Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus.

<h4>Background</h4>Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of globally significant arboviruses of livestock including bluetongue virus (BTV), African horse sickness virus (AHSV) and the recently emerging Schmallenberg virus (SBV). From 2006-2009 out...

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Main Authors: Eva Veronesi, Frank Antony, Simon Gubbins, Nick Golding, Alison Blackwell, Peter Pc Mertens, Joe Brownlie, Karin E Darpel, Philip S Mellor, Simon Carpenter
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0070800
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author Eva Veronesi
Frank Antony
Simon Gubbins
Nick Golding
Alison Blackwell
Peter Pc Mertens
Joe Brownlie
Karin E Darpel
Philip S Mellor
Simon Carpenter
author_facet Eva Veronesi
Frank Antony
Simon Gubbins
Nick Golding
Alison Blackwell
Peter Pc Mertens
Joe Brownlie
Karin E Darpel
Philip S Mellor
Simon Carpenter
author_sort Eva Veronesi
collection DOAJ
description <h4>Background</h4>Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of globally significant arboviruses of livestock including bluetongue virus (BTV), African horse sickness virus (AHSV) and the recently emerging Schmallenberg virus (SBV). From 2006-2009 outbreaks of BTV in northern Europe inflicted major disruption and economic losses to farmers and several attempts were made to implicate Palaearctic Culicoides species as vectors. Results from these studies were difficult to interpret as they used semi-quantitative RT-PCR (sqPCR) assays as the major diagnostic tool, a technique that had not been validated for use in this role. In this study we validate the use of these assays by carrying out time-series detection of BTV RNA in two colony species of Culicoides and compare the results with the more traditional isolation of infectious BTV on cell culture.<h4>Methodology/principal findings</h4>A BTV serotype 1 strain mixed with horse blood was fed to several hundred individuals of Culicoides sonorensis (Wirth & Jones) and C. nubeculosus (Mg.) using a membrane-based assay and replete individuals were then incubated at 25°C. At daily intervals 25 Culicoides of each species were removed from incubation, homogenised and BTV quantified in each individual using sqPCR (Cq values) and virus isolation on a KC-C. sonorensis embryonic cell line, followed by antigen enzyme-linked immunosorbent assay (ELISA). In addition, comparisons were also drawn between the results obtained with whole C. sonorensis and with individually dissected individuals to determine the level of BTV dissemination.<h4>Conclusions/significance</h4>Cq values generated from time-series infection experiments in both C. sonorensis and C. nubeculosus confirmed previous studies that relied upon the isolation and detection of infectious BTV. Implications on the testing of field-collected Culicoides as potential virus vectors by PCR assays and the use of such assays as front-line tools for use in diagnostic laboratories in this role are discussed.
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spelling doaj-art-f09a98ca23a54dbf982dbf2b38678ecb2025-08-20T02:35:43ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0188e7080010.1371/journal.pone.0070800Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus.Eva VeronesiFrank AntonySimon GubbinsNick GoldingAlison BlackwellPeter Pc MertensJoe BrownlieKarin E DarpelPhilip S MellorSimon Carpenter<h4>Background</h4>Culicoides biting midges (Diptera: Ceratopogonidae) are the biological vectors of globally significant arboviruses of livestock including bluetongue virus (BTV), African horse sickness virus (AHSV) and the recently emerging Schmallenberg virus (SBV). From 2006-2009 outbreaks of BTV in northern Europe inflicted major disruption and economic losses to farmers and several attempts were made to implicate Palaearctic Culicoides species as vectors. Results from these studies were difficult to interpret as they used semi-quantitative RT-PCR (sqPCR) assays as the major diagnostic tool, a technique that had not been validated for use in this role. In this study we validate the use of these assays by carrying out time-series detection of BTV RNA in two colony species of Culicoides and compare the results with the more traditional isolation of infectious BTV on cell culture.<h4>Methodology/principal findings</h4>A BTV serotype 1 strain mixed with horse blood was fed to several hundred individuals of Culicoides sonorensis (Wirth & Jones) and C. nubeculosus (Mg.) using a membrane-based assay and replete individuals were then incubated at 25°C. At daily intervals 25 Culicoides of each species were removed from incubation, homogenised and BTV quantified in each individual using sqPCR (Cq values) and virus isolation on a KC-C. sonorensis embryonic cell line, followed by antigen enzyme-linked immunosorbent assay (ELISA). In addition, comparisons were also drawn between the results obtained with whole C. sonorensis and with individually dissected individuals to determine the level of BTV dissemination.<h4>Conclusions/significance</h4>Cq values generated from time-series infection experiments in both C. sonorensis and C. nubeculosus confirmed previous studies that relied upon the isolation and detection of infectious BTV. Implications on the testing of field-collected Culicoides as potential virus vectors by PCR assays and the use of such assays as front-line tools for use in diagnostic laboratories in this role are discussed.https://doi.org/10.1371/journal.pone.0070800
spellingShingle Eva Veronesi
Frank Antony
Simon Gubbins
Nick Golding
Alison Blackwell
Peter Pc Mertens
Joe Brownlie
Karin E Darpel
Philip S Mellor
Simon Carpenter
Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus.
PLoS ONE
title Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus.
title_full Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus.
title_fullStr Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus.
title_full_unstemmed Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus.
title_short Measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi-quantitative rt-PCR assay and isolation of infectious virus.
title_sort measurement of the infection and dissemination of bluetongue virus in culicoides biting midges using a semi quantitative rt pcr assay and isolation of infectious virus
url https://doi.org/10.1371/journal.pone.0070800
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