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Background: Algeria like other North African countries is experiencing recurrent episodes of West Nile Virus (WNV) emergences and new health threats associated with the introduction of Aedes albopictus in 2010 are to be feared. To improve the surveillance of mosquito-borne pathogens, we performed a study using innovative tools based on multiplex molecular methods. Methods: We combined two approaches: a high-throughput chip based on the BioMark Dynamic array system to detect arboviruses in mosquitoes, and a set of immunologic methods (ELISA, microsphere immunoassays (MIA) and virus microneutralization tests (MNT)) for serological surveys in animal hosts. We investigated two distinct regions: a first zone located in the coastal humid region and a second one in the Saharan desert region. Principal findings: We collected a total of 1,658 mosquitoes belonging to nine different species and found predominantly Culex pipienss. l. (56.5%) and Cx. perexiguus (27.5%). From 180 pools of 10 mosquitoes, we detected four arboviruses: Banna virus (BAV), chikungunya virus (CHIKV), Sindbis virus (SINV), and Usutu virus (USUV). Moreover, we examined 389 blood samples from equids and poultry and found that 52.4% were positive for flavivirus antibodies in ELISA, while 30.8% were positive for WNV and two chickens and two equids were positive for USUV by MNT and MIA respectively. Conclusions: To our knowledge, this is the first report of five arboviruses circulating in Algeria, with three reported for the first time (CHIKV, BAV, and USUV). Our study brings evidence that reinforcing surveillance using more discriminant tools may help in anticipating future emergences and propose adapted control measures. Author summary: Arboviruses are a significant threat to public health because of their epidemic and zoonotic potential. The geographical distribution of mosquito-borne diseases such as West Nile Fever has expanded over the last decades. Countries of the Mediterranean region are not spared. In this context, surveillance of the circulation of such viruses needs to be achieved before the appearing of human or animal cases. The aim of our study was to use innovative and highly efficient tools to highlight the circulation of arboviruses in mosquito vectors, animal reservoirs or exposed animals in Algeria. A total of 1,658 mosquitoes belonging to nine different species were collected and screened for arboviruses usinghighthroughput chips based on the BioMark Dynamic arrays system, capable of screening various arboviruses in a single experiment. Moreover, we analyzed 389 blood samples from equids and poultry using 3 different serologic methods. Our results bring, for the first time in Algeria, evidence of the cryptic circulation of 5 arboviruses: West Nile virus, chikungunya virus, Usutu virus, Sindbis virus and for the first time out of the Asian region, Banna virus. This approach, as an early warning system, is enabling for an early detection of pathogens circulation above-threshold before disease appearance in humans. [ABSTRACT FROM AUTHOR]

The diversity and abundance of vectors are essential parameters in the transmission dynamics of West Nile virus (WNV) between its avian reservoirs and clinically susceptible mammalian species. Knowing the determinants of vector abundance could be thus useful in preventing West Nile fever (WNF) cases and associated socio‐economic impact. We designed a survey at the wildlife–livestock interface to test the hypothesis that variations in environmental favourability between anthropized and wild scenarios modulate WNV vector abundance and transmission risk. In a continental Mediterranean region where WNF has recently emerged, we selected nine sampling sites and allocated three areas to every site with a decreasing gradient of wildlife–livestock interaction: A1—a horse farm where interaction is maximal; A2—a zone of intermediate interaction 500–1000 m from the farm; and A3—an entirely wild zone of low interaction 1–5 km from the farm. At a fortnightly frequency, we estimated mosquito abundance at each of the 27 study sites in May–December 2018 and April–July 2019. We estimated bird and mammal abundance, collected meteorological information and characterised mosquito habitat at the site scale. Thereafter, we studied the determinants of Culex spp., Culex pipiens sensu lato (s.l.) Linnaeus, 1758 (Diptera: Culicidae) and Culex theileri  Theobald, 1903 abundance by constructing negative binomial generalised linear mixed models. We identified 20 mosquito species, with a notable predominance of Culex spp. and, particularly, of Cx. pipiens s.l. We found differences in the spatiotemporal distribution of Culex spp. abundance and confirmed our hypothesis by finding important effects of local environmental variations in abundance. The accumulated rainfall in fortnights 4–14 and the mean temperature of the two fortnights before sampling were positively and statistically significantly associated with the abundance of Cx. pipiens s.l. (Z = 13.09, p < 0.001, and Z = 9.91, p < 0. 001, respectively) and Culex spp. (Z = 13.35, p < 0.001, and Z = 6.99, p < 0.001, respectively), while the mean temperature of the two previous fortnights was a positive statistically significant predictor (Z = 14.69, p < 0.001) of the abundance of Cx. theileri. The farm environment was the most conducive predictor to hosting Culex spp. compared with wild settings. Our results indicate that continental Mediterranean environments are favourable for WNV circulation and maintenance, especially the environment of anthropized rural settings such as farms. These results will have an impact on the spatiotemporal risk prediction of WNF emergence in continental Mediterranean environments. [ABSTRACT FROM AUTHOR]

Purpose: To provide an overview of pre-selected emerging arboviruses (arthropod-borne viruses) that cause ocular inflammation in humans. Methods: A comprehensive review of the literature published between 1997 and 2023 was conducted in PubMed database. We describe current insights into epidemiology, systemic and ocular manifestations, diagnosis, treatment, and prognosis of arboviral diseases including West Nile fever, Dengue fever, Chikungunya, Rift Valley fever, Zika, and Yellow fever. Results: Arboviruses refer to a group of ribonucleic acid viruses transmitted to humans by the bite of hematophagous arthropods, mainly mosquitoes. They mostly circulate in tropical and subtropical zones and pose important public health challenges worldwide because of rising incidence, expanding geographic range, and occurrence of prominent outbreaks as a result of climate change, travel, and globalization. The clinical signs associated with infection from these arboviruses are often inapparent, mild, or non-specific, but they may include serious, potentially disabling or life-threatening complications. A wide spectrum of ophthalmic manifestations has been described including conjunctival involvement, anterior uveitis, intermediate uveitis, various forms of posterior uveitis, maculopathy, optic neuropathy, and other neuro-ophthalmic manifestations. Diagnosis of arboviral diseases is confirmed with either real time polymerase chain reaction or serology. Management involves supportive care as there are currently no specific antiviral drug options. Corticosteroids are often used for the treatment of associated ocular inflammation. Most patients have a good visual prognosis, but there may be permanent visual impairment due to ocular structural complications in some. Community-based integrated mosquito management programs and personal protection measures against mosquito bites are the best ways to prevent human infection and disease. Conclusion: Emerging arboviral diseases should be considered in the differential diagnosis of ocular inflammatory conditions in patients living in or returning from endemic regions. Early clinical consideration followed by confirmatory testing can limit or prevent unnecessary treatments for non-arboviral causes of ocular inflammation. Prevention of these infections is crucial. [ABSTRACT FROM AUTHOR]

The article discusses the need for enhanced surveillance and response strategies for arbovirus outbreaks in Italy. It highlights factors contributing to the reemergence of arboviruses, such as viral adaptation, climate change, and increased population mobility. The article introduces ArboItaly, a centralized repository that consolidates epidemiological data and integrates information on different hosts to facilitate the identification of trends and improve control measures. It emphasizes the importance of international collaboration, genomic surveillance, and proactive approaches in managing the evolving threat of arboviruses. The document is a list of references for scientific articles related to arboviral diseases, providing a range of perspectives and research findings on topics such as transmission dynamics, surveillance systems, control methods, and the impact of environmental factors on disease spread. [Extracted from the article]

