West Nile Virus Infection Research Articles

Subgenomic flaviviral RNAs and human proteins: in silico exploration of anti-host defense mechanisms

Flaviviruses pose significant global health threats, infecting over 300 million people annually. Among their evasion strategies, the production of subgenomic flaviviral RNAs (sfRNAs) from the 3′ UTR of viral genomes is particularly notable. Utilizing a comprehensive in silico approach with the catRAPID algorithm, we analyzed over 300,000 interactions between sfRNAs and human proteins derived from more than 8000 flavivirus genomes, including Dengue, Zika, Yellow Fever, West Nile, and Japanese Encephalitis viruses. By providing the first extensive atlas of sfRNA interactions, we offer new insights into how flaviviruses can manipulate host cellular machinery to facilitate viral survival and persistence. Our study not only validated known interactions but also revealed novel human proteins that could be involved in sfRNA-mediated host defense evasion, including helicases, splicing factors, and chemokines. These findings significantly expand the known interactome of sfRNAs with human proteins, underscoring their role in modulating host cellular pathways. Intriguingly, we predict interaction with stress granules, a critical component of the cellular response to viral infection, suggesting a mechanism by which flaviviruses inhibit their formation to evade host defenses. Moreover, a set of highly-interacting proteins in common among the sfRNAs showed predictive power to identify sfRNA-forming regions, highlighting how protein signatures could be used to annotate viruses. This atlas not only serves as a resource for exploring therapeutic targets but also aids in the identification of sfRNA biomarkers for improved flavivirus diagnostics.

Differential susceptibility of human motor neurons to infection with Usutu and West Nile virus

West Nile virus (WNV) and Usutu virus (USUV) are closely related flaviviruses with differing capacities to cause neurological disease in humans. WNV is thought to use a transneural route of neuroinvasion along motor neurons and causes severe motor deficits. The potential for use of transneural routes of neuroinvasion by USUV has not been investigated experimentally, and evidence from the few clinical case reports of USUV-associated neuroinvasive disease is lacking. We hypothesised that, compared with WNV, USUV is less able to infect motor neurons, and therefore determined the susceptibility of human induced pluripotent stem cell (iPSC)-derived spinal cord motor neurons to infection. Both viruses could grow to high titres in iPSC-derived neural cultures. However, USUV could not productively infect motor neurons due to restriction by the antiviral response, which was not induced upon WNV infection. Inhibition of the antiviral response allowed for widespread infection and transportation of USUV along motor neurons within a compartmented culture system. These results show a stark difference in the ability of these two viruses to evade initiation of intrinsic antiviral immunity. Our data suggests that USUV cannot infect motor neurons in healthy individuals but in case of immunodeficiency may pose a risk for motor-related neurological disease and transneural invasion.

Seropositivity of West Nile virus among acute febrile patients in Ilorin, Nigeria.

West Nile Virus (WNV), a member of Flaviviridae family, is one of the most widely distributed arboviruses in the world. In developing countries like Nigeria, fever resulting from the WNV infection is often presumptively ascribed to malaria or typhoid due to misdiagnosis and low-level awareness of the viral infection. This study determined the prevalence of WNV IgM and IgG antibodies among febrile patients in the Ilorin metropolis. A total of two hundred (200) blood samples were collected from consenting patients and each serum was screened for anti-WNV IgM and IgG antibodies using indirect enzyme-linked immunosorbent assay (ELISA). Statistical correlation and logistic regression analysis were conducted. Overall, 6% (12/200) anti-WNV IgM seropositivity rate was recorded amongst the acute febrile patients with higher prevalence (6.30%) in females than in males (5.45%). Anti-WNV IgG positivity rate of 52% (104/200) was recorded, with 50.67% positivity rate in males and 38.95% in female participants. The convalescence phase posited by the 5.4% (11/200) co-detection of anti-WNV IgG and IgM antibodies among the participants was recorded. A statistical correlation was noticed with the age and religion of respondents to WNV serological positivity while gender, occupation, use of mosquito nets and formal education had no positive correlation at p < 0.05. However, based on odd ratio at 95% CI and logistic regression coefficients, the evaluated risk factors such as blood transfusion, residency, malaria parasite, and proximity to stagnant water and bush were significant to anti-WNV IgG and IgM positivity. The findings of this study show the circulation of WNV in the study area. There is an urgent need for clinicians/physicians to include screening for the West Nile virus in cases of febrile patients before the commencement of treatment.

