Can we predict emergence and spread of Culicoides-borne arboviruses in Europe according to genetic drivers of vector competence and virome diversity? – Culiome

Culicoides biting midges (Diptera: Ceratopogonidae) are currently the most important
biological vectors of livestock arboviruses in Europe. Outbreaks of bluetongue virus (BTV)
and Schmallenberg virus (SBV) continue to have a significant economic impact through
clinical disease and the imposition of animal trade movement restrictions. At least three
Culicoides-borne viruses recently identified in Europe possess an unknown origin, hence
future outbreaks involving described or undescribed strains or species of Culicoides-borne
viruses have a high potential of occurring in the future. These viruses could include further
incursions of known arboviruses (including additional species of Culicoides-borne
arboviruses such as African horse sickness or Epizootic Haemorhagic Disease Virus) or as
yet undescribed species with an unknown pathogenicity to livestock or humans.
In this project we will dissect Culicoides vector-arbovirus relationships across multiple
ecosystems and species and in unprecedented detail to provide data useful for both
defining risk of incursion and subsequent spread. Using newly developed methods to
blood-feed Culicoides viruses of epidemiological interest, we will assess
barriers associated with vector competence that may underlie restrictions to arbovirus
movement in Europe. The fundamental genetic drivers determining vector competence in
Culicoides will then be explored using genomic techniques to identify panels of candidate
genes influencing this process. Following identification, comparative genomics will identify
species specific differences in panels which will be examined across ecosystems in
Northern and Southern Europe. In addition, we will also examine the virome of European
Culicoides of veterinary importance as a potential influence on vector competence and as
a means of understanding how viral diversity within populations can be used to infer risk
of outbreak. Using metagenomic analyses we will examine viromes from Culicoides
populations across the participating countries that have already been the subject of
targetted sampling for surveillance purposes. We expect this to reveal for the first time
the true diversity of viruses present within Culicoides and to begin to untangle their role in
the epidemiology of pathogenic virus transmission, opening a new field of research for
animal virus vectors.