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Current Opinion in Insect Science Aug 2017West Nile virus (WNV Flaviviridae; Flavivrus) is the most geographically widespread arbovirus in the world and the leading cause of arboviral encephalitis globally.... (Review)
Review
West Nile virus (WNV Flaviviridae; Flavivrus) is the most geographically widespread arbovirus in the world and the leading cause of arboviral encephalitis globally. Worldwide, WNV is maintained in an enzootic cycle between primarily Culex spp. mosquitoes and birds, with human infection and disease resulting from enzootic spillover. Dynamic and complex intrinsic and extrinsic factors contribute to the temporal and spatial variability in WNV transmission. The most current information on the relative contribution of each of these factors is reviewed and a case to incorporate detailed and localized environmental and genetic data into predictive models is presented.
Topics: Animals; Birds; Culicidae; Humans; Mosquito Vectors; West Nile Fever; West Nile virus
PubMed: 28805636
DOI: 10.1016/j.cois.2017.05.002 -
Methods in Molecular Biology (Clifton,... 2023West Nile virus (WNV) is a mosquito-borne, single-stranded, positive-sense RNA virus belonging to the Flaviviridae family. After WNV gains entry through an infected...
West Nile virus (WNV) is a mosquito-borne, single-stranded, positive-sense RNA virus belonging to the Flaviviridae family. After WNV gains entry through an infected mosquito bite, it replicates in a variety of human cell types and produces a viremia. Although the majority of infected individuals remain asymptomatic, the manifested symptoms in some people range from a mild fever to severe neurological disorder with high morbidity and mortality. In addition, many who recover from WNV neuroinvasive infection present with long-term deficits, including weakness, fatigue, and cognitive problems. Since entering the USA in 1999, WNV has become the most common mosquito-borne virus in North America. Despite the intensive research over 20 years, there are still no approved vaccines or specific treatments for humans, and it remains an urgent need to understand the pathogenesis of WNV and develop specific therapeutics and vaccines.
Topics: Animals; Humans; West Nile virus; West Nile Fever; Viremia; North America
PubMed: 36331759
DOI: 10.1007/978-1-0716-2760-0_1 -
Journal of Medical Microbiology Jul 2023West Nile virus (WNV) is a positive-sense single-stranded RNA virus belonging to the family and is maintained in an enzootic cycle between avian hosts and mosquito...
West Nile virus (WNV) is a positive-sense single-stranded RNA virus belonging to the family and is maintained in an enzootic cycle between avian hosts and mosquito vectors. Humans, horses and other mammals are susceptible to infection but are dead-end hosts due to a low viraemia. The disease can manifest itself in a variety of clinical signs and symptoms in people and horses from mild fever to severe encephalitis and morbidity. There are no vaccines licensed for human protection, but parts of Europe, North America, Africa and Australia have vaccines commercially available for horses.
Topics: Humans; Animals; Horses; West Nile virus; West Nile Fever; Mammals; Europe; Africa
PubMed: 37459154
DOI: 10.1099/jmm.0.001730 -
Viruses Jul 2020West Nile virus (WNV) is a flavivirus transmitted by mosquitoes. Birds are the reservoir for the virus; humans, horses and other mammals are dead-end hosts. Infections...
West Nile virus (WNV) is a flavivirus transmitted by mosquitoes. Birds are the reservoir for the virus; humans, horses and other mammals are dead-end hosts. Infections caused by WNV in humans can vary from asymptomatic infections to West Nile fever (WNF) or West Nile neuroinvasive disease (WNND). In 1995, a serosurvey was performed in Slovenia on forest workers, and WNV specific IgG antibodies were confirmed in 6.8% of the screened samples, indicating that WNV is circulating in Slovenia. No human disease cases were detected in Slovenia until 2013, when the first case of WNV infection was confirmed in a retrospective study in a 79-year old man with meningitis. In 2018, three patients with WNND were confirmed by laboratory tests, with detection of IgM antibodies in the cerebrospinal fluid of the patients. In one of the patients, WNV RNA was detected in the urine sample. In 2017, 2018 and 2019, a mosquito study was performed in Slovenia. Mosquitoes were sampled on 14 control locations and 35 additional locations in 2019. No WNV was detected in mosquitoes in 2017 and 2019, but we confirmed the virus in a pool of sp. mosquitoes in 2018. The virus was successfully isolated, and complete genome sequence was acquired. The whole genome of the WNV was also sequenced from the patient's urine sample. The whole genome sequences of the WNV virus detected in Slovenian patient and mosquito indicate the virus most likely spread from the north, because of the geographic proximity and because the sequences cluster with the Austrian and Hungarian sequences. A sentinel study was performed on dog sera samples, and we were able to confirm IgG antibodies in 1.8% and 4.3% of the samples in 2017 and 2018, respectively. Though Slovenia is not a highly endemic country for WNV, we have established that the virus circulates in Slovenia.
