Introduction: the Centers for Disease Control and Prevention's Epi-Aids--a fond recollection.

The Epidemic Intelligence Service (EIS) has served the United States and the world for >58 years by being an extraordinary apprenticeship in the fundamentals of practical field epidemiology: a training program, a professional entry point, the basis for lifelong careers, and a closely supervised and mentored opportunity for research, analysis, and community service. Epidemic-assistance investigations, a key element of the EIS experience, are the written summaries of each field investigation undertaken by the EIS officer. The resulting reports enter the record of the Centers for Disease Control and Prevention (CDC), provide scientific feedback to the state and locality where the epidemic or health problem occurred, and often form the basis for a subsequent manuscript to be submitted to a peer-reviewed medical journal. The EIS Program was created in 1951 to be a defense against potential bioterrorism, serve the immediate needs for field investigation, and provide for future workforce demands by combining epidemiology and laboratory science. During the past 60 years, CDC and public health practitioners have broadened their areas of responsibility by adding programs in reproductive health, environmental health, chronic diseases, nutrition, injury control and prevention, and noncommunicable disease risk factors. Epidemic-assistance investigations have evolved similarly. The papers in this Journal supplement reflect the evolution of public health responsibilities and the growth and development of CDC. They are a testimony to the value of clear, concise information and analysis, communicated to those who need to know as a public health and societal good.

Lessons and innovations from the West and Central African Smallpox Eradication Program.

In 1966, the Centers for Disease Control began training medical officers and public health advisors for a program that would encompass 20 countries of West and Central Africa with the objective of eradicating smallpox and controlling measles. The program was funded by the US Agency for International Development with a target of smallpox eradication within 5 years and the immunization of children from 6 months to 6 years of age against measles in all areas of every country. The 40 plus field staff were directed by a Regional Office in Lagos, Nigeria and a headquarters group in Atlanta, Georgia. The teams greatly expanded the knowledge of smallpox epidemiology, helped to expand the capabilities of Ministries of Health, pioneered the use of jet injectors to provide millions of immunizations, and expanded the use of surveillance/containment to become a primary strategy for interrupting smallpox transmission. Smallpox transmission was interrupted in three and one half years, a year and a half before the time targeted and under budget. Measles transmission was interrupted in one country, The Gambia, and significantly reduced in the other 19 countries.

The role of research in viral disease eradication and elimination programs: lessons for malaria eradication.

By examining the role research has played in eradication or regional elimination initiatives for three viral diseases--smallpox, poliomyelitis, and measles--we derive nine cross-cutting lessons applicable to malaria eradication. In these initiatives, some types of research commenced as the programs began and proceeded in parallel. Basic laboratory, clinical, and field research all contributed notably to progress made in the viral programs. For each program, vaccine was the lynchpin intervention, but as the programs progressed, research was required to improve vaccine formulations, delivery methods, and immunization schedules. Surveillance was fundamental to all three programs, whilst polio eradication also required improved diagnostic methods to identify asymptomatic infections. Molecular characterization of pathogen isolates strengthened surveillance and allowed insights into the geographic source of infections and their spread. Anthropologic, sociologic, and behavioural research were needed to address cultural and religious beliefs to expand community acceptance. The last phases of elimination and eradication became increasingly difficult, as a nil incidence was approached. Any eradication initiative for malaria must incorporate flexible research agendas that can adapt to changing epidemiologic contingencies and allow planning for posteradication scenarios.