Getting a handle on West Nile virus
Several aspects of the transmission cycle of WNV, from its introduction into new areas to the spillover events, are still poorly understood. This RNA virus has a variable genome (at least five WNV lineages have been identified in Europe), making it a generalist pathogen adaptable to new vectors and host species which can varies among geographic areas and thus very difficult to control. The co-circulation of different lineages with variable pathogenicity represents a challenge for public health also in relation to the need to guarantee the safety of blood transfusions and organs transplantation. The EU-funded 'European West Nile collaborative research project' (EUROWESTNILE) studied WNV variants in Europe to address knowledge gaps in the ecology, pathogenicity, diagnostic and modelling. Project members collaborated closely with the EU-funded project EDENext and other projects to streamline EU research on WNV. A WNV database and biobanks were successfully established by collecting and characterising the major WNV strains circulating in Europe and neighbouring countries. A recombinant live-attenuated virus that can be used in future vaccine efforts was also produced. Novel animal models for WNV were standardised to assess pathogenicity of WNV variants. Mosquitoes from Austria, Spain, Italy, Israel, Russia and Senegal were captured to identify species involved in NV transmission and collect blood-fed females that help in identifying the host species most preferred by mosquitoes for their blood meal. Additionally, colonies of Culex pipiens were established in the Italian National Institute of Health to assess vector competence for various lineages. EUROWESTNILE researchers characterised the virome of mosquitoes and analysed viral interactions between WNV and other viruses as well as its commonly detected vectors. Innovative prototype kits for WNV diagnostics and surveillance, able to discriminate various WNV lineages, were also developed. Climatic and land-use change maps have been generated for the study sites and models developed to predict mosquito abundance in relation to climate change. EUROWESTNILE will shed light on the virulence and emergence of WNV in new territories by considering the most probable driving factors. Understanding the mechanisms of viral replication and transmission will help scientists to find novel treatment solutions to prevent or treat WNV infections.
Keywords
West Nile virus, genetics, ecology, epidemiology, pathogen, mosquitoes, mathematical modelling
