title: Implicating Culicoides biting midges as vectors of Schmallenberg virus using semi-quantitative RT-PCR.
abstract: BACKGROUND
  The recent unprecedented emergence of arboviruses transmitted by Culicoides biting midges in northern Europe has necessitated the development of techniques to differentiate competent vector species. At present these techniques are entirely reliant upon interpretation of semi-quantitative RT-PCR (sqPCR) data in the form of Cq values used to infer the presence of viral RNA in samples.
  
  
  RESULTS
  This study investigates the advantages and limitations of sqPCR in this role by comparing infection and dissemination rates of Schmallenberg virus (SBV) in two colony lines of Culicoides. Through the use of these behaviorally malleable lines we provide tools for demarcating arbovirus infection and dissemination rates in Culicoides which to date have prevented clear implication of primary vector species in northern Europe. The study demonstrates biological transmission of SBV in an arthropod vector, supporting the conclusions from field-caught Culicoides and provides a general framework for future assessment of vector competence of Culicoides for arboviruses using sqPCR.
  
  
  CONCLUSIONS
  When adopting novel diagnostic technologies, correctly implicating vectors of arboviral pathogens requires a coherent laboratory framework to fully understand the implications of results produced in the field. This study illustrates these difficulties and provides a full examination of sqPCR in this role for the Culicoides-arbovirus system.
authors.affiliation: VVD Program, The Pirbright Institute, Pirbright, Surrey, United Kingdom.
authors.forename: Eva
authors.initials: E
authors.lastname: Veronesi
authors.forename: Mark
authors.initials: M
authors.lastname: Henstock
authors.forename: Simon
authors.initials: S
authors.lastname: Gubbins
authors.forename: Carrie
authors.initials: C
authors.lastname: Batten
authors.forename: Robyn
authors.initials: R
authors.lastname: Manley
authors.forename: James
authors.initials: J
authors.lastname: Barber
authors.forename: Bernd
authors.initials: B
authors.lastname: Hoffmann
authors.forename: Martin
authors.initials: M
authors.lastname: Beer
authors.forename: Houssam
authors.initials: H
authors.lastname: Attoui
authors.forename: Peter Paul Clement
authors.initials: PP
authors.lastname: Mertens
authors.forename: Simon
authors.initials: S
authors.lastname: Carpenter
mesh_terms: D000818:Animals; D002044:Bunyaviridae Infections / Q000235:genetics / Q000635:transmission / Q000821:virology; D002519:Ceratopogonidae / Q000235:genetics / Q000821:virology*; D007303:Insect Vectors / Q000235:genetics / Q000821:virology*; D016851:Orthobunyavirus / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*