Risk mapping of peste des petits ruminants virus spread in nine countries surrounding the black sea: a spatial multicriteria decision analysis approach.

Introduction: Peste des petits ruminants (PPR) is a highly contagious viral disease of small ruminants (SR) with major socioeconomic impacts. Although targeted for global eradication by 2030, PPR continues to spread and reemerge in previously free areas. In countries surrounding the Black Sea, where small ruminant production is critical for rural livelihoods and national economies, PPR is endemic in Türkiye and has recently emerged in neighboring countries, raising concerns about further transboundary spread, including into the European Union. This study, conducted prior to the 2024-2025 outbreaks, aimed to map areas at higher risk for PPR spread following an initial incursion in nine countries surrounding the Black Sea: Armenia, Azerbaijan, Belarus, Bulgaria, Georgia, Republic of Moldova, Romania, Türkiye, and Ukraine. Methods: A spatial multicriteria decision analysis (GIS-MCDA) approach was applied using five risk factors (RFs) selected based on literature review, data availability and regional relevance: SR abundance, proportion of smallholder farming, seasonal movements of SRs, proximity to livestock markets, and proximity to previous outbreaks. Risk factor weights were derived through expert elicitation using the Analytical Hierarchy Process (AHP). A total of 18 expert responses that met consistency thresholds were used to calculate the final RF weights. Georeferenced RF data were sourced, processed and then combined with RF weights using weighted linear combination (WLC) to produce the final suitability map. Results: High risk areas for PPR spread included the majority of Türkiye, the Bulgaria-Türkiye (Thrace) border, and southern-central Georgia. Low-risk areas included Belarus, Ukraine, central and northern Bulgaria, and parts of Armenia. Discussion: This risk map can guide the prioritization of PPR surveillance, biosecurity measures, and awareness campaigns, supporting both PPRV eradication by 2030 and broader transboundary animal disease preparedness to reduce the impact of other high-priority ruminant infectious diseases.