Objective: Unknown etiology Background: West Nile virus (WNV) is a vector-borne flavivirus that is typically transmitted by Aedes and Anopheles mosquitos. WNV infection typically presents with symptoms consistent with viral meningitis, which include fever, headache, and meningeal signs. WNV infections are typically self-resolving, with symptoms lasting 3-10 days. Although uncommon, patients with WNV infection can be afflicted with hyponatremia, although the etiology is unclear. Because of encephalitis, neuroinflammation may be involved in the deterioration of adrenal signaling, leading to salt wasting. Case Report: We present the case of a 75-year-old man who presented with headache, neck pain, photophobia, and viral illness symptoms. He was found to be profoundly hyponatremic, concerning for SIADH. He had a sodium drop to 117 mmol/L, leading to further lethargy and confusion. He received 3% saline, fluid restriction, and salt tablets, and more common causes of SIADH were ruled out. MRI revealed the absence of the posterior pituitary bright spot. He was subsequently found to have positive WNV titers and improved with continued supportive treatment. Conclusions: WNV presents a unique challenge to providers due to its difficult diagnosis and association with hyponatremia. There is no clear role for specific medical treatment such as corticosteroids vs IV immunoglobulins. Supportive care is recommended for those testing positive for WNV. Clinicians should consider the possibility of viral infections, such as WNV, in patients living in endemic areas who present with unexplained hyponatremia, cognitive symptoms, and relevant history. [ABSTRACT FROM AUTHOR]

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. Brief summary: West Nile virus, but not Usutu virus, can productively infect human motor neurons as a possible route of neuroinvasion. [ABSTRACT FROM AUTHOR]

A group of self-limiting and frequently neglected diseases exist in the literature like Rickettsial disease, Malaria, Dengue fever, Chikungunya, West Nile virus infection, Rift Valley fever, Bartonellosis, or Lyme disease which are poorly understood due to lack of proper diagnostic testing. Currently, multimodal imaging has become a critical modality in the diagnosis and management of ocular diseases. Optical coherence tomography (OCT) is one such remarkable imaging modality in the field of ophthalmology providing high-resolution, cross-sectional images of the retina and choroid with the recent advances such as enhanced depth imaging and swept source OCT. Additionally, OCT angiography (OCTA) has further revolutionised dynamic imaging of retinal and choroidal vasculature non-invasively. This review article highlights the OCT and OCTA biomarkers in the diagnosis and prognosis of the aforementioned neglected diseases. [ABSTRACT FROM AUTHOR]

Ivermectin (IVM)-treated birds provide the potential for targeted control of Culex mosquitoes to reduce West Nile virus (WNV) transmission. Ingestion of IVM increases mosquito mortality, which could reduce WNV transmission from birds to humans and in enzootic maintenance cycles affecting predominantly bird-feeding mosquitoes and from birds to humans. This strategy might also provide an alternative method for WNV control that is less hampered by insecticide resistance and the logistics of large-scale pesticide applications. Through a combination of field studies and modeling, we assessed the feasibility and impact of deploying IVM-treated birdfeed in residential neighborhoods to reduce WNV transmission. We first tracked 105 birds using radio telemetry and radio frequency identification to monitor their feeder usage and locations of nocturnal roosts in relation to five feeder sites in a neighborhood in Fort Collins, Colorado. Using these results, we then modified a compartmental model of WNV transmission to account for the impact of IVM on mosquito mortality and spatial movement of birds and mosquitoes on the neighborhood level. We found that, while the number of treated lots in a neighborhood strongly influenced the total transmission potential, the arrangement of treated lots in a neighborhood had little effect. Increasing the proportion of treated birds, regardless of the WNV competency status, resulted in a larger reduction in infection dynamics than only treating competent birds. Taken together, model results indicate that deployment of IVM-treated feeders could reduce local transmission throughout the WNV season, including reducing the enzootic transmission prior to the onset of human infections, with high spatial coverage and rates of IVM-induced mortality in mosquitoes. To improve predictions, more work is needed to refine estimates of daily mosquito movement in urban areas and rates of IVM-induced mortality. Our results can guide future field trials of this control strategy.

OBJECTIVES: The objective of this study was to report on the development of neuroinvasive West Nile virus (WNV) infection in the context of anti-CD20 monotherapy for multiple sclerosis (MS). METHODS: This is a case series study. RESULTS: In 2021-2022, we observed 4 cases of neuroinvasive WNV infection in our patient population of 2009 patients with MS on ocrelizumab, compared with a total of 46 cases of neuroinvasive WNV infection reported in Pennsylvania and 40 in New Jersey. Odds were 258 times that of the general population (95% confidence interval 97-691), χ2 p < 0.0001). All were women aged 41-61 years with variable disease duration, level of disability, and duration of anti-CD20 therapy. All presented in summer/early fall with fever, headache, and encephalopathy consistent with meningoencephalitis. Three patients had acute cerebellitis. Two had anterior nerve root involvement progressing to quadriparesis, and 1 developed refractory nonconvulsive status epilepticus. All required intubation and experienced significant morbidity. All had CSF pleocytosis. Two patients were WNV IgM positive in both the serum and CSF, 1 patient had positive serum IgM and CSF metagenomic next-generation sequencing (mNGS), while 1 had positive CSF mNGS with negative serum and CSF antibodies. DISCUSSION: Neuroinvasive WNV infection can develop with anti-CD20 monotherapy in the absence of additional immunosuppression. WNV serologies may be negative in the setting of anti-CD20 treatment; in the appropriate clinical context, one should consider direct detection methods such as PCR or mNGS-based testing.

Upon researching predictive models related toWest Nile virus disease, it is discovered that there are numerous parameters and extensive information in most models, thus contributing to unnecessary complexity. Another challenge frequently encountered is the lead time, which refers to the period for which predictions are made and often is too short. This paper addresses these issues by introducing a parsimonious method based on ICC curves, offering a logistic distribution model derived from the vector-borne SEIR model. Unlike existing models relying on diverse environmental data, our approach exclusively utilizes historical and present infected human cases (number of new cases). With a yearlong lead time, the predictions extend throughout the 12 months, gaining precision as new data emerge. Theoretical conditions are derived to minimize Bayesian loss, enhancing predictive precision. We construct a Bayesian forecasting probability density function using carefully selected prior distributions. Applying these functions, we predict monthspecific infections nationwide, rigorously evaluating accuracy with probabilistic metrics. Additionally, HPD credible intervals at 90%, 95%, and 99% levels is performed. Precision assessment is conducted for HPD intervals, measuring the proportion of intervals that does not include actual reported cases for 2020e2022. [ABSTRACT FROM AUTHOR]

The aim of the work was to study the epidemiological situation on West Nile fever (WNF) in the Republic of Tatarstan in 2023.Materials and methods. An operational epidemiological analysis of WNF cases registered in the Republic of Tatarstan in 2023 was performed. In order to establish sources and risk factors for infection of the population, 987 samples of zoo-entomological material were examined for the presence of West Nile virus (WNV) markers. A set of laboratory diagnostic methods was used: ELISA, RT-PCR, sequencing.Results and discussion. It has been established that all cases of WNF were registered in the region in the summer-autumn period of 2023, mainly in August, among residents of the city of Kazan who had not traveled outside the Russian Federation and the Republic of Tatarstan over the past six months. The incidence rate of WNF in the Republic of Tatarstan was 0.20 per 100 thousand population, the mortality rate reached 12.5 %. Signs of damage to the central nervous system were present in 6 out of 8 (75 %) patients. The majority of people with severe clinical symptoms belonged to older age groups and had concomitant diseases. Cases of the infection were reported in all age groups, with the exception of children and adolescents. The spatial characteristics of morbidity have been investigated, indicating the diffuse nature of the distribution of cases. The integrated use of methods, consisting in the concurrent use of polymerase chain reaction and enzyme-linked immunosorbent assay, made it possible to laboratory confirm cases of WNF in patients at different stages of the disease. The circulation of a subvariant of the WNV of the second genotype in the Republic of Tatarstan, currently dominant in the southern and central regions of Russia, has been established. A set of measures has been proposed to optimize epidemiological surveillance and control of WNF in the Republic of Tatarstan.

