West Nile virus (WNV), a mosquito-borne flavivirus, has circulated in the United States since 1999. In 2025, Florida was home to 24 million people, with projected increases in population and urbanization in a changing climate. The southern house mosquito, Culex quinquefasciatus, is found in every county, and is a major vector for WNV. Describing shifting WNV transmission risk is important to inform public health and vector control planning. Using published estimates of thermal suitability of WNV transmission by Cx. quinquefasciatus, with climate models and population data, we calculated and mapped baseline and projected county-level transmission suitability and people at risk for 2000, 2030, and 2050. Five general circulation models and two mitigation scenarios (SSP2-4.5, SSP5-8.5) were used to explore future trajectories. At baseline, all 67 counties in Florida experienced 5-9 months of transmission suitability. Using the year 2000 census estimates, 2.33 million people in 2 counties experienced 9 months, and in 2030, across climate models, 8.93-12.26 million people (10-20 counties; SSP2-4.5), and 8.95-18.10 million people (11-26 counties; SSP5-8.5) are projected to experience 9 or more months of transmission suitability. In 2050, for both SSP2-4.5 and SSP5-8.5, 17.08-20.42 million people (23-26 counties), ranging to approximately 70% of the projected population of Florida will experience 9 or more months. The 10 most populated counties in 2000 are projected to experience 1-3 months of additional climate-driven transmission suitability in the future. The southern house mosquito was previously managed as a seasonal nuisance in Florida, but now represents an increasing public health exposure risk. Projections across climate trajectories underscore an increasing suitability and exposure risk for WNV in Florida, ranging as high as around 70% of the population exposed to suitable climate conditions for transmission for 9 or more months of the year in the 2050s. This means the types of operations and number of employees needed in vector control and public health will also increase.

Integrative bioinformatics prediction of West Nile Virus-derived microRNAs reveals potential host regulatory interactions.

Systematic transcriptomic analysis enables targeted drug repurposing for neurotropic flavivirus infections.

“Persistent ecological impacts related to West Nile virus revealed using community science and vector surveillance data”

West Nile Virus inhibits type I interferon response via TRIM71 in human microglial cells.

Mosquito-borne orthoflaviviruses, such as Japanese encephalitis virus (JEV), West Nile virus (WNV), dengue virus (DENV), and Zika virus (ZIKV), pose considerable public health challenges due to their zoonotic potential and the absence of specific therapeutics. Conventional detection methods exhibit critical limitations in multiplexing capability, prolonged turnaround time, and procedural complexity. These factors hinder rapid outbreak response and underscore the necessity for improved detection platforms. This study developed a quadruplex quantitative real-time PCR (qRT-PCR) assay utilizing Minor Groove Binder (MGB) probes for the simultaneous detection of JEV, WNV, DENV, and ZIKV. The MGB probe-based qPCR assay demonstrated high specificity in distinguishing these four orthoflaviviruses and exhibited significantly enhanced sensitivity compared to conventional TaqMan probes, achieving detection limit of 2 copies/reaction. This method was successfully applied to detect virus-positive samples in cell cultures, laboratory mosquitoes, and field-collected mosquitoes, thereby validating the practical utility of the MGB probe-based qPCR assay. Compared to conventional multiplex detection methods, our MGB-based approach provides a promising detection platform, thereby demonstrating its potential utility in the high-throughput surveillance of mosquito-borne orthoflaviviruses.

Viral encephalitis (VE), is a life-threatening neurological disorder marked by inflammation of brain parenchyma, driven by direct viral cytotoxicity and host immune-mediated injury. Globally, its incidence ranges from 1.4 to 13.8 cases per 100,000 individuals annually, with significant morbidity and mortality in endemic regions such as India, among children. Neurotropic viruses including herpes simplex virus (HSV), Japanese encephalitis virus (JEV) and West Nile virus, enter central nervous system via hematogenous or neuronal routes, triggering viral replication, cytokine release and blood-brain barrier disruption, resulting in seizures, cerebral edema and long-term neurological deficits. Current management in neurological intensive care relies on immunity-oriented strategies: Acyclovir as first-line antiviral for HSV and varicella-zoster virus, antiepileptics to control seizures and limit secondary neuronal injury and corticosteroids to modulate harmful neuroinflammation and cerebral edema. Emerging therapies, including novel antivirals (favipiravir, remdesivir, brincidofovir), monoclonal antibodies, cytokine inhibitors (tocilizumab, anakinra) and B-cell/plasma cell-targeted agents (rituximab, daratumumab), offer promise by simultaneously addressing viral replication and immune dysregulation. Personalized biomarker-guided integrating pathogen-directed and host-targeted therapies may optimize outcomes, reduce neuronal injury and improve recovery. This review underscores the importance of a multidimensional, immunity-oriented treatment paradigm, highlighting both established and emerging strategies to enhance prognosis and long-term neurological functions in patients with viral encephalitis.

