scholarly journals Experimental Evolution of West Nile Virus at Higher Temperatures Facilitates Broad Adaptation and Increased Genetic Diversity

Viruses ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1889
Author(s):  
Rachel L. Fay ◽  
Kiet A. Ngo ◽  
Lili Kuo ◽  
Graham G. Willsey ◽  
Laura D. Kramer ◽  
...  
Keyword(s):  
West Nile Virus ◽  
West Nile ◽  
Replicative Fitness ◽  
Natural Systems ◽  
Mosquito Cells ◽  
Before And After ◽  
Increasing Temperature ◽  
Genetic Signatures ◽  
Temperature Impacts ◽  
The Impact

West Nile virus (WNV, Flaviviridae, Flavivirus) is a mosquito-borne flavivirus introduced to North America in 1999. Since 1999, the Earth’s average temperature has increased by 0.6 °C. Mosquitoes are ectothermic organisms, reliant on environmental heat sources. Temperature impacts vector–virus interactions which directly influence arbovirus transmission. RNA viral replication is highly error-prone and increasing temperature could further increase replication rates, mutation frequencies, and evolutionary rates. The impact of temperature on arbovirus evolutionary trajectories and fitness landscapes has yet to be sufficiently studied. To investigate how temperature impacts the rate and extent of WNV evolution in mosquito cells, WNV was experimentally passaged 12 times in Culex tarsalis cells, at 25 °C and 30 °C. Full-genome deep sequencing was used to compare genetic signatures during passage, and replicative fitness was evaluated before and after passage at each temperature. Our results suggest adaptive potential at both temperatures, with unique temperature-dependent and lineage-specific genetic signatures. Further, higher temperature passage was associated with significantly increased replicative fitness at both temperatures and increases in nonsynonymous mutations. Together, these data indicate that if similar selective pressures exist in natural systems, increases in temperature could accelerate emergence of high-fitness strains with greater phenotypic plasticity.

scholarly journals 1787. The Effects of a Systemwide Diagnostic Stewardship Change on West Nile Virus Disease Ordering Practices

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S658-S658
Author(s):  
Andrew H Karaba ◽  
Paul W Blair ◽  
Kevin M Martin ◽  
Mustapha O Saheed ◽  
Karen C Carroll ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Virus Disease ◽  
Case Fatality ◽  
Cost Savings ◽  
Primary Objective ◽  
Neurological Deficits ◽  
West Nile ◽  
Hospital System ◽  
Elisa Testing ◽  
Before And After

Abstract Background Neuroinvasive West Nile Virus (WNV) often leads to prolonged neurological deficits and carries a high case fatality rate. The CSF IgM (MAC-ELISA) is preferred over the CSF nucleic acid-based test (NAAT) by the CDC due to its higher sensitivity. However, our hospital system was observed to have an over-utilization of NAAT testing compared with MAC-ELISA testing. The primary objective was to compare the number of MAC-ELISA and NAAT WNV tests ordered before and after a diagnostic stewardship intervention. The secondary objectives were to determine whether this change to lead to any cost savings and increased detection of probable cases of WNV-ND. Methods In an effort to increase the use of the MAC-ELISA and to decrease unnecessary NAAT testing, the NAAT test was removed in April 2018 from the test menu in the electronic health record of a health system comprising five hospitals in the Maryland and Washington, D.C. area. NAAT testing remained possible via a paper order form. This study was a retrospective review of WNV testing done on CSF samples from July 2016 through December 2018. The seasonal and yearly number of total tests, positive tests, and total costs were determined from the period of July, 2017 to April, 2018 and were compared with May, 2018 to January, 2019. A paired t-test was performed to evaluate for differences in total testing, total positives, and total costs during non-winter months before and after the intervention. Results A total of 12.59 MAC-ELISA tests/month (95% CI: 10.29, 14.89) increased to 41 tests/month (95% CI: 34.35, 47.65) which was significantly different (P < 0.001). In contrast, there were 46.23 NAAT tests/month (95% CI: 39.55, 52.91) which decreased to 0 NAAT tests/month after the intervention (P < 0.001). This resulted in an average decrease in WNV test spending from $7200 per month to $471 per month (P < 0.001). Preceding the intervention in test ordering, 0.23% of WNV CSF tests were positive (NAAT+MAC-ELISA) while 2.44% WNV CSF tests were positive after the intervention (P = 0.03). Conclusion Elimination of electronic WNV NAAT ordering is an effective way of decreasing inappropriate WNV NAAT testing, decreasing associated costs, and may lead to improved diagnosis of WNV-ND. Disclosures All authors: No reported disclosures.

