WHEN WORLDS COLLIDE: Micro versus Macro

Introduction

Humans share the world with microbes — organisms too small to see in detail without the aid of a microscope. For most of human history, microorganisms were unknown and unsuspected. Microorganisms are an essential component of the environment, but they can also cause diseases.

The advent of microscopes, powerful enough to magnify by a factor of 100 times or more, ultimately produced a revolution in the scientific understanding of infectious disease. Researchers began to recognize and inventory specific pathogens — agents that cause infectious diseases — that had plagued humanity for millennia.

Another technological revolution, a counterpart of the larger ongoing information revolution, is now enabling scientists to "see" the microbial world in different and highly detailed ways. Vast atlases of genomic information — information relating to the genetic components of pathogens and people — are rapidly being assembled. This increasing storehouse of genetic information constitutes a resource for biomedical research going into the next millennium, a knowledge base to enable the creation of new, highly targeted therapeutic drugs. This mountain of genetic data is already changing the boundaries of research, allowing scientists to study more mechanisms of disease at the molecular level.

Despite the extraordinary advances of science and medicine, infectious disease will likely endure as a potential and actual health threat. Devastating diseases, such as AIDS, have been seen to appear suddenly or to expand their reach. New, sometimes drug-resistant strains of known pathogens emerge and re-emerge. And our living and traveling habits in a complex global society are such that a disease-causing agent can spread throughout the world in just weeks or days.