American Journal of Epidemiology

1. American Journal of Epidemiology December 1, 2011 174 (11)

2. 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.

3. Epidemic Assistance by the Centers for Disease Control and Prevention: Role of the Epidemic Intelligence Service, 1946–2005 Since 1946, the Centers for Disease Control and Prevention has responded to urgent requests from US states, federal agencies, and international organizations through epidemic-assistance investigations (Epi-Aids). The authors describe the first 60 years of Epi-Aids, breadth of problems addressed, evolution of methodologies, scope of activities, and impact of investigations on population health. They reviewed Epi-Aid reports and EIS Bulletins, contacted current and former Epidemic Intelligence Service staff, and systematically searched the PubMed and Web of Science databases. They abstracted information on dates, location, staff involved, health problems, methods, and impacts of investigations according to a preplanned protocol. They assessed the methods presented as well as the quality of reports. During 1946–2005, a total of 4,484 investigations of health events were initiated by 2,815 Epidemic Intelligence Service officers. In the early years, the majority were in response to infectious agents, although environmental problems emerged. Investigations in subsequent years focused on occupational conditions, birth defects, reproductive health, tobacco use, cancer, violence, legal debate, and terrorism. These Epi-Aids heralded expansion of the agency's mission and presented new methods in statistics and epidemiology. Recommendations from Epi-Aids led to policy implementation, evaluation, or modification. Epi-Aids provide the Centers for Disease Control and Prevention with the agility to respond rapidly to public health crises.

4. Vaccine-preventable Diseases, Immunizations, and the Epidemic Intelligence Service During 1946–2005, vaccine-preventable diseases were the topic of approximately 20% of all epidemic-assistance investigations by the Centers for Disease Control and Prevention. Both in the United States and abroad, current and former Epidemic Intelligence Service officers have played a critical role in describing the epidemiology of vaccine-preventable diseases, contributing to development of immunization policies, participating in the implementation of immunization programs, and establishing effective means for assessing adverse events following immunization. As newer vaccines are developed and introduced, they will continue to play similar roles and most likely will be involved increasingly in investigations of the factors that affect people's willingness to accept vaccination for themselves or their children.

5. Overview of the Impact of Epidemic-Assistance Investigations of Foodborne and Other Enteric Disease Outbreaks, 1946–2005 Epidemic-assistance investigations (Epi-Aids) in response to outbreaks of foodborne and other enteric pathogens have identified novel pathogens, clinical syndromes, and sequelae; described new reservoirs and vehicles of transmission; evaluated existing prevention strategies; and identified deficiencies in the food safety systems on local, national, and international levels. Since the first Epi-Aid was issued in 1946, approximately 23% (1,023 of 4,484 for which investigations were initiated) of all Epi-Aids have been related to foodborne or other enteric diseases. Epi-Aid results have yielded valuable insights into the epidemiology of these pathogens and have molded prevention strategies for detecting, responding to, and preventing future outbreaks. New challenges, brought about in part by centralization and globalization of the food supply, will continue to emerge. The need for Epi-Aids of such outbreaks undoubtedly will persist as an integral part of future public health response efforts, prevention strategies, and training programs.

6. Epidemic Intelligence Service Investigations of Respiratory Illness, 1946–2005 Infectious respiratory pathogens were the suspected cause of 480 outbreaks investigated by the Centers for Disease Control and Prevention's Epidemic Intelligence Service officers during 1946–2005. All epidemic-assistance investigation reports and associated articles from scientific journals were reviewed. Investigations identified 25 different infectious respiratory pathogens including, most frequently, tuberculosis, influenza, and legionellosis. Other bacterial-, viral-, and fungal-related pathogens also were identified. Epidemic-assistance investigations were notable for first identifying Legionnaires disease and Pontiac fever, hantavirus pulmonary syndrome, and new strains of human and avian influenza, as well as emerging challenges (e.g., multidrug-resistant tuberculosis and pneumococcus). The investigations provided clinical insights into such diseases as pulmonary anthrax and identified high risks of serious respiratory illnesses for persons infected with human immunodeficiency virus, other immunocompromised persons, and persons with diabetes. They identified settings placing persons at high risk of acquiring disease, including nursing homes, prisons, homeless shelters, and hospitals. Travel also placed persons at risk. Key environmental factors related to spread of diseases and occupational risks for brucellosis and psittacosis were identified. The outbreak investigations constitute a wealth of prevention experience and provide the basis for recommendations to mitigate outbreaks and reduce future risks.

