More than a century of research, sparked by the germ theory of disease, underlies our current appreciation of microbe-host-environment interactions. Our “war” on infectious microbes has restricted the spread of several pathogens and drastically reduced the burden of human disease, but the tide of the human conquest shows many signs of turning. Over the past 30 years, 37 new human pathogens have been identified as disease threats, and an estimated 12 percent of known human pathogens have been recognized as either emerging or re-emerging. Due in large part to the HIV/AIDS pandemic, the number of deaths attributable to infection in the U.S. began to increase in the early 1980s, having fallen steadily since the turn of the century. Infectious diseases continue to cause high morbidity and mortality throughout the world, and particularly in developing countries; in 2001, infectious diseases accounted for an estimated 26 percent of deaths worldwide.
Clearly, a reconsideration of our interactions with pathogenic microbes is warranted, and it must be founded on a better understanding of host-microbe relationships in general. Estimates indicate that 90 to 99 percent of the approximately 1014 cells that comprise a healthy human body belong to the complex microbiota that shares our space. Only a small fraction of the 500 or so bacterial species that inhabit our bodies cause illness; very little is known about the other non-pathogenic bacteria, or even about microbes that in most cases cause chronic, asymptomatic infections in humans, and that only occasionally produce illness and death. Research into our own microbial ecology and that of our fellow eukaryotes, including plants, appears certain to reveal new strategies for preventing and treating a broad spectrum of infectious disease.
To investigate these prospects, the Institute of Medicine's Forum on Microbial Threats hosted a public workshop on May 20 and 21, 2008, in the KECK Building, located at 500 Fifth St. NW in Washington D.C., to inform the Forum and the general public about the many scientific and policy contributions of Dr. Joshua Lederberg to the life sciences, medicine, and public policy. Through invited presentations and discussions among participants, the workshop explored existing knowledge and unanswered questions regarding host-microbe relationships. Participants examined existing models of host-microbe interactions and evidence of the dynamic forces that shape them; the rise of antimicrobial resistance; microbial evolution/adaptation; and the impacts of globalization on the emergence, reemergence and evolution of "novel" infectious diseases.