Remote sensing of temperature-dependent mosquito and viral traits predicts field surveillance-based disease risk.

Mosquito-borne diseases contribute substantially to the global burden of disease, and are strongly influenced by environmental conditions. Ongoing and rapid environmental change necessitates improved understanding of the response of mosquito-borne diseases to environmental factors like temperature, and novel approaches to mapping and monitoring risk. Recent development of trait-based mechanistic models has improved understanding of the temperature dependence of transmission, but model predictions remain challenging to validate in the field. Using West Nile virus (WNV) as a case study, we illustrate the use of a novel remote sensing-based approach to mapping temperature-dependent mosquito and viral traits at high spatial resolution and across the diurnal cycle. We validate the approach using mosquito and WNV surveillance data controlling for other key factors in the ecology of WNV, finding strong agreement between temperature-dependent traits and field-based metrics of risk. Moreover, we find that WNV infection rate in mosquitos exhibits a unimodal relationship with temperature, peaking at ~24.6-25.2°C, in the middle of the 95% credible interval of optimal temperature for transmission of WNV predicted by trait-based mechanistic models. This study represents one of the highest resolution validations of trait-based model predictions, and illustrates the utility of a novel remote sensing approach to predicting mosquito-borne disease risk.

Application of chimeric antigens to paper-based diagnostics for detection of West Nile virus infections of Crocodylus porosus – A novel animal test case

Laboratory-based diagnostics such as plaque reduction neutralisation tests (PRNT) and ELISA are commonly used to detect seroconversion to flavivirus infections. However, faster, qualitative screening methods are essential for quicker diagnosis and improved patient outcomes. Lateral flow assays (LFAs) offer rapid results (5–15 mins) at the point-of-care, but few commercial flavivirus antibody detection LFAs are available.We developed an LFA using novel chimeric viral antigens produced by genetically modifying the mosquito restricted Binjari virus (BinJV) to display the outer virion proteins of pathogenic viruses like West Nile virus (WNV). The BinJV chimeric platform offers several advantages for diagnostic assay development, including rapid construction of new chimeras in response to emerging viral variants, safe, scalable antigen manufacturing, and structural indistinguishability to the wild-type pathogenic virion.To demonstrate feasibility, we applied the chimeric WNV (BinJV/WNV) antigen to LFA as the capture/test line reagent for detecting seroconversion in crocodilians to WNV – a virus affecting crocodilians across multiple continents. We confirmed the antigenic conservation of the chimera on the LFA detection surface using monoclonal antibodies. Utilising well-characterised sera (n=60) from WNV-seropositive or flavivirus-naive Australian saltwater crocodiles (Crocodylus porosus), the assay exhibited 98.8 % sensitivity and 100 % specificity, with results obtained in under 15 minutes. The LFA also accurately detected seroconversion in animals experimentally infected with WNV.This qualitative screening method can be performed both inside and outside of a laboratory, and the assay design will guide the optimisation of similar tests for detecting vector-borne viral infections in humans and other animals.

Detection of RNA Markers of West Nile Virus in Zoological and Entomological Material from Various Regions of the European Part of Russia in 2021–2023