Background. Annual studies of West Nile virus (WNV) circulating in endemic areas are necessary to characterize its properties and track them over time. Given the lack of specific antiviral therapy for West Nile fever (WNF), it is of interest to study sensitivity to drugs widely used in modern practice. The aim of the study is to study the sensitivity of West Nile virus strains circulating in the Russian Federation in 2018–2021 to drugs used to treat viral infections.Material and methods. The sensitivity of WNV strains to ribavirin, riamilovir, and umifenovir was determined using Vero cell culture.Results and discussion. A study of the sensitivity of WNV strains circulating in the Russian Federation in 2018–2021 to therapeutic drugs used to treat viral infections showed their heterogeneity in this regard. Thus, 5 strains (WNV_Volgograd_601/18, Volgograd_723/18, Volgograd_830/18, Voronezh_794/21, Astrachan_962/21) out of 10 studied were characterized by some differences in resistance to ribavirin and riamilovir. No statistically significant differences were revealed when comparing drug resistance indicators of the group of WNV strains of the «old» genovariant with those of the «new» group.Conclusion. Further analysis of the genome of the studied WNV strains will allow us to establish genetic characteristics, which may contribute to the establishment of molecular mechanisms of resistance to ribavirin, riamilovir, and umifenovir.

The distribution, epidemiology, and socioeconomic impact of Rift Valley fever (RVF) and West Nile (WN) viruses are poorly known in areas of sub‐Saharan countries like Ethiopian pastoral region. The human and livestock density in the area has increased greatly in recent years, but little work has been done on arboviral diseases and their potential impact on human and livestock health. The aim of this study was to detect the circulation of zoonotic arboviruses such as Rift Valley fever virus and West Nile viruses in the livestock population and to estimate seroprevalence in Afar pastoral area northeast Ethiopia. Cross‐sectional serological survey was carried out in 736 serum samples from which cattle (224), camel (155), goats (121), sheep (144), and donkeys (92) were tested for the presence of anti‐RVFV and anti‐WNV IgG using a competitive enzyme‐linked immunosorbent assay (c‐ELISA) in two purposively selected districts of the Afar region. The present study revealed a 9.1% (95% CI = 8.86–9.29) seroprevalence of co‐circulation of RVF and WNV. High 32/155 (20.7%) seroprevalence of co‐circulation was seen in camels, followed by goat 14/121 (11.6%), cattle 16/224 (7.14%), and sheep 5/144 (3.5%), respectively, and higher 41/421 (9.7%) seroprevalence of co‐circulation was observed in Amibara district than Haruka district. Camels were seven times (OR: 7.016, 95% CI = 2.639–18.653) more likely to be seropositive for the co‐circulation than sheep (p ≤ 0.001). Livestock herds found in Amibara district were 1.2 times (OR: 1.165, 95% CI = 0.680–1.996) more likely to be seropositive for RVFV infection than those in Haruka areas. Given the co‐occurrence of RVFV and WNV circulations, along with often suboptimal human and animal health surveillance in many similar areas' attention should be given. Investigation of the potential socioeconomic and health impacts of zoonotic arbovirus infections in such areas is crucial. Since both RVFV and WNFV are transmitted through a mosquito vector, avoiding mosquito bites is the primary method of prevention. [ABSTRACT FROM AUTHOR]

Background and purpose: Culicidae plays a crucial role in the spread of diseases like Malaria and arboviral diseases such as Japanese Encephalitis, Zika virus, Chikungunya, Dengue fever, Yellow fever, and West Nile fever. Different mosquito species have different abundance and distribution due to a variety of factors, such as physicochemical factors, weather conditions, vegetation, and human activities. The characteristics of larval habitats are among the factors affecting the population, and diversity, and determining the preferred breeding places of the species. For this reason, a study was conducted to examine the species diversity of Culicidae and their larval habitats in Shushtar County. Materials and methods: This cross-sectional study was conducted in Shushtar County from the central, Mian Ab and Shuaibiya districts, 2021. Larvae were collected from the breeding places in the sampling areas including Noormohammadi, Konarpir, Saheli, Abu Gerva, and Pirdalu by using the dipping technique in spring and summer and kept in lactophenol solution. Then, a microscopic slide was prepared from the samples using licidophor, which were identified with valid diagnostic keys. Characteristics of larval habitat such as habitat type, water condition, vegetation, substrate type, water quality, and light condition were also recorded. To analyze the data and determine the relationship between the frequency and characteristics of larval habitats, SPSS version 16 software and a chi-square statistical test were used. Qualitative variables were also reported as numbers (percentages). Abundance and distribution maps of samples were prepared using ArcGIS software version 10.5. Results: In this study, a total of 527 larvae were identified, including five species of Anopheles stephensi, Culex pusillus, and Cx. sinaiticus, Cx. theileri and, Cx. Perexiguus. Anopheles stephensi with the lowest frequency (8.48%) was reported only from the Saheli area. This species was collected from temporary, stationary, without vegetation, mud substrate, cloudy water, sunny, and natural habitats. Culex theileri, one of the important vectors of arboviral diseases, was observed in temporary and natural habitats, stagnant waters without vegetation, and cloudy and sunny waters habitates. Culex pusillus was the only species observed in Pirdalo and Abu Gerva. By examining the larval habitats of Culicidae in Shushtar County, Cx. pusillus was the most abundant collected species, from temporary habitat (82.7%), stagnant waters (73.6%), mud substrate (100%), turbid waters (78.6%), natural (95%), and sunny (82.7%). Also, the abundance of collected larvae in temporary habitats, stagnant waters, in areas with vegetation, and mud substrate was high. Besides, it was more abundant in turbid waters and sunny areas, and these differences were statistically significant (P<0.0001). Conclusion: In this study, Cx.pusillus was the most common species, while An. stephensi was the least common abundance among collected species. It was observed significant difference between this species and the type of habitat, water flow, vegetation, water quality, and light conditions. Conducting more comprehensive studies in this field, especially regarding the possible role of different species of Culicidae, helped to solve the health and medical problems of humans and veterinary medicine in the future. [ABSTRACT FROM AUTHOR]

