By Ethan Covey
The incidence of foodborne illnesses in the United States has resumed, and in some cases surpassed, levels found prior to the COVID-19 pandemic, according to a recent CDC report.
Better collaborative efforts among food growers, processors, retail stores, restaurants, regulators and others are needed to address these enteric infections (MMWR Morb Mortal Wkly Rep 2023;72[26]:701-706).
“To understand the importance of these findings, we need to look to both the past and the future and consider our progress in preventing foodborne illnesses,” Daniel L. Weller, PhD, the acting Foodborne Diseases Active Surveillance Network (FoodNet) team lead, Enteric Diseases Epidemiology Branch, CDC’s Division of Foodborne, Waterborne, and Environmental Diseases, told Infectious Disease Special Edition.
During the pandemic, significant decreases were observed in the numbers of infections reported to FoodNet.
“At the time, we were not sure how much of that change was a result of our efforts to address the root causes of foodborne illness and how much was a result of changes in people’s behaviors during the pandemic,” Dr. Weller said.
The current report features preliminary estimates of pathogen-specific annual incidences during the 2022 calendar year.
During 2022, the annual incidence of illnesses caused by the pathogens Campylobacter, Salmonella, Shigella and Listeria were similar to those documented from 2016 to 2018. However, the incidence of Shiga toxin-producing Escherichia coli, Yersinia, Vibrio and Cyclospora illnesses was higher.
“The fact that infections generally returned to or exceeded levels observed in 2016-2018—pre-pandemic—indicates the decreases we saw before were likely the result of pandemic-related behavioral changes, not true progress,” Dr. Weller said.
“Looking to the future, we did not find signs of progress toward the Healthy People 2030 goals for reducing foodborne illness,” he added. “This shows that much more work is needed. We’d like to see public health agencies, regulatory agencies, industry and consumer groups continue to improve working relationships to identify and implement strategies to reduce foodborne illness, reach national prevention targets, and lower the amount of enteric infections.”
Dr. Weller noted a couple of other interesting findings detailed in the report.
One was that the percentage of Salmonella infections resulting in death was higher in 2022 than during the 2016-2018 reference period. “Understanding contributing factors could help us prevent severe illnesses from Salmonella and other foodborne pathogens in the future,” he said.
The second was the influence culture-independent diagnostic tests, or CIDTs, have had on foodborne illnesses.
“In 2022, continued increases in the use of these tests contributed to the increased detection of infections,” Dr. Weller added. “CIDTs help to rapidly identify treatable infections and detect infections that would have otherwise been missed. Before CIDTs, not many people were tested for some illnesses, including Yersinia infection. But now, doctors can check for many different foodborne infections with just one test. This is very helpful, but it can also complicate the interpretation of surveillance data. Use of these tests raises the question,
“How do we distinguish the impact of changing detection methods from actual changes in incidence?”
Future work will help clarify the effect that CIDTs may have on surveillance counts.
“FoodNet is routinely surveying clinical laboratories about the adoption of new testing methods to detect enteric pathogens,” Dr. Weller said. “We are also collecting epidemiological and laboratory data on reports of culture-confirmed and CIDT-positive bacterial infections. The data we collect will help us better understand the influence of increasing CIDT use on the surveillance of foodborne illnesses.”
