Shots - Health Blog
Fri July 1, 2011
European Disease Detectives Zero In On Fenugreek As E. Coli Source
Originally published on Fri July 1, 2011 4:56 pm
The kidney-destroying E. coli strain called O14:H4 has struck again, this time in France. And the latest outbreak is giving disease detectives more clues about how the germ is getting into Europeans' food.
It's the fenugreek seeds, they think.
The evidence against the seeds is still circumstantial. Authorities don't have a microbiological smoking gun of E. coli contamination, either of the fenugreek seeds or sprouts grown from seeds of any type. That kind of proof is apparently very hard to get. Still, European health officials think the pieces are beginning to fit together.
The tipoff was a school picnic in the town of Begles, a suburb of Bordeaux in southwestern France. Eleven people got sick after attending the event. Nine of the 11 ate dishes containing sprouts of fenugreek, a clover-like plant whose seeds are used as a spice, along with mustard and arugula. It's not yet known what the other two ate.
According to a joint report from the European Centre for Disease Control and the European Food Safety Authority, three of the 11 Bordeaux patients were infected with a dangerous strain of E. coli O104:H4 very similar, if not identical, to the strain that has sickened more than 3,000 people in northern Germany and killed almost 50.
Analysis of the French bug shows it has the same pattern of antibiotic resistance as the one that's been rampaging in Germany. Like the German E. coli strain, it also has affected mostly adult women, and most of the French victims have hemolytic uremia syndrome or HUS, which can destroy kidneys and cause death. About a quarter of the infected Germans developed HUS.
None of the French victims has died, and although the outbreak eventually affected 15 people in all, it's thought to be over because the incubation period from the June 8 picnic is past.
But if the sprouts-and-seeds hypothesis is right — as seems increasingly likely — then European authorities reason the danger isn't past, because there are probably more contaminated seeds out there. So the fearsome O104:H4 strain could pop up again when unwitting growers (either commercial or the home-gardener variety) incubate the infected seeds to grow sprouts to add to their summer salads or sandwiches.
Some U.S. health officials think the hypothesis has merit. Take Dr. Thomas Frieden, chief of the Centers for Disease Control and Prevention, who told NPR's All Things Considered last month that he swore off eating sprouts after he got a nasty infection while living in India from eating sprouts he'd grown from seeds he had brought from America.
Over the past 15 years, scientists have discovered that seeds can harbor E. coli and other bacteria for a long time. The warm, damp conditions of a sprouting medium can make the bacteria population take off.
So European authorities are warning all people to avoid eating sprouts of all kinds unless they're well-cooked. They're also asking doctors to be on the lookout for people suffering from intestinal upsets, especially if those that involve bloody diarrhea.
Meanwhile, a British company fingered by French officials as a possible source of contaminated