The common house mosquito (Culex pipiens) is a native vector for West Nile virus (WNV). Invasive species like the tiger mosquito (Aedes albopictus) and Asian bush mosquito (Aedes japonicus) are rapidly spreading through Europe, posing a major threat as vectors for dengue, chikungunya (CHIKV), and Japanese encephalitis virus (JEV). These mosquitoes share a similar ecological niche as larvae, but the carry-over effects of aquatic larval interactions to the terrestrial adult stage remain largely unknown and their medical relevance requires further investigation. This study examines the context dependency of larval interactions among Aedes albopictus, Aedes japonicus, and Culex pipiens. The survival, development time, growth, and energetic storage were measured in different European populations within density-response (intraspecific) experiments and replacement (interspecific) experiments at 20 °C and 26 °C. Overall, Ae. japonicus was the weakest competitor, while competition between Ae. albopictus and Cx. pipiens varied with temperature. Adults emerging from this larval competition were infected as follows: Culex pipiens with WNV, Ae. albopictus with CHIKV, and Ae. japonicus with JEV. While no JEV infection was observed, mosquitoes experiencing interspecific interactions during their larval stages exhibited higher infection rates and viral RNA titers for CHIKV and WNV. This increased susceptibility to viral infection after larval competition suggests a higher risk of arbovirus transmission in co-occurring populations. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This article explores the role of microglia, a type of immune cell in the central nervous system, in viral-induced neuroinflammation. It discusses the different types of viruses that can cause central nervous system infections and how they infiltrate the CNS. The article highlights the responses of glial cells, particularly astrocytes and microglia, to viral infections and suggests that microglia play a crucial role in regulating the immune response and neuroinflammation associated with viral infections. It also mentions the potential implications of viral infections, such as COVID-19, on the function and activation of microglia and astrocytes. The document includes a list of references that can be valuable resources for researchers and library patrons interested in studying these topics. [Extracted from the article]

Microglia, the resident macrophages of the central nervous system, exhibit altered gene expression in response to various neurological conditions. This study investigates the relationship between West Nile Virus infection and microglial senescence, focusing on the role of LGALS3BP, a protein implicated in both antiviral responses and aging. Using spatial transcriptomics, RNA sequencing and flow cytometry, we characterized changes in microglial gene signatures in adult and aged mice following recovery from WNV encephalitis. Additionally, we analyzed Lgals3bp expression and generated Lgals3bp-deficient mice to assess the impact on neuroinflammation and microglial phenotypes. Our results show that WNV-activated microglia share transcriptional signatures with aged microglia, including upregulation of genes involved in interferon response and inflammation. Lgals3bp was broadly expressed in the CNS and robustly upregulated during WNV infection and aging. Lgals3bp-deficient mice exhibited reduced neuroinflammation, increased homeostatic microglial numbers, and altered T cell populations without differences in virologic control or survival. These data indicate that LGALS3BP has a role in regulating neuroinflammation and microglial activation and suggest that targeting LGALS3BP might provide a potential route for mitigating neuroinflammation-related cognitive decline in aging and post-viral infections. [ABSTRACT FROM AUTHOR]

Mosquitoes of the Culex genus are responsible for a large burden of zoonotic virus transmission globally. Collectively, they play a significant role in the transmission of medically significant diseases such as Japanese encephalitis virus and West Nile virus. Climate change, global trade, habitat transformation and increased urbanisation are leading to the establishment of Culex mosquitoes in new geographical regions. These novel mosquito incursions are intensifying concerns about the emergence of Culex-transmitted diseases and outbreaks in previously unaffected areas. New mosquito control methods are currently being developed and deployed globally. Understanding the complex interaction between pathogens and mosquitoes is essential for developing new control strategies for Culex species mosquitoes. This article reviews the role of Culex mosquitos as vectors of zoonotic disease, discussing the transmission of viruses across different species, and the potential use of Wolbachia technologies to control disease spread. By leveraging the insights gained from recent successful field trials of Wolbachia against Aedes-borne diseases, we comprehensively discuss the feasibility of using this technique to control Culex mosquitoes and the potential for the development of next generational Wolbachia-based control methods. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

West Nile virus (WNV) is the most common mosquito-borne disease in the United States, resulting in hundreds of reported cases yearly in California alone. The transmission cycle occurs mostly in birds and mosquitoes, making meteorological conditions, such as temperature, especially important to transmission characteristics. Given that future increases in temperature are all but inevitable due to worldwide climate change, determining associations between temperature and WNV incidence in humans, as well as making predictions on future cases, are important to public health agencies in California. Using surveillance data from the California Department of Public Health (CDPH), meteorological data from the National Oceanic and Atmospheric Administration (NOAA), and vector and host data from VectorSurv, we created GEE autoregressive and zero-inflated regression models to determine the role of temperature and other environmental factors in WNV incidence and predictions. An increase in temperature was found to be associated with an increase in incidence in 11 high-burden Californian counties between 2017–2022 (IRR = 1.06), holding location, time of year, and rainfall constant. A hypothetical increase of two degrees Fahrenheit—predicted for California by 2040—would have resulted in upwards of 20 excess cases per year during our study period. Using 2017–2021 as a training set, meteorological and host/vector data were able to closely predict 2022 incidence, though the models did overestimate the peak number of cases. The zero-inflated model closely predicted the low number of cases in winter months but performed worse than the GEE model during high-transmission periods. These findings suggests that climate change will, and may be already, altering transmission dynamics and incidence of WNV in California, and provides tools to help predict incidence into the future. Author summary: West Nile Virus is a disease that is spread by mosquitoes. Though it commonly infects birds, transmission to humans is possible and can lead to severe health effects. Temperature is known to affect the transmission cycle of West Nile virus, but it is unclear how global warming might change who, or how many people, may get infected with the virus. In this study, the researchers looked at how climate change may affect West Nile virus in California, and how health officials may better be able to predict future cases. The study found that there could be an increase in West Nile virus cases in humans due to increases in temperature in the next 20 years, but that we already have many tools and sources of data to predict cases. These findings reinforce the possible consequences of climate change on human health, and aid in the understanding in the complex relationship between climate and infectious diseases. [ABSTRACT FROM AUTHOR]

Aedes albopictus, also known as the Asian tiger mosquito, is indigenous to the tropical forests of Southeast Asia. Ae. albopictus is expanding across the globe at alarming rates, raising concern over the transmission of mosquito-borne diseases, such as dengue, West Nile fever, yellow fever, and chikungunya fever. Since Ae. albopictus was reported in Houston (Harris County, Texas) in 1985, this species has rapidly expanded to at least 32 states across the United States. Public health efforts aimed at controlling Ae. albopictus, including surveillance and adulticide spraying operations, occur regularly in Harris County. Despite rotation of insecticides to mitigate the development of resistance, multiple mosquito species including Culex quinquefasciatus and Aedes aegypti in Harris County show organophosphate and pyrethroid resistance. Aedes albopictus shows relatively low resistance levels as compared to Ae. aegypti, but kdr-mutation and the expression of detoxification genes have been reported in Ae. albopictus populations elsewhere. To identify potential candidate detoxification genes contributing to metabolic resistance, we used RNA sequencing of field-collected malathion-resistant and malathion-susceptible, and laboratory-maintained susceptible colonies of Ae. albopictus by comparing the relative expression of transcripts from three major detoxification superfamilies involved in malathion resistance due to metabolic detoxification. Between these groups, we identified 12 candidate malathion resistance genes and among these, most genes correlated with metabolic detoxification of malathion, including four P450 and one alpha esterase. Our results reveal the metabolic detoxification and potential cuticular-based resistance mechanisms associated with malathion resistance in Ae. albopictus in Harris County, Texas. Author summary: The Asian tiger mosquito, Aedes albopictus, is an invasive species rapidly expanding worldwide. It is the main vector for several arboviruses, including dengue virus, Zika virus, and chikungunya virus. These viral diseases pose a substantial threat to global public health. Ae. albopictus has developed resistance to insecticides such as malathion, making its control more challenging. To uncover the genetic basis of this resistance, we conducted a study using RNA sequencing-based transcriptome profiling. In this study, we obtained gene expression patterns in malathion-resistant and susceptible mosquitoes. The transcriptomic information allowed us to identify potential key genes in detoxification gene families associated with metabolic resistance to malathion. Our discovery provides insights into the molecular mechanisms behind malathion resistance in Ae. albopictus. Our research not only contributes to the understanding of mosquito biology and control but also highlights the future direction for continued efforts in developing innovative strategies to mitigate rapid development of insecticide resistance in Ae. albopictus. [ABSTRACT FROM AUTHOR]