7. Health Care–Associated Infection Outbreak Investigations by the Centers for Disease Control and Prevention, 1946–2005 Since 1946, Centers for Disease Control and Prevention (CDC) personnel have investigated outbreaks of infections and adverse events associated with delivery of health care. CDC Epidemic Intelligence Service officers have led onsite investigations of these outbreaks by systematically applying epidemiology, statistics, and laboratory science. During 1946–2005, CDC Epidemic Intelligence Service officers conducted 531 outbreak investigations in facilities across the United States and abroad. Initially, the majority of outbreaks involved gastrointestinal tract infections; however, in later years, bloodstream, respiratory tract, and surgical wound infections predominated. Among pathogens implicated in CDC outbreak investigations, Staphylococcus aureus, Enterococcus species, Enterobacteriaceae, nonfermentative Gram-negative bacteria, or yeasts predominated, but unusual organisms (e.g., the atypical mycobacteria) were often included. Outbreak types varied and often were linked to transfer of colonized patients or health care personnel between facilities (multihospital outbreaks), national distribution of contaminated products, use of invasive medical devices, or variances in practices and procedures in health care environments (e.g., intensive care units, water reservoirs, or hemodialysis units). Through partnerships with health care facilities and local and state health departments, outbreaks were terminated and lives saved. Data from investigations invariably contributed to CDC-generated guidelines for prevention and control of health care–associated infections.

8. Environmental- and Injury-related Epidemic-Assistance Investigations, 1946–2005 This paper summarizes environmental investigations (n = 458) conducted during the first 60 years of the epidemic-assistance investigation program at the Centers for Disease Control and Prevention. These investigations were grouped into 10 categories: toxic chemicals (n = 102), indoor air quality and outdoor air toxics (n = 21), new or rare epidemic diseases and unexplained syndromes (n = 29), natural disasters (n = 81), terrorism and unintentional human-made disasters (n = 9), substance use and abuse (n = 13), environmental aspects of infectious disease (n = 132), those affecting neonates and infants (n = 11), violence and injuries (n = 51), and miscellaneous (n = 9). Among the most important or prominent were studies of lead and arsenic toxicity at smelters, mercury in paint and beauty creams, dioxin in waste oil in Missouri, polychlorinated biphenyls and multiple other toxic chemicals, global pesticide poisoning outbreaks, hepatic angiosarcoma among vinyl chloride workers, toxic oil syndrome in Spain, eosinophilia-myalgia syndrome from contaminated L-tryptophan, diethylene glycol poisoning in Haiti, aflatoxicosis in Kenya, Gulf War illness among veterans, impact and needs assessments during natural disasters (e.g., Hurricane Katrina (2005) and the Mount St. Helens volcano eruptions (1980)), risk factors for heat-related mortality, domestic and international terrorist attacks, Parkinsonism related to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in California, and unintentional injury- and violence-related events.

