In October, we reported on a session on foodborne illness outbreaks at the IDWeek conference. In this story, we review the steps public health is taking to identify these outbreaks and prevent future ones from occurring, especially with the advent of another recent high-profile outbreak linked to romaine lettuce.
Outbreaks of foodborne illness have become commonplace, but in a year that both started and ended with E. coli outbreaks linked to romaine lettuce, these outbreaks may have been the most high-profile public health story in the U.S. in 2018.
Traceability remains key to identifying the source of a foodborne illness outbreak, but the progress that agencies such as the FDA and CDC have made in tracking and sourcing these outbreaks has been evident with the amount of information available with each successive outbreak this year.
However, Stephen Morse, PhD, of the Columbia University Mailman School of Public Health in New York, told MedPage Today that this year, “we learned tracing the source still remains a difficulty.”
“For a long time, people talked about being able to do traceability — farm to fork, but we’re still pretty far from being able to do this,” he said. “We’re getting better at it, but traceability is still a weak link in the system.”
The year started with an outbreak of E. coli O157:H7 that ended in January. In the CDC’s final investigation report, it stated, “the source of the romaine lettuce linked to the Canadian outbreak, or where it became contaminated, was not identified.”
A second outbreak of E. coli O157:H7 linked to romaine lettuce dominated headlines throughout the spring and summer — with 210 illnesses from 36 states, including five deaths. In early November, the FDA released its final report on this outbreak, which was described as “the largest [Shiga-toxin producing E. coli] outbreak in over a decade.”
In its conclusions, the agency encouraged the “leafy green industry” to review the Food Safety Modernization Act (FSMA) Produce Safety Rule and the FSMA Preventive Controls for Human Foods Rule, and that “other available science-based information relevant to the reduction or elimination of human pathogens on leafy greens should also be considered.”
“Outbreaks involving leafy greens can be challenging to investigate because of the short shelf-life of the product, the wide distribution and consumption of leafy greens, and the complex supply chain between the farm and the end user,” the FDA wrote in its report.
Then 2 weeks later, the CDC issued another alert on an outbreak related to E. coli O157:H7 linked to romaine lettuce on November 20 — an investigation that remains ongoing.
But there has been some progress on the traceability side, even in the last month. On November 26, the FDA issued a statement that declared “romaine lettuce entering the market will now be labeled with a harvest location and harvest date.”
This presumably allowed the CDC in its most recent statement on December 18 to advise consumers not to eat any romaine lettuce from the Central Coast growing regions of northern and central California. But they also had to tack on a final warning — “if you don’t know where the romaine is from, do not eat it.”
“It’s still possible that we’re only seeing the tip of the iceberg,” Morse said. “Many foodborne outbreaks are not detected because we grin and bear them until it reaches a certain stage where people need to seek medical attention.”
Morse said that one measure of an outbreak might be human disease, but “that varies from jurisdiction to jurisdiction.”
But information on potential outbreaks is getting to patients a lot faster. Aaron Glatt, MD, spokesperson for the Infectious Diseases Society of America (IDSA) and chairman of medicine at South Nassau Communities Hospital in Oceanside, N.Y., credited “mass dissemination of information through various portals” in keeping clinicians informed.
“There have been superb communications between clinicians and public health, so that people can become familiar with new clinical information,” Glatt told MedPage Today. “The wealth of information we get from public health, such as the CDC, is critically important for clinicians.”
Morse pointed out that during outbreaks of foodborne illness, much like influenza-like illness, a patient will never see the doctor unless it’s a bad illness and “those are the ones that we’re missing,” he said.
“By the time it gets to that stage, it’s probably something serious,” Morse added. “The problem is that this creates a burden for the public health department — so many of these infections look alike, and it’s expensive to test. Scalability is a problem.”
Crowdsourcing Outbreaks: The Wave of the Future?
While traceability remains a problem for agricultural products, such as romaine lettuce, it may be getting easier thanks to advances in technology. At the beginning of the year, an article from the Journal of the American Medical Informatics Association examined this using online restaurant reviews to trace sources of foodborne illness.
Morse said that the New York City health department has been using Yelp to help identify foodborne illness outbreaks for a while, with one article from Columbia stating this has been done since 2012. But he said there’s the potential to take this technology even further.
“This could be done more systematically — it doesn’t take a lot of people to make a foodborne outbreak evident,” he noted. “It would be an easy thing to report without the health department having to look for it,” adding the potential for an app that could report outbreaks “the same as we do for finding when your next subway is coming.”
Glatt also saw potential in using more advanced technology to track outbreaks, saying that as these advances occur, “we could pick these things up by seeing spikes in various social media-type information.” For example, Google might notice a spike in certain illnesses or traffic, he said.
“There are already some technologies that can capitalize on blips in social media,” Glatt said. “These early warning systems might be able to clue in public health officials even faster.”