Although preventive measures against infectious disease have focused primarily on developing rapid and accurate diagnostic methods as well as prevention of the spread of disease after an outbreak, it is necessary to understand the interactions among environments, pathogens and their hosts which are responsible for inducing and spreading infectious diseases in order to help experts respond to infectious diseases proactively to reduce the damage of the outbreak of infectious diseases. However, we don’t have enough data yet to verify the interactions. The first event of the outbreak of infectious diseases is encounter of pathogens with their hosts. Therefore, we need to know their ecologies. On the other hand, human has been altering vastly the environments in various ways. Therefore, to understand how the pathogen and host are linked under some environments is indispensable to propose implementations for alleviate the outbreak of the infectious diseases. In this symposium, after exchanging the information of pathogens and their hosts under some specific environments, we are going to discuss perspectives of disease ecology and propose urgent ecological research subjects to carry out.