition from delayed detection to enhanced passive surveillance facilitated early clinical recognition and targeted removal (“tooth extraction”) of infected animals, effectively limiting intra-herd transmission without full depopulation. Importantly, irrespective of the uncertain carrier status, strict biosecurity and rapid response protocols appeared effective in mitigating both external introduction and within-farm transmission of ASFV. These findings suggest that, under appropriate management and biosecurity conditions, convalescent sows may be reintegrated into production systems with caution. Full article

Rabies is a fatal zoonotic disease once clinical symptoms develop. In Europe, sustained animal rabies control programs have led to a marked decline in animal rabies and subsequently human rabies cases; however, sporadic infections continue to occur. In July 2025, a fatal case of autochthonous (locally acquired) human rabies was confirmed in Romania following a stray dog bite in a patient who did not receive post-exposure prophylaxis (PEP). Here, we report the first molecular characterization of a human rabies virus (RABV) strain isolated in Romania and place it in the context of contemporaneously circulating animal-derived RABV strains. Rabies virus infection was confirmed intra vitam by fluorescent antibody testing and both conventional and real-time RT-PCR on cerebrospinal fluid and saliva, with postmortem confirmation on skin and brain tissue. Whole-genome sequencing was performed on the human isolate and on 22 animal-derived RABV strains collected in northern Romania in 2025. Phylogenetic analyses revealed that all recent Romanian sequences clustered within the North-East European (NEE) rabies virus phylogenetic group and segregated into two geographically distinct genetic clusters: a north-western cluster, closely related to strains from Slovakia and Poland, and a larger north-eastern cluster, linked to viruses circulating in eastern Romania and the Republic of Moldova. The human-derived RABV genome was grouped within the north-eastern cluster and showed the highest genetic similarity to animal viral strains from the same geographical area, supporting a local transmission event. This demonstrates the importance of integrating human viral genomic data into the national rabies surveillance framework. Full article

Plant viruses pose serious threats to global crop production, and members of the genus Tobamovirus are particularly problematic due to their environmental stability, efficient mechanical transmission and rapid global spread. Tomato brown rugose fruit virus (ToBRFV) has emerged as one of the most damaging tobamovirus affecting tomato, a crop of major economic importance worldwide. ToBRFV has been reported in more than 45 countries, including Portugal. However, to date, no peer-reviewed molecular characterization of local isolates has been published, and official records classify its presence in Portugal as transient. This study confirms the occurrence of ToBRFV and provides the first comprehensive genomic and phylogenetic characterization of local virus isolates in Portugal. RNA-seq generated 192,852,438 reads, of which 103,882,115 (58.9%) mapped to ToBRFV, allowing reconstruction of a complete 6393 nt viral genome. A second full-length consensus sequence was independently obtained from the same composite sample using an overlapping Sanger sequencing strategy, differing by only two SNPs. Comparative genomic, functional, structural, and phylogenetic analysis revealed low diversity, with most variation located in replicase-coding regions, while movement and coat protein genes remained highly conserved. Nucleotide-based phylogenies resolved geographically structured clades, although the Portuguese sequences formed a strongly supported subclade with a Chinese isolate. These findings support recent global dissemination of ToBRFV and reinforce the importance of integrated surveillance and genomic monitoring for effective virus management. Full article

SARS-CoV-2 infection has emerged worldwide. To reduce the number of cases and limit the transmission of the virus, health and local authorities have implemented several strategies. Mass screening is a key strategy for mitigating the damage caused by this pandemic. This strategy is based on the use of qRT-PCR and pooling to diagnose SARS-CoV-2 infection. The present work explores the performance and limitations of this strategy for the molecular diagnosis of SARS-CoV-2 infection. Three important technical aspects were retained: the comparison of two commercial extraction kits (BIGFISH and BIOER), the simulation of a non-compliant nasopharyngeal swab, and the evaluation of the pooling strategy. A total of 97 SARS-CoV-2-positive nasopharyngeal samples were used. The comparison of the two extraction kits was based on threshold cycles (Ct) values. The results showed a significant difference (IC = 95%) in the Ct of the nucleocapsid gene (N; p = 0.0000384) and RNA-dependent RNA polymerase (RdRp; p = 0.0254). However, no significant difference was observed between the Internal Control gene (IC; p = 0.0723) and Envelope gene (E; p = 0.150). The Ct values resulting from the BIGFISH extraction kit were generally lower than those obtained from BIOER. In terms of sensitivity, the RT-qPCR technique allows for the detection of viral RNA up to 10⁻³ as a dilution factor. This study demonstrated that the pooling strategy is an effective diagnostic technique. Positive samples remained detectable even in pools of 1000 or even 10,000 samples. However, the size of the pool under diagnostic conditions should not exceed a limit that must be dynamically adapted to prevalence to ensure economic and analytical viability. Full article