scholarly journals When to Spray: a Time-Scale Calculus Approach to Controlling the Impact of West Nile Virus

2009 ◽  
Vol 14 (2) ◽  
Author(s):  
Diana Thomas ◽  
Marion Weedermann ◽  
Lora Billings ◽  
Joan Hoffacker ◽  
Robert A. Washington-Allen
Keyword(s):  
West Nile Virus ◽  
Time Scale ◽  
West Nile ◽  
Time Scale Calculus ◽  
The Impact

Effects of climate change on vector-borne diseases: an updated focus on West Nile virus in humans

2019 ◽  
Vol 3 (2) ◽  
pp. 143-152 ◽  
Author(s):  
Shlomit Paz
Keyword(s):  
Climate Change ◽  
West Nile Virus ◽  
The West ◽  
West Nile ◽  
Local Conditions ◽  
Transmission Season ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
The Impact ◽  
Impacts Of Climate Change

Abstract One of the main impacts of climate change on health is the influence on vector-borne diseases (VBDs). During the last few years, yearly outbreaks of the West Nile virus (WNV) have occurred in many locations, providing evidence of ongoing transmission. Currently, it is the most widely distributed arbovirus in the world. Increases in ambient temperature have impacts on WNV transmission. Indeed, clear associations were found between warm conditions and WNV outbreaks in various areas. The impact of changes in rainfall patterns on the incidence of the disease is influenced by the amount of precipitation (increased rainfall, floods or droughts), depending on the local conditions and the differences in the ecology and sensitivity of the species of mosquito. Predictions indicate that for WNV, increased warming will result in latitudinal and altitudinal expansions of regions climatically suitable for transmission, particularly along the current edges of its transmission areas. Extension of the transmission season is also predicted. As models show that the current climate change trends are expected to continue, it is important to reinforce WNV control efforts and increase the resilience of population health. For a better preparedness, any assessment of future transmission of WNV should consider the impacts of the changing climate.

scholarly journals The Impact of Cycling Temperature on the Transmission of West Nile Virus

2016 ◽  
Vol 53 (3) ◽  
pp. 681-686 ◽  
Author(s):  
Mary E. Danforth ◽  
William K. Reisen ◽  
Christopher M. Barker
Keyword(s):  
West Nile Virus ◽  
West Nile ◽  
The Impact ◽  
Cycling Temperature

scholarly journals A New Insect-Specific Flavivirus from Northern Australia Suppresses Replication of West Nile Virus and Murray Valley Encephalitis Virus in Co-infected Mosquito Cells

PLoS ONE ◽  
2013 ◽  
Vol 8 (2) ◽  
pp. e56534 ◽  
Author(s):  
Jody Hobson-Peters ◽  
Alice Wei Yee Yam ◽  
Jennifer Wei Fei Lu ◽  
Yin Xiang Setoh ◽  
Fiona J. May ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Encephalitis Virus ◽  
Infected Mosquito ◽  
Northern Australia ◽  
Murray Valley Encephalitis Virus ◽  
West Nile ◽  
Mosquito Cells

scholarly journals The Diffusive Model for West Nile Virus on a Periodically Evolving Domain

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Abdelrazig K. Tarboush ◽  
Zhengdi Zhang
Keyword(s):  
West Nile Virus ◽  
Numerical Simulations ◽  
Basic Reproduction Number ◽  
Reproduction Number ◽  
Evolution Rate ◽  
Time Behavior ◽  
The West ◽  
West Nile ◽  
West Nile Virus Transmission ◽  
The Impact

In this paper, we investigate the impact of a periodically evolving domain on the dynamics of the diffusive West Nile virus. A reaction-diffusion model on a periodically and isotropically evolving domain which describes the transmission of the West Nile virus is proposed. In addition to the classical basic reproduction number, the spatial-temporal basic reproduction number depending on the periodic evolution rate is introduced and its properties are discussed. Under some conditions, we explore the long-time behavior of the virus. The virus will go extinct if the spatial-temporal basic reproduction number is less than or equal to one. The persistence of the virus happens if the spatial-temporal basic reproduction number is greater than one. We consider special case when the periodic evolution rate is equivalent to one to better understand the impact of the periodic evolution rate on the persistence or extinction of the virus. Some numerical simulations are performed in order to illustrate our analytical results. Our theoretical analysis and numerical simulations show that the periodic change of the habitat range plays an important role in the West Nile virus transmission, in particular, the increase of periodic evolution rate has positive effect on the spread of the virus.

scholarly journals Persistent impacts of West Nile virus on North American bird populations

