Community Epidemiology Framework for Classifying Disease Threats

摘要

Recent evidence suggests that most parasites caninfect multiple host species and that these are primarilyresponsible for emerging infectious disease outbreaks inhumans and wildlife. However, the ecologic and evolution-ary factors that constrain or facilitate such emergences arepoorly understood. We propose a conceptual frameworkbased on the pathogen's between- and within-speciestransmission rates to describe possible configurations of amultihost-pathogen community that may lead to diseaseemergence. We establish 3 dynamic thresholds separating4 classes of disease outcomes, spillover, apparent multi-host, true multihost, and potential emerging infectious dis-ease; describe possible disease emergence scenarios;outline the population dynamics of each case; and clarifyexisting terminology. We highlight the utility of this frame-work with examples of disease threats in human andwildlife populations, showing how it allows us to understandwhich ecologic factors affect disease emergence and pre-dict the impact of host shifts in a range of disease systems