Hepatitis E virus (HEV) is a zoonotic pathogen of global concern that circulates in both domestic and wild swine populations. Understanding its presence and dynamics in wildlife reservoirs is crucial for assessing spillover risks and designing One Health surveillance strategies. This study investigated the occurrence, genetic diversity, and evolutionary relationships of HEV in wild boars from mainland Portugal. A total of 120 animals from seven districts were tested, with HEV RNA detected in four cases (3.3%), all from the Évora district near the Spanish border. One positive sample was successfully sequenced, and phylogenetic analysis based on the complete genome classified it within the HEV-3m subtype, clustering with predominantly human-derived sequences from Spain and France, which highlights its zoonotic potential. A second phylogenetic analysis based on a partial genomic fragment, including sequences from domestic pigs in Portugal, revealed the co-circulation of subtypes 3e, 3f, and 3m without clear spatial or temporal patterns. Phylogeographic analysis suggested that the identified strain was most likely introduced from Spain, supporting the hypothesis of cross-border transmission through wild boar movement. No recombination events were detected in the sequence obtained in this study. These findings provide the first molecular evidence of HEV-3m circulation in wild boars in Portugal, offering valuable insight into the HEV strain circulation in European wildlife populations. The zoonotic potential of HEV and the likelihood of interspecies transmission highlight the need for coordinated cross-border surveillance and integrated One Health strategies. Full article

Despite increased interest in virus survival on surfaces, data on bovine herpesvirus type 1 (BoHV-1) interactions with metal surfaces remain limited. This study aimed to assess the effects of copper, zinc, and iron on BoHV-1 viability, viral titre, and DNA stability under different conditions. MDBK-adapted BoHV-1 was used to investigate the virucidal effect of copper, zinc and stainless steel surfaces. The virus was exposed for 1 and 24 h under both wet and dry conditions. Inactivation was assessed based on changes in TCID₅₀ log₁₀ values, qPCR Ct results, and calculating half-lives of the virus and its DNA. Virus stability varied depending on surface type, environmental conditions, and duration of exposure. Copper demonstrated the strongest virucidal effect, significantly reducing viral titres and DNA levels under all conditions. After 1 h in wet conditions, copper reduced viral titre to 4.7 log₁₀, while zinc and stainless steel showed minimal impact. Under dry conditions, copper reduced viral titres to the limit of detection after 24 h. Half-life analysis confirmed rapid inactivation on copper, with the shortest persistence observed across all conditions. Zinc showed moderate virucidal activity but required longer exposure times. These findings highlight copper’s superior antiviral properties and suggest its potential application in reducing viral transmission on surfaces. Full article

Located on the traditional and ancestral homelands of the Arapaho, Cheyenne, and Ute Nations, Colorado State University’s Mountain Campus hosted the 25th Annual Rocky Mountain Virology Association meeting. The three-day event, held from 26 September to 28 September 2025, welcomed 152 participants focused on the following topics: viruses, prions, immunology, transmission, structural biology, and vector biology. This year’s Randall Jay Cohrs Keynote Presentation summarized ongoing research on viral glycoproteins in relation to viral entry and assembly. Understanding the role of viral glycoproteins is essential in vaccine and antiviral development for enveloped RNA viruses. Alongside rigorous scientific discourse and networking, attendees made the most of their time by hiking amidst beautiful fall colors, wildlife, and young aspens starting the forest anew. On behalf of the Rocky Mountain Virology Association, this report summarizes select presentations from the 25th annual meeting. Full article

