Lutte biologique et écologie spatiale                                                  Biological control and Spatial Ecology
june 2013

Spatial epidemiology focuses on the spatial dynamics of populations of harmful organisms (insect pests, invasive species, pathogens), and on the factors determining their emergence, spread and persistence in time and space. These processes include all interactions between these organisms and their host or habitat, and with their biotic and physical environment, and these are viewed from an spatially-explicit perspective.

Over the years, we have been working on a number of livestock diseases, including bird flu, bovine tuberculosis and bluetongue. We now concentrate our research along four major axes of developpment:

The geography of highly pathogenic avian influenza (HPAI). Since 2005, we have been trying to better understand the geography of HPAI H5N1 virus, mostly in Asia, and more specifically to characterise the environmental and socio-economic conditions that relate to the spread and persistence of the disease at various spatial and temporal scales. We now try to better understand the conditions favouring emergence of new avian influenza viruses, and aim to better integrate the knowledge gained from large-scale studies of agro-ecological factors with that arising from experimental approaches and phylogenetic analysis. Our main previous collaborators in this topic are Vincent Martin and Scott Newman (FAO, Rome, Italy), Xiangming Xiao (Univ. Oklahoma, US), and D. Pfeiffer (Royal Vet. College, London). 

Patterns and processes of agricultural intensification in the livestock sector. Diseases emerging in livestock are influenced by the way animals are raised, and intensification of animal production leads to very particular conditions of living, which may promote disease emergence. In addition, intensive animal production has many other detrimental effects on the environment. We aim to study the geography of intensification of the livestock sector in order to reconstruct trajectories of intensification at the sub-national level.  Our main collaborators in this topic is Tim Robinson (ILRI, Nairobi, Kenya).

Mapping people and livestock. High-resolution maps of people and livestock are essential tools in environmental and agricultural sciences and particularly in spatial epidemiology, because the density of hosts (people, or livestock, or both) is a key variable affecting the emergence, persistence and spread of infectious diseases. We contributed to  recent developments in this field for the Afripop and Gridded Livestock of the World databases, and aim to work on further improvements of the census data disaggregation algorithms. Our main collaborators on this topic are Tim Robinson (ILRI, Nairobi, Kenya), William Wint (ERGO, Oxford, UK) & Andy Tatem (Univ. Southampton, UK).  

Modelling the spread of invading organisms. Invading organisms spreading though a heterogeneous landscape are difficult to study using conventional statistical models, and there is no established methodology to analyse those space-time data sets. We aim to develop new methodology to study those type of data, to review existing methods, and to compare all methods in their capacity to detect the influence of landscape heterogeneity on the pattern of spread. Our main collaborators on this topic are Renaud Lancelot (CIRAD, Montpellier, France) and William Wint & Guy Hendrickx  (Euro-AEGIS).