Herd contact structure based on shared use of water points and grazing points in the Highlands of Ethiopia.

The use of shared common water points (WPs) and grazing points (GPs) at two different levels of administrative aggregation (village and kebelle) in a region of the Highlands of Ethiopia was explored by means of a questionnaire survey and social network analysis. Despite GPs being more abundant than WPs (208 and 154, respectively), individual GPs provide more contact opportunities for animals. There was great variability in the contact structure of the selected villages within kebelles for both networks, with this variability being higher in the GP networks for each kebelle. Contrary to the commonly held view that WPs are critical for the potential transmission of infectious diseases, intervention at GPs in the Ethiopian Highlands may have greater impact on contacts and thereby opportunities for transmission of infectious diseases between flocks. Some villages appear naturally at much lower risk of introducing disease. These findings could help the design of surveillance and control activities for directly transmitted infectious diseases.