Topics: Aged; Animals; Antibodies, Viral; Culex; Culicidae; Dog Diseases; Dogs; Female; Genome, Viral; Humans; Male; Middle Aged; Phylogeny; Retrospective Studies; Slovenia; West Nile Fever; West Nile virus
PubMed: 32635155
DOI: 10.3390/v12070720 -
Clinical Infectious Diseases : An... Aug 2021West Nile virus (WNV) is the most commonly reported mosquito-borne disease in the USA. California reports more WNV disease than any other state.
BACKGROUND
West Nile virus (WNV) is the most commonly reported mosquito-borne disease in the USA. California reports more WNV disease than any other state.
METHODS
We identified WNV-associated hospitalizations from 2004 through 2017 in California and estimated hospitalization incidence using Patient Discharge Data. We described demographic, geographic, and clinical characteristics of WNV hospitalizations; identified risk factors for in-hospital death; and tabulated hospitalization charges.
RESULTS
From 2004 through 2017, 3109 Californians were hospitalized with WNV (median, 214 patients/year; range, 72-449). The majority were male (1983; 63.8%) and aged ≥60 years (1766; 56.8%). The highest median annual hospitalization rate (0.88 hospitalizations/100 000 persons) was in the Central Valley, followed by southern California (0.59 hospitalizations/100 000 persons). Most patients (2469; 79.4%) had ≥1 underlying condition, including hypertension, cardiovascular disease, diabetes, chronic kidney disease, or immunosuppression due to medications or disease. Median hospitalization length of stay was 12 days (interquartile range, 6-23 days). During hospitalization, 1317 (42%) patients had acute respiratory failure and/or sepsis/septic shock, 772 (24.8%) experienced acute kidney failure, and 470 (15.1%) had paralysis; 272 (8.8%) patients died. Nearly 47% (1444) of patients were discharged for additional care. During these 14 years, $838 680 664 (mean $59.9 million/year) was charged for WNV hospitalizations, 73.9% through government payers at a median charge of $142 321/patient.
CONCLUSIONS
WNV-associated hospitalizations were substantial and costly in California. Hospitalization incidence was higher in males, elderly persons, and patients with underlying conditions. WNV persists as a costly and severe public health threat in California.
Topics: Aged; Animals; California; Female; Hospital Mortality; Hospitalization; Humans; Male; Vaccines; West Nile Fever; West Nile virus
PubMed: 32525967
DOI: 10.1093/cid/ciaa749 -
Nature Communications Oct 2023It is unclear whether West Nile virus (WNV) circulates between Africa and Europe, despite numerous studies supporting an African origin and high transmission in Europe....
It is unclear whether West Nile virus (WNV) circulates between Africa and Europe, despite numerous studies supporting an African origin and high transmission in Europe. We integrated genomic data with geographic observations and phylogenetic and phylogeographic inferences to uncover the spatial and temporal viral dynamics of WNV between these two continents. We focused our analysis towards WNV lineages 1 (L1) and 2 (L2), the most spatially widespread and pathogenic WNV lineages. Our study shows a Northern-Western African origin of L1, with back-and-forth exchanges between West Africa and Southern-Western Europe; and a Southern African origin of L2, with one main introduction from South Africa to Europe, and no back introductions observed. We also noticed a potential overlap between L1 and L2 Eastern and Western phylogeography and two Afro-Palearctic bird migratory flyways. Future studies linking avian and mosquito species susceptibility, migratory connectivity patterns, and phylogeographic inference are suggested to elucidate the dynamics of emerging viruses.
Topics: Animals; West Nile virus; West Nile Fever; Phylogeny; Europe; South Africa; Birds
PubMed: 37833275
DOI: 10.1038/s41467-023-42185-7 -
Sub-cellular Biochemistry 2023RNA virus infections have been a leading cause of pandemics. Aided by global warming and increased connectivity, their threat is likely to increase over time. The...
RNA virus infections have been a leading cause of pandemics. Aided by global warming and increased connectivity, their threat is likely to increase over time. The flaviviruses are one such RNA virus family, and its prototypes such as the Japanese encephalitis virus (JEV), Dengue virus, Zika virus, West Nile virus, etc., pose a significant health burden on several endemic countries. All viruses start off their life cycle with an infected cell, wherein a series of events are set in motion as the virus and host battle for autonomy. With their remarkable capacity to hijack cellular systems and, subvert/escape defence pathways, viruses are able to establish infection and disseminate in the body, causing disease. Using this strategy, JEV replicates and spreads through several cell types such as epithelial cells, fibroblasts, monocytes and macrophages, and ultimately breaches the blood-brain barrier to infect neurons and microglia. The neurotropic nature of JEV, its high burden on the paediatric population, and its lack of any specific antivirals/treatment strategies emphasise the need for biomedical research-driven solutions. Here, we highlight the latest research developments on Japanese encephalitis virus-infected cells and discuss how these can aid in the development of future therapies.
