Getting to the Bottom of the Uptick in Foodborne Illnesses
Recently, a resident and I were discussing a young patient in our clinic with a newly diagnosed functional gastrointestinal disorder (FGID). Our rambling dialogue covered disease prevalence, clinical presentation, and management; however, when the resident asked about the cause of FGIDs, I chose to focus on the risk factors instead and mentioned the recent reports suggesting a link between acute gastrointestinal infections and the subsequent development of an FGID. The resident responded, "We should encounter many more, in view of the number of cases of foodborne Salmonella, Listeria, and Escherichia coli that are in the news." Her point is well taken. A search of the US Food and Drug Administration (FDA) Outbreaks: Investigation, Response & Evaluation or Food Safety News reveals a spate of recent outbreaks. Salmonella alone causes an estimated 1.2 million illnesses and 450 deaths in the United States each year.
Therefore, this commentary reflects on the broad impact of acute gastrointestinal infections—including the short-term effects (sick days, hospitalizations, and even death) and the increasingly recognized long-termimplications (the burden of FGIDs)—and also addresses several questions: How well documented is the link between foodborne illnesses and FGIDs? What are the current data regarding the prevalence of acute gastrointestinal infections? How safe is our food? And what preventive measures are needed to reduce the risk?
Establishing a Link
In multiple studies, pathogen-induced acute gastroenteritis has been cited as a risk factor for the development of irritable bowel syndrome (IBS) and other FGIDs.[2,3,4,5] Individuals at the age extremes, as well as those with compromised immune systems, are at greatest risk for infection and consequences due to foodborne pathogens such as Salmonella, Listeria, Campylobacter, and E coli. This may be especially relevant to early life exposures, because children are particularly vulnerable due to the immaturity of their intestinal barrier, enteric nervous system, and immune response to pathogens.
Pensabene and colleagues prospectively investigated the occurrence of post-infectious FGIDs, diagnosed according to the Rome III criteria, in children with acute diarrhea of different infectious etiologies, including rotavirus (57% of the cases), salmonella (30%), adenovirus (7%), norovirus (3%), and Giardia lamblia (3%). Children who tested positive for any of these enteric infections were assessed shortly after recovery from the episode. FGIDs were found to be significantly more common in exposed patients compared with controls within 1 month (41% vs 13%, respectively), 3 months (53% vs 16%), and 6 months (47% vs 16%) after the episode of acute diarrhea. The effects, therefore, may persist.
Cremon and colleagues investigated whether acute gastroenteritis in early life increases the risk for IBS throughout adulthood. They identified and monitored a 1994 culture-proven foodborne Salmonella enteritidis outbreak (1811 individuals) that resulted from ingestion of contaminated tuna sauce in 36 schools in Bologna, Italy. Long-term effects were reassessed 16 years after the outbreak. Of the adults exposed to Salmonella as children, 37% reported having IBS compared with 23% of controls. The odds ratio for IBS among people exposed to Salmonella was 1.92. The prevalence of IBS was not found to be higher in individuals exposed as adults, compared with controls. The mechanism responsible for "post-infectious FGID" is not clear.[3,4,5,6,7]
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Cite this: Unsafe at Any Lunch? - Medscape - Feb 08, 2016.