Search Results (390)

Tomato yellow leaf curl virus (TYLCV) is a major plant pathogen that spreads worldwide through persistent circulative transmission by Bemisia tabaci. During transmission, TYLCV crosses several physiological barriers in the insect vector, evading immune defenses and altering host metabolic pathways to facilitate viral accumulation. Polyamines, essential for maintaining nucleic acid stability and promoting cellular processes, are known to play a critical role in viral accumulation. However, their role in TYLCV accumulation within B. tabaci is not well understood. Here, we demonstrate that TYLCV infection leads to significant alterations in polyamine levels in B. tabaci, with polyamine availability positively affecting viral DNA accumulation. Polyamine availability leads to higher viral loads and suppresses the expression of immune and MAPK signaling genes. These findings provide new insights into virus–vector and metabolic interactions underlying viral persistence in insect vectors. Full article

Tick-borne encephalitis virus (TBEV) is a major arthropod-borne flavivirus responsible for severe neurological disease in humans across Europe and Asia. It is maintained in nature through complex interactions within ticks and between tick vectors, vertebrate hosts and environmental factors. This review summarizes current knowledge on TBEV–tick interactions, focusing on virus acquisition, dissemination, vector competence, and long-term persistence within tick vectors. TBEV is acquired by ticks during blood feeding on viremic hosts or through co-feeding transmission under experimental conditions. Transovarial transmission has also been reported, as indicated by the detection of infected larvae in nature, although its efficiency appears to be low and variable. Following ingestion, TBEV infects and replicates in the tick midgut before dissemination via the hemolymph to secondary tissues, including the salivary glands and reproductive organs, which are essential for viral persistence and transmission. Vector competence and capacity vary between tick species and are shaped by intrinsic and extrinsic factors. Although transstadial transmission and transovarial transmission contribute to long-term virus maintenance, their efficiency is generally low and variable. In vitro models, including tick cell lines, have provided valuable insights into virus–tick interactions. Nevertheless, important knowledge gaps remain, particularly in understanding early events at the tick–host interface and mechanisms underlying viral dissemination and persistence within ticks. Full article

Wheat streak mosaic (WSM), historically attributed to wheat streak mosaic virus (WSMV) and transmitted by the wheat curl mite (WCM; Aceria tosichella), remains a major cause of yield loss in the Texas High Plains. In recent years, Triticum mosaic virus (TriMV), also transmitted by WCM, has emerged as an increasingly important component of the WSM disease complex. Under field conditions, TriMV is most frequently detected in mixed infections with WSMV. Management of WSM relies primarily on resistant cultivars carrying genes such as Wsm1 or Wsm2. Although synergistic interactions between WSMV and TriMV have been documented under controlled conditions, their dynamics during natural field infections—particularly during the latent phase between initial infection and symptom development—remain poorly understood. Moreover, the extent to which host genotype influences virus–virus interactions and vector acquisition dynamics in the field has not been fully resolved. Replicated field trials conducted over two growing seasons were used to quantify temporal accumulation patterns and relative ratios of WSMV and TriMV in susceptible (TAM 304) and resistant cultivars differing in resistance source (BT [Wsm1] and Joe [Wsm2]) under natural disease spread. WSMV remained the predominant virus in mixed infections across cultivars, sampling times, and disease stages. However, as plants aged and entered senescence, WSMV titers declined more rapidly than TriMV titers, resulting in a progressive reduction in the WSMV-to-TriMV ratio. From early infection through disease development, the Wsm1 cultivar (BT) consistently supported significantly lower TriMV accumulation than the Wsm2 cultivar (Joe), providing a mechanistic explanation for the comparatively stronger disease suppression associated with WSM. Mites feeding on BT also acquired lower TriMV titers. Although viral concentrations in wheat tissue were strongly correlated with those detected in feeding mites, substantial differences in plant-level WSMV-to-TriMV ratios among cultivars were not mirrored within the vector. These findings indicate that while host resistance regulates absolute virus accumulation, vector-associated factors may influence the relative proportions of viruses detected following acquisition, with important implications for WSM epidemiology and resistance deployment in field systems. Full article