Relevance. In epidemiological surveillance of West Nile fever (WNF), infection of West Nile virus (WNV) in zoological and entomological material is an important indicator of the activity of the natural focus, which can be used to predict the development of the epidemiological situation, adjust the scope and timing of prophylactic and anti-epidemic measures. It is noteworthy that there were no positive findings or single detections of WNV markers in zoological and entomological material in most subjects of the European part of the Russia. Aims. To obtain estimated data on the intensity of the epizootic process of WNF in the territory of the European part of Russia. Materials and methods. Collection of zoological and entomological material of WNV in 2021-2023 was conducted in the territories of 32 entities of the Russian Federation in accordance with the current regulatory and methodological documents. Field material was analyzed by RT-PCR using the AmpliSense WNV-FL test system, and genotyping of samples positive for WNV RNA was performed using the Ampligen-WNV-genotype-1/2/4 test system. Results and Discussion. During the period 2021–2023, in the course of this study vertebrates were captured: 774 birds, 1126 small mammals, and 22 frogs; and arthropods were collected: 142600 bloodsucking mosquitoes, 33 bloodsuckers, 3070 midges, 14049 ixodid ticks, and 71 argas ticks. WNV RNA was detected in 9 out of 1922 studied vertebrate animals and in 112 out of 8047 pools of blood-sucking arthropods. The infection rate of blood-sucking mosquitoes was 0.07%, ixodid ticks – 0.09%, birds – 0.9%, frogs – 9.1%, which indicates that these animal groups are widely involved in the epizootic process. Markers of WNV in field material were detected in 14 entities. In 6 of them positive findings were obtained for the first time. WNV RNA of 1 genotype was detected in pools from the Central Federal District, 2 genotypes - in all surveyed districts, 4 genotypes - from the Southern Federal District. Conclusions. Active reconnaissance studies led to the expansion of our ideas about the existence of WNF foci in the European part of Russia. In populations of birds and blood-sucking arthropods in this area, WNV is steadily circulating. WNV-infected birds were found in the Southern Federal District and the Central Federal District, mosquitoes – in all surveyed federal districts, amphibians and ticks – only in the Southern Federal District

Scrub Typhus Meningoencephalitis Presenting as Generalized Convulsive Status Epilepticus with Basal Ganglia and Extra-limbic Cortical Involvement, Complicated by Cortical Multifocal Myoclonus

Background Scrub typhus is an acute febrile infectious disease highly prevalent in the Asia Pacific region, often referred to as the “tsutsugamushi triangle.” This mite-borne rickettsial zoonosis is caused by Orientia tsutsugamushi, an intracellular Gram-negative organism that primarily targets endothelial cells. The resulting vasculitis leads to multisystem involvement. In terms of neurological manifestations, meningoencephalitis is the most common presentation of scrub typhus. Other frequent neurological manifestations include cranial nerve paresis, transverse myelitis, and polyneuropathy. Status epilepticus, while reported, is a rare presenting feature of this infection. Although scrub typhus has been documented to present as limbic encephalitis, there have been no previous descriptions in the literature of neuroradiological patterns affecting the basal ganglia or extra-limbic cortices in this condition. Case Report We report a case of a 23-year-old previously healthy woman who presented with scrub typhus meningoencephalitis. The condition manifested as encephalitis with involvement of the basal ganglia and extra-limbic cortices. She presented with generalized convulsive status epilepticus, which was complicated by cortical multifocal myoclonus. Discussion Scrub typhus can be a significant diagnostic challenge, potentially presenting with generalized convulsive status epilepticus and mimicking both clinical and radiological features of arboviral encephalitides, such as those caused by West Nile and Japanese encephalitis viruses. Furthermore, as demonstrated in this case, its radiological presentation can resemble that of autoimmune encephalitis. Given that scrub typhus is amenable to treatment with antibiotics, such as doxycycline and azithromycin, which do not increase seizure risk, it should be considered in the differential diagnosis for patients presenting with seizures or encephalitis, especially in endemic areas.

West Nile virus triggers intestinal dysmotility via T cell-mediated enteric nervous system injury.

Intestinal dysmotility syndromes have been epidemiologically associated with several antecedent bacterial and viral infections. To model this phenotype, we previously infected mice with the neurotropic flavivirus, West Nile Virus (WNV) and demonstrated intestinal transit defects. Here, we find that within one week of WNV infection, enteric neurons and glia become damaged, resulting in sustained reductions of neuronal cells and their networks of connecting fibers. Using cell-depleting antibodies, adoptive transfer experiments, and mice lacking specific immune cells or immune functions, we show that infiltrating WNV-specific CD4+ and CD8+ T cells damage the enteric nervous system (ENS) and glia, which leads to intestinal dysmotility; these T cells use multiple and redundant effector functions including perforin and Fas ligand. In comparison, WNV-triggered ENS injury and intestinal dysmotility appears to not require infiltrating monocytes and damage may be limited by resident muscularis macrophages. Overall, our experiments support a model whereby antigen specific T cell subsets and their effector molecules responding to WNV infection direct immune pathology against enteric neurons and supporting glia that results in intestinal dysmotility.

