Preface to the Field Epidemiology Manual

Field epidemiology, defined as "epidemiology with the goal of immediate action to address a public health problem of concern" (see Chapter 1), is a primary function in US public health practice and has been integral to the mission of CDC since the creation of the agency's Epidemic Intelligence Service (EIS) Program in 1951. After several years in development, the first edition of Field Epidemiology, edited by Michael B. Gregg, MD, was published in 1996. In the preface to that edition, Carl W. Tyler, Jr., MD—who had helped conceive the need for the initial text during his tenure as Director of CDC's Epidemiology Program Office during the mid-1980s—wrote, "There is a need for a clearly written, highly usable book devoted to field epidemiology—the timely use of epidemiology in solving public health problems. This process involves the application of basic epidemiologic principles as in real time, place, and person to solve health problems of an urgent or emergency nature." The uptake, use, and success of that first edition led to second and third editions, the latter published in 2008. The decade after the 2008 edition has been marked by the continuing emergence of public health challenges that require epidemiologic field investigative responses as well as innovations in the science and art of the methods of field epidemiology. For these reasons, CDC recognized the need to update the volume's scope and contents. The result of this renewal is this fourth edition, now under a new title, the CDC Field Epidemiology Manual, to reflect the evolution in scope, methods, venues, and other aspects of the application of field epidemiology.

The preface to the first edition stated, "This book takes its roots from the experience of the Centers for Disease Control and Prevention (CDC) over more than 40 years of training health professionals in the science and art of field epidemiology." This new, fourth edition sustains that tradition: the principles of field epidemiology in this manual continue to draw from and reflect the foundation of the curriculum used each year in training newly arriving EIS officers. However, this focus on principles central to CDC's training of EIS officers should not be interpreted as limiting the book's utility only to epidemiologic field investigations conducted by CDC. As was the case for the previous editions, one of the new edition's main goals is for public health professionals and many other allied health workers to be able to use all the chapters in addressing a broad spectrum of problems in multiple field settings.

Another major goal we pursued in developing this new edition was to make the book more usable to epidemiologists in the planning and implementation phases of field investigations. Also as noted in the first edition's preface, "Copies of this book should be more often in the briefcases of field epidemiologists than on the shelves of libraries." However, the page length of previous editions had expanded dramatically, from 267 pages in the first edition, to 411 in the second, and 523 in the third. To enable this new edition to have greater utility in the field, we pursued a more readable format, including boxes and bulleted points, as are sometimes used in portable clinical manuals. We hope public health practitioners and other readers will find the tighter chapters and easier-to-read format helpful when using this manual in epidemiologic field investigations.

In this edition, we also removed the background chapters on principles of epidemiology and surveillance because we expect that most users already have a basic fund of knowledge of these areas and because other sources cover these topics in great depth. For similar reasons, we also removed other chapters, including the chapters on communicating epidemiologic findings, which focused on how to write a scientific paper, and immunization practices. Because this new edition is designed to be used in planning and implementing investigations in a greater spectrum of field settings, we also removed the chapter on field investigations from the state and local health department perspective.

This fourth edition of CDC's compendium on field epidemiology has preserved the core elements in approaching field investigations of public health problems that require prompt action and solutions. Meanwhile, this edition has augmented the core elements by incorporating a broad set of innovations, including design changes that impart portability, increased utilities, and enhanced readability, and an expansion in scope that accommodates major evolutionary changes in methods for epidemiologic field investigations that have emerged since the last edition's publication in 2008. To undertake such substantial change and to ensure that this new edition is responsive to the needs of persons who actively perform field investigations, we established a steering committee made up of members with broad experiences in field epidemiology in local, state, national, and international settings. We then charged those committee members with proposing new chapter topics and authors for the fourth edition as well as making recommendations for maximizing the manual's usefulness across wide-ranging field settings. We are grateful to the committee members (listed in the Acknowledgments) who provided this expert guidance early in this edition's development.

Since the inception of Field Epidemiology as CDC's first dedicated edition on field epidemiology, this domain's core principles have remained unchanged, and the representation of those principles has remained consistent across all of the editions. In contrast, however, substantial changes have occurred in certain approaches, methods, and types of settings in which field investigations are conducted. Accordingly, in this fourth edition, all chapters have been updated to include the latest advances in field epidemiology wherever possible. As in the previous editions, chapters in this edition's first section on "The Field Investigation" remain organized according to the progression of the basic steps in an outbreak investigation, including, for example, the sequencing from "Defining Field Epidemiology" and "Initiating Operations," to "Developing Interventions" and "Communicating During an Outbreak or Public Health Investigation." Each chapter in this first section focuses on an activity, as evidenced by their action-oriented titles.

This edition also places an increased emphasis on the importance of collaborations during field investigations. Accordingly, the chapter on laboratory science now is included in the first section on Field Investigations but has been strengthened and retitled ("Optimizing Epidemiology–Laboratory Collaborations") to give greater attention to the importance of these collaborations, beginning at the earliest phase of planning an investigation. The importance of collaborations in multistate and international settings is now highlighted by the addition of new chapters addressing these concerns in the section on Special Considerations ("Coordination of Multiple States and Federal Agencies" and "Multinational Outbreak Investigations"). Finally, to address the need for collaboration in investigating public health problems that might be associated with malicious use of biologic or toxic agents, a new chapter ("Suspected Intentional Use of Biologic and Toxic Agents") covers collaborations between public health, law enforcement, and other nontraditional partners.

The new edition has recognized substantive advances in some of the key tools used during field investigations through the addition of new chapters and updates to others. For example, because portable computers are now a standard, fully integrated component in field investigations, the chapter on this topic from the previous edition has been supplanted by a new chapter ("Using Technologies for Data Collection and Management") that discusses an expanding array of technologies—from mobile devices to environmental sensors—that can improve the efficiency and effectiveness of field responses. Other additions covering advances in tools are a new chapter on the use of geographic information system data and, to encompass the increasing use of qualitative data in epidemiology, a new chapter on "Collecting and Analyzing Qualitative Data."

Finally, because of a progression in the types of scenarios that might prompt epidemiologic field investigations, this edition includes new chapters reflecting these scenarios. For example, a chapter in the third edition on the scenario of investigations in out-of-home child care settings has been supplanted in this edition by a new chapter ("Community Congregate Settings") that covers such situations as educational institutions, workplaces, mass gatherings, and detention facilities. A new chapter on "Acute Enteric Disease Outbreaks" provides information on methods for detecting, investigating, and controlling foodborne, waterborne, and other enteric pathogen–associated outbreaks, with a particular focus on multijurisdictional investigations of foodborne illness. Finally, to address the epidemiologic phenomenon of the spread of violent injury in patterns that echo the transmission of certain infectious conditions, this fourth edition includes a new chapter on field investigations of "Suicide, Violence, and Other Forms of Injury."

Although this new edition features many changes, we have retained historically important principles and traditions of field epidemiology to preserve the spirit of CDC's earlier progenitors of this branch of epidemiology. Foremost among these leaders were Alexander Langmuir, MD, originator of the EIS Program and powerful advocate for broader uses of epidemiology in public health practice; Philip Brachman, MD, long-time director of CDC's Bureau of Epidemiology, who promoted the EIS Program and led in the creation of the globe-spanning Field Epidemiology Training Program based on the EIS; Carl Tyler, MD, former director of CDC's Epidemiology Program Office who had a vision for continually modernizing field epidemiology and who championed creation of the first edition of Field Epidemiology; and Michael B. Gregg, MD, editor of the first three editions, who also served as editor of CDC's Morbidity and Mortality Weekly Report (MMWR) for 21 years and as CDC's dean of training in field epidemiology.

We hope investigators will find the chapters in this fourth edition useful as they seek to address public health challenges and identify interventions to decrease disease and disability and save lives.

— Sonja A. Rasmussen Atlanta, Georgia
— Richard A. Goodman (Associate Editor, Field Epidemiology, First Edition, 1996) Atlanta, Georgia