CDC Detectives Respond to Disease Outbreaks

CDC's Epidemic Intelligence Service (EIS) officers are elite global health sleuths.

EIS officers are epidemiologists, statisticians, veterinarians and doctors. In the event of a suspected disease outbreak, they are called on to answer key questions: what is causing people to get sick? How can we prevent disease from spreading and how can we prevent another outbreak? They are on CDC′s front lines, working 24/7 to save lives and protect people from health threats. As the best of the best, these Officers will continue to respond to the current outbreak, as they have responded to hundreds in the past. CDC′s Epidemic Intelligence Service is a unique two year program of service and training for health professionals interested in the practice of epidemiology, the study of the causes, distribution, and control of disease in populations.

Photo: Officer giving vaccinations in the field

Every year, CDC selects 70 to 80 individuals from among the nation′s top health professionals to enter the program and pursue training in applied epidemiologic skills.

CDC EIS officers must be ready to assist 24/7 when asked. In the US, local and state health departments that can′t find the source of a new public health problem can then request federal health agencies to help.
Like investigators at the scene of a crime, disease detectives begin by looking for clues and gathering information about what happened. Disease detectives have various jobs and may work in different places, such as in laboratories where they look for viruses, or bacteria in blood samples, or in public locations where an unknown outbreak is occurring.

Solving Mysteries around the World

In late September, 2006, headlines declared a "mystery illness" responsible for numerous deaths and almost two dozen seriously ill patients in the Latin American nation of Panama. As the Minister of Health, Camilo Alleyne, worked to keep people informed and calm, officials from the ministry and the Gorgas Memorial Institute of Health Research (GMIHR) in Panama City requested help from the CDC, Pan American Health Organization (PAHO), and U.S. Food and Drug Administration (FDA) in tracking the unknown killer.
Originally there were far more questions than answers: Is it contagious? Is it somehow related to West Nile Virus? Dengue fever? Influenza? No one knew for sure.

Doctors working in the Social Security hospital recognized and began to track a pattern of sickness; diarrhea and feverprogressed to acute kidney failure, paralysis, and death. It seemed to strike mostly men over 60 who were receiving treatments for high blood pressure, diabetes, or kidney disorders. The doctors reported the suspicious pattern to the Ministry of Health, which requested international help.

Closing in on a Killer Disease

Photo: Officer taking notes in the field

The director of GMIHR contacted CDC Global Health offices on October 2. CDC′s Global Disease Detection (GDD) division immediately began coordinating CDC′s response. Dr. Joshua Schier led CDC′s deployment team, which included two medical epidemiologists, a laboratorian, a neuro–epidemiologist, a bi–lingual epidemiologist, and risk communication specialist. They and others hit the ground running in Panama, gathering medical samples from patients, as well as from a variety of suspected poisoning sources, and sending them back to the labs in Atlanta.

Early evidence, such as no clustering of sickness within families and the fact that no healthcare providers were getting sick, suggested the event was not contagious. CDC′s team still tested specimens of kidney and nerve tissue while simultaneously examining products such as high blood pressure medication and simple cough syrup found in patients′ homes. Just nine days after the CDC team landed in Panama, diethylene glycol (DEG) – often used as an industrial solvent and component of antifreeze and brake fluid – was isolated as the deadly culprit.

“From the start, this took a lot of effort from a lot of people," says Dr. Carol Rubin, then chief of the Health Studies Branch, NCEH. "This amazing collaboration identified the probable cause of this syndrome within a remarkable 11 days of the initiation of the investigation by the Ministry of Health." Thanks to solid epidemiological detective work and constant evidence gathering on the ground in Panama, the answer was found.

Since 1951, over 3,000 EIS officers have responded to requests for epidemiologic assistance within the United States and throughout the world. Yet, CDC′s EIS program is only one part of a complex public health infrastructure designed to protect people from emerging disease threats at home and around the globe.

FoodCORE: Enhancing foodborne disease outbreak response

In 2012, the Centers for Disease Control and Prevention (CDC) monitored between 16 and 57 potential food poisoning clusters each week and investigated more than 200 multistate clusters. These investigations led to the identification of contaminated sources, which resulted in actions to stop the outbreaks. These actions, which kept further illnesses from happening, included the recalls of more than 300 products, such as peanut butter and peanut butter products, leafy greens, cantaloupes, sprouts, ground beef, raw scraped ground tuna, mangoes, dry dog food, and ricotta salata cheese.