Presumptive West Nile Virus infection in a Komodo Dragon (Varanus komodoensis)

Abstract A 3-yr-old, male Komodo dragon (Varanus komodoensis) presented acutely in early October 2021 with an abnormal posture and asymmetric tetraparesis. The subadult lizard had spent the previous 4 months either in an outdoor space or in an indoor space with open windows. Physical examination, radiographs, and complete blood count and chemistry panel failed to reveal the cause of the neurologic signs. West Nile virus (WNV) plaque reduction serum neutralization on presentation was negative (1:20), as was WNV polymerase chain reaction (PCR) testing and viral isolation on whole blood. Empirical treatment with a daily corticosteroid, course of antibiotics, and encouragement of mild exercise was initiated. Magnetic resonance imaging of the brain and spinal cord was unremarkable, and a lumbar cerebrospinal fluid (CSF) tap revealed a mononuclear pleocytosis and protein elevation. Follow-up WNV serology revealed rising titer and seroconversion 13 days after presentation (1:80) and 32 days after presentation (1:640); however, WNV PCR testing of CSF fluid was negative. Thi Komodo dragon gradually improved over six weeks before being put back on public display 74 days after presentation. The WNV titer remained high (1:640) through the winter of 2021-22, and an anamnestic response was observed following a vaccination series with a killed equine vaccine in the spring of 2022. There is a previous brief report of WNV infection in a captive crocodile monitor (Varanus salvadorii), and an unpublished case in the same species at the first author’s institution. This is the first report of neurologic disease from presumptive WNV infection in a Komodo dragon. We recommend that WNV infection be a differential diagnosis if a varanid lizard present with acute neurologic signs with a history of arthropod vector exposure, particularly in the summer or fall.

Etravirine Prevents West Nile Virus and Chikungunya Virus Infection Both In Vitro and In Vivo by Inhibiting Viral Replication.

Diseases transmitted by arthropod-borne viruses such as West Nile virus (WNV) and chikungunya virus (CHIKV) pose threat to global public health. Unfortunately, to date, there is no available approved drug for severe symptoms caused by both viruses. It has been reported that reverse transcriptase inhibitors can effectively inhibit RNA polymerase activity of RNA viruses. We screened the anti-WNV activity of the FDA-approved reverse transcriptase inhibitor library and found that 4 out of 27 compounds showed significant antiviral activity. Among the candidates, etravirine markedly inhibited WNV infection in both Huh 7 and SH-SY5Y cells. Further assays revealed that etravirine inhibited the infection of multiple arboviruses, including yellow fever virus (YFV), tick-borne encephalitis virus (TBEV), and CHIKV. A deeper study at the phase of action showed that the drug works primarily during the viral replication process. This was supported by the strong interaction potential between etravirine and the RNA-dependent RNA polymerase (RdRp) of WNV and alphaviruses, as evaluated using molecular docking. In vivo, etravirine significantly rescued mice from WNV infection-induced weight loss, severe neurological symptoms, and death, as well as reduced the viral load and inflammatory cytokines in target tissues. Etravirine showed antiviral effects in both arthrophlogosis and lethal mouse models of CHIKV infection. This study revealed that etravirine is an effective anti-WNV and CHIKV arbovirus agent both in vitro and in vivo due to the inhibition of viral replication, providing promising candidates for clinical application.

Nifuroxazide Prevents Chikungunya Virus Infection Both In Vitro and In Vivo via Suppressing Viral Replication.

Chikungunya virus (CHIKV) is a reemerging arbovirus causing disease on a global scale, and the potential for its epidemics remains high. CHIKV has caused millions of cases and heavy economic burdens around the world, while there are no available approved antiviral therapies to date. In this study, nifuroxazide, an FDA-approved antibiotic for acute diarrhea or colitis, was found to significantly inhibit a variety of arboviruses, although its antiviral activity varied among different target cell types. Nifuroxazide exhibited relatively high inhibitory efficiency in yellow fever virus (YFV) infection of the hepatoma cell line Huh7, tick-borne encephalitis virus (TBEV) and west nile virus (WNV) infection of the vascular endothelial cell line HUVEC, and CHIKV infection of both Huh7 cells and HUVECs, while it barely affected the viral invasion of neurons. Further systematic studies on the action stage of nifuroxazide showed that nifuroxazide mainly inhibited in the viral replication stage. In vivo, nifuroxazide significantly reduced the viral load in muscles and protected mice from CHIKV-induced footpad swelling, an inflammation injury within the arthrosis of infected mice. These results suggest that nifuroxazide has a potential clinical application as an antiviral drug, such as in the treatment of CHIKV infection.