Simple Summary: Insect-borne viruses, such as those of the Flaviviridae family, pose a serious risk to global health. WNV, a mosquito-borne flavivirus, is transmitted primarily by the Culex mosquito. Despite the increasing exposure of populations to mosquito-borne flaviviruses and the expanding range of the vector mosquito, there are limited resources available to prevent or treat flavivirus infections. Using the model organism Drosophila melanogaster, commonly known as the fruit fly, we previously found that insulin signaling reduces WNV infection. We translated these finding to mosquitoes and human cells and showed similar mechanisms of insulin-mediated antiviral activity. However, insect and mammalian hormones can regulate insulin signaling. Specifically, decretin hormones suppress insulin secretion, especially during periods of starvation and low glucose intake. In this study, we show that the insect decretin, Limostatin, and its mammalian ortholog, Neuromedin U, can promote WNV infection. These results suggest that the inhibition of decretin signaling may be a novel therapeutic target to control WNV infection. The arbovirus West Nile virus (WNV) is a danger to global health. Spread primarily by mosquitoes, WNV causes about 2000 cases per year in the United States. The natural mosquito immune response controls viral replication so that the host survives but can still transmit the virus. Using the genetically malleable Drosophila melanogaster model, we previously dissected innate immune pathways used to control WNV infection. Specifically, we showed that insulin/IGF-1 signaling (IIS) activates a JAK/STAT-mediated immune response that reduces WNV. However, how factors that regulate IIS in insects control infection has not been identified. D. melanogaster Limostatin (Lst) encodes a peptide hormone that suppresses insulin secretion. Its mammalian ortholog, Neuromedin U (NMU), is a peptide that regulates the production and secretion of insulin from pancreatic beta cells. In this study, we used D. melanogaster and human cell culture models to investigate the roles of these insulin regulators in immune signaling. We found that D. melanogaster Lst mutants, which have elevated insulin-like peptide expression, are less susceptible to WNV infection. Increased levels of insulin-like peptides in these flies result in upregulated JAK/STAT activity, leading to protection from infection. Treatment of human cells with the insulin regulator NMU results in increased WNV replication. Further investigation of methods to target Lst in mosquitoes or NMU in mammals can improve vector control methods and may lead to improved therapeutics for human and animal infection. [ABSTRACT FROM AUTHOR]

Background: Autochthonous human West Nile virus (WNV) infections were notified in the infectious disease surveillance system in Germany in 2018 for the first time and every year since then. Since clinically apparent infections are infrequent, we conducted two studies to investigate subclinical infections of this emerging disease in Germany in 2019 to detect infections not visible to surveillance based on symptomatic infections: limited-scope blood donor testing and a serosurvey among employees at two Berlin zoos with a history of demonstrated WNV infections in animals. Methods: For the zoo study, employees of the two zoos in Berlin were invited to participate in the study in late 2019. Blood samples were drawn and tested for the presence of antibodies (immunoglobulin M [IgM] and immunoglobulin G [IgG]) against WNV, and two other flaviviruses present in Germany: Usutu virus and Tick-borne encephalitis virus (TBEV). For the study in blood donors, four blood establishments with collection sites in regions with documented WNV-infected animals in 2018 and 2019 participated in the study. All donations in these regions were tested for WNV genome from July to November 2019. Results: In the enzyme-linked immunosorbent assay, none of the 70 tested zoo employees were WNV IgM-positive, 8 were WNV IgG-positive, additional 2 participants had equivocal results. All 10 were negative in the virus neutralization test (VNT) for WNV, but positive in the VNT for TBEV. None of the 4273 samples from blood donors tested in areas with WNV-infected animals was positive for WNV-RNA. Conclusion: Our results indicate that WNV circulation in Germany, though clearly documented in animals in 2019, apparently affected very few humans. Still areas with WNV-positive animals remain risk areas for human infection as well. [ABSTRACT FROM AUTHOR]

The document discusses the importance of linking health data with climate data to address the impact of climate change on global health. It emphasizes the need for a climate-health data infrastructure to increase climate resiliency and protect public health. The text highlights the strain climate change places on healthcare systems and the necessity for collaboration between the health and meteorological sectors to develop early warning systems and effective public health policies. Additionally, it stresses the significance of merging climate and health data to improve diagnosing, planning, and surveillance in healthcare systems. [Extracted from the article]

Loss of enteric neurons leading to long-term gastrointestinal dysfunction is common to many diseases, and the path to functional recovery is unclear. In this issue of the JCI, Janova et al. report that West Nile virus killed enteric neurons and glia via CD4+ and CD8+ T cells acting through the perforin and Fas ligand pathways. Enteric glial cells contributed to neurogenesis and at least partial replacement of affected neurons. While neurogenesis is important for recovery, dysmotility and disruptions to the network structure persisted. Following enteric injury, the contribution of neurogenesis and the conditions that support restoration of enteric neural circuits for functional recovery remain for further investigation. [ABSTRACT FROM AUTHOR]

The article published in the Journal of Medical Virology discusses the impact of severe fever with thrombocytopenia syndrome (SFTS) caused by the SFTS virus (SFTSV) on the central nervous system (CNS) of infected individuals. The study focuses on the role of A1-reactive astrocytes and IFNAR signaling in inducing neuronal cell death during SFTSV infection in IFNAR1−/− mice. The research highlights the importance of understanding the molecular mechanisms of virus-induced neuronal pathogenesis and the potential for developing therapeutics and vaccines for SFTS treatment and prevention. [Extracted from the article]

BackgroundWest Nile virus (WNV) is the leading cause of mosquito-borne disease in humans in the United States. Since the introduction of the disease in 1999, incidence levels have stabilized in many regions, allowing for analysis of climate conditions that shape the spatial structure of disease incidence.ObjectivesOur goal was to identify the seasonal climate variables that influence the spatial extent and magnitude of WNV incidence in humans.MethodsWe developed a predictive model of contemporary mean annual WNV incidence using U.S. county-level case reports from 2005 to 2019 and seasonally averaged climate variables. We used a random forest model that had an out-of-sample model performance of R2=0.61.ResultsOur model accurately captured the V-shaped area of higher WNV incidence that extends from states on the Canadian border south through the middle of the Great Plains. It also captured a region of moderate WNV incidence in the southern Mississippi Valley. The highest levels of WNV incidence were in regions with dry and cold winters and wet and mild summers. The random forest model classified counties with average winter precipitation levels

An analysis of the epidemiological situation on West Nile fever (WNF) in the Russian Federation in 2023 has revealed an increase in the number of cases (210) relative to the year 2022 by 6.3 times, the long-term average value by 1.2 times. Manifestations of the epidemic process were characterized by a significant expansion in the number of territories, where cases of the disease were confirmed (24 constituent entities, including in 13 – for the first time); a long epidemic season; an increase in the proportion of cases with a severe clinical course and fatality rate, which significantly exceeded the long-term average across Russia (8.5 and 1.2 %, respectively). Patients with fever and other similar manifestations of WNF were examined for the presence of the disease markers in 50 entities of the Russian Federation. Continued trend towards a decrease in the volume of diagnostic studies carried out by medical organizations and an increase in the time required for the etiological deciphering of disease cases has been established. Serological examination of sample groups of healthy population was performed in 65 entities. Epizootiological monitoring was carried out in 74 entities, rate of infection of carriers and vectors with West Nile virus (WNV) was confirmed in 14 entities. In the territory of the European part of Russia and the North Caucasus, the circulation of WNV lineages 1, 2 and 4 with the dominance of WNV lineage 2 has been established. Data on the genetic heterogeneity of WNV lineage 2 strains that circulated in Russia in 2023 have been obtained. Based on an analysis of climatic factors, a forecast of WNF incidence in the Russian Federation for 2024 was prepared.

