Food Poisoning and Post-Infectious IBS
Yesterday, the U.S. media began reporting that Cargill, a major meat processing company, has issued a voluntary recall of ground turkey products from one of its plants in Springdale, Arkansas. Meat from other companies and other Cargill locations is not affected. Cargill took this action after reports of salmonella were linked to its products. According to the U.S. Centers for Disease Control (CDC), 76 people in 26 states have become ill and one person has died as a result.
This unfortunate development seems to be an appropriate time to discuss post-infectious IBS, often abbreviated as IBS-PI. Occasionally, people mistake this to mean that IBS itself is an infection, but that is inaccurate. Post-infectious IBS is a subgroup of IBS that arises suddenly, shortly after the person has had a bacterial gastrointestinal illness. This infection may be from various causes, including exposure to contaminated food and/or water. IBS-PI occurs after the infection has ended. The functioning of the bowel has been disrupted, leading to symptoms of IBS.
Robin Spiller, MD of University Hospital in Nottingham, UK is an authority on IBS-PI. He writes in a fact sheet for IFFGD, that various studies have reported the risk of developing post-infectious IBS in the range of 4-35%, with larger studies reporting about 10%. Among the people involved in this research, 6-17% believed the first onset of their IBS was connected to a recent infection. According to the article, statistically, the greatest risk factor is the severity of the initial infection, but gender, age, psychological factors like recent stress, and the ability of the bacteria to produce toxins also play roles. Dr Spiller states that studies in the IBS-PI subgroup have shown evidence of inflammation, so that anti-inflammatory medication has been tried, but so far, has not been shown to be effective. As of now, there is no treatment specifically to prevent or cure post-infectious IBS, although the usual treatments recommended to all people with IBS may be helpful. He reports that about half of those with IBS-PI will “recover” eventually, but that it may take several years.
What are people with IBS and others to make of this information? For one thing, because in post-infectious IBS, there is a presumed known and recent cause, research on this subgroup has yielded important insights that may eventually have implications for all people with IBS. One good example is the contamination of the water supply in Walkerton, Ontario Canada in 2000, where 2300 residents became ill. Of those people, more than 36% eventually developed IBS symptoms. In 2010, from long-term studies in Walkerton, researchers from McGill and McMaster Universities reported identifying genetic variants that predisposed some residents to IBS-PI, opening the door to future advances in understanding the genetics of IBS.
At this point, however, even with a presumed cause for those in the IBS-PI subgroup, IBS management remains complex. As many people with IBS know all too well, some of us will be fortunate to have mild and/or sporadic symptoms, and/or quickly find the interventions that work well for them. Others will struggle for years through severe and constant symptoms and endless trial and error with various treatment approaches,never finding adequate relief. Still others will fall in the middle of this spectrum. IBS is notoriously individual and unpredictable. Even if peer reviewed scientific studies are able to give us guidance as to what is statistically more likely to happen in a given situation, it’s not much comfort to those who, for no reason they can identify or control, happen to find their experiences in the minority. For example, although greater severity of the triggering infection correlates with higher risk of IBS-PI, anecdotally, some people who believe they have IBS-PI report that they were ill, but not severely, or know they were recently exposed to a pathogen but were not noticeably ill until the onset of IBS soon afterward.
How seriously should we take recalls of suspect food, accidental water main breaks and such? The low end of Dr. Spiller’s range, at 4% risk, doesn’t sound like much. The high end of over 36% in Walkerton looks considerably more alarming. But if we know that preventing GI infections is the only known way to prevent some cases of IBS, then it seems that the IBS community should be using incidents like the current recall as high profile public awareness opportunities. If our non-affected relatives, friends, coworkers or anyone accidentally encountering this blog knew they might be risking years of chronic GI issues, would they think more carefully before eating recalled products, forgotten leftovers or a quick meal from a questionable restaurant or street vendor because it looks all right and one should not waste food? Would those of us who suspect our IBS resulted from post-infectious causes make different decisions if we could turn back the clock? Food for thought.