Spread of livestock endemic diseases on contact networks
Résumé
One of the main transmission pathways of enzootic diseases in livestock populations is represented by animal movement between holdings. Therefore, the global picture of the pathogen spread at a regional level between in-contact herds should incorporate the investigation of the underlying structure represented by animal trade network and the coupling of intra-herd infection dynamics. Here, we first analyse the French cattle movement network from 2005 to 2009 using tools from graph theory, for different spatial granularities and temporal windows, to investigate the stability of its main descriptors. Proxies for pathogen spread, such as percolation and reachability ratio, accounting for network time-varying properties, are also computed to explore contrasting strategies for the prevention of epidemics. Then, we couple intra-herd infection dynamics, described by stochastic models in discrete time, to model the spread at a regional scale of pathogens (such as BVDV and Map, responsible for bovine viral diarrhoea and paratuberculosis, respectively). We also evaluate control strategies by numerical explorations