Topics: Child; Humans; Encephalitis Virus, Japanese; Flavivirus; West Nile virus; Zika Virus; Blood-Brain Barrier; Zika Virus Infection
PubMed: 38159231
DOI: 10.1007/978-3-031-40086-5_10 -
Microbes and Infection Feb 2015West Nile virus (WNV) is a widespread global pathogen that results in significant morbidity and mortality. Data from animal models provide evidence of persistent renal... (Review)
Review
West Nile virus (WNV) is a widespread global pathogen that results in significant morbidity and mortality. Data from animal models provide evidence of persistent renal and neurological infection from WNV; however, the possibility of persistent infection in humans and long-term neurological and renal outcomes related to viral persistence remain largely unknown. In this paper, we provide a review of the literature related to persistent infection in parallel with the findings from cohorts of patients with a history of WNV infection. The next steps for enhancing our understanding of WNV as a persistent pathogen are discussed.
Topics: Animals; Disease Models, Animal; Humans; Renal Insufficiency, Chronic; United States; West Nile Fever; West Nile virus
PubMed: 25499188
DOI: 10.1016/j.micinf.2014.12.003 -
Pathogens and Global Health Jul 2018Eastern Europe (EE) has been severely affected by mosquito-borne viruses (moboviruses). In this review, we summarize the epidemiology of moboviruses, with particular... (Review)
Review
Eastern Europe (EE) has been severely affected by mosquito-borne viruses (moboviruses). In this review, we summarize the epidemiology of moboviruses, with particular attention to West Nile virus (WNV). The study of WNV human cases in EE between 2010 and 2016, revealed that the epidemiology of WNV in EE is complex with the combination of introduction of different WNV strains from lineages 1 and 2, and the establishment of endemic cycles. We found a positive correlation between the risk of WNV re-emergence in an area and the number of human cases reported in the previous year. We also report the main ecological and biological characteristics of the key mosquito species vectors of moboviruses. Recent expansion of invasive mosquito species in EE, mainly Aedes albopictus but also Aedes aegypti and Culex quinquefasciatus, may result in new scenarios with an increased risk of transmission of moboviruses. Main gaps of knowledge in relation to moboviruses and their vectors in EE are identified. Understanding the epidemiology of moboviruses in EE is essential for the improvement of their surveillance and the control of the diseases they cause.
Topics: Aedes; Animals; Culex; Disease Transmission, Infectious; Europe, Eastern; Humans; Mosquito Vectors; Risk Assessment; West Nile Fever; West Nile virus
PubMed: 29979950
DOI: 10.1080/20477724.2018.1483567 -
Journal of Medical Entomology Oct 2019The introduction of West Nile virus (WNV) to North America in 1999 and its subsequent rapid spread across the Americas demonstrated the potential impact of arboviral... (Review)
Review
The introduction of West Nile virus (WNV) to North America in 1999 and its subsequent rapid spread across the Americas demonstrated the potential impact of arboviral introductions to new regions, and this was reinforced by the subsequent introductions of chikungunya and Zika viruses. Extensive studies of host-pathogen-vector-environment interactions over the past two decades have illuminated many aspects of the ecology and evolution of WNV and other arboviruses, including the potential for pathogen adaptation to hosts and vectors, the influence of climate, land use and host immunity on transmission ecology, and the difficulty in preventing the establishment of a zoonotic pathogen with abundant wildlife reservoirs. Here, we focus on outstanding questions concerning the introduction, spread, and establishment of WNV in the Americas, and what it can teach us about the future of arboviral introductions. Key gaps in our knowledge include the following: viral adaptation and coevolution of hosts, vectors and the virus; the mechanisms and species involved in the large-scale spatial spread of WNV; how weather modulates WNV transmission; the drivers of large-scale variation in enzootic transmission; the ecology of WNV transmission in Latin America; and the relative roles of each component of host-virus-vector interactions in spatial and temporal variation in WNV transmission. Integrative studies that examine multiple factors and mechanisms simultaneously are needed to advance our knowledge of mechanisms driving transmission.
Topics: Adaptation, Biological; Animals; Central America; Host-Pathogen Interactions; Humans; North America; South America; West Nile Fever; West Nile virus; Zoonoses
PubMed: 31549719
DOI: 10.1093/jme/tjz151