A single-cell atlas of the Culex tarsalis midgut during West Nile virus infection.

The mosquito midgut functions as a key interface between pathogen and vector. However, studies of midgut physiology and associated virus infection dynamics are scarce, and in Culex tarsalis - an extremely efficient vector of West Nile virus (WNV) - nonexistent. We performed single-cell RNA sequencing on Cx. tarsalis midguts, defined multiple cell types, and determined whether specific cell types are more permissive to WNV infection. We identified 20 cell states comprised of 8 distinct cell types, consistent with existing descriptions of Drosophila and Aedes aegypti midgut physiology. Most midgut cell populations were permissive to WNV infection. However, there were higher levels of WNV RNA (vRNA) in enteroendocrine cells and cells enriched for mitochondrial genes, suggesting enhanced replication in these populations. In contrast, proliferating intestinal stem cell (ISC) populations had the lowest levels of vRNA, a finding consistent with studies suggesting ISC proliferation in the midgut is involved in viral control. Notably, we did not detect significant WNV-infection induced upregulation of canonical mosquito antiviral immune genes (e.g., AGO2, R2D2, etc.) at the whole-midgut level. Rather, we observed a significant positive correlation between immune gene expression levels and vRNA in individual cells, suggesting that within midgut cells, high levels of vRNA may trigger antiviral responses. Our findings establish a Cx. tarsalis midgut cell atlas, and provide insight into midgut infection dynamics of WNV by characterizing cell-type specific enhancement/restriction of, and immune response to, infection at the single-cell level.

Combined Analysis of Multi-Study miRNA and mRNA Expression Data Shows Overlap of Selected miRNAs Involved in West Nile Virus Infections.

The emerging zoonotic West Nile virus (WNV) has serious impact on public health. Thus, understanding the molecular basis of WNV infections in mammalian hosts is important to develop improved diagnostic and treatment strategies. In this context, the role of microRNAs (miRNAs) has been analyzed by several studies under different conditions and with different outcomes. A systematic comparison is therefore necessary. Furthermore, additional information from mRNA target expression data has rarely been taken into account to understand miRNA expression profiles under WNV infections. We conducted a meta-analysis of publicly available miRNA expression data from multiple independent studies, and analyzed them in a harmonized way to increase comparability. In addition, we used gene-set tests on mRNA target expression data to further gain evidence about differentially expressed miRNAs. For this purpose, we also studied the use of target information from different databases. We detected a substantial number of miRNA that emerged as differentially expressed from several miRNA datasets, and from the mRNA target data analysis as well. When using mRNA target data, we found that the targetscan databases provided the most useful information. We demonstrated improved miRNA detection through research synthesis of multiple independent miRNA datasets coupled with mRNA target set testing, leading to the discovery of multiple miRNAs which should be taken into account for further research on the molecular mechanism of WNV infections.

Epidemiological situation of natural focal infections in the Volgograd region in 2022

The article is devoted to the analysis of the epidemiological situation of natural focal infections (NFI) in the Volgograd region in 2022. Materials and methods: The work used the official statistics of the institutions of Rospotrebnadzor on NFI for 2022. The main research method is epidemiological analysis. Results and discussion: It has been established that the numbers of small mammals, potential carriers of NFI, as well as ixodid ticks in the territory of the Volgograd region in the season of 2022 were higher than the same indicators of the previous year (SIPY). The number of mosquitoes, carriers of arbovirus infections, did not exceed the average long-term indicators in any species. When examining environmental objects for the presence of markers of NFI pathogens, a slight increase in the proportion of positive samples compared to SIPY in all nosological forms was noted. Sporadic cases of West Nile fever (WNF), Crimean hemorrhagic fever (CHF), hemorrhagic fever with renal syndrome (HFRS), ixodes ricinus-borne diseases (TBDs), Q fever have been registered; no cases of tularemia, rabies, leptospirosis were detected. The morbidity rates of the population of the Volgograd region for all NFI were at the level or lower than those for the Russian Federation and the Southern Federal District.