Objective: to study the intensity of contact with the causative agent of West Nile fever (WNF) of the population of certain central and southern territories of Russia.Materials and methods: the screening survey covered 1,230 people in 11 regions of the Russian Federation. The work used molecular genetic, immunological and statistical methods.Results: WNVmarkers, indicating an acute infectious process, were detected in 1.4% of samples. For the first time, local cases of the disease were confirmed in 9 regions of central Russia and the North Caucasus. The circulation of West Nile virus genotype 1 in the territory of the Republics of Ingushetia and Mordovia, genotype 2 in the Ivanovo and Nizhny Novgorod regions, Chuvash and Kabardino- Balkarian Republics is shown. The results of studying the immune layer revealed the presence of antibodies to the West Nile virus of the IgG class in 4.5% of the examined local population, with the highest rates in the Chechen Republic (10%) and the Republic of North Ossetia-Alania (14%). The maximum level of population immunity was noted among people in the age groups 20–29 years old and amounted to 9.7%, 30–39 years old – 7.8%.Conclusion: the results obtained significantly supplemented our understanding of the spread of WNV in Russia and the activity of disease foci, and can be used in planning and conducting monitoring studies.

Objective: to study the level of the immune layer of the population to pathogens of natural focal infectious diseases in order to establish the epidemic activity of natural foci of particularly dangerous infectious diseases in the Rostov region.Materials and methods: blood serums of healthy donors living in the administrative territories of the region were collected in the period from 2020 to 2022. Specific antibodies in blood sera were determined by the ELISA method. Serum specific IgG class immunoglobulins were used as a serological marker of the transmitted infection.Results: IgG to the Crimean hemorrhagic fever virus was not detected in 2020. In 2021, the share of seropositive results was 0.7%, in 2022 — 2.0%. The proportion of IgG to West Nile virus in 2020 was 8.7%, in 2021 — 9.9%, in 2022 — 12.4%. Serological testing revealed an immune layer to ixodic tick–borne borreliosis in 2020–2022: 3.1%, 2.6% and 2.0%, respectively. Antibodies to hantaviruses, pathogens of hemorrhagic fever with renal syndrome in the blood of residents of the region in 2020 were found in 7.0% of samples, in 2021 — 4.5%, in 2022 — 7.1%. The share of positive samples in the study for Ku fever in 2022 was 2.3%. Conclusion: Seropositive samples were detected for all studied natural focal infections. The greatest variety of natural focal infections confirmed by serological monitoring data was detected in cities (Rostov-on-Don, Taganrog, Zernograd, Kamensk-Shakhtinsky) and districts of RO (Salsky, Neklinovsky, Remontnensky).Conclusion. The results of the serological monitoring made it possible to identify the circulation of pathogens of KGL, LZN, ICB, Ku fever, hantaviruses in the territory of two districts of the region. The detection of specific antibodies in the blood sera of healthy donors indicates the epidemic activity of natural foci. Also, a comprehensive study of healthy donors expanded the understanding of the area of the most relevant natural focal infections such as (KGL, LZN, ICB), and less frequently registered at present (HFRS and Ku fever).

Introduction. The relevance of the study is due to the need to assess the real expansion of West Nile fever (WNF) in Russia, analyze the manifestations of epizootic and epidemic processes and study the population structure of West Nile virus (WNV). Aim. To obtain objective data on the intensity of WNV circulation in certain territories of Russia and study the properties of the isolated strains of the pathogen. Materials and methods. 4564 samples of field material from 23 subjects of the Russian Federation and 1547 samples of clinical material from 12 subjects of the Russian Federation were examined. A set of laboratory diagnostic methods was used: ELISA, RT-PCR, virological, sequencing. Results. In 20 out of 1331 (1.5%) examined febrile patients, IgM antibodies to WNV were detected, including positive cases identified for the first time in the Karachay-Cherkess Republic, Tver and Vladimir regions. The presence of immunity to WNV was found on average in 8.6% of 11 federal subjects' population with high seroprevalence rates in Zaporozhye (24,5%), Tula (15,4%) and Kursk (11,1%) regions. Low-avidity IgG antibodies were detected in 44 (33,1%) samples from a population of 9 federal subjects. Intensive circulation of WNV lineage 2 in the epizootic cycle in the southern part of European Russia was confirmed. 12 WNV isolates were obtained, including those isolated for the first time in the Republic of Crimea, the Karachay-Cherkess Republic and the Stavropol Territory. The heterogeneity of circulating WNF causative agent's strains related to the two clades of the WNV lineage 2 formed in 2021 and 2022 was established. Conclusion. In the course of comprehensive monitoring studies, a new northern border of the WNF range was established, which as of 2022 passes through the territory of the Tver region. Data from seroepidemiological studies, including the detection of low-avidity IgG antibodies, confirm fairly intense, but undiagnosed contact of the population of the European part of Russia with the WNF pathogen. In the southern region of the European part of Russia, WNV genotype 2 predominantly circulates, belonging to at least two clades formed in 2021 and 2022.

Background: Dengue fever (DF) and West Nile fever (WNF) have become endemic worldwide in the last two decades. Studies suggest that individuals with diabetes mellitus (DM) are at a higher risk of developing severe complications from these diseases. Identifying the factors associated with a severe clinical presentation is crucial, as prompt treatment is essential to prevent complications and fatalities. This article aims to summarize and assess the published evidence regarding the link between DM and the risk of severe clinical manifestations in cases of DF and WNF. Methodology/Principal findings: A systematic search was conducted using the PubMed and Web of Science databases. 27 studies (19 on DF, 8 on WNF) involving 342,873 laboratory-confirmed patients were included in the analysis. The analysis showed that a diagnosis of DM was associated with an increased risk for severe clinical presentations of both DF (OR 3.39; 95% CI: 2.46, 4.68) and WNF (OR 2.89; 95% CI: 1.89, 4.41). DM also significantly increased the risk of death from both diseases (DF: OR 1.95; 95% CI: 1.09, 3.52; WNF: OR 1.74; 95% CI: 1.40, 2.17). Conclusions/Significance: This study provides strong evidence supporting the association between DM and an increased risk of severe clinical manifestations in cases of DF and WNF. Diabetic individuals in DF or WNF endemic areas should be closely monitored when presenting with febrile symptoms due to their higher susceptibility to severe disease. Early detection and appropriate management strategies are crucial in reducing the morbidity and mortality rates associated with DF and WNF in diabetic patients. Tailored care and targeted public health interventions are needed to address this at-risk population. Further research is required to understand the underlying mechanisms and develop effective preventive and therapeutic approaches. Author summary: In our study, we investigated the association between diabetes mellitus (DM) and the risk of severe clinical manifestations in cases of dengue fever (DF) and West Nile fever (WNF). By analyzing 27 studies involving over 342,000 laboratory-confirmed patients, we found compelling evidence supporting a link between DM and an increased risk of severe complications in both DF and WNF. Moreover, DM was found to significantly raise the risk of mortality from these diseases. Our findings emphasize the importance of early detection and appropriate management strategies for diabetic individuals residing in endemic areas. Healthcare providers should be vigilant in monitoring diabetic patients with febrile symptoms, as they are more susceptible to developing severe disease. Tailored care and targeted interventions are crucial to minimize the morbidity and mortality rates associated with DF and WNF in diabetic individuals. These findings have significant implications for public health, highlighting the need for awareness campaigns and preventive measures aimed at diabetic individuals. Further research is needed to understand the underlying mechanisms and develop effective strategies for prevention and treatment. By addressing these issues, we can reduce the impact of DF and WNF on individuals with DM. [ABSTRACT FROM AUTHOR]

