scholarly journals Country-wide distribution of bluetongue virus with expanding host spectrum and evidence of vector competence in Hungary

2019 ◽  
Vol 63 (02) ◽  
pp. 229-234
Author(s):  
M. DOMÁN ◽  
S. MARTON ◽  
P. MALIK ◽  
K. BÁNYAI ◽  
Á. HORNYÁK
Keyword(s):  
Bluetongue Virus ◽  
Vector Competence ◽  
Wide Distribution ◽  
Host Spectrum

scholarly journals Vector competence is strongly affected by a small deletion or point mutations in bluetongue virus

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
René G. P. van Gennip ◽  
Barbara S. Drolet ◽  
Paula Rozo Lopez ◽  
Ashley J. C. Roost ◽  
Jan Boonstra ◽  
...  
Keyword(s):  
Virus Replication ◽  
Bluetongue Virus ◽  
Vector Competence ◽  
Outer Shell ◽  
Virus Propagation ◽  
Virus Growth ◽  
Shell Protein ◽  
Vector Borne

Abstract Background Transmission of vector-borne virus by insects is a complex mechanism consisting of many different processes; viremia in the host, uptake, infection and dissemination in the vector, and delivery of virus during blood-feeding leading to infection of the susceptible host. Bluetongue virus (BTV) is the prototype vector-borne orbivirus (family Reoviridae). BTV serotypes 1–24 (typical BTVs) are transmitted by competent biting Culicoides midges and replicate in mammalian (BSR) and midge (KC) cells. Previously, we showed that genome segment 10 (S10) encoding NS3/NS3a protein is required for virus propagation in midges. BTV serotypes 25–27 (atypical BTVs) do not replicate in KC cells. Several distinct BTV26 genome segments cause this so-called ‘differential virus replication’ in vitro. Methods Virus strains were generated using reverse genetics and their growth was examined in vitro. The midge feeding model has been developed to study infection, replication and disseminations of virus in vivo. A laboratory colony of C. sonorensis, a known competent BTV vector, was fed or injected with BTV variants and propagation in the midge was examined using PCR testing. Crossing of the midgut infection barrier was examined by separate testing of midge heads and bodies. Results A 100 nl blood meal containing ±105.3 TCID50/ml of BTV11 which corresponds to ±20 TCID50 infected 50% of fully engorged midges, and is named one Midge Alimentary Infective Dose (MAID50). BTV11 with a small in-frame deletion in S10 infected blood-fed midge midguts but virus release from the midgut into the haemolymph was blocked. BTV11 with S1[VP1] of BTV26 could be adapted to virus growth in KC cells, and contained mutations subdivided into ‘corrections’ of the chimeric genome constellation and mutations associated with adaptation to KC cells. In particular one amino acid mutation in outer shell protein VP2 overcomes differential virus replication in vitro and in vivo. Conclusion Small changes in NS3/NS3a or in the outer shell protein VP2 strongly affect virus propagation in midges and thus vector competence. Therefore, spread of disease by competent Culicoides midges can strongly differ for very closely related viruses.

scholarly journals Vector Competence of Italian Populations of Culicoides for Some Bluetongue Virus Strains Responsible for Recent Northern African and European Outbreaks

Viruses ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 941 ◽  
Author(s):  
Valentina Federici ◽  
Maria Goffredo ◽  
Giuseppe Mancini ◽  
Michela Quaglia ◽  
Adriana Santilli ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Vector Competence ◽  
Oral Infection ◽  
Balearic Islands ◽  
Rt Pcr ◽  
Vector Species ◽  
Vaccination Programs ◽  
Culicoides Obsoletus ◽  
Culicoides Imicola ◽  
Virus Strains

