Emerging and Re-Emerging Infectious Diseases: Influenza as a Prototype of the HostPathogen Balancing Act

To respond to emerging and re-emerging infections, it is necessary to understand the interactions between microbial pathogens and their hosts and the impact of environmental and social factors on these interactions. The importance of understanding host-pathogen interactions is underscored by the emergence of virulent H5N1 avian influenza viruses and their transmission to humans, and the potential pandemic threat they pose.