Happy 75th Anniversary to the CDC’s Disease Detective Program

The phone rang on the evening of February 28, 2020.

“We need you deployed to Seattle. Meet with your team at Roybal tomorrow and additional details will be provided.”

For weeks, the Centers for Disease Control and Prevention had been closely monitoring the spread of the novel coronavirus. Disease detectives from the Epidemic Intelligence Service (EIS) program were on alert, sitting by their phones anxiously waiting for ‘the call’. When the phone rang, an impending deployment followed. Within 24 hours, every member of the team called up that evening – including one of us, Eric Chow – had boarded a plane to Seattle. Little did we realize that we would be investigating the first known outbreak of Covid-19 in the United States.

Over the past 75 years, CDC’s EIS program has trained more than 4,300 people to become the next generation of public health leaders. While the program began as a response to the threat of biological warfare during the Korean War, it evolved to become a critical part of the CDC’s public health response structure, responding to public health emergency calls in the United States and around the world.

In 1951, Alexander D. Langmuir, then chief epidemiologist at the CDC, led the creation of the EIS with the goal of training a group of qualified epidemiologists ready to investigate the cause of disease, how it spreads, who suffers from it, and ultimately how to prevent these health threats from harming our communities.

In the years since, reflecting the growth and evolution of CDC’s focus areas, the EIS program has expanded training to include infectious disease threats, animal diseases, and noncommunicable diseases such as chronic diseases, injuries, gun violence, substance use, worker safety, environmental toxins, and more.

Since its inception, EIS has prioritized hands-on training in which agents, during their two-year journey, work alongside subject matter experts from CDC, state, local, tribal, and territorial health departments to conduct disease and outbreak investigations. In some cases, the health threat is initially unknown, hence the nickname “disease detectives.” The program’s logo, a worn shoe leather, symbolizes the field work that has long characterized the officers’ hands-on training experience.

The EIS has also adapted to meet the growing needs of the public health field, as evidenced by the training courses of incoming promotions. The first promotion of the EIS included 22 doctors and a health engineer. Newer classes include doctoral-level scientists, veterinarians, pharmacists, entomologists, dentists, nurses and other healthcare professionals.

As epidemiologists, we are trained to ask “Why?” » and “How?” questions that reveal the causes of disease, identify factors associated with hospitalization and death, assess the impact on underserved communities, and ultimately control disease. Through EIS, these investigative skills are developed and honed in the field, which over the past seven decades have included landmark public health investigations: smallpox, HIV/AIDS, childhood lead poisoning, Ebola outbreaks, influenza pandemics, Legionnaires’ disease, toxic shock syndrome, hantavirus pulmonary syndrome, 2001 anthrax attacks, hurricane-related health events, lung injuries associated with the use of electronic cigarettes or vaping products. (EVALI), the Covid-19 pandemic, the global mpox epidemic in 2022 and many more.

In many cases, EIS officers have conducted investigations that described new diseases, discovered the causative agents of an emerging disease, or stopped the outbreak.

Outside of historical disease events, public health regularly responds to epidemics and community health issues that extend into our daily lives.

In 2019, an investigation into a multistate mumps outbreak traced more than 60 cases to a local wedding and contained the outbreak with a measles, mumps, and rubella vaccination campaign in the affected community.

In 2022, an outbreak of gastrointestinal illness among rafters and backpackers in the Grand Canyon sparked a public health investigation in which local health, state health, two EIS officers, the CDC, and National Park Service colleagues collaborated to conduct interviews, environmental assessments, tailor rapid prevention messages, and testing of pooled samples from portable toilets to reveal the causative agent as norovirus.

These field investigations not only provide valuable learning experiences for EIS officers, but also help control outbreaks and limit the spread of disease. From field intervention to investigative analyzes and study design, to creating partnerships and communicating key preventative measures, officers gain key skills and experiences that then shape their careers in public health.

Arguably, the EIS program’s greatest impact has been in filling critical public health roles, both inside and outside the United States, with its graduates. After completing their training, 97% pursue a career in public health while others may bring their experience to academic research or clinical practice. For state, tribal, local, and territorial health departments, EIS-trained epidemiologists play critical leadership roles that respond to our communities where they are. Approximately 13% of recent graduates work in state, territorial, tribal, and local health care positions. By 2026, 1 in 3 state epidemiologists and nearly half of current public health veterinarians are EIS alumni.

Historically, the EIS program has also served as a conduit for recruiting highly qualified and experienced professionals into leadership and technical positions within the CDC and other federal agencies. Among the three graduating classes leading up to 2025, 61% work at the CDC and 8% work in other federal agencies. Between 1966 and 2025, four of the CDC’s 12 directors were EIS alumni, including William Foege, who is credited with leading the efforts that ultimately eradicated smallpox.

The EIS program will celebrate its 75th anniversary this week at its annual conference in Atlanta. This is an event that typically draws more than 2,000 alumni and public health officials in person to hear about the work being done and the latest investigations being conducted by EIS officers. From cutting-edge field surveys to the application of complex analytical methodologies and forward-thinking outreach techniques, this flagship project provides an opportunity to share and exchange information that advances the practice of public health and makes our communities healthier.

The EIS Conference is also the time when a new class of EIS officers joins the ranks, meets the vast alumni network, and determines where they will train over the next two years. Beyond the training itself, the EIS builds strong bonds and relationships within and between classes that contribute to a network of alumni closely linked by their time spent in the EIS training. The EIS Conference provides a rare opportunity to bring together the Atlanta alumni network to build on the relationships necessary for rapid communication and coordination in an emergency.

As we celebrate 75 years of training disease detectives, we reflect on the many ways CDC’s EIS program has helped shape the practice of public health. Our partnerships are strengthened through collaboration with many public health colleagues, including laboratory leaders who have graduated from our sister program, the Laboratory Leadership Service. EIS and its alumni network have endured the constant ebb and flow of changes in the public health system while maintaining a legacy defined by scientific discovery and safer communities. Whether the threat is environmental exposure or a communicable disease, the EIS program and its collaborators ensure that someone is always ready to answer the call.

Eric J. Chow, MD, MS, MPH, is an Epidemic Intelligence Service Alumni (2018-2020) and is President-elect of the Epidemic Intelligence Service Alumni Association. Ariella Perry Dale, Ph.D., MPH, is an Epidemic Intelligence Service Alumni (2020-2022) and serves as President of the Epidemic Intelligence Service Alumni Association. Matthew Donahue, MD, is an Epidemic Intelligence Service Alumni (2019-2021) and serves as Secretary-Treasurer of the Epidemic Intelligence Service Alumni Association.