West Nile virus (WNV) is a vector-borne flavivirus that causes an increasing number of human and equine West Nile fever cases in Europe. While the virus has been present in the Mediterranean basin and the Balkans since the 1960s, recent years have witnessed its northward expansion, with the first human cases reported in Germany in 2018 and the Netherlands in 2020. WNV transmission and amplification within mosquitoes are temperature-dependent. This study applies a mathematical modelling approach to assess the conditions under which WNV circulation occurs based on the proportion of mosquito bites on WNV-competent birds (dilution), vector-host ratios, mosquito season length and the observed daily temperature data. We modelled five distinct European regions where previous WNV circulation has been observed within the Netherlands, Germany, Spain, Italy, and Greece. We observed that the number of days in which the basic reproduction number (R0) is above one, increased over the last 40 years in all five regions. In the Netherlands, the number of days in which the R0 is above one, is 70% lower than in Spain. The temperature in Greece, Spain and Italy allowed for circulation under low vector-host ratios, and at a high dilution. On the other hand in the Netherlands and Germany, given the observed daily temperature, the thresholds for circulation requires a lower dilution and higher vector-host ratios. For the Netherlands, a short window of introductions between late May and mid-June would result in detectable outbreaks. Our findings revealed that the temperate maritime climate of the Netherlands allows WNV circulation primarily during warmer summers, and only under high vector-host ratios. This research contributes valuable insights into the dynamic relationship between temperature, vector properties, and WNV transmission, offering guidance for proactive strategies in addressing this emerging health threat in Europe. Author summary: West Nile virus (WNV) is a virus that is transmitted by mosquitoes, and that leads to West Nile fever cases in humans and horses. Although the virus has been in certain parts of Europe since the 1960s, it has recently spread northward, with the first human cases reported in Germany in 2018 and the Netherlands in 2020. Here, we use mathematical modelling to understand the conditions necessary for WNV transmission. We consider the proportion of mosquito bites on birds that can carry the virus, the number of hosts and vectors, the length of mosquito season, and temperature data in specific European regions where WNV has been observed previously (Netherlands, Germany, Spain, Italy, and Greece). We found that the number of days suitable for WNV transmission (determined by the basic reproduction number, R0) has increased over the last 40 years in all these regions. Furthermore, we found differences among these regions. In the Netherlands, for instance, the conditions for virus circulation requires higher vector-host ratios, while in warmer regions like Greece, Spain, and Italy, circulation occurs under lower ratios. Understanding the connection between temperature, mosquito traits, and WNV transmission is crucial for implementing surveillance and preventive measures. [ABSTRACT FROM AUTHOR]

West Nile virus (WNV) is an arbovirus spread primarily by Culex mosquitoes, with humans being a dead-end host. WNV was introduced to Florida in 2001, with 467 confirmed cases since. It is estimated that 80 percent of cases are asymptomatic, with mild cases presenting as a non-specific flu-like illness. Currently, detection of WNV in humans occurs primarily in healthcare settings via RT-PCR or CSF IgM when patients present with severe manifestations of disease including fever, meningitis, encephalitis, or acute flaccid paralysis. Given the short window of detectable viremia and requirement for CSF sampling, most WNV infections never receive an official diagnosis. This study utilized enzyme-linked immunosorbent assay (ELISA) to detect WNV IgG antibodies in 250 patient serum and plasma samples collected at Tampa General Hospital during 2020 and 2021. Plaque reduction neutralization tests were used to confirm ELISA results. Out of the 250 patients included in this study, 18.8% of them were IgG positive, consistent with previous WNV exposure. There was no relationship between WNV exposure and age or sex. [ABSTRACT FROM AUTHOR]

Background In 2021, the state of Arizona experienced the largest focal outbreak of West Nile virus (WNV) in US history. Timely and accurate diagnostic testing remains a challenge for WNV due to transient viremia and limited immunoassay specificity. Recent studies have identified whole blood (WB) and urine as more sensitive specimen types for the detection of WNV RNA. Methods We evaluated ordering practices, test performance, and patient characteristics of probable and confirmed cases. In total, we identified 190 probable and proven cases, including 127 patients (66.8%) with neuroinvasive disease. Results Among all cases, only 29.5% had WNV polymerase chain reaction (PCR) testing ordered on WB, of which 80.3% resulted as positive, including 7 cases in which WNV serologic testing was negative and 5 cases for which serologic testing was not ordered. In comparison, only 23.7% of cases that had cerebrospinal fluid (CSF) PCR ordered had a positive result, including 3 cases that were negative by PCR on WB. In contrast, WNV PCR on WB detected 12 neuroinvasive cases that were CSF PCR negative. WNV PCR testing in urine was only ordered on 2 patients, both of whom were positive. Crossing cycle threshold (Ct) values were not significantly different between WB and CSF specimen types, nor was there a correlation between Ct value and days from symptom onset at the time of sample collection; all specimen types and time points had Ct values, with 98% above 30. WB was positive by WNV PCR in several patients for >7 days (range, 7–25 days) after symptom onset, as was the CSF PCR. Conclusions Taken together, these findings indicate that WNV PCR testing on WB may be the best initial test for timely diagnosis of WNV infection, irrespective of clinical manifestation; however, if negative in patients with suspected neuroinvasive disease, WNV PCR testing on CSF should be ordered. [ABSTRACT FROM AUTHOR]

Astroviruses have been found in cattle and other species with encephalitis. Our objective was to determine the frequency of neurotropic bovine astrovirus (BoAstV) in cases of encephalitis in cattle ≥ 4-mo-old. Of 56 cases of idiopathic lymphocytic encephalitis examined retrospectively (1988–2019), fixed brain from 11 cases (19%) tested positive by semi-quantitative RT-PCR for BoAstV CH13/NeuroS1. None of the control cases tested positive, including 32 with other forms of encephalitis and 40 with no neurologic disease. Most astrovirus-positive cases were 1–2-y-old, with a range of 7 mo to 7 y, and affected both beef and dairy breeds with wide geographic distribution. BoAstV-positive cases had acute onset of neurologic signs of 12 h to 7 d before death or euthanasia. Affected cattle had lymphocytic inflammation throughout the brain including cerebrum, thalamus, midbrain, cerebellum, medulla oblongata, and spinal cord, and affecting gray and white matter. Further PCR testing identified a possible cause in 9 of the 45 (20%) remaining idiopathic cases of lymphocytic encephalitis, including eastern equine encephalitis virus, Listeria monocytogenes, bovine viral diarrhea virus, bovine alphaherpesvirus 1, and ovine gammaherpesvirus 2 (malignant catarrhal fever); we found no cases of infection by West Nile virus, rabies virus, or Chlamydia spp. No cause was identified in 36 of 56 (64%) cases of lymphocytic encephalitis. We frequently identified neurotropic BoAstV in cases of lymphocytic encephalitis that had no previously identified cause. Neurotropic BoAstV infections had gone undetected for decades, but the frequency of BoAstV infections has not increased among contemporary cases. [ABSTRACT FROM AUTHOR]