West Nile Virus Infections in Children: What Clinicians Need to Know.

West Nile virus (WNV) remodels the endoplasmic reticulum (ER) membrane in cells to aid virus production. However, the molecular mechanisms underlying this process remain unclear. PDZD8 is an ER-resident protein that mediates ER-mitochondria contact and lipid transfer, both of which are associated with membrane remodeling. In this study, we found that WNV infection suppressed the expression of PDZD8, leading to a reduction in ER-mitochondria contact sites. By contrast, PDZD8 suppressed WNV production by inhibiting the processes of viral particle assembly and release. These findings suggest that WNV suppresses PDZD8 expression to partially counteract its inhibitory effect on WNV production.

Orthoflavivirus, such as West Nile Virus (WNV), dengue virus (DENV), and ZIKA virus (ZIKV), are globally distributed pathogens that pose substantial threats to human health. Currently, there are still no effective antiviral drugs for WNV or ZIKV. Despite the availability of two licensed DENV vaccines, their use remains limited due to potential risks, highlighting an urgent need for antiviral drug development. The highly conserved orthoflavivirus protease NS2B/NS3 is required for viral replication, making it a promising antiflavivirus target. A major challenge, however, is the highly charged active site of this enzyme, which requires charged chemical matters with low bioavailability. An alternative and more attractive strategy is to target potential allosteric sites or folding intermediate states of the protease. In this work, we employ the topology-based coarse-grained Go̅ modeling to explore the coupled binding and folding pathways of WNV NS2B/NS3 protease and study the effects of the widely used experimental construct with a G4SG4 linker between NS2B and NS3 on stability and folding. Our results provide a holistic conformational landscape of protease binding and folding, including several key intermediate states. We find that the presence of the G4SG4 linker alters the folding pathways and destabilizes the NS2B C-terminus. The latter is consistent with experimental observations that the G4SG4-linked protease has lower activity and adopts an open state without the substrate in crystal structures. Together, these findings provide, for the first time, a complete picture of the binding and folding of the NS2B/NS3 protease and identify important folding intermediate states that could be targeted for allosteric antiviral drug development.

Human outbreaks of West Nile virus (WNV) are an imminent threat in North America, with many annual infections and numerous cases of severe neuroinvasive disease. There are no licensed treatments for WNV disease. Previous research identified WNV-86 as an ultrapotent neutralizing human antibody that binds domain II of the major envelope (E) glycoprotein in mature virions. Here, we report the structure of mature WNV in complex with the Fab of WNV-86, at a resolution of 3.8 Å, solved using cryogenic electron microscopy. Structure-based epitope mapping identifies a new class of E dimer epitope (EDE) antibodies that we designate as EDE3 antibodies. A partial overlap of WNV-86 and pre-membrane protein (prM) binding regions at more than one site ensures selective binding of WNV-86 to mature virions. The structure reveals the quaternary epitope of the neutralizing Fab and supports a model in which engaging both protomers of the dimer likely interferes with fusion-triggering rearrangements. This study identifies critical residues for binding, neutralization, and immune escape and clarifies the promise of this molecule for future immunotherapeutic interventions.

Transcriptional profiling of the Crocodylus porosus liver cell response to Kunjin virus reveal novel insights into the host-virus interface.

Arboviral diseases in Indonesia remain a public health problem and a threat. The annual increase in cases is caused by changes in bioclimatological factors, increased reports of resistance to insecticides and larvicides, and low community participation in vector control, resulting in an uncontrolled abundance of the species. Therefore, an alternative, safe, effective, and evidence-based vector control approach is needed. This narrative review, conducted via the SANRA protocol encompassing PubMed, Scopus, and Web of Science (2014-2024), aims to (1) synthesize current Insect-Specific Flavivirus (ISF) biology, classification, and distribution with emphasis on Indonesia and Southeast Asia; (2) evaluate evidence for ISF-mediated interference with pathogenic flavivirus transmission; (3) compare ISF with Wolbachia-based biocontrol strategies; and (4) identify research priorities and implementation considerations for ISF-based vector control in Indonesia. Eleven articles were further analyzed. Three ISF species ( cell-fusion agent virus , Culex flavivirus , and Aedes flavivirus ) have been detected in Indonesian mosquito populations. Experimental studies have shown that Nhumirim virus reduces Zika transmission, whereas Palm Creek virus suppresses West Nile virus replication. The Binjari virus -based chimeric vaccine platform produced a good prevention and control model; however, the varying vertical transmission of ISF, lack of field validation, and absence of a regulatory framework are barriers to implementation. However, ISF still requires optimization of population persistence and the development of large-scale application methods. Research priorities include field effectiveness validation, characterization of ISF interactions, and development of standardized release protocols for the translation of ISF technology as a complement to integrated vector control in Indonesia.