Monkeypox (Mpox), caused by the monkeypox virus (MPXV), has re-emerged as a significant global public health concern, particularly following the 2022 outbreaks. Understanding its transmission dynamics is essential for designing effective control strategies. In this study, we develop and analyze a deterministic compartmental model that captures both human-to-human and rodent-to-human transmission pathways in order to better reflect the zoonotic nature of the disease. The model is investigated using qualitative and quantitative analytical techniques, including stability analysis, bifurcation theory, and sensitivity analysis. The basic reproduction number, $R_0$, is derived and used to determine threshold conditions for disease persistence or eradication. We show that the disease-free equilibrium is globally asymptotically stable when $R_0<1$, while an endemic equilibrium exists and is stable when $R_0>1$. Furthermore, the model exhibits backward bifurcation, indicating that reducing $R_0$ below unity may not be sufficient for disease elimination. Sensitivity analysis identifies key parameters driving transmission, particularly the rodent-to-human and human-to-human contact rates. Numerical simulations further demonstrate that reducing cross-species transmission and improving isolation of infected individuals significantly decrease disease burden. These findings highlight the complexity of Mpox transmission and emphasize that effective control requires not only lowering $R_0$, but also targeting critical transmission pathways. This study provides useful insights for public health planning by identifying priority intervention strategies such as minimizing rodent–human interactions and strengthening isolation measures. Full article

Herpes simplex virus (HSV) infection is highly prevalent worldwide and poses important risks during pregnancy due to the potential for vertical transmission and severe neonatal disease. HSV-1 is traditionally associated with orofacial lesions and HSV-2 with genital infection; however, HSV-1 has emerged as a significant cause of genital and neonatal herpes. Physiological immunomodulation during pregnancy may facilitate viral reactivation and replication. Vertical transmission may occur intrauterinely, intrapartum, or postnatally, with approximately 85% of neonatal infections acquired during delivery through contact with infected genital secretions. The risk is highest when primary maternal infection occurs in the third trimester, before adequate transplacental transfer of protective antibodies. Neonatal infection may present as disease limited to the skin, eyes, and mouth; central nervous system involvement; or disseminated multiorgan disease, the latter associated with high morbidity and mortality. Maternal infection ranges from asymptomatic viral shedding to painful vesiculoulcerative lesions and, rarely, disseminated disease. Because asymptomatic shedding is common, diagnosis relies on laboratory confirmation using polymerase chain reaction (PCR) or viral culture, with type-specific serology aiding in distinguishing primary from recurrent infection. Management aims to reduce symptoms, viral shedding, recurrences near delivery, and vertical transmission. Acyclovir and valacyclovir are safe and effective in pregnancy. Suppressive therapy from 36 weeks’ gestation reduces recurrences and viral shedding at delivery and decreases the need for cesarean delivery, which is recommended when active lesions or prodromal symptoms are present at labor. Neonatal herpes requires prompt recognition and intravenous acyclovir therapy to reduce mortality and neurological sequelae. Preventive strategies include counseling, behavioral risk reduction, suppressive antiviral therapy, and avoidance of neonatal exposure to active lesions. Full article

Fibropapillomatosis, a disease associated with Scutavirus chelonidalpha5, commonly known as Chelonid alphaherpesvirus 5 (ChHV5), manifests as benign tumors that impair the motor, visual, and physiological functions of affected sea turtles. In this study, blood and tissue samples were collected from turtles exhibiting fibropapilloma-like lesions as well as from clinically healthy individuals. A nested PCR approach was employed to amplify the viral UL30 and UL28 genes for the detection and characterization of the virus variants. The mitochondrial control region was used to assess the relationship between the turtle population and the viral variant. Among the 19 turtles analyzed, six tested positive for ChHV5, including both symptomatic and asymptomatic turtles. Phylogenetic analysis revealed that three positive samples belonged to the Western Atlantic/Caribbean clade, whereas the other three grouped within the Atlantic clade. New oligonucleotides and probes were designed for ChHV5 qPCR detection, accounting for the globally accumulated genetic variability. The qPCR test parameters demonstrated an optimized assay with an efficiency of 101.4% and a detection limit of 2.4 genome copy equivalents (GCE)/μL. This study confirms the presence of two ChHV5 viral variants in rescued turtles from the Caribbean region of Colombia, including both clinically affected and asymptomatic individuals. Therefore, these results support the association between ChHV5 and fibropapillomatosis. Furthermore, analysis of the mitochondrial control region supports the hypothesis of horizontal transmission of the virus. A novel qPCR protocol with a synthetic control is proposed to improve early diagnosis and strengthen conservation and prevention strategies. Full article