scholarly journals West Nile Virus Restriction in Mosquito and Human Cells: A Virus under Confinement

Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 256
Author(s):  
Marie-France Martin ◽  
Sébastien Nisole
Keyword(s):  
West Nile Virus ◽  
Current Knowledge ◽  
Mammalian Species ◽  
Human Cells ◽  
Health Concern ◽  
Broad Host Range ◽  
Restriction Factors ◽  
West Nile ◽  
Viral Propagation ◽  
Viral Restriction

West Nile virus (WNV) is an emerging neurotropic flavivirus that naturally circulates between mosquitoes and birds. However, WNV has a broad host range and can be transmitted from mosquitoes to several mammalian species, including humans, through infected saliva during a blood meal. Although WNV infections are mostly asymptomatic, 20% to 30% of cases are symptomatic and can occasionally lead to severe symptoms, including fatal meningitis or encephalitis. Over the past decades, WNV-carrying mosquitoes have become increasingly widespread across new regions, including North America and Europe, which constitutes a public health concern. Nevertheless, mosquito and human innate immune defenses can detect WNV infection and induce the expression of antiviral effectors, so-called viral restriction factors, to control viral propagation. Conversely, WNV has developed countermeasures to escape these host defenses, thus establishing a constant arms race between the virus and its hosts. Our review intends to cover most of the current knowledge on viral restriction factors as well as WNV evasion strategies in mosquito and human cells in order to bring an updated overview on WNV–host interactions.

scholarly journals A 15 Year Evaluation of West Nile Virus in Wisconsin: Effects on Wildlife and Human Health

2020 ◽  
Vol 17 (5) ◽  
pp. 1767
Author(s):  
Johnny A. Uelmen ◽  
Charles Brokopp ◽  
Jonathan Patz
Keyword(s):  
West Nile Virus ◽  
Human Population ◽  
Mammalian Species ◽  
Keystone Species ◽  
The United States ◽  
Positive Influence ◽  
Incidence Rates ◽  
Rural Regions ◽  
West Nile ◽  
Statewide Assessment

West Nile virus (WNV) is the most important and widespread mosquito-borne virus in the United States (U.S.). WNV has the ability to spread rapidly and effectively, infecting more than 320 bird and mammalian species. An examination of environmental conditions and the health of keystone species may help predict the susceptibility of various habitats to WNV and reveal key risk factors, annual trends, and vulnerable regions. Since 2002, WNV outbreaks in Wisconsin varied by species, place, and time, significantly affected by unique climatic, environmental, and geographical factors. During a 15 year period, WNV was detected in 71 of 72 counties, resulting in 239 human and 1397 wildlife cases. Controlling for population and sampling efforts in Wisconsin, rates of WNV are highest in the western and northwestern rural regions of the state. WNV incidence rates were highest in counties with low human population densities, predominantly wetland, and at elevations greater than 1000 feet. Resources for surveillance, prevention, and detection of WNV were lowest in rural counties, likely resulting in underestimation of cases. Overall, increasing mean temperature and decreasing precipitation showed positive influence on WNV transmission in Wisconsin. This study incorporates the first statewide assessment of WNV in Wisconsin.

scholarly journals Early detection of West Nile virus in France: quantitative assessment of syndromic surveillance system using nervous signs in horses

2016 ◽  
Vol 145 (5) ◽  
pp. 1044-1057 ◽  
Author(s):  
C. FAVERJON ◽  
F. VIAL ◽  
M. G. ANDERSSON ◽  
S. LECOLLINET ◽  
A. LEBLOND
Keyword(s):  
West Nile Virus ◽  
Early Detection ◽  
Surveillance System ◽  
Syndromic Surveillance ◽  
Real Data ◽  
Detection Algorithm ◽  
Health Concern ◽  
False Alarms ◽  
West Nile ◽  
Syndromic Surveillance System

SUMMARYWest Nile virus (WNV) is a growing public health concern in Europe and there is a need to develop more efficient early detection systems. Nervous signs in horses are considered to be an early indicator of WNV and, using them in a syndromic surveillance system, might be relevant. In our study, we assessed whether or not data collected by the passive French surveillance system for the surveillance of equine diseases can be used routinely for the detection of WNV. We tested several pre-processing methods and detection algorithms based on regression. We evaluated system performances using simulated and authentic data and compared them to those of the surveillance system currently in place. Our results show that the current detection algorithm provided similar performances to those tested using simulated and real data. However, regression models can be easily and better adapted to surveillance objectives. The detection performances obtained were compatible with the early detection of WNV outbreaks in France (i.e. sensitivity 98%, specificity >94%, timeliness 2·5 weeks and around four false alarms per year) but further work is needed to determine the most suitable alarm threshold for WNV surveillance in France using cost-efficiency analysis.