The foods involved in these clusters are many and varied, which can complicate the investigation of foodborne disease outbreaks. Fast and effective outbreak investigations are therefore needed to identify and remove contaminated food from the market to prevent additional illnesses. Identifying contaminated foods and learning how the contamination happened also help public health officials develop ways to prevent similar outbreaks in the future. However, most state health departments lack the resources to perform comprehensive foodborne disease surveillance and to conduct rapid, coordinated detection and response to multistate outbreaks. FoodCORE is a program supported by CDC that helps states improve their capacity to detect and respond to multistate foodborne disease outbreaks.

What is FoodCORE?

“FoodCORE” stands for Foodborne Diseases Centers for Outbreak Response Enhancement. TheFoodCORE centers work together to develop new and better methods to detect, investigate, respond to, and control multistate outbreaks of foodborne diseases. Efforts are primarily focused on outbreaks caused by bacteria, including Salmonella, Shiga toxin-producing Escherichia coli(STEC), and Listeria. The ability to detect and investigate viral and parasitic foodborne disease outbreaks will also be strengthened.

FoodCORE in action

Investigating outbreaks of foodborne disease

Figure 1 (larger version)

During the program’s first year (October 1, 2010 to September 30, 2011), the FoodCORE laboratories received a total of 8,264Salmonella, 916 STEC, and 89 Listeria isolate-yielding specimens; of these, 7,677 (93%) Salmonella, 787 (86%) STEC, and 83 (93%) Listeria isolates, respectively, were from patients with distinct cases of illness.

FoodCORE resources supported additional capacity for epidemiologic interview and investigation, resulting in an increased proportion of ill persons for whom epidemiology programs attempted an interview. Data from the first half of year one were combined and used as a comparative baseline for the last quarter of year one. For Salmonella infections, the average proportion of ill persons with an attempted interview increased from 88% (range 53-100%) at baseline to 94% (range 78-100%) during the last quarter. The average proportion of attempted interviews for ill persons with STEC infection increased from 90% (range 60-100%) during baseline, to 97% (range 89-100%) during the last quarter. For Listeria infections, the average proportion of cases with an attempted interview remained at 100% for all of year one.

In addition to attempting an interview for the majority of reported ill persons, FoodCORE centers also improved the timeliness of interviews. The average turn-around time from notification to first attempted interview decreased as follows: for Salmonella cases, from 1.3 days (range 0-3 days) during baseline to 0.6 days (range 0-2 days) during the last quarter; for STEC infections, from 2.7 days (range 1-5 days) during baseline to 0.6 days (range 0-1 day) during the last quarter; and for Listeria infections, from 7 days (range 3-11 days) during baseline to 0.7 days (range 0-1 day) during the last quarter.

Better, faster, and more complete foodborne outbreak investigations

Leveraging laboratory, epidemiology, and environmental health capacity, the centers have successfully used FoodCORE resources to improve the way they conduct outbreak investigations and to strengthen routine foodborne disease response activities. FoodCORE centers have built capacity for both routine and surge responses, making faster, more complete investigations possible. Using FoodCORE resources, the centers have solved outbreaks that would not have been solved otherwise, thereby preventing illnesses. These additional resources have supported collection and analysis of foodborne disease-related data and records, resulting in more rapid food recall actions. Identifying suspected and confirmed contaminated foods associated with illness helps mitigate ongoing outbreaks, but also informs prevention and education efforts to keep similar outbreaks from happening in the future.

FoodCORE is establishing model practices for the detection, investigation, response, and control of foodborne diseases. FoodCORE centers work collaboratively to identify and implement public health practices that can help shorten the time it takes to identify a source of infection and pinpoint how and why contamination occurred, in order to limit additional illnesses and help prevent future outbreaks.

Pathogen Genomics

Pathogen Genomics for Public Health

The Centers for Disease Control and Prevention (CDC) is well known for its work in monitoring, investigating, and controlling infectious diseases in the United States and worldwide. Genetic information from viruses, bacteria, and other infectious organisms has long played a crucial role in these efforts.

Advances in molecular technologies and bioinformatics have made it possible to examine pathogen genomes in much greater detail. Now, falling cost and turnaround time are bringing high-throughput genetic sequencing within reach for use by clinical and public health investigators.

Public health applications of pathogen genomics include:

Diagnosing infection (Legionella ; Plasmodium knowlesi )
Investigating outbreaks (Listeria ; HCAI )
Describing transmission patterns (Tuberculosis ; Dengue )
Monitoring antimicrobial resistance (HIV ; Salmonella )
Developing interventions, including vaccines (Influenza ; Influenza A )

CDC’s Advanced Molecular Detection (AMD) Initiative

[PDF 392.40 KB] aims to build critical molecular sequencing and bioinformatics capacities at national and state levels to support public health efforts to control infectious diseases. For additional information, see the A New Landscape for Combatting Infectious Diseases

[PDF 693.38 KB].