CDC participant investigates sources of enteric outbreaks Meet Alexandra Palacios

CDC participant investigates sources of enteric outbreaks

As part of the Centers for Disease Control and Prevention (CDC) Research Participation Program, Alexandra Palacios investigates multistate enteric illness outbreaks to identify infection sources and protect public health. Photo Credit: Keely Larre Walker

Every year, millions of cases of foodborne illness and thousands of associated hospitalizations and deaths occur in the United States. One of the leading causes of foodborne illnesses are enteric pathogens, such as Salmonella, Escherichia coli and Listeria monocytogenes, all of which can cause serious infections when humans eat contaminated food or come into contact with infected animals or reptiles.

As part of the Centers for Disease Control and Prevention (CDC) Research Participation Program, recent public health graduate Alexandra Palacios is conducting research on enteric illnesses and their spread to solve multistate outbreaks and protect public health.

The CDC Research Participation Programs are educational and training programs designed to provide students, recent graduates and university faculty opportunities to participate in project-specific CDC research, current public health research and developmental activities. Palacios first heard about the program from a professor while completing her master’s degree at the University of Illinois at Chicago, and knew it would be the perfect opportunity to gain experience in outbreak response.

Palacios is serving her appointment within the Outbreak Response and Prevention Branch (ORPB) of the Division of Foodborne, Waterborne, and Environmental Diseases, located within the National Center for Emerging and Zoonotic Infectious Diseases. Her research is conducted as part of the Listeria Unit of the Foodborne Outbreak Response Team.

Under the guidance of her mentor, Amanda Conrad, Palacios helps coordinate multistate foodborne investigations to determine the source of infections. Her primary focus is on the enteric pathogen Listeria monocytogenes, which causes a serious infection called listeriosis. According to CDC, an estimated 1,600 people get listeriosis each year, and about 260 die. The infection is most likely to sicken vulnerable people, including pregnant women and their newborns, adults aged 65 or older and people with weakened immune systems.

Much of Palacios’ research involves collaborating closely with state and local health departments and federal partners such as the U.S. Food and Drug Administration and U.S. Department of Agriculture Food Safety and Inspection Service. A typical day for Palacios includes monitoring clusters, coordinating with health partners and collecting and compiling epidemiologic, laboratory and traceback information to identify the source of illness for multistate outbreaks.

“One thing I really love about being with ORPB in the Listeria Unit is that every day is different,” said Palacios. “Because we respond to outbreaks, we must be ready to respond as quickly as we can when new information becomes available or new clusters are detected.”

Throughout the course of her appointment, Palacios has been involved in several major foodborne and zoonotic outbreak investigations. In 2020, she helped link the source of a multinational Listeria monocytogenes outbreak to enoki mushrooms imported from South Korea. She also assisted the Enteric Zoonoses Team on the 2020 outbreaks of Salmonella infections linked to backyard poultry, the largest and longest outbreak of backyard poultry to date. Most recently, Palacios assisted in the investigation of a multistate outbreak of Listeria monocytogenes linked to Queso Fresco.

“This investigation was unique because multistate outbreaks of Listeria monocytogenes are usually slow-moving and take a bit longer to solve compared to other pathogens,” said Palacios.

“However, this investigation moved quickly and within 23 days, we had confirmed the source of the outbreak to be Queso Fresco and the product was recalled. The quick turnaround time from opening the investigation to having a recall is unusual for Listeria and a huge accomplishment.”

Palacios’ research plays an important role in developing new ways to prevent multistate outbreaks from happening in the future. Investigating these outbreaks also leads to direct public health action like product recalls or safety alerts, which can prevent additional illnesses and even deaths. Palacios has gained invaluable experience learning how to effectively respond to, manage and investigate multistate outbreaks.

“It has been great to see successful outbreak investigations as well as experiencing unsuccessful or unsolved outbreak investigations,” said Palacios. “All this experience has supported my future career goals because my goal is to continue to investigate and respond to outbreaks.”

In the future, Palacios hopes to apply the skills she gained during her fellowship as an outbreak epidemiologist at CDC or a state health department. She highly recommends the CDC Research Participation Program to anyone seeking a career in STEM, and is grateful for all of the opportunities the program has provided her.

“It has truly been an amazing experience,” said Palacios. “I’m excited to continue to be part of the team and learn more.”

The CDC Research Participation Program is managed by the Oak Ridge Institute for Science and Education (ORISE) under an agreement between CDC and the U.S. Department of Energy (DOE). ORISE is managed for DOE by ORAU.