A reporter virus particle seroneutralization assay for tick-borne encephalitis virus overcomes ELISA limitations.

Tick-borne encephalitis (TBE) virus is the most prevalent tick-transmitted orthoflavivirus in Europe. Due to the nonspecific nature of its symptoms, TBE is primarily diagnosed by ELISA-based detection of specific antibodies in the patient serum. However, cross-reactivity between orthoflaviviruses complicates the diagnosis. Specificity issues may be mitigated by serum neutralization assays (SNT), although the handling of clinically relevant orthoflaviviruses requires biosafety level (BSL) 3 conditions and they have highly divergent viral kinetics and cell tropisms. In the present study, we established a reporter virus particle (RVP)-based SNT in which the infectivity is measured by luminescence and that can be performed under BSL-2 conditions. The RVP-based SNT for TBEV exhibited a highly significant correlation with the traditional virus-based SNT (R2 = 0.8637, p < 0.0001). The RVP-based assay demonstrated a sensitivity of 92.3% (95% CI: 79.7%-97.4%) and specificity of 100% (95% CI: 81.6%-100%). We also tested the cross-reactivity of serum samples in RVP-based assays against other orthoflaviviruses (yellow fever virus, dengue virus type 2, Zika virus, West Nile virus and Japanese encephalitis virus). Interestingly, all serum samples which had tested TBEV-positive by ELISA but negative by RVP-based SNT were reactive for antibodies against other orthoflaviviruses. Thus, the RVP-based seroneutralization assay provides an added value in clinical diagnostics as well as in epidemiological studies.

Phylogenetic analysis and molecular genetic characteristics of West Nile virus lineage 2 isolates circulating in the Russian Federation.

Since its initial detection in Africa, the West Nile virus has disseminated widely across all continents, becoming endemic in numerous countries, including the Russian Federation. A substantial expansion of the West Nile virus range was observed in the European part of the Russian territory in 1999. In light of this epidemiological trend, research endeavours focusing on monitoring West Nile virus circulation activity in endemic regions of the country have gained paramount significance. A substantial dataset has been accrued from 2007 onwards regarding genomic variability and dissemination dynamics across the country throughout the entire monitoring period for the West Nile fever pathogen. The objective of this study was to characterise West Nile virus isolates that have been circulating in the Russian Federation and identify their molecular and genetic characteristics. A phylogenetic analysis of 55 complete genome sequences revealed that the West Nile virus population within the Russian Federation is genetically heterogeneous and is represented by four major clades. One of these clades is currently exhibiting extensive spread into new regions of the country.

Orthoflavivirus surveillance in the Netherlands: Insights from a serosurvey in horses & dogs and a questionnaire among horse owners.

Zoonotic arboviruses (arthropod-borne) of the Orthoflavivirus genus, such as West Nile virus (WNV), Usutu virus (USUV) and Tick-borne encephalitis virus (TBEV), are emerging in Northwestern Europe and pose a threat to both human and animal health. In the Netherlands, passive symptomatic surveillance (notification of clinical cases) in horses is one of the main pillars for the early detection of WNV. For such passive surveillance to work properly, horse owners and veterinarians need to recognize symptoms and report suspected cases to the authorities. Currently, little is known about the seroprevalence of orthoflaviviruses in domestic animals in the Netherlands. Therefore, this study aims at identifying the seroprevalence of WNV and USUV in horses and dogs in the Netherlands. Additionally, this study seeks to evaluate the knowledge and perceptions of Dutch horse owners towards mosquito-borne viruses. A cross-sectional serosurvey in horses and dogs was conducted between May 2021 and May 2022. Serum samples were screened using an ELISA and doubtful and positive samples were confirmed by Virus Neutralization Tests for WNV, USUV and TBEV. A validated questionnaire, the MosquitoWise survey, was used to assess the knowledge and perceptions of Dutch horse owners towards mosquito-borne viruses between July and October 2022. The serosurvey revealed a low seroprevalence for WNV in horses and no WNV-positive dogs were found. Similarly, a low USUV seroprevalence was found in dogs. The MosquitoWise survey revealed a high knowledge level for horse owners and high awareness of WNV vaccination but a more limited intent to vaccinate. The low seroprevalences of WNV and USUV indicate many dogs and horses remain susceptible, offering opportunities for trend analysis and surveillance. However, despite multiple recent detections of WNV, USUV, and TBEV in humans, the role of dogs and horses in early detection of human cases is debatable. High awareness among horse owners and the absence of detected equine WNV cases highlight this uncertainty. Continued surveillance is crucial for detecting increased virus circulation and protecting both animal and human health.

