Epidemic-assistance Investigations Research Articles

Elective Medical and Veterinary Student Rotations in Applied Epidemiology at the Centers for Disease Control and Prevention, 1975-2012

Health professionals who can bridge the gap between public health and clinical medicine are needed. The Centers for Disease Control and Prevention Epidemiology Elective Program (EEP) offers a rotation in public health for medical and veterinary students that provides an introduction to public health, preventive medicine, and the principles of applied epidemiology through real-world, hands-on experiential learning. To describe EEP, including its role in the integration of medicine and public health, and career paths for those who subsequently have enrolled in the Epidemic Intelligence Service (EIS). A review of files of EEP students participating June 1975 to May 2012 and EIS files to determine which EEP participants subsequently enrolled in EIS and their current employment. During January 1975 to May 2012, a total of 1548 students participated in EEP. Six hundred thirty-eight (41.2%) EEP students participated in field-based epidemic-assistance investigations. Among 187 students completing an exit survey implemented during 2007, a total of 175 (93.6%) indicated an increased understanding or competence in applied epidemiology and public health, and 98 (52.4%) indicated that they would apply to EIS. Among the 165 (10.7%) who enrolled in and completed EIS by July 2012, 106 (64.2%) are currently employed in public health and 65 (39.4%) are board-certified in preventive medicine, board eligible, or currently enrolled in the Centers for Disease Control and Prevention Preventive Medicine Residency or Fellowship. The CDC Epidemiology Elective Program offers opportunities for medical and veterinary students to participate in real-world public health learning activities. The Epidemiology Elective Program provides increased understanding and competence in applied epidemiology, provides students with opportunities to learn about population health and health care problems and the tools to help them bridge the gap between clinical medicine and public health, and serves as a source for EIS and other public health-related training and careers.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Editorial: Epidemic-Assistance Investigations by the Centers for Disease Control and Prevention--The First 60 Years

In a supplement to this issue of the Journal, a series of papers describe the epidemic-assistance investigations (Epi-Aids) that the Centers for Disease Control and Prevention (CDC) conducted during the first 60 years of its existence (1946–2005). The vast majority of Epi-Aids were led by officers of the Epidemic Intelligence Service (EIS), the CDC’s renowned, 2-year field training program for epidemiologists initiated by Alexander Langmuir in 1951 to help address the CDC mission of providing US federal support to state and local health departments (1). In this supplement, a paper by Thacker et al. (2) reviews the types of health problems that were investigated by the CDC, as well as the progressively more sophisticated epidemiologic and statistical methods used in this work. Six papers focus on selected areas that together represent a large proportion of the investigations during this period. CDC was founded in 1946 as the Communicable Disease Center, and 4 papers focus on investigations of infectious disease outbreaks (vaccine-preventable diseases, foodborne/enteric disease outbreaks, respiratory illnesses, and infection outbreaks in health care settings) (3–6). Over time, CDC’s mandate broadened to include noninfectious public health problems, as reflected by a paper on environmental- and injury-related investigations (7) and one on maternal and child health investigations (8). For the most part, CDC provided this assistance to US state and local health departments, but the agency also responded to almost 500 international requests for assistance during this period. A paper by Rolle et al. (9) summarizes the nature of those investigations. The supplement also includes a paper summarizing 178 Epi-Aids that involved American Indian and Alaska Native populations (10). What can be learned from this 60-year history? The CDC is the world leader in field epidemiology, and this supplement chronicles this agency’s unparalleled experience in performing “shoe leather” epidemiology. This work also demonstrates the critical importance of a federal rapid epidemic-assistance program for addressing public health problems in the United States and worldwide. One measure of that importance is the demand for this service: the CDC conducted almost 4,500 Epi-Aids during this 60-year period. A second measure is the many important scientific and public health advances that resulted directly from CDC investigations, including the discovery of novel agents, transmission routes, and disease associations. In a very notable 1976 investigation, CDC became involved in an outbreak of pneumonia that resulted in 29 fatalities among attendees at an American Legion celebration of the US bicentennial in Philadelphia, Pennsylvania (11). This work led to the discovery of Legionella, a novel bacterial pathogen that CDC subsequently linked to previous respiratory disease outbreaks (12) and to the self-limited, influenza-like illness known as Pontiac fever (13). In 1981, investigations of Kaposi’s sarcoma and Pneumocystis carinii pneumonia among homosexual men in New York City and California provided the initial indication of the impending pandemic of human immunodeficiency virus (14, 15). CDC Epi-Aids also provide “surge capacity” for large-scale public health emergencies. In 2001, 126 EIS officers were deployed in response to the attack on the World Trade Center and the mailing of anthrax-containing letters soon thereafter (2). This supplement also demonstrates the value of CDC records as a window into the evolution of public health practice in the United States. To make this supplement possible, Thacker et al. (2) reviewed bound copies of all Epi-Aid reports for this period and other sources. They abstracted information on the nature of the health problems investigated, as well as information on dates, location, and participating CDC staff. Efforts are now under way at CDC to create an online version of the collection that will be available to the public, which should be a valuable resource for epidemiologists and other public health professionals. What will the next 60 years hold in terms of epidemic assistance by the CDC? As Yogi Berra, the Hall of Fame baseball player, once observed, “It’s tough to make predictions, especially about the future.” Globalization, climate change, technological intervention, and other less obvious factors will undoubtedly lead to public health problems that we cannot foresee, but rapid expert epidemiologic assistance by the CDC will be an essential component of the response to those challenges.