The distribution of Bluetongue virus (BTV) in Europe can be represented by two distinct and interconnected epidemiological systems (episystems), each characterized by different ecological characteristics and vector species. This study investigated the vector competence of Italian populations of Culicoides imicola and Culicoides obsoletus/scoticus to some representative BTV strains after artificial oral infection. The BTV strains were selected according to their ability to spread to one or both episystems and included BTV-4 ITA, responsible of the recent Italian and French BTV-4 outbreaks; the BTV-2 strain which caused the first BTV incursion in Italy, Corsica, and Balearic Islands; BTV-4 MOR, responsible for the epidemic in Morocco; and BTV-8, the strain which spread through Europe between 2006 and 2008. Blood-soaked cotton pledgets and Hemotek membrane feeder using Parafilm® membrane were used to artificially feed midges. For each population/strain, recovery rates (positive/tested heads) were evaluated using serogroup- and serotype-specific RT-PCR. The trial demonstrated that, except for the Abruzzo population of C. obsoletus/C. scoticus, which was refractory to BTV-4 MOR infection, all the investigated Culicoides populations are susceptible to the selected BTV strains and that, if prompt vaccination programs and restriction measures had not been implemented, BTV-2 and BTV-4 MOR could have spread all over Europe.

Vector competence of certain Culex and Aedes mosquitoes for the Chittoor virus, the Indian variant of the Batai virus

2018 ◽  
Vol 64 (8) ◽  
pp. 581-588
Author(s):  
A.B. Sudeep ◽  
Neda Shaikh ◽  
Y.S. Ghodke ◽  
V.S. Ingale ◽  
M.D. Gokhale
Keyword(s):  
Neutralizing Antibodies ◽  
Vector Competence ◽  
Mosquito Species ◽  
Horizontal Transmission ◽  
Clinical Manifestations ◽  
Hemorrhagic Fever ◽  
Wide Distribution ◽  
Genetic Reassortment ◽  
Aedes Mosquitoes ◽  
Batai Virus

Chittoor virus (CHITV), a mosquito-borne bunyavirus (Orthobunyavirus: Bunyaviridae) isolated in India, has been found to be antigenically close to the Batai virus (BATV), which has a wide distribution across Asia, Europe, and Africa. The latter virus causes influenza-like illness in humans and mild illness in sheep and goats. BATV has been involved in genetic reassortment with other bunyaviruses, generating novel genome combinations and causing severe clinical manifestations including hemorrhagic fever. Conversely, CHITV has never been associated with any major outbreaks in India, although neutralizing antibodies have been detected in humans and domestic animals. Repeated isolations and seroprevalence have prompted us to determine the vector competence of three important mosquito species, viz., Culex quinquefasciatus, Culex tritaeniorhynchus, and Aedes aegypti, for CHITV. The three mosquito species replicated CHITV to titers of 6.3, 5.0, and 5.2 log10 TCID50/mL, respectively, and maintained the virus for substantial periods. Both of the Culex species demonstrated vector competence, while A. aegypti did not. Horizontal transmission to infant mice was also demonstrated by both Culex species. Active circulation of the virus and the availability of both susceptible hosts and competent vector mosquitoes pose a serious threat to public health should there be a reassortment.

scholarly journals The genome of the biting midge Culicoides sonorensis and gene expression analyses of vector competence for bluetongue virus

BMC Genomics ◽  
2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Ramiro Morales-Hojas ◽  
Malcolm Hinsley ◽  
Irina M. Armean ◽  
Rhiannon Silk ◽  
Lara E. Harrup ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bluetongue Virus ◽  
Vector Competence ◽  
Biting Midge ◽  
Culicoides Sonorensis ◽  
Gene Expression Analyses

scholarly journals Vector competence of pre-alpine Culicoides (Diptera: Ceratopogonidae) for bluetongue virus serotypes 1, 4 and 8

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Anca Ioana Paslaru ◽  
Alexander Mathis ◽  
Paul Torgerson ◽  
Eva Veronesi
Keyword(s):  
Bluetongue Virus ◽  
Vector Competence

scholarly journals The genome of the biting midge Culicoides sonorensis and gene expression analyses of vector competence for Bluetongue virus

2018 ◽  
Author(s):  
Ramiro Morales-Hojas ◽  
Malcolm Hinsley ◽  
Irina M. Armean ◽  
Rhiannon Silk ◽  
Lara E. Harrup ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bluetongue Virus ◽  
Reference Genome ◽  
Vector Competence ◽  
Expression Profiles ◽  
Yield Potential ◽  
Future Research ◽  
Biting Midges ◽  
Culicoides Sonorensis ◽  
Gene Expression Analyses