scholarly journals Delving Below the Species Level To Characterize the Ecological Diversity within the Global Virome: An Exploration of West Nile Virus

2019 ◽  
Author(s):  
Tong Kong ◽  
Kelly Mei ◽  
Ammie Wang ◽  
Danny Krizanc ◽  
Frederick M. Cohan
Keyword(s):  
New York ◽  
West Nile Virus ◽  
Host Range ◽  
Species Level ◽  
Broad Host Range ◽  
Significant Heterogeneity ◽  
Virus Species ◽  
Ecological Diversity ◽  
West Nile ◽  
A Genome

SummaryEfforts to describe the diversity of viruses have largely focused on classifying viruses at the species level. However, substantial ecological diversity, both in virulence level and host range, is known within virus species. Here we demonstrate a proof of concept for easily discovering ecological diversity within a virus species taxon. We have focused on the West Nile Virus to take advantage of its broad host range in nature. We produced a genome-based phylogeny of world diversity of WNV and then used Ecotype Simulation 2 to hypothesize demarcation of genomes into 69 putative ecotypes (ecologically distinct populations), based only on clustering of genome sequences. Then we looked for evidence of ecological divergence among ecotypes based on differences in host bird associations within the Connecticut-New York region. Our results indicated significant heterogeneity among ecotypes for their associations with different bird hosts. Ecological diversity within other zoonotic viruses could be easily discovered using this approach. Opportunities for extending this line of research to human associations of virus ecotypes are limited by missing geographic metadata on human samples.

scholarly journals The Role of Microglia during West Nile Virus Infection of the Central Nervous System

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 485 ◽  
Author(s):  
Sarah Stonedahl ◽  
Penny Clarke ◽  
Kenneth L. Tyler
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
West Nile Virus ◽  
Immune Cells ◽  
Neuronal Cell ◽  
The United States ◽  
Health Concern ◽  
West Nile ◽  
The Central Nervous System

Encephalitis resulting from viral infections is a major cause of hospitalization and death worldwide. West Nile Virus (WNV) is a substantial health concern as it is one of the leading causes of viral encephalitis in the United States today. WNV infiltrates the central nervous system (CNS), where it directly infects neurons and induces neuronal cell death, in part, via activation of caspase 3-mediated apoptosis. WNV infection also induces neuroinflammation characterized by activation of innate immune cells, including microglia and astrocytes, production of inflammatory cytokines, breakdown of the blood-brain barrier, and infiltration of peripheral leukocytes. Microglia are the resident immune cells of the brain and monitor the CNS for signs of injury or pathogens. Following infection with WNV, microglia exhibit a change in morphology consistent with activation and are associated with increased expression of proinflammatory cytokines. Recent research has focused on deciphering the role of microglia during WNV encephalitis. Microglia play a protective role during infections by limiting viral growth and reducing mortality in mice. However, it also appears that activated microglia are triggered by T cells to mediate synaptic elimination at late times during infection, which may contribute to long-term neurological deficits following a neuroinvasive WNV infection. This review will discuss the important role of microglia in the pathogenesis of a neuroinvasive WNV infection. Knowledge of the precise role of microglia during a WNV infection may lead to a greater ability to treat and manage WNV encephalitis.

scholarly journals Surveillance of the major pathogenic arboviruses of public health concern in Gabon, Central Africa: increased risk of West Nile virus and dengue virus infections

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yuri Ushijima ◽  
Haruka Abe ◽  
Georgelin Nguema Ondo ◽  
Rodrigue Bikangui ◽  
Marguerite Massinga Loembé ◽  
...  
Keyword(s):  
Public Health ◽  
West Nile Virus ◽  
Dengue Virus ◽  
Central Africa ◽  
Fever Virus ◽  
Health Concern ◽  
Virus Infections ◽  
Public Health Concern ◽  
Serum Samples ◽  
West Nile

