Emerging pathogens--the white horse of the apocalypse?

The concept of emerging microbial disease is discussed both in a historical and contemporary perspective. Major factors contributing to emergence of viral, bacterial, rickettsial, and parasitic diseases over the last 25 years are discussed. Forty agents are listed in a table by year of recognition/emergence, mode of transmission, geographical distribution, and symptom complex. Public health prevention and control measures and long-term public health implications are also summarized. Suggestions are offered on how to retrieve appropriate information on newly emerging pathogens and to obtain authoritative and timely information on surveillance data using electronic mail access.