Mayors need a framework appropriately complex to respond to the emergence of zoonotic diseases (ie. diseases that cross over from animal populations into human populations) (Sapient Circle, 2004). These threats make demands on emergency response systems that are not merely complicated, but are complex. This means that the interconnections of animal and human health systems, through diseases such as SARS, West Nile Disease, BSE, E-Coli and Avian Influenza, create exponential levels of complexity. It appears that zoonotic bio-emergencies are more dynamic and subject to sudden jumps in severity, than non-bio-emergencies, because the underlying viral/biological elements are capable of learning or adapting to their human environments/life conditions. Thus they require complex non-linear approaches to develop successful response strategies.