AbstractBackgroundThe use of the new genomic technologies has led to major advances in control of several arboviruses of medical importance such as Dengue. However, the development of tools and resources available for vectors of non-zoonotic arboviruses remains neglected. Biting midges of the genus Culicoides transmit some of the most important arboviruses of wildlife and livestock worldwide, with a global impact on economic productivity, health and welfare. The absence of a suitable reference genome has hindered genomic analyses to date in this important genus of vectors. In the present study, the genome of Culicoides sonorensis, a vector of bluetongue virus (BTV) in the USA, has been sequenced to provide the first reference genome for these vectors. In this study, we also report the use of the reference genome to perform initial transcriptomic analyses of vector competence for BTV.ResultsOur analyses reveal that the genome is 197.4 Mb, assembled in 7,974 scaffolds. Its annotation using the transcriptomic data generated in this study and in a previous study has identified 15,629 genes. Gene expression analyses of C. sonorensis females infected with BTV performed in this study revealed 165 genes that were differentially expressed between vector competent and refractory females. Two candidate genes, glutathione S-transferase (gst) and the antiviral helicase ski2, previously recognized as involved in vector competence for BTV in C. sonorensis (gst) and repressing dsRNA virus propagation (ski2), were confirmed in this study.ConclusionsThe reference genome of C. sonorensis has enabled preliminary analyses of the gene expression profiles of vector competent and refractory individuals. The genome and transcriptomes generated in this study provide suitable tools for future research on arbovirus transmission. These provide a significant resource for these vector lineage, which diverged from other major Dipteran vector families over 200 million years ago. The genome will be a valuable source of comparative data for other important Dipteran vector families including mosquitoes (Culicidae) and sandflies (Psychodidae), and yield potential targets for transgenic modification in vector control and functional studies.

scholarly journals Evidence of reduced viremia, pathogenicity and vector competence in a re-emerging European strain of bluetongue virus serotype 8 in sheep

2018 ◽  
Author(s):  
John Flannery ◽  
Beatriz Sanz-Bernardo ◽  
Martin Ashby ◽  
Hannah Brown ◽  
Simon Carpenter ◽  
...  
Keyword(s):  
Bluetongue Virus ◽  
Vector Competence ◽  
Transmission Efficiency ◽  
Infected Sheep ◽  
Clinical Disease ◽  
Livestock Industry ◽  
Specific Antibodies ◽  
Virus Serotype ◽  
Culicoides Sonorensis ◽  
Kinetics Of

SummaryThe outbreak of bluetongue virus (BTV) serotype 8 (BTV-8) during 2006-2009 in Europe was the most costly epidemic of the virus in recorded history. In 2015, a BTV-8 strain re-emerged in France which has continued to circulate since then. To examine anecdotal reports of reduced pathogenicity and transmission efficiency, we investigated the infection kinetics of a 2007 UK BTV-8 strain alongside the re-emerging BTV-8 strain isolated from France in 2017. Two groups of eight BTV-naïve British mule sheep were inoculated with 5.75 log10TCID50 ml−1 of either BTV-8 strain. BTV RNA was detected by 2 dpi in both groups with peak viremia occurring between 5-9 dpi. A significantly greater amount of BTV RNA was detected in sheep infected with the 2007 strain (6.0-8.8 log10 genome copies mL−1) than the re-emerging BTV-8 strain (2.9-7.9 log10 genome copies mL−1). All infected sheep developed BTV-specific antibodies by 9 dpi. BTV was isolated from 2 dpi to 12 dpi for 2007 BTV-8-inoculated sheep and from 5 to 10 dpi for sheep inoculated with the remerging BTV-8. In Culicoides sonorensis feeding on the sheep over the period 7-12 dpi, vector competence was significantly higher for the 2007 strain than the re-emerging strain. Both the proportion of animals showing moderate (as opposed to mild or no) clinical disease (6/8 vs 1/8) and the overall clinical scores (median 5.25 vs 3) were significantly higher in sheep infected with the 2007 strain, compared to those infected with the re-emerging strain. However, one sheep infected with the re-emerging strain was euthanized at 16 dpi having developed severe lameness. This highlights the potential of the re-emerging BTV-8 to still cause illness in naïve ruminants with concurrent costs to the livestock industry.SummaryThe re-emerging Bluetongue virus serotype 8 still presents a threat to naïve ruminants in Europe despite reduced virulence

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