Epidemiology of shared pathogens at the domestic-wild ungulate interface

The transmission of pathogens between domestic and wild hosts greatly impacts animal and public health, biodiversity conservation and socio-economic contexts. The present PhD thesis deals with the study of the epidemiology of shared pathogens relevant for veterinary medicine in the Iberian Peninsula, with a special focus on the wildlife-livestock interface. The related epidemiological background, as well as the current research perspectives and knowledge blanks, are reviewed throughout the introduction section. In the first chapter of this thesis (Chapter 1), an innovative blood extraction method is proposed as an alternative to conventional sampling techniques in wild ruminants, representing a relevant step forward to better perform high quality sampling for disease surveillance and epidemiological wildlife studies. Chapter 2 describes the first Schmallenberg disease outbreak in Spain and assesses the local spread of the causative virus and associated risk factors in livestock. In Chapter 3, nation-wide studies evaluate the role played by wild ruminant species in the maintenance and transmission of this emerging pathogen (Chapter 3.1), as well as of pestiviruses (Chapter 3.2), a group of viruses endemic to livestock in Iberia. Finally, in Chapter 4, a finer approach to the wildlife-livestock interface is developed in Doñana National Park to provide in-depth information on the interspecies transmission of pathogens, which can follow different routes and pathways: pathogens directly transmitted through close or non-close interactions (Chapter 4.1) and pathogens indirectly transmitted through vectors (Chapter 4.2). Diverse serological methods, alone or combined with anatomical, pathological, and molecular tools, were used in each section. The blood sampling method developed in this PhD thesis could be systematically used in wild ruminant species for wildlife disease surveillance at international level favouring more accurate data comparisons. Likewise, epidemiological findings provide additional information on the spatio-temporal dynamics of both emerging and endemic shared pathogens and the epidemiological role played by wild ruminant species in mainland Spain. Overall, our findings revealed the usefulness of shared disease monitoring to better drive and prioritise control strategies in specific wildlife-livestock interfaces.