Mosquitoes are recognized as the arthropod group with the greatest vectorial capacity, and the viruses they transmit constitute a significant concern in the context of global One Health. In addition, these insects act as hosts for a wide diversity of insect-specific viruses (ISVs), which exclusively infect arthropods. Expanding knowledge of ISVs is particularly relevant, given their potential influence on arbovirus replication and their role in elucidating the evolutionary processes that shape virus–vector interactions. In this study, we report the isolation and molecular analysis of three negeviruses associated with different mosquito species of the genera Culex, Coquillettidia, Mansonia, and Ochlerotatus, collected in Belém, Pará State, in the Brazilian Amazon: Loreto virus, Wallerfield virus, and a putative new species, designated Terra firme virus. Eleven pools exhibited cellular alterations consistent with cytopathic effects in invertebrate C6/36 cells but showed no evidence of replication in vertebrate Vero cells. Notably, simultaneous infections by two or three negeviruses were detected in some mosquito pools, indicating the occurrence of multiple viral infections within individual samples. Genomic analyses revealed that the isolated strains share conserved domains with previously described isolates from other countries. Phylogenetic inferences demonstrated that the investigated strains are classified within the clades Nelorpivirus and Sandewavirus. Taken together, these findings expand the currently known diversity of the negevirus group and contribute to a more comprehensive understanding of its host range and geographic distribution. Full article

Yellow fever (YF) remains a re-emerging vector-borne zoonotic disease in tropical regions of the Americas despite the availability of an effective vaccine. In South America, the virus is maintained through a jungle transmission cycle involving Haemagogus and Sabethes mosquitoes and non-human primates (NHPs), which act as amplifying hosts and key epidemiological sentinels. This narrative review examines the current status of YF epizootics in South America, with a focus on the role of NHPs in viral circulation, early detection, and spillover risk to human populations. We synthesize recent evidence on epizootic patterns across endemic countries, the differential susceptibility of neotropical primates, and the ecological and environmental drivers influencing transmission, including deforestation, habitat fragmentation, and human encroachment into forested areas. In addition, we analyze current surveillance strategies, including wildlife monitoring, entomological and genomic surveillance, and their integration within a One Health framework. This review highlights that YF epizootics are expanding geographically and are closely linked to environmental change and human–ecosystem interactions. Strengthening integrated, multidisciplinary surveillance systems is essential to improve early detection, guide vaccination strategies, and prevent human outbreaks. These findings underscore the critical importance of operationalizing the One Health approach to enhance preparedness and response to YF in South America. Full article

Aedes aegypti is a primary vector for globally significant arboviruses such as dengue virus (DENV). The mosquito’s metavirome, particularly its insect-specific virus (ISV) component, is recognized as a key modulator of arboviral transmission. However, the natural ecology of these interactions in populations remains poorly understood. This study presents the first comparative analysis of the metavirome in wild-caught A. aegypti from Vietnam based on natural DENV infection status. Metaviromic analysis was performed on 69 DENV-positive pools from six central provinces. The results obtained were compared with previously obtained metaviromic data from 7 DENV-negative pools (from the same region). Analysis suggests the presence of a stable ‘core metavirome’ of 11 ISVs present in both groups. Interestingly, six ISVs were detected only in DENV-negative mosquitoes, which may suggest potential antagonistic interactions requiring further investigation. Conversely, five ISVs were found only in DENV-positive pools, including Aedes partiti-like virus 1 and Aedes anphevirus. The latter may suggest possible synergistic relationships that facilitate arboviral replication. Phylogenetic analysis of prevalent ISVs, such as Phasi Charoen-like phasivirus (PCLV) and Chaq-like virus, revealed patterns of both local circulation and genetic diversity. The findings describe distinct ISV profiles associated with DENV infection in a natural setting, providing a data-driven foundation for hypothesizing specific virus–virus interactions. The data underscores the complexity of the mosquito metavirome. Here, we identified several candidate ISVs for future experimental studies aimed at understanding potential functional impact on arboviral vector competence. Full article

