Shared risk factors for multiple livestock diseases: a case study of bovine tuberculosis and brucellosis.

Livestock diseases can result in reduced farm productivity. The bacterial diseases tuberculosis (TB) and brucellosis may share some transmission characteristics which, if managed in common, would result in more cost-effective management. Here, we identify risk factors shared between these diseases using a case-control approach and information theoretic modelling. One-hundred cattle farmers in Atlantic Spain were interviewed about farm characteristics and management practices. The risk factor shared between both diseases was intra- and inter-herd contact between cattle. Disease-specific risk factors were the presence of wildlife for TB, and cattle movement between farms for brucellosis. An integrated approach to disease management needs to consider cattle movement and farm biosecurity, reinforced by an education campaign to increase farmer awareness. This would be likely to bring benefits in reducing both diseases and improve the efficiency of any interventions.

Spatial and temporal interactions between livestock and wildlife in South Central Spain assessed by camera traps.

The diversification of livestock farms into hunting estates in South Central Spain (SCS) may impede the success of Mycobacterium bovis eradication programmes by facilitating transmission between wildlife and livestock. In this observational study we aimed to provide information of relevance about the nature and frequency of interactions (observed visits to study points) between livestock (cattle and domestic pigs) and wildlife (wild boar and red deer). The study was conducted in an extensive cattle farm in SCS where the land is also used for game hunting. During a period of one year, camera traps (n=16) were placed at a priori risk points for interspecies interactions: water (natural and artificial troughs), food placed on the ground for baiting wildlife, and pasture. To define indirect interspecies interactions, a critical time window for M. bovis to survive in the environment was selected based on the literature. Results suggest that wildlife frequented food and pasture points more often than water points, and that the number of visits increased through the dry season, peaking during the acorn season (October-January) and the deer breeding season (June-July). Direct interactions were rare (n=10), as opposed to indirect interactions (n=8992). Wildlife-followed-by-livestock interactions (n=7714) occurred much more often than livestock-followed-by-wildlife (n=1278) and were frequent at water points (66% water points, 17% food, 17% pasture). Results also suggest that water points are a hotspot for indirect interactions and might therefore be a source of infection at the wildlife-livestock interface in the territory covered, particularly for M. bovis, as it is around water where the bacteria seem to survive the longest. Preventing aggregation and therefore reducing contact rates between domestic and wild animals especially at water points may be valuable for disease control in South Central Spain.