West Nile virus (WNV) is capable of causing severe neurologic disease in both humans and equines, making it a disease of importance in both human medicine and veterinary medicine. No targeted treatments exist for WNV infection in either humans or equines. Infection is treated symptomatically through management of symptoms like fever and seizures. As treatment for WNV is purely supportive, the response to WNV has focused primarily on methods of disease prevention. To this end, research efforts have yielded several effective vaccines for equine use as well as numerous conventional mosquito control techniques. Even with the implementation of these techniques, disease caused by WNV remains a concern since no human vaccine exists. Due to the lack of a human vaccine, novel preventative strategies are under active research and development. Of these strategies, some of the most conceptually promising are techniques using genetically modified mosquitoes, addressing the disease at the vector level with minimal ecological side effects. Taken together, the use of combined, synergistic methods, such as physical barriers, transgenic mosquitoes, and immunological targets, will be the best way to prevent WNV disease. [ABSTRACT FROM AUTHOR]

West Nile virus (WNV) neuroinvasive disease (WNND) occurs in approximately 1 percent of WNV-infected patients and typically presents as encephalitis, meningitis, or acute flaccid paralysis (AFP). WNND remains a difficult inpatient diagnosis, creating significant challenges for prognostication and therapy selection. We characterized the clinical and diagnostic features of WNND cases at two major academic medical centers in New York City in routine clinical practice. We retrospectively reviewed the charts of thirty-six patients with WNND, including twenty-six encephalitis, four meningitis, and six AFP cases. The most common presenting symptoms were fever (86.1%) and gastrointestinal symptoms (38.9%) in addition to altered mental status (72.2%), lethargy (63.9%), gait disturbances (46.2%), and headache (44.4%). Fourteen (48.3%) patients displayed acute magnetic resonance imaging (MRI) findings, particularly T2 hyperintensities in the bilateral thalami, brainstem, and deep white matter. New York State Department of Health WNV CSF IgM testing was utilized for diagnosis in 58.3% of patients; however, just 38.1% had the result by discharge, compared to 85.6% of those who underwent serum IgM testing. The median length of stay was 13.5 days, 38.9% were intubated, and three patients (8.9%) died during acute hospitalization. Our findings underscore the morbidity, mortality, and diagnostic challenges of WNND, suggesting the potential utility of serum IgM testing in combination with confirmatory CSF testing to expedite diagnosis in the acute setting. [ABSTRACT FROM AUTHOR]

Background: To describe a case of bilateral multifocal chorioretinitis as the only presentation of acute West Nile virus (WNV) infection in the absence of neurological involvement. Case presentation: A 78-year-old Italian woman was admitted to our emergency department because she noticed blurry vision in both eyes. She did not report fever, fatigue, or neurological symptoms in the last few days. Multimodal imaging showed the presence of bilateral hyperfluorescent lesions with a linear distribution, that corresponded to hypocyanescent spots on indocyanine green angiography. Antibody serology showed the presence of IgM antibodies, IgG antibodies, and ribonucleic acid (RNA) for WNV. Magnetic resonance imaging (MRI) of the brain ruled out central nervous system involvement. Three months later, the patient reported spontaneous resolution of her symptoms and remission of the chorioretinal infiltrates. Conclusions: In endemic areas, it is important to think of acute WNV infection as an explanatory etiology in cases of multifocal chorioretinitis, even without neurological involvement. [ABSTRACT FROM AUTHOR]

Natural killer (NK) cells are cytotoxic lymphocytes important for viral defense. West Nile virus (WNV) infection of the central nervous system (CNS) causes marked recruitment of bone marrow (BM)‐derived monocytes, T cells and NK cells, resulting in severe neuroinflammation and brain damage. Despite substantial numbers of NK cells in the CNS, their function and phenotype remain largely unexplored. Here, we demonstrate that NK cells mature from the BM to the brain, upregulate inhibitory receptors and show reduced cytokine production and degranulation, likely due to the increased expression of the inhibitory NK cell molecule, MHC‐I. Intriguingly, this correlated with a reduction in metabolism associated with cytotoxicity in brain‐infiltrating NK cells. Importantly, the degranulation and killing capability were restored in NK cells isolated from WNV‐infected tissue, suggesting that WNV‐induced NK cell inhibition occurs in the CNS. Overall, this work identifies a potential link between MHC‐I inhibition of NK cells and metabolic reduction of their cytotoxicity during infection. [ABSTRACT FROM AUTHOR]

This document summarizes a study on the correlation between aging and the severity of dengue fever. The study found that older individuals experienced more severe symptoms and worse disease outcomes compared to younger individuals, regardless of the presence of non-communicable diseases (NCDs). Age was identified as an independent risk factor for severe dengue, and the study suggests that age-specific assessments and interventions are necessary. The document also discusses the impact of aging on the immune system and emphasizes the importance of considering age-related factors in diagnosing and treating dengue in older adults. [Extracted from the article]

Vector-borne diseases like West Nile virus (WNV) pose a global health challenge, with rising incidence and distribution. Culex mosquitoes are crucial WNV vectors. Avian species composition and bird community diversity, along with vector communities, influence WNV transmission patterns. However, limited knowledge exists on their impact in southwestern Spain, an area with active WNV circulation in wild birds, mosquitoes, and humans. To address this, we conducted a comprehensive study investigating the contributions of migratory and exotic bird species to WNV transmission and the influence of mosquito community composition. Analysing 1194 serum samples from 44 avian species, we detected WNV antibodies in 32 samples from 11 species, four for the first time in Europe. Migratory birds had higher WNV exposure likelihood than native and exotic species, and higher phylogenetic diversity in bird communities correlated with lower exposure rates. Moreover, in 5859 female mosquitoes belonging to 12 species, we identified WNV competent vectors like Cx. pipiens s.l. and the Univittatus subgroup. Birds with WNV antibodies were positively associated with competent vector abundance, but negatively with overall mosquito species richness. These findings highlight the complex interactions between bird species, their phylogenetics, and mosquito vectors in WNV transmission. Understanding these dynamics will help to implement effective disease control strategies in southwestern Spain. [ABSTRACT FROM AUTHOR]

Summary: Human autoantibodies (auto‐Abs) neutralizing type I IFNs were first discovered in a woman with disseminated shingles and were described by Ion Gresser from 1981 to 1984. They have since been found in patients with diverse conditions and are even used as a diagnostic criterion in patients with autoimmune polyendocrinopathy syndrome type 1 (APS‐1). However, their apparent lack of association with viral diseases, including shingles, led to wide acceptance of the conclusion that they had no pathological consequences. This perception began to change in 2020, when they were found to underlie about 15% of cases of critical COVID‐19 pneumonia. They have since been shown to underlie other severe viral diseases, including 5%, 20%, and 40% of cases of critical influenza pneumonia, critical MERS pneumonia, and West Nile virus encephalitis, respectively. They also seem to be associated with shingles in various settings. These auto‐Abs are present in all age groups of the general population, but their frequency increases with age to reach at least 5% in the elderly. We estimate that at least 100 million people worldwide carry auto‐Abs neutralizing type I IFNs. Here, we briefly review the history of the study of these auto‐Abs, focusing particularly on their known causes and consequences. [ABSTRACT FROM AUTHOR]