African swine fever (ASF), a highly contagious and lethal viral disease caused by the African swine fever virus (ASFV), poses a severe threat to the global swine industry. Recent outbreaks across Asia, Europe, and the Caribbean are exacerbating the challenge. Current control measures rely mainly on early detection, culling and strict biosecurity practices, underscoring the urgent need for a safe and effective vaccine. Since the mid-1960s, diverse vaccine strategies, including inactivated, subunit, DNA/mRNA, vectored, and live attenuated virus (LAV) vaccines, have been explored. Inactivated vaccines have consistently failed to confer protection due to insufficient functional antigen presentation and weak cellular immune activation. Subunit vaccines targeting single or multiple ASFV antigens have also shown limited success, often failing to induce sterile or long-lasting immunity. Among these approaches, LAV vaccines have demonstrated the greatest promise in eliciting robust and durable immune responses. However, major knowledge gaps remain regarding ASFV biology, ASFV–host interactions, ASFV immune evasion mechanisms, protective and cross-protective immunity, stable cell lines for LAV production, virulence reversion of LAVs, and the lack of harmonized standards for evaluating vaccine safety and efficacy, all of which impede the development of safe and broadly effective ASF vaccines. This narrative review summarizes recent advances in ASF vaccine research and highlights the critical obstacles that must be overcome to achieve successful ASF vaccine development. Full article

West Nile virus (WNV) is a mosquito-borne flavivirus that remains an important public and veterinary health concern across Europe. Periodic outbreaks affecting humans, horses, and wildlife highlight the complex ecological interactions underlying viral circulation. This narrative review aims to synthesize current knowledge regarding WNV epidemiology, transmission dynamics, and surveillance strategies in Europe, with particular attention to the Romanian context. Available surveillance data indicate recurrent seasonal transmission in several European regions; however, reported case numbers may be influenced by differences in diagnostic capacity, reporting practices, and surveillance intensity among countries. Recent studies suggest that environmental variability, vector adaptation, and host community composition play important roles in shaping regional transmission risk, although the relative contribution of these factors remains incompletely quantified. Despite expanding surveillance networks and One Health initiatives, important knowledge gaps persist regarding the integration of environmental risk indicators, vector ecology, and operational preparedness into coherent risk-assessment frameworks. This review therefore examines current epidemiological patterns, evaluates surveillance approaches, and discusses emerging drivers of WNV transmission in Europe. As a narrative synthesis based on published literature and surveillance reports, this review is subject to limitations related to heterogeneity in available data and differences in national reporting systems. Nevertheless, a clearer understanding of these interacting factors may support improved surveillance strategies and more adaptive public health responses to future WNV transmission events. Reported surveillance data should be interpreted cautiously, as differences in national surveillance intensity, diagnostic capacity, and reporting frameworks across Europe may influence notified case numbers. Consequently, reported outbreaks do not necessarily reflect proportional differences in transmission intensity. Full article

Artificial intelligence (AI) is rapidly transforming virology by strengthening pandemic preparedness, enhancing our molecular understanding of virus–host interactions, and accelerating the discovery and development of novel antiviral therapies. Yet, the same technologies also pose urgent biosecurity risks, particularly by enabling the development of bioweapons or identifying strategies that maximize harm. This paper presents a critical content analysis of current and emerging AI applications in virology, including tools used to detect synthetic alterations in viral genomes, assess the severity of new variants, and design clinical vectors for gene therapy. It also highlights the potential for misuse, whether intentional or due to poor data quality and flawed model training. Drawing on case studies, public databases, and documented applications from research institutions and biotechnology firms, the analysis shows that AI can integrate large datasets to reduce reliance on animal testing in drug development, improve therapeutic precision, and allocate resources more effectively during outbreaks. However, the increasing accessibility of AI tools and genomic data also creates vulnerabilities, especially as models become capable of autonomously interpreting the scientific literature and mining bioinformatics databases. To address this dual-use dilemma, the paper proposes targeted and adaptable policy recommendations for governments, research institutions, and commercial biotech firms, emphasizing pre-emptive oversight, responsible innovation, and ethical AI deployment. These recommendations are designed for immediate relevance yet flexible enough to evolve alongside the expanding role of AI in global health. Full article