2015 ◽  
Vol 112 (46) ◽  
pp. 14290-14294 ◽  
Author(s):  
T. Luke George ◽  
Ryan J. Harrigan ◽  
Joseph A. LaManna ◽  
David F. DeSante ◽  
James F. Saracco ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Disease Risk ◽  
Phylogenetic Analyses ◽  
West Nile ◽  
Factors Affecting ◽  
Bird Populations ◽  
Continental Scale ◽  
North American Bird ◽  
Avian Populations ◽  
The Impact

Since its introduction to North America in 1999, West Nile virus (WNV) has had devastating impacts on native host populations, but to date these impacts have been difficult to measure. Using a continental-scale dataset comprised of a quarter-million birds captured over nearly two decades and a recently developed model of WNV risk, we estimated the impact of this emergent disease on the survival of avian populations. We find that populations were negatively affected by WNV in 23 of the 49 species studied (47%). We distinguished two groups of species: those for which WNV negatively impacted survival only during initial spread of the disease (n = 11), and those that show no signs of recovery since disease introduction (n = 12). Results provide a novel example of the taxonomic breadth and persistent impacts of this wildlife disease on a continental scale. Phylogenetic analyses further identify groups (New World sparrows, finches, and vireos) disproportionally affected by temporary or persistent WNV effects, suggesting an evolutionary dimension of disease risk. Identifying the factors affecting the persistence of a disease across host species is critical to mitigating its effects, particularly in a world marked by rapid anthropogenic change.

scholarly journals Role of the mutant spectrum in adaptation and replication of West Nile virus

2007 ◽  
Vol 88 (3) ◽  
pp. 865-874 ◽  
Author(s):  
Alexander T. Ciota ◽  
Kiet A. Ngo ◽  
Amy O. Lovelace ◽  
Anne F. Payne ◽  
Yangsheng Zhou ◽  
...  
Keyword(s):  
West Nile Virus ◽  
Reverse Genetics ◽  
Viral Fitness ◽  
West Nile ◽  
Mosquito Cells ◽  
The Usa ◽  
Mutant Spectrum ◽  
Vertebrate Hosts ◽  
Adaptive Constraints

West Nile virus (WNV) has successfully spread throughout the USA, Canada, Mexico, the Caribbean and parts of Central and South America since its 1999 introduction into North America. Despite infecting a broad range of both mosquito and avian species, the virus remains highly genetically conserved. This lack of evolutionary change over space and time is common with many arboviruses and is frequently attributed to the adaptive constraints resulting from the virus cycling between vertebrate hosts and invertebrate vectors. WNV, like most RNA viruses studied thus far, has been shown in nature to exist as a highly genetically diverse population of genotypes. Few studies have directly evaluated the role of these mutant spectra in viral fitness and adaptation. Using clonal analysis and reverse genetics experiments, this study evaluated genotype diversity and the importance of consensus change in producing the adaptive phenotype of WNV following sequential mosquito cell passage. The results indicated that increases in the replicative ability of WNV in mosquito cells correlate with increases in the size of the mutant spectrum, and that consensus change is not solely responsible for alterations in viral fitness and adaptation of WNV. These data provide evidence of the importance of quasispecies dynamics in the adaptation of a flavivirus to new and changing environments and hosts, with little evidence of significant genetic change.

scholarly journals Projection of Climate Change Influences on U.S. West Nile Virus Vectors

2015 ◽  
Vol 19 (18) ◽  
pp. 1-18 ◽  
Author(s):  
Heidi E. Brown ◽  
Alex Young ◽  
Joceline Lega ◽  
Theodore G. Andreadis ◽  
Jessica Schurich ◽  
...  
Keyword(s):  
Climate Change ◽  
West Nile Virus ◽  
Simulation Model ◽  
Disease Risk ◽  
Weather Data ◽  
Effect Of Temperature ◽  
West Nile ◽  
Virus Vectors ◽  
Daily Weather Data ◽  
The Impact

Abstract While estimates of the impact of climate change on health are necessary for health care planners and climate change policy makers, models to produce quantitative estimates remain scarce. This study describes a freely available dynamic simulation model parameterized for three West Nile virus vectors, which provides an effective tool for studying vectorborne disease risk due to climate change. The Dynamic Mosquito Simulation Model is parameterized with species-specific temperature-dependent development and mortality rates. Using downscaled daily weather data, this study estimates mosquito population dynamics under current and projected future climate scenarios for multiple locations across the country. Trends in mosquito abundance were variable by location; however, an extension of the vector activity periods, and by extension disease risk, was almost uniformly observed. Importantly, midsummer decreases in abundance may be offset by shorter extrinsic incubation periods, resulting in a greater proportion of infective mosquitoes. Quantitative descriptions of the effect of temperature on the virus and mosquito are critical to developing models of future disease risk.

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