Abstract
Spatial transmission kernel modelling is a powerful approach for modelling disease transmission risks between localized population units, such as livestock farms. In this study, we applied this modelling approach to African Swine Fever (ASF) transmission in Latvian wild boars, using spatial grid cells representing local wild boar habitat areas as population units. In particular, we consider the context of designing wild boar vaccination programs and use the risk maps to investigate the influence of vaccination coverage on transmission risk. Using transmission kernel estimates obtained from outbreak data in Estonia and wild boar hunting bag information from Latvia, we first calculated spatial transmission risk maps for ASF in Latvian wild boars. We expect comparing close-by countries the transmission kernel estimated for ASF transmission in Estonian wild boar will also be representative of the Latvian context. However, considering the occurrence of attenuated ASF virus in Latvia since 2017, we also expect that the Latvian outbreak data could as well be different from the one used for Estonia, particularly since the infection might have evolved and epidemic dynamics could be different from those observed 5 years ago. We used these risk maps to identify predicted high-risk areas of transmission and compared, retrospectively these to actual ASF transmission patterns observed in Latvia. Subsequently, we investigated how predicted transmission risks scale down for different wild boar vaccination coverage scenarios. We discuss the possible implications for the effectiveness of vaccination strategies in the Latvian wild boar population, considering both attenuated and acute ASF virus strains.