Orthoflaviviruses are genetically related, yet cause distinct disease patterns ranging from hepatitis and vascular shock syndrome to encephalitis and congenital abnormalities. There is an incomplete understanding of the cellular pathways co-opted by orthoflaviviruses, and differences in host response to infection may underlie the diverse pathologies caused. We present a single-cell approach (Quantification of Infection and CRISPR guide sequencing; QIC-seq) that combines CRISPR/Cas9 knockout with virus-inclusive transcriptomics to systematically compare host factor requirements and host transcriptional response to orthoflaviviral challenge. Using a CRISPR library focused on select ER-proteostasis genes, we show that dengue and yellow fever viruses are strictly dependent on subunits of the oligosaccharyltransferase complex, while the more distantly related West Nile and Langat viruses are dependent on components of the ER-associated degradation machinery. Our data further shows virus-induced upregulation of interferon-stimulated genes, and activation of the unfolded protein response. QIC-seq enables quantitative comparisons of viral host factor utilization, which may inform development of host-directed antiviral therapies.

Culex mosquitoes are widespread in temperate regions and play a key role in transmitting veterinary and human vector-borne diseases. In the United Kingdom, Culex pipiens s.l. is highly prevalent and a competent vector of West Nile and Usutu viruses. Coupled with the northward expansion of West Nile virus in Europe, this raises concerns about emergence in the UK. For public and animal health preparedness, and effective vector control planning, it is essential to better understand the distribution of Culex mosquitoes in this area.This study developed species distribution maps for Culex pipiens pipiens, Culex pipiens molestus, and Culex torrentium abundance using data from the first nationwide stratified active mosquito surveillance programme in England and Wales in 2023, supplemented with adaptive surveillance in 2024. Culex p. pipiens models predicted higher abundances than the other two taxa. Regions of high abundance occurred across most of England, apart from the northwest, with the highest in eastern regions and estuarine areas. In contrast, higher elevation areas, including most of Wales, the North Pennines, and Yorkshire Dales, showed markedly lower abundances. Environmental drivers differed between forms. Culex p. pipiens abundance was strongly associated with precipitation-related covariates, whereas Culex p. molestus was mostly influenced by temperature covariates. These findings highlight the importance of modelling the two forms separately in risk analyses and distribution studies.The resulting models provide timely ecological insights to support surveillance prioritisation and provide a foundation for future work aimed at guiding public health planning and targeted vector management.

IntroductionEmerging infectious diseases (EIDs) cause significant health and economic burdens in the USA and globally. Existing methods and analyses fall short of what is required to prioritise diseases for health technology research and development (R&D), including for medical countermeasure (MCM) development within rapid response frameworks by the Center for Biomedical Advanced Research and Development Authority, part of the Administration for Strategic Preparedness and Response within the U.S. Department of Health and Human Services.MethodsWe developed a method for quantifying and ranking health and economic disease burdens (‘full burdens’) and applied it to 15 high-priority EIDs for 223 countries and territories, including the USA and US territories, historically from 2000 to 2022 and prospectively from 2025 to 2034. Health burdens consisted of disability-adjusted life-year losses, converted into monetary values using the value of a statistical life-year. Economic burdens consisted of direct and indirect costs during the acute stage of illness for hospitalised cases. We computed unweighted and weighted burden measures, the latter controlling for global disparities in ability-to-pay to avoid EID burdens. We projected future disease burdens using Monte Carlo simulation.ResultsPandemics caused the largest historical and projected unweighted and weighted full burdens in the USA and globally. Among non-pandemics, across unweighted and weighted burdens, dengue and cholera imposed the largest historical and projected full burdens globally; West Nile Virus imposed the largest historical and projected full burdens in the USA, and dengue imposed the largest historical full burdens in the US territories. Weighted full burdens exceeded five times the unweighted ones. Regionally, the Americas and Africa faced the largest per capita weighted burdens while the Western Pacific region faced the smallest.ConclusionR&D priority-setting, including MCM development, depends on multiple criteria, including disease burdens. Our full burden quantification methods and results, along with other such criteria, can inform optimal priority-setting.