An Update on the Entomology, Virology, Pathogenesis, and Epidemiology Status of West Nile and Dengue Viruses in Europe (2018-2023).

In recent decades, increases in temperature and tropical rainfall have facilitated the spread of mosquito species into temperate zones. Mosquitoes are vectors for many viruses, including West Nile virus (WNV) and dengue virus (DENV), and pose a serious threat to public health. This review covers most of the current knowledge on the mosquito species associated with the transmission of WNV and DENV and their geographical distribution and discusses the main vertebrate hosts involved in the cycles of WNV or DENV. It also describes virological and pathogenic aspects of WNV or DENV infection, including emerging concepts linking WNV and DENV to the reproductive system. Furthermore, it provides an epidemiological analysis of the human cases of WNV and DENV reported in Europe, from 1 January 2018 to 31 December 2023, with a particular focus on Italy. The first autochthonous cases of DENV infection, with the most likely vector being Aedes albopictus, have been observed in several European countries in recent years, with a high incidence in Italy in 2023. The lack of treatments and effective vaccines is a serious challenge. Currently, the primary strategy to prevent the spread of WNV and DENV infections in humans remains to limit the spread of mosquitoes.

Development of 3'-Deoxy-3',4'-didehydro-nucleoside Prodrug Inhibitors of West Nile and Zika Viruses.

The antiviral enzyme viperin catalyzes the formation of 3'-deoxy-3',4'-didehydro-cytidine-5'-triphosphate (ddhCTP). ddhCTP is incorporated into viral genomes and terminates genomic replication to confer broad-spectrum antiviral effects. We have previously utilized phosphoramidate pronucleotide (ProTide) technology to enable metabolic production of ddhCTP in cells from an exogenously dosed 3'-deoxy-3',4'-didehydro-cytidine ProTide, which confers inhibitory activity against West Nile virus (WNV) and Zika virus (ZIKV). Herein, we synthesized 3'-deoxy-3',4'-didehydro-nucleosides containing all native nucleobases (thymine, uracil, adenine, guanine, and hypoxanthine), elaborated each to a ProTide, and measured their activity for controlling WNV and ZIKV infection. In comparison to the ddhC ProTide, we found that the ProTides of 3'-deoxy-3',4'-didehydro-guanosine and 3'-deoxy-3',4'-didehydro-adenosine possess 2- and 4-fold greater antiviral effects against ZIKV, respectively. Collectively, this work advances the development of 3'-deoxy-3',4'-didehydro nucleosides as promising compounds for further development into broad-spectrum antiviral agents.

Emerging Microorganisms and Infectious Diseases: One Health Approach for Health Shared Vision.

Emerging infectious diseases (EIDs) are newly emerging and reemerging infectious diseases. The National Institute of Allergy and Infectious Diseases identifies the following as emerging infectious diseases: SARS, MERS, COVID-19, influenza, fungal diseases, plague, schistosomiasis, smallpox, tick-borne diseases, and West Nile fever. The factors that should be taken into consideration are the genetic adaptation of microbial agents and the characteristics of the human host or environment. The new approach to identifying new possible pathogens will have to go through the One Health approach and omics integration data, which are capable of identifying high-priority microorganisms in a short period of time. New bioinformatics technologies enable global integration and sharing of surveillance data for rapid public health decision-making to detect and prevent epidemics and pandemics, ensuring timely response and effective prevention measures. Machine learning tools are being more frequently utilized in the realm of infectious diseases to predict sepsis in patients, diagnose infectious diseases early, and forecast the effectiveness of treatment or the appropriate choice of antibiotic regimen based on clinical data. We will discuss emerging microorganisms, omics techniques applied to infectious diseases, new computational solutions to evaluate biomarkers, and innovative tools that are useful for integrating omics data and electronic medical records data for the clinical management of emerging infectious diseases.