The Forum on Emerging Infections was created in 1996 in response to a request from the Centers for Disease Control and Prevention and the National Institutes of Health. The goal of the forum is to provide structured opportunities for representatives from academia, industry, professional and interest groups, and government to examine and discuss scientific and policy issues that relate to research, prevention, detection, and management of emerging infectious diseases. A critical part of this mission has been the convening of a series of workshops. "Public Health Systems and Emerging Infections" summarizes the fourth in a series of five workshops. With a focus on our knowledge and understanding of the role of private and public health sectors in emerging infectious disease surveillance and response, the participants explored the effects of privatization of public health laboratories and the modernization of public health care. The issues discussed included epidemiological investigation, surveillance, communication, coordination, resource allocations, and economic support.