Detection and sequencing of Usutu virus during mosquito surveillance: Use of multiple assays and techniques for identification at low levels.

Background/Objectives: West Nile virus (WNV) remains a significant threat to human health, with no approved antiviral treatments or vaccine available. A better understanding of the molecular mechanisms governing flavivirus-host interactions is needed to identify host regulatory pathways involved in infection. This study aimed to investigate how WNV infection remodels the host miRNA-mRNA regulatory landscape. Methods: WNV-induced changes in host miRNA expression in HEK-293 cells were profiled using miRNA-Seq. Transcriptome-wide host gene expression changes in WNV-infected cells were analysed using RNA-Seq. Gene Ontology and pathway enrichment analyses were conducted using DAVID. Integrated miRNA-mRNA network reconstruction was performed using Cytoscape based on the experimentally validated miRNA-mRNA interactions in miRNet database. Results: WNV infection induced global changes in host miRNA expression, with pathogenic NY99 and non-pathogenic Kunjin strains of the virus producing overlapping and strain-specific alterations in the miRNA landscape. Transcriptome analysis showed strong induction of interferon-related responses and activation of NF-κB and MAPK signalling pathways in the infected cells. In contrast, pathways associated with RNA processing, splicing, and proteasomal degradation were downregulated. Integrated miRNA-mRNA network analysis identified miR-197-3p, miR-301b-3p, miR-129-3p, miR-3662, and miR-128-5p as candidate regulatory hubs involved in WNV-induced transcriptome remodelling. These networks suggested that miRNA-mediated regulation may influence antiviral signalling, apoptosis, and RNA metabolism during infection. Conclusions: These findings suggest that WNV infection broadly remodels host miRNA-mRNA regulatory networks and identifies candidate miRNAs that may contribute to the regulation of antiviral and cellular stress responses. These predicted regulatory interactions provide a foundation for future experimental validation.

Emerging and re-emerging arboviral infections are a risk to blood safety. We conducted an international survey on how blood establishments respond to current and future arbovirus threats. A questionnaire on arbovirus donor deferral strategies, pathogen reduction, and donation screening was distributed to members of the International Society of Blood Transfusion working party on transfusion-transmitted infectious diseases. Data from 2024 were gathered and analyzed. A total of 23 survey responses were received from 21 countries. This covered a population of 1.45 billion people and 29.9 million blood donations collected in 2024. All respondents applied travel-based donor deferrals, whereas pathogen reduction, implemented by half of the respondents, was mostly applied for a selection of plasma and platelet donations. West Nile virus (WNV) was the only arbovirus blood donations were screened for by nine respondents from eight countries, with 256 donations confirmed as WNV RNA-positive in 2024. No transfusion-transmitted WNV infections were reported. Blood safety measures remain limited and unevenly distributed globally, and in their present form, are unlikely to provide protection against the growing range of emerging arboviruses. Donor deferral may not always be a sustainable blood safety strategy alone for all blood operators, due to large-scale outbreaks associated with these viruses. While pathogen reduction methodologies are being developed to be applied to all blood components, risk assessments for (re)-emerging arboviruses, such as dengue, chikungunya, and Zika viruses, should be performed to determine if additional mitigation, such as blood donation screening, is warranted.

The Asian bush mosquito, Aedes japonicus (Theobald, 1901), is an invasive species and a competent vector for several arboviruses, including chikungunya virus, dengue virus, Japanese encephalitis virus, West Nile virus, and Zika virus. Field studies have also detected La Crosse virus in wild populations, further supporting its potential role in arbovirus transmission. To address the fragmented and incomplete state of knowledge regarding its spread, we have assembled a global dataset of documented presences from 1950 to 2025. This data descriptor presents a curated database of geolocated records, formatted as points, derived primarily from peer-reviewed literature and supplemented with validated national survey data and selectively integrated records from the Global Biodiversity Information Facility (GBIF) following rigorous quality control. We detail the methodology for data acquisition, coordinate assignment, and the rigorous validation steps applied. This first comprehensive repository specifically for Ae. japonicus, containing 4618 validated records, provides a critical resource for spatial mapping and risk assessment of this vector and its associated pathogens.