Background/Objectives: Recombinant adeno-associated virus (AAV) vectors have revolutionized gene therapy for monogenic diseases such as Duchenne muscular dystrophy (DMD). However, high systemic doses required for muscle transduction cause a spectrum of toxicities ranging from transient hepatic inflammation to fatal multi-organ failure leading to death. These adverse events have reshaped the risk–benefit considerations for gene therapy in DMD. Methods: We conducted a narrative review describing complications associated with AAV-mediated gene therapies in the DMD field. PubMed and Clinicaltrials databases were used to search for peer-reviewed manuscripts published between 1987 and 2025. Publicly available abstracts and press releases were also used to describe AAV-mediated adverse events that have been discovered. Priority was given to large prospective cohorts, meta-analyses, and high-impact publications. Results: We outlined the mechanistic basis of AAV toxicity—spanning innate and adaptive immune activation, vector–host interactions, transgene overexpression, and host vulnerability—and discussed their therapeutic implications for DMD. We also highlighted ongoing strategies for vector re-design, immune modulation, patient selection, and regulatory adaptation, aiming to improve efficacy with safety in the next generation of muscular dystrophy gene therapies. Conclusions: Patient safety remains the number one priority in the AAV-mediated gene therapies field. Achieving long-term benefits requires continued optimization of existing vectors, implementation of strict criteria for patient selection, and regulation of immune responses, with close collaboration and transparent dialog among scientists, clinicians, and regulatory agencies, informed by both successful cases as well as tragic deaths reported in the fields of neuromuscular diseases. Full article

West Nile virus (WNV) is a mosquito-borne flavivirus with one of the widest global distributions. Since its discovery in Uganda in 1937, it has become a major zoonotic pathogen, and after its introduction into the United States in 1999, it spread rapidly across the Americas, becoming the leading cause of neuroinvasive arboviral disease. Its expansion illustrates a remarkable ecological adaptability, further intensified by climate change. In Latin America and the Caribbean, WNV circulation has been consistently documented in birds, horses, and mosquitoes; however, confirmed human cases remain disproportionately scarce compared with North America and Europe. Reports include sporadic human cases in Brazil (>100 since 2014), Mexico (~13), Argentina (2006–2007), Puerto Rico (2007), Nicaragua, and Haiti, while animal and vector evidence extends to Guatemala, El Salvador, Belize, Costa Rica, Bolivia, Paraguay, Colombia, Venezuela, Cuba, and Ecuador. This paradox likely reflects structural limitations within regional health systems, including underdiagnosis, restricted diagnostic capacity, and significant surveillance gaps, particularly in contexts where mild febrile syndromes may be misclassified as dengue, Zika, or Chikungunya. The regional risk of emergence is further amplified by climatic variability, ecological change, and intensifying human–wildlife interactions. Experiences from Europe highlight the importance of early detection, transfusion safety, and integrated surveillance within a One Health framework. Strengthening preparedness in Latin America will require investments in diagnostic infrastructure, implementation of standardized seroepidemiological surveys, development of predictive models tailored to local ecological contexts, and robust intersectoral collaboration. Full article

Hepatitis E virus (HEV) is a zoonotic pathogen that can infect pregnant women and cause adverse pregnancy outcomes, including miscarriage and preterm delivery. The previous study demonstrated that HEV genotype 3 (HEV-3) inhibits complete autophagic flux in both mouse placental tissue and human trophoblast cells (JEG-3), evidenced by reduced expression of ATG proteins (including LC3, Beclin1, ATG4B, ATG5, and ATG9A) and accumulation of p62. However, the specific regulatory pathway involved remains unclear. Thus, eukaryotic expression vectors for HEV open reading frames (ORFs) were constructed, and ORF2 and ORF3 proteins were transiently overexpressed in JEG-3 cells via liposome transfection. While both ORF2 and ORF3 significantly reduced LC3B protein levels (p < 0.01), only ORF2 induced p62 accumulation (p < 0.01), indicative of autophagic inhibition, which indicates that ORF2 was the key viral protein mediating autophagy suppression in JEG-3. The results of WB and RT-qPCR showed that ORF2 suppressed the PI3K/Akt/mTOR pathway while enhancing nuclear translocation of TFEB (p < 0.01) and AMPK phosphorylation (p < 0.01), suggesting paradoxical activation of upstream autophagy regulators. Through co-transfection of mCherry-LC3 with ORF2, co-localization studies, and AlphaFold 3-based intermolecular interaction predictions, we propose that ORF2 directly binds LC3B to block autophagosome formation. Finally, co-immunoprecipitation confirmed physical interaction between HEV ORF2 and LC3B, elucidating the molecular mechanism of HEV-induced autophagy suppression in trophoblasts. These findings reveal the molecular mechanism by which HEV inhibits autophagy leading to miscarriage in mice, providing new insights into HEV-induced reproductive damage. Full article