Abstract Background Increasing arbovirus infections have been a global burden in recent decades. Many countries have experienced the periodic emergence of arbovirus diseases. However, information on the prevalence of arboviruses is largely unknown or infrequently updated because of the lack of surveillance studies, especially in Africa. Methods A surveillance study was conducted in Gabon, Central Africa, on arboviruses, which are a major public health concern in Africa, including: West Nile virus (WNV), dengue virus (DENV), Zika virus (ZIKV), yellow fever virus (YFV), chikungunya virus (CHIKV), and Rift Valley fever virus (RVFV). Serological and molecular assays were performed to investigate past infection history and the current status of infection, using serum samples collected from healthy individuals and febrile patients, respectively. Results The overall seroprevalence during 2014˗2017 was estimated to be 25.3% for WNV, 20.4% for DENV, 40.3% for ZIKV, 60.7% for YFV, 61.2% for CHIKV, and 14.3% for RVFV. No significant differences were found in the seroprevalence of any of the viruses between the male and female populations. However, a focus on the mean age in each arbovirus-seropositive individual showed a significantly younger age in WNV- and DENV-seropositive individuals than in CHIKV-seropositive individuals, indicating that WNV and DENV caused a relatively recent epidemic in the region, whereas CHIKV had actively circulated before. Of note, this indication was supported by the detection of both WNV and DENV genomes in serum samples collected from febrile patients after 2016. Conclusions This study revealed the recent re-emergence of WNV and DENV in Gabon as well as the latest seroprevalence state of the major arboviruses, which indicated the different potential risks of virus infections and virus-specific circulation patterns. This information will be helpful for public health organizations and will enable a rapid response towards these arbovirus infections, thereby preventing future spread in the country.

scholarly journals Effects of weather and landscape on the equine West Nile virus infection risk in Mississippi, USA

2015 ◽  
Vol 10 (2) ◽  
Author(s):  
Guiming Wang
Keyword(s):  
West Nile Virus ◽  
Land Cover ◽  
Hierarchical Models ◽  
West Nile Virus Infection ◽  
Weather Conditions ◽  
Health Concern ◽  
West Nile ◽  
Bayesian Hierarchical ◽  
Agricultural Areas ◽  
Equine West Nile Virus

The West Nile virus (WNv) continues to be a public health concern in North America. Dry weather appears to increase human WNv infection risks, but it is uncertain whether dry weather conditions exert similar effects on the corresponding equine WNv infection. This study assessed the effects of precipitation of the previous year and land cover diversity on the equine WNv risk of Mississippi, USA, at the county level in the year 2002 using Bayesian hierarchical models. The risk estimated for 2002 was found to be inversely related to annual precipitation of the preceding year. Equine WNv risks were lower with greater land cover diversity probably due to the diluting effects of biodiversity. Correlation between the equine and human WNv risks was positive but relatively low. Dry weather conditions of the previous year might reduce mosquito competitors and predators and subsequently increase mosquito abundances and equine WNv risks in agricultural areas with low biodiversity.

scholarly journals The Role of Birds of Prey in West Nile Virus Epidemiology

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 550 ◽  
Author(s):  
Beatriz Vidaña ◽  
Núria Busquets ◽  
Sebastian Napp ◽  
Elisa Pérez-Ramírez ◽  
Miguel Ángel Jiménez-Clavero ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Current Knowledge ◽  
Critical Role ◽  
Cost Effective ◽  
Birds Of Prey ◽  
West Nile ◽  
Transmission Cycle ◽  
Mediterranean Countries ◽  
Dead End ◽  
Lineage 2

Reported human cases of West Nile virus (WNV) in Europe increased dramatically in 2018. Lineage 1 strains had been circulating in Euro-Mediterranean countries since the early 1990s. The subsequent introduction of WNV lineage 2 has been responsible for the remarkable upsurge of European WNV outbreaks since 2004, including the dramatic increase in human cases observed since 2018. The virus exists in a natural cycle between mosquitoes and wild birds, with humans and horses acting as dead-end hosts. As the key vertebrate hosts in the transmission cycle of WNV, avian species have been the focus of surveillance across many countries. Raptors appear particularly susceptible to WNV infection, resulting in higher prevalence, and in some cases exhibiting neurological signs that lead to the death of the animal. In addition, birds of prey are known to play an important role as WNV reservoir and potentially amplifying hosts of infection. Importantly, raptor higher susceptibility/prevalence may indicate infection through predation of infected prey. Consequently, they are considered important target species when designing cost-effective surveillance for monitoring both seasonal WNV circulation in endemic countries and its emergence into new areas, where migrating raptors may play a critical role in virus introduction. This review summarizes the different aspects of the current knowledge of WNV infection in birds of prey and evaluates their role in the evolution of the epizootic that is spreading throughout Europe.

