The landscape epidemiology of foot-and-mouth disease in South Africa: A spatially explicit multi-agent simulation

Abstract

a b s t r a c tThis study aimed at understanding how landscape heterogeneity influences outbreaks of contagious diseases in southern Africa. Landscape attributes influence patterns of movement and behaviour of animal hosts, virus spread and survival, as well as land use practices. A multi-agent simulation was developed to represent the spatial and temporal dynamics of pathogens between human-livestock and wildlife interfaces at the fringe of large wildlife conservation areas. The model represents the three main elements associated with epidemics -populations, space, and time -to simulate direct contacts between wildlife and livestock. The dynamics of these populations emerge from interactions between agents and the landscape. The model was calibrated to represent the transmission of foot-and-mouth disease through direct contact at the border of the Kruger National Park in South Africa. In the region, African buffaloes (Syncerus caffer) act as reservoirs of the virus and spread the infection to domestic cattle bordering the park. We tested the sensitivity of various factors influencing contact rate between buffaloes and cattle, and thus the risk of foot-and-mouth disease transmission. Results show that cattle-buffalo contacts mostly depend on the range of displacements of cattle and buffaloes, as influenced by the landscape configuration, and on the number of fence breakages multiplied by the time between breakage and repair. Contacts take place not only close to water-points but also in grazing areas, within an area up to 6 km from the fence.

Transmission of foot and mouth disease at the wildlife/livestock interface of the Kruger National Park, South Africa: Can the risk be mitigated?

“…Recently, some authors have developed sophisticated spatially explicit models to assess the risk of FMDV outbreaks outside KNP. Those models took into account landscape heterogeneity and spatially represented contacts between buffaloes and cattle essentially outside the KNP interface (Dion and Lambin, 2012;Dion et al, 2011). Our model is different since i) it simplified the KNP interface landscape as a whole homogenous unit and ii) integrated more detailed information on FMDV transmission between buffalo and cattle based on updated available literature…”

Contacts and foot and mouth disease transmission from wild to domestic bovines in Africa

“…Although strict land policies, animal movement controls and fencing can largely resolve the problem if strictly applied (Thomson 1995), the un-sustainability of these control options and the indirect costs induced have raised concern for decades among conservationists (e.g., Taylor and Martin 1987). Even the best maintained fences cannot restrain the movements of all wild animals (Sutmoller et al 2000, Dion et al 2011, and these events may result in outbreaks of infectious diseases in neighboring livestock, including FMD (Hargreaves et al 2004). In many areas in southern Africa fences, separating livestock populations from wild reservoirs of FMD, are absent or no longer functional because they have not been properly maintained and/or because they have been destroyed by wildlife or people (e.g., Ferguson and Hanks 2010).…”

Clinical Features of Patients of Different Ages with Postoperative Multi-space Maxillofacial Infection

“…The spread of suppurative inflammation to the adjacent space causes cellulitis or abscess. Spreading across the nerve system and the blood vessels can cause other severe complications and even eventual death [1]. As the notion to operate under sterile condition is emphasized more, the maxillofacial infection occurs less and less in recent years.…”