scholarly journals Comparison of whole genomes of tick-borne encephalitis virus from mountainous alpine regions and regions with a lower altitude

Virus Genes ◽  
2021 ◽  
Author(s):  
G. Lemhöfer ◽  
L. Chitimia-Dobler ◽  
G. Dobler ◽  
M. Bestehorn-Willmann
Keyword(s):  
Sea Level ◽  
Alpine Region ◽  
Northern Asia ◽  
Lower Altitude ◽  
Genetic Traits ◽  
Viral Genomes ◽  
Alpine Regions ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus ◽  
Favorable Conditions

AbstractTick-borne encephalitis (TBE) has been a notifiable disease in Germany since 2001. Its causative agent, the TBE virus (TBEV), is the most important arbovirus in Europe and Northern Asia. The illness, caused by the European Subtype usually displays flu-like symptoms, but can result in sequelae and, in 2 % of all cases, in death. Over the last few decades, the virus has spread into new habitats, such as higher altitudes in the Alpine region. For this study, it was hypothesized that the environmental challenges that the virus might be exposed to at such altitudes could lead to the selection of viral strains with a higher resilience to such environmental factors. To determine whether strains identified at higher altitudes possessed different genetic traits compared to viruses from lower altitudes, an analysis of viral genomes from higher Alpine altitudes (> 500 m above sea level) (n = 5) and lower altitudes (< 500 m above sea level) (n = 4) was performed. No common phylogenetic ancestry or shared amino acid substitutions could be identified that differentiated the alpine from the lowland viral strains. These findings support the idea of many individual introductions of TBEV into the alpine region and the establishment of foci due to non-viral specific factors such as favorable conditions for vector species and host animals due to climate change.

scholarly journals Evaluation of Viral RNA Recovery Methods in Vectors by Metagenomic Sequencing

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 562
Author(s):  
Joyce Odeke Akello ◽  
Stephen L. Leib ◽  
Olivier Engler ◽  
Christian Beuret
Keyword(s):  
Fold Increase ◽  
Extraction Methods ◽  
Viral Rna ◽  
Health Concern ◽  
Metagenomic Sequencing ◽  
Optimal Method ◽  
Viral Genomes ◽  
Tick Borne Encephalitis ◽  
Langat Virus ◽  
Tick Borne Encephalitis Virus

Identification and characterization of viral genomes in vectors including ticks and mosquitoes positive for pathogens of great public health concern using metagenomic next generation sequencing (mNGS) has challenges. One such challenge is the ability to efficiently recover viral RNA which is typically dependent on sample processing. We evaluated the quantitative effect of six different extraction methods in recovering viral RNA in vectors using negative tick homogenates spiked with serial dilutions of tick-borne encephalitis virus (TBEV) and surrogate Langat virus (LGTV). Evaluation was performed using qPCR and mNGS. Sensitivity and proof of concept of optimal method was tested using naturally positive TBEV tick homogenates and positive dengue, chikungunya, and Zika virus mosquito homogenates. The amount of observed viral genome copies, percentage of mapped reads, and genome coverage varied among different extractions methods. The developed Method 5 gave a 120.8-, 46-, 2.5-, 22.4-, and 9.9-fold increase in the number of viral reads mapping to the expected pathogen in comparison to Method 1, 2, 3, 4, and 6, respectively. Our developed Method 5 termed ROVIV (Recovery of Viruses in Vectors) greatly improved viral RNA recovery and identification in vectors using mNGS. Therefore, it may be a more sensitive method for use in arbovirus surveillance.

The role of IFITM proteins in tick-borne encephalitis virus infection

2021 ◽  
Author(s):  
Alicja M. Chmielewska ◽  
Maria Gómez-Herranz ◽  
Paulina Gach ◽  
Marta Nekulova ◽  
Małgorzata Tyrakowska ◽  
...  
Keyword(s):  
Cell Death ◽  
Immune Responses ◽  
Encephalitis Virus ◽  
Restriction Factors ◽  
Northern Asia ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus ◽  
Tbev Infection ◽  
Cell Spread