scholarly journals West Nile Virus Associations in Wild Mammals: An Update

Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 459 ◽  
Author(s):  
J. Jeffrey Root ◽  
Angela M. Bosco-Lauth
Keyword(s):  
West Nile Virus ◽  
Severe Disease ◽  
Mammalian Species ◽  
Population Level ◽  
Didelphis Virginiana ◽  
Mammal Species ◽  
West Nile ◽  
Wild Mammals ◽  
Major Review ◽  
Virginia Opossum

Although West Nile virus (WNV) is generally thought to circulate among mosquitoes and birds, several historic and recent works providing evidence of WNV activity in wild mammals have been published. Indeed, a previous review tabulated evidence of WNV exposure in at least 100 mammalian species. Herein, we provide an update on WNV activity in wild and select other mammals that have been reported since the last major review article on this subject was published in early 2013. Of interest, new species, such as Hoffman’s two-toed sloths (Choloepus hoffmanni), are now included in the growing list of wild mammals that have been naturally exposed to WNV. Furthermore, new instances of WNV viremia as well as severe disease presumably caused by this virus have been reported in wild mammals (e.g., the Virginia opossum [Didelphis virginiana]) from natural and semi-captive (e.g., zoological institution) settings. Regrettably, few recent challenge studies have been conducted on wild mammals, which would provide key information as to their potential role(s) in WNV cycles. Largely based on these recent findings, important future lines of research are recommended to assess which mammalian species are commonly exposed to WNV, which mammal species develop viremias sufficient for infecting mosquitoes, and which mammal species might be negatively affected by WNV infection at the species or population level.

scholarly journals Human MicroRNA miR-532-5p Exhibits Antiviral Activity against West Nile Virus via Suppression of Host Genes SESTD1 and TAB3 Required for Virus Replication

2015 ◽  
Vol 90 (5) ◽  
pp. 2388-2402 ◽  
Author(s):  
Andrii Slonchak ◽  
Rory P. Shannon ◽  
Gabor Pali ◽  
Alexander A. Khromykh
Keyword(s):  
West Nile Virus ◽  
Antiviral Response ◽  
Human Cells ◽  
Hek293 Cells ◽  
Type I ◽  
Virus Infections ◽  
West Nile ◽  
Viral Pathogen ◽  
Host Genes

ABSTRACTWest Nile virus (WNV) is a mosquito-transmitted flavivirus that naturally circulates between mosquitos and birds but can also infect humans, causing severe neurological disease. The early host response to WNV infection in vertebrates primarily relies on the type I interferon pathway; however, recent studies suggest that microRNAs (miRNAs) may also play a notable role. In this study, we assessed the role of host miRNAs in response to WNV infection in human cells. We employed small RNA sequencing (RNA-seq) analysis to determine changes in the expression of host miRNAs in HEK293 cells infected with an Australian strain of WNV, Kunjin (WNVKUN), and identified a number of host miRNAs differentially expressed in response to infection. Three of these miRNAs were confirmed to be significantly upregulated in infected cells by quantitative reverse transcription (qRT)-PCR and Northern blot analyses, and one of them, miR-532-5p, exhibited a significant antiviral effect against WNVKUNinfection. We have demonstrated that miR-532-5p targets and downregulates expression of the host genes SESTD1 and TAB3 in human cells. Small interfering RNA (siRNA) depletion studies showed that both SESTD1 and TAB3 were required for efficient WNVKUNreplication. We also demonstrated upregulation of mir-532-5p expression and a corresponding decrease in the expression of its targets, SESTD1 and TAB3, in the brains of WNVKUN-infected mice. Our results show that upregulation of miR-532-5p and subsequent suppression of the SESTD1 and TAB3 genes represent a host antiviral response aimed at limiting WNVKUNinfection and highlight the important role of miRNAs in controlling RNA virus infections in mammalian hosts.IMPORTANCEWest Nile virus (WNV) is a significant viral pathogen that poses a considerable threat to human health across the globe. There is no specific treatment or licensed vaccine available for WNV, and deeper insight into how the virus interacts with the host is required to facilitate their development. In this study, we addressed the role of host microRNAs (miRNAs) in antiviral response to WNV in human cells. We identified miR-532-5p as a novel antiviral miRNA and showed that it is upregulated in response to WNV infection and suppresses the expression of the host genes TAB3 and SESTD1 required for WNV replication. Our results show that upregulation of miR-532-5p and subsequent suppression of the SESTD1 and TAB3 genes represent an antiviral response aimed at limiting WNV infection and highlight the important role of miRNAs in controlling virus infections in mammalian hosts.

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