Plant viral diseases cause significant agricultural losses worldwide and are shaped by complex virus-host and virus-virus interactions. Unlike fungal or bacterial pathogens, viruses cannot be directly controlled with chemicals, and their management relies on insect vector control and the development of virus-resistant plant varieties. Plants deploy endogenous epigenetic (DNA/chromatin-based) and epitranscriptomic (RNA-based) mechanisms to limit viral infections. RNA silencing pathways, particularly post-transcriptional gene silencing (PTGS) mediated by small RNAs, restrict viral replication and shape viral populations. Additional layers, including RNA-directed DNA methylation (RdDM), N6-methyladenosine (m⁶A) RNA modifications, histone modifications and chromatin remodeling, further modulate host–virus interactions. DNA methylation can be inherited and may confer resistance to future generations, although its stability is partial and context-dependent. Virus-derived 24-nt small interfering RNAs (siRNAs) act as mobile signals, inducing systemic gene silencing and potentially influencing viral population dynamics. Understanding these epigenetic and epitranscriptomic mechanisms can improve virus diagnosis, pathogenesis studies and disease management, while also providing insights into viral diversity and co-infection dynamics. This review synthesizes current knowledge of these mechanisms and discusses their implications for developing sustainable antiviral strategies. Full article

Vectoring tomato spotted wilt virus (TSWV) by two well-known thrips species, Frankliniella occidentalis Pergande and F. intonsa Trybom (Thysanoptera: Thripidae), is facilitated in different ways. Symbiotic bacteria positively influence thrips fitness, but the interaction between these bacteria and tospovirus inside the thrips’ body remains unknown. Metagenomic profiling of symbionts in nonviruliferous and viruliferous Frankliniella thrips was performed to elucidate the interactions between symbiotic bacteria and the virus. A total of 97 operational taxonomic units (OTUs) were identified by profiling the microbes, where Proteobacteria was the most abundant phylum, with a high richness in Serratia spp. F. occidentalis showed lower variation in bacterial diversity between nonviruliferous and viruliferous treatments than F. intonsa. RT-qPCR validation for Serratia and Escherichia revealed opposite abundance patterns between the two thrips species. In contrast, Enterobacteriaceae and Pantoea showed similar patterns with higher abundance in nonviruliferous conditions. Wolbachia was detected exclusively in F. intonsa, with a higher bacterial titer in the viruliferous sample. Our findings suggest that TSWV association may influence the abundance of different bacterial symbionts within the thrips’ body, potentially via induction of antimicrobial peptides in response to viral invasion, and to our knowledge this is the first report addressing this tripartite interaction. These findings improve our understanding of how virus–symbiont association contributes to thrips vector competence. Full article

Tomato brown rugose fruit virus (ToBRFV), a highly stable and mechanically transmissible tobamovirus, poses a significant threat to solanaceous crops worldwide, particularly tomato (Solanum lycopersicum). While its transmission via human activities and contaminated materials is well-documented, the role of common phytophagous insects in its epidemiology remains less understood. Henosepilachna vigintioctopunctata, the Hadda beetle, is a common pest of Solanaceae with a host range that overlaps extensively with that of ToBRFV. This study aimed to quantify the beetle’s capacity to act as a mechanical vector and to assess its potential epidemiological impact. Using reverse transcription quantitative PCR (RT-qPCR), we evaluated beetle-mediated transmission efficiency, the persistence of its virus-carrying capacity, and its ability to vector the virus to various solanaceous hosts. Our results demonstrate that H. vigintioctopunctata efficiently acquires and transmits ToBRFV to tomato and other key hosts, including black nightshade (S. nigrum), pepper (Capsicum annuum), and eggplant (Solanum melongena). The virus was retained and remained transmissible by beetles for up to 48 h post-acquisition, providing a significant window for dispersal. Viral particles were most abundant in the digestive tract, consistent with ingestion of infected tissue, and declined rapidly on external body parts, confirming a non-circulative, mechanical transmission mechanism. Furthermore, feeding wounds created by non-viruliferous beetles increased plant susceptibility to subsequent infection from environmental contamination. We conclude that H. vigintioctopunctata acts as a potential mechanical vector that might amplify ToBRFV spread at local and landscape levels. This highlights a synergistic interaction between a native pest and an invasive pathogen, underscoring the necessity of incorporating beetle management into integrated strategies for controlling ToBRFV. Full article