ANIHWA call2: Can we predict emergence and spread of Culicoides-borne arboviruses in Europe according to genetic drivers

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 targeted 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.

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.

While the impact on animal health of these outbreaks has been geographically broad, this masks a complex and incomplete epidemiological picture characterized by differential spread in Europe of arbovirus strains. In the Mediterranean basin, studies by Partners 3 and 4 have demonstrated that transmission of arboviruses is dominated by C. imicola, an afrotropical species that is highly abundant in this region. In contrast, Partner 1 has shown that transmission in Northern Europe is dominated by a range of vectors of which the most convincingly implicated is the C. obsoletus/C. scoticus complex. To date, standardized comparison of vector competence for arbovirus strains between these vector groups have not been conducted with studies limited to single countries. This currently prevents examination of barriers to movement of arboviruses between Southern and Northern Culicoides-arbovirus 'episystems'. Following the recent initiation of the Culicoides genome project (Partners 1 and 2: BBSRC project BB/J016721/1) and advances in technologies to dissect vector-arbovirus relationships, a unique opportunity exists to examine this area in multiple ecosystems and in unprecedented detail.

The impact of CuliOme will fall on the following major areas in addition to Academic Beneficiaries outlined previously.

To key policy makers:
Contact with policy makers will be ensured by the contacts held both within the group and through direct attendance of CuliOme members in policymaking initiatives. In this regard the attendance of two CuliOme members (TPI: SC and IZS: MG) on the OIE working group for Culicoides and in EFSA working groups on BTV and SBV, will provide a natural outlet for novel discoveries. Periodic reports will be made available to ANIWHA funders upon demand, as to other stakeholders (EU, FAO, OIE, national organisations, livestock industry, policy makers). We expect the project to influence policy with regard to assessing the potential for BTV emergence in epidemic areas and additionally assessing the impact of coninfection on transmission in the field. Both of these areas should enhance the preparedness of Europe for emergence of BTV.

To the general public:
Partner 1 and 3 participate actively in communicating to the general audience on Culicoides-borne diseases related topics through websites www.bluetongue.cirad.fr and www.Culicoides.NET. Highlights of the annual reports will be released to the public via these websites. All press releases will be produced with multiple language options, taking advantage of the multi-national nature of the collaboration. Vector-borne diseases in general have a high profile both in terms of applied and fundamental interest in the public domain and we expect this project to improve understanding at a basic level. This will be achieved through measures discussed in the impact plan.

Intellectual property:
Knowledge generated by CuliOme will be defined prior to the project initiation through the drawing up of a common Memorandum of Understanding or Consortium Agreement, generated by TPI as coordinator, and being circulated to all partners following confirmation of funding. It will detail, amongst other things, IPR management relating to foreground/results, rules for dissemination and communication, task allocations, deliverables and resources for each partner, and rules governing exploitation of the results. As a general rule, intellectual property will remain the property of the specific partners involved in its development.