FSIS Role in Outbreak Investigations, Including Use of Epidemiologic Data

In 1998, FSIS added eight field epidemiologists to its staff within the Office of Public Health & Science (OPHS). These field epidemiologists are assigned to cover specific U.S. states and territories. The mission of these epidemiologists is to track reports of illness and outbreaks in the U.S. population, particularly if the suspected vehicle is an FSIS inspected product. The major portion of the data collection, interviews, and data analysis lies with the state departments of public health and often CDC. OPHS epidemiologists assist in the interpretation of these data in relation to determining cause and product traceback. Product recalls can be recommended when there is adequate epidemiologic or consumer information that can tie in a specific product.


In 2000 and 2001, the field epidemiologists assisted in numerous outbreak investigations. In 2000, there were 29 reports of outbreaks or illness that resulted in full investigations by the epidemiology officers. In 2001, there were 26 reports of outbreaks or illness that resulted in full investigations. The most common pathogen investigated is E. coli O157:H7 followed by Listeria monocytogenes. The preliminary statistics from the 2001 FoodNet data indicate an encouraging decrease in foodborne disease due to the major foodborne pathogens. However, foodborne disease outbreaks continue to occur, and FSIS needs to remain vigilant and responsive to outbreak situations.


Denise Riedel Lewis, Ph.D., M.P.H.
Chief, Foodborne Disease & Emergency Response Branch
Human Health Sciences Division, Office of Public Health & Science, FSIS, USDA, Washington, DC

Dr. Lewis began her career as a medical technologist in microbiology at the George Washington University Medical Center in Washington, DC. After setting a goal on a career in public health, she entered the master of public health program at the Yale University School of Medicine in New Haven, CT. She concentrated her efforts on infectious disease epidemiology and wrote her master’s essay on the Human T Cell Leukemia Virus Type I (HTLV-I) prevalence in a population in Barbados. In 1987, Dr. Lewis entered the doctoral program in epidemiology at the Johns Hopkins University in Baltimore, MD (now referred to as the Bloomberg School of Public Health). Her focus was in both infectious disease and cancer epidemiology. Her dissertation topic reviewed the infectious disease history of cases and controls in a study of multiple myeloma. Upon graduating from Hopkins in 1993, Dr. Lewis became an environmental epidemiologist with the US Environmental Protection Agency in Chapel Hill, NC. She worked mostly on arsenic in drinking water issues dealing with human health effects, and pesticide exposure and reproductive health. In 1999, Dr. Lewis joined the Food Safety and Inspection Service with USDA as the Chief of the Foodborne Disease and Emergency Response Branch. She supervises a staff of seven field epidemiologists and oversees investigations of foodborne illness related to meat, poultry, and egg products.