An Integrative Approach to the Management of Disease in Mixed Wildlife-Livestock Systems

Livestock diseases have a significant impact on human health and economic activity. Where multi-host pathogens are present in mixed wildlife-livestock systems, wildlife reservoirs of disease may prevent eradication in livestock. Management of such diseases requires an understanding of the biological processes governing their transmission, and also of the socio-economic factors influencing stakeholder’s management decisions. This thesis aims to identify risk factors for the presence of single and multiple diseases in livestock, quantify direct and indirect interactions between multiple wildlife and livestock species and evaluate the effectiveness and practicality of the resulting possible management interventions.

The study mainly uses the example of tuberculosis in south-central Spain, a region which suffers high prevalence in both cattle and wildlife. Risk factors for disease were evaluated with questionnaires and participatory mapping. Potential opportunities for disease transmission through direct and indirect interactions between different host species were measured using proximity logging and GPS collars attached to multiple wildlife and livestock species, and base stations placed at resource and control points on a cattle farm. The resultant possible disease management interventions were ranked by stakeholders using best-worst scaling.

Risk factors for tuberculosis in cattle were the presence of wildlife, the number of streams per hectare on a farm and the provision of cattle food on the ground. Intra- and inter-herd contacts between cattle were risk factors for multiple livestock diseases. Direct interactions between species happened so rarely that they are not likely to account for all disease transmission. Indirect interactions, particularly between cattle, red deer and pigs, warrant further investigation. These results were used to identify possible management interventions. An expert panel ranked a ban on supplementary feeding of game species as the most effective intervention. Different stakeholder groups varied in which interventions they considered practical. Management of livestock diseases in mixed systems requires the targeted prevention of indirect interactions between livestock and wildlife, using interventions that are effective, practical and supported by relevant stakeholders.