West Nile virus in Europe: After action reviews of preparedness and response to the 2018 transmission season in Italy, Slovenia, Serbia and Greece

Background: After Action Reviews (AAR) with a One Health perspective were performed in Slovenia, Italy, Serbia and Greece following a severe West Nile virus (WNV) transmission season in 2018. A protocol combining traditional techniques and organizational process analysis was developed and then implemented in each country. Results: In 2018, response to the unusually intense transmission season of WNV in Slovenia, Italy, Serbia and Greece took place through routine response mechanisms. None of the four countries declared a national or subnational emergency. We found a very strong consensus on the strengths identified in responding to this event. All countries indicated the availability of One Health Plans for surveillance and response; very high laboratory diagnostic capacity in the human, veterinary and entomology sectors and strong inter-sectoral collaboration with strong commitment of engaged institutions as critical in the management of the event. Finally, countries implementing One Health surveillance for WNV (in terms of early warning and early activation of prevention measures) consistently reported a positive impact on their activities, in particular when combining mosquito and bird surveillance with surveillance of cases in humans and equids. Recurring priority areas for improvement included: increasing knowledge on vector-control measures, ensuring the sustainability of vector monitoring and surveillance, and improving capacity to manage media pressure. Conclusions: The AARs presented here demonstrate the benefit of cross-sectoral and cross-disciplinary approaches to preparedness for West Nile virus outbreaks in Europe. In the coming years, priorities include fostering and strengthening arrangements that: enable coordinated One Health surveillance and response during WNV transmission seasons; ensure adequate laboratory capacities; strengthen risk communication; and fund longer-term research to address the knowledge gaps identified in this study.