9. Maternal and Child Health Epidemic-Assistance Investigations, 1946–2005 In this article, the authors focus on epidemic-assistance investigations that dealt with maternal and child health problems, including unintended and adolescent pregnancy and family planning; international reproductive health surveys among refugees; pregnancy outcomes, including abortion, maternal mortality, infant mortality, and birth defects; leukemia; and Reye syndrome. During 1946–2005, a total of 1,969 investigations had sufficient data to classify them as possibly related to maternal and child health and were characterized by distinctive periods. Those related to family planning, pregnancy intention, and reproductive health among refugees began in the early 1970s and continued through 2005. Abortion-related investigations occurred during 1971–1982. Investigations of non-abortion-related maternal morbidity and mortality began in 1979 and included 2 international epidemic-assistance investigations. Investigations of clusters of disease among infants began in the 1960s, with a special focus on Reye syndrome during 1964–1984. Investigations of childhood cancer and birth defects began in the late 1950s. The Centers for Disease Control and Prevention has used the epidemic-assistance investigations mechanism to respond to a wide range of health concerns of women and children. The investigations of abortion-related health problems might have had the best-documented impact on public policy and public health.

10. Epidemic Assistance From the Centers for Disease Control and Prevention Involving American Indians and Alaska Natives, 1946–2005 The authors describe 169 Centers for Disease Control and Prevention epidemic-assistance investigations involving American Indians and Alaska Natives that occurred during 1946–2005. The unique relation between the US federal government and American Indian and Alaska Native tribes is described in the context of transfer in the 1950s of responsibility for Indian health to the US Public Health Service, which at the time included the Communicable Disease Center, the Centers for Disease Control and Prevention’s precursor. The vast majority of epidemic-assistance investigations were for infectious disease outbreaks (86%), with a relatively limited number, since 1980 only, involving environmental exposures and chronic disease. Although outbreaks investigated were often widespread geographically, the majority were limited in scope, typically involving fewer than 100 patients. Epidemic-assistance investigations for hepatitis A, gastrointestinal and foodborne infectious diseases, vaccine-preventable diseases, zoonotic and vectorborne diseases, acute respiratory tract infections, environmental exposures, and chronic diseases are described chronologically in more detail.

11. Fifty-Five Years of International Epidemic-Assistance Investigations Conducted by CDC’s Disease Detectives For more than 60 years, the Centers for Disease Control and Prevention (CDC) has used its scientific expertise to help people throughout the world live healthier, safer, longer lives through science-based health action. In 1951, CDC officially established the Epidemic Intelligence Service to help build public health capacity. During 1950–2005, CDC’s Epidemic Intelligence Service officers conducted 462 international epidemiologic field investigations in 131 foreign countries and 7 territories. Investigations have included responding to emerging infectious and noninfectious disease outbreaks, assisting in disaster response, and evaluating core components of public health programs worldwide. Approximately 81% of investigations were responses to infectious disease outbreaks, but the proportion of investigations related to chronic and other noninfectious conditions increased 7-fold (6%–45%). These investigations have contributed to detecting and characterizing new pathogens (e.g., severe acute respiratory syndrome–associated coronavirus) and conditions, provided insights regarding factors that cause or contribute to disease acquisition (e.g., Ebola hemorrhagic fever), led to development of new diagnostics and surveillance technologies, and provided information upon which global health policies and regulations can be based. CDC’s disease detectives will undoubtedly continue to play a critical role in global health and in responding to emerging global disease threats.

12. CommentaryAfterword In 1949, Alexander Langmuir became the first chief epidemiologist at the Communicable Disease Center (CDC) in Atlanta, Georgia. Among his many contributions to the agency and to public health, 2 of the most important—the Epidemic Intelligence Service (EIS) and his particular brand of epidemic-assistance investigation (the Epi-Aid)—are highlighted in this supplement to the American Journal of Epidemiology. What makes these and many other of Langmuir’s innovations so remarkable is their continued relevance to the health challenges we face in this new century. CDC (now the Centers for Disease Control and Prevention) is recognized globally for its quality science, not only in epidemiology and laboratory practice but also in the behavioral and social sciences, statistics, and economics. Support to state and local health departments has been instrumental to CDC’s success during its first 60 years, and the articles describing Epi-Aids in this supplement capture this partnership elegantly. They also reflect the evolution of CDC from an agency focused almost entirely on communicable diseases to one engaged in a broad array of global public health challenges.