Print PageFocus on concern over zoonotic influenza emergence as a source of a global pandemic has grown over the last decade, with the emergence of H1N1 and H5N1. Although neither virus has the full effect of the 1918 influenza pandemic, which spread rapidly (as has H1N1), and caused high mortality (as has H5N1), they have heightened awareness that influenza continues to be threat. It is clear that strains of influenza that circulate in both domestic and wild animals continue to be a key source of new genetic recombinants and mutations. Thus we seek to understand the role of livestock-based economies in biodiverse areas as a source of potential influenza outbreaks. We have implemented an SIR model of a mixture of wild birds, farms, and humans as a multi-patch model, with farms of various sizes (backyard to industrial). We explore the effect for differing rates of contact between wild birds and livestock, based on farm type, and differing rates of connectivity between farms.
Results/Conclusions
We find that complex population structures help prolong epidemics, relative to simple aspatial populations. This can include the multiple 'islands' of small backyard birds and production oriented nomadic rearing, plus more 'mainland' industrial farms. Spread both to and from wild birds, particularly migratory waterfowl, can also play a role in sustaining outbreaks.