Tick-borne encephalitis virus (TBEV), of the genus Flavivirus, is a causative agent of severe encephalitis in endemic regions of northern Asia and central and northern Europe. Interferon induced transmembrane proteins (IFITMs) are restriction factors that inhibit the replication cycles of numerous viruses, including flaviviruses such as the West Nile virus, dengue virus, and Zika virus. Here, we demonstrate the role of IFITM1, IFITM2, and IFITM3 in the inhibition of TBEV infection and in protection against virus-induced cell death. We show the most significant role being that of IFITM3, including the dissection of its functional motifs by mutagenesis. Furthermore, through the use of CRISPR–Cas9-generated IFITM1/3-knockout monoclonal cell lines, we confirm the role and additive action of endogenous IFITMs in TBEV suppression. However, the results of co-culture assays suggest that TBEV might partially escape IFN- and IFITM-mediated suppression during high-density co-culture infection when the virus enters naïve cells directly from infected donor cells. Thus, cell-to-cell spread may constitute a strategy for virus escape from innate host defenses. Importance: TBEV infection may result in encephalitis, chronic illness or death. TBEV is endemic in northern Asia and Europe; however, due to climate change, new endemic centers arise. Although effective TBEV vaccines have been approved, vaccination coverage is low, and, due to the lack of specific therapeutics, infected individuals depend on their immune responses to control the infection. The IFITM proteins are components of the innate antiviral defenses that suppress cell entry of many viral pathogens. However, no studies regarding the role of IFITM proteins in the TBEV infection have been published so far. Understanding of antiviral innate immune responses is crucial for future development of antiviral strategies. Here, we show the important role of IFITM proteins in the inhibition of TBEV infection and virus-mediated cell death. However, our data suggest that TBEV cell-to-cell spread may be less prone to both IFN- and IFITM-mediated suppression, potentially facilitating escape from IFITM-mediated immunity.

scholarly journals Identification of host antiviral genes differentially induced by clinically diverse strains of Tick-Borne Encephalitis Virus

2021 ◽  
Author(s):  
Niluka Goonawardane ◽  
Laura Upstone ◽  
Mark Harris ◽  
Ian M Jones
Keyword(s):  
Mammalian Cells ◽  
Encephalitis Virus ◽  
Therapeutic Interventions ◽  
Virus Genotype ◽  
Northern Asia ◽  
Tick Borne Encephalitis ◽  
Novel Host ◽  
Tick Borne Encephalitis Virus ◽  
Positive Strand Rna ◽  
Tbev Infection

AbstractTick Borne Encephalitis Virus (TBEV) is an important human arthropod-borne virus, which causes tick-borne encephalitis (TBE), an acute viral infection of the central nervous system (CNS) that causes neurological symptoms of varying severity. TBEV is prevalent in large parts of central- and northern-Europe as well as Northern Asia, and strains of varying pathogenicity have been described. Both host and viral specific characteristics have been postulated to determine the outcome of TBEV infection, but the exact basis of their clinical variability remains undefined.Here, we report the generation of Spinach RNA aptamer labelled TBEV replicons of high (Hypr) and low (Vs) pathogenicity isolates and perform the first direct comparison of both strains in cell culture. We show that pathogenic Hypr replicates to higher levels than Vs in mammalian cells, but not in arthropod cells, and that the basis of this difference maps to the NS5 region, encoding the methyltransferase and RNA polymerase. For both Hypr and Vs strains, NS5 and the viral genome localized to defined intracellular structures typical of positive strand RNA viruses, but Hypr was associated with significant activation of IRF-3, caspase-3 and caspase-8, whilst Vs activated Akt, affording protection against caspase-mediated apoptosis. Activation of TIAR and the formation of cytoplasmic stress granules were an additional early feature of Vs but not Hypr replication. Taken together, these findings highlight NS5 and novel host cell responses as key underling factors for the differential clinical characteristics of TBEV strains.ImportanceTick-borne encephalitis virus (TBEV) is an emerging virus of the flavivirus family spread by ticks. Tick bite can transfer the virus and lead to a febrile infection, Tick-borne encephalitis, of varying severity. There is no specific therapeutic treatment and control in endemic areas is by vaccination. The basis of the different pathologies shown following TBEV infection, from mild to fatal, is not clear although the virus genotype clearly has a role. Mapping the basis of their differential effects would allow focus on the stages of the replication cycle responsible, which might guide the development of therapeutic interventions or the creation of purposefully attenuated strains as candidate vaccines.

TBE in South Korea

2019 ◽  
Author(s):  
Joon Young Song
Keyword(s):  
South Korea ◽  
Human Case ◽  
Encephalitis Virus ◽  
Surveillance Studies ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

Although no human case of tick-borne encephalitis (TBE) has been documented in South Korea to date, surveillance studies have been conducted to evaluate the prevalence of tick-borne encephalitis virus (TBEV) in wild ticks.

TBE in Slovakia

2019 ◽  
Author(s):  
Jana Kerlik
Keyword(s):  
Encephalitis Virus ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus

The former Czechoslovak Republic was one of the first countries in Europe where the tick-borne encephalitis virus (TBEV) was identified.

TBE in Sweden

2020 ◽  
Keyword(s):  
Genetic Characterization ◽  
Immunoglobulin M ◽  
Enzyme Linked Immunosorbent Assay ◽  
Second Phase ◽  
Serum Samples ◽  
Tick Borne Encephalitis ◽  
Specific Immunoglobulin ◽  
Tick Borne Encephalitis Virus ◽  
First Time

Tick-borne encephalitis virus (TBEV) was isolated for the first time in Sweden in 1958 (from ticks and from 1 tick-borne encephalitis [TBE] patient).1 In 2003, Haglund and colleagues reported the isolation and antigenic and genetic characterization of 14 TBEV strains from Swedish patients (samples collected 1991–1994).2 The first serum sample, from which TBEV was isolated, was obtained 2–10 days after onset of disease and found to be negative for anti-TBEV immunoglobulin M (IgM) by enzyme-linked immunosorbent assay (ELISA), whereas TBEV-specific IgM (and TBEV-specific immunoglobulin G/cerebrospinal fluid [IgG/CSF] activity) was demonstrated in later serum samples taken during the second phase of the disease.

Chapter 11: General epidemiology of TBE

2020 ◽  
Keyword(s):  
Eastern Siberia ◽  
Genetic Lineages ◽  
Phylogenetic Studies ◽  
Tick Borne Encephalitis ◽  
Natural Foci ◽  
Genetic Sequences ◽  
Tick Borne Encephalitis Virus ◽  
Almost All ◽  
Far Eastern ◽  
Reservoir Hosts

Tick-borne encephalitis virus (TBEV) exists in natural foci, which are areas where TBEV is circulating among its vectors (ticks of different species and genera) and reservoir hosts (usually rodents and small mammals). Based on phylogenetic studies, four TBEV subtypes (Far-Eastern, Siberian, European, Baikalian) and two putative subtypes (Himalayan and “178-79” group) are known. Within each subtype, some genetic lineages are described. The European subtype (TBEV-EU) (formerly known also as the “Western subtype”) of TBEV is prevalent in Europe, but it was also isolated in Western and Eastern Siberia in Russia and South Korea. The Far-Eastern subtype (TBEV-FE) was preferably found in the territory of the far-eastern part of Eurasia, but some strains were isolated in other regions of Eurasia. The Siberian (TBEV-SIB) subtype is the most common and has been found in almost all TBEV habitat areas. The Baikalian subtype is prevalent around Lake Baikal and was isolated several times from ticks and rodents. In addition to the four TBEV subtypes, one single isolate of TBEV (178-79) and two genetic sequences (Himalayan) supposed to be new TBEV subtypes were described in Eastern Siberia and China. The data on TBEV seroprevalence in humans and animals can serve as an indication for the presence or absence of TBEV in studied area.

MONITORING STUDIES OF ARBOVIRUS INFECTIONS TRANSMITTED BY MOSQUITOES ON THE TERRITORY OF THE VOLGOGRAD REGION

2019 ◽  
pp. 60-66
Author(s):  
E.V. Molchanova ◽  
D.N. Luchinin ◽  
A.O. Negodenko ◽  
D.R. Prilepskaya ◽  
N.V. Boroday ◽  
...  
Keyword(s):  
Virus Antigen ◽  
Elisa Test ◽  
Serum Samples ◽  
Blood Sucking ◽  
Tick Borne Encephalitis ◽  
Volgograd Region ◽  
Two Samples ◽  
Probable Presence ◽  
California Serogroup ◽  
Tick Borne Encephalitis Virus

The paper presents data from the monitoring studies’ results of arbovirus infections transmitted by mosquitoes in the Volgograd region. West Nile virus antigen (WNV) in 9 samples, Tahyna virus in one sample, Batai virus in two samples were detected in the study of 110 samples of field material (blood-sucking mosquitoes) by ELISA test. Antibodies to WNV in 16.58 percent of the samples, to tick-borne encephalitis virus in 1.08 percent, to viruses of the California serogroup and Ukuniemi in 1.09 percent, to the virus Sindbis in 2.17 percent were detected as a result of the study of blood serum samples from donors in the Volgograd region. Thus, we obtained data on the probable presence of the Batai, Sindbis, Ukuniemi and Californian serogroup viruses along with the circulation of WNV on the territory of the Volgograd region.

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