Scenarios of transmission risk of foot-and-mouth with climatic, social and landscape changes in southern Africa

Part of southern Africa is endemic to foot-and-mouth disease. African buffaloes (. Syncerus caffer) living in the Kruger National Park act as virus reservoirs and spread the infection to domestic cattle by close contacts. The landscape pattern influences movements and behaviour of animals and the risk of contacts. This study explores potential factors influencing the spatial and temporal risk of disease transmission, based on a spatially-explicit multi-agent simulation that represents the dynamics of buffalo-cattle contacts. Factors analyzed are linked to climatic, social and landscape changes. Various scenarios were formulated and analyzed in terms of the number of buffaloes escaping the park and the number of contacts between cattle and buffaloes. Results show that environmental and land management changes affect the spatial and temporal distribution of escapes and contacts. The most influential factor is the effectiveness of the separation between wildlife and cattle through a park fence. The size and spatial distribution of human settlements and landscape patterns also influence the risk of transmission of infections from wildlife to livestock. The presence of human settlements has a repulsive effect on buffaloes. A heterogeneous landscape disperses animals more widely. The number of buffaloes escaping the park was not always related to the number of buffalo-cattle contacts. Contacts take place close to water points, in grazing areas, away from villages, with seasonal fluctuations. This study demonstrated the role played by climatic, social and landscape factors on disease transmission via direct and indirect impacts on the movement of animals. Spatial variations in disease risk depend not only on the presence and area of critical habitats but also on their spatial configuration. The knowledge gained through model simulation experiments is useful to prevent disease transmission and improve the management of disease risk. Spatially-explicit model simulations help to target spatially critical areas where buffaloes are most likely to escape from the park and encounter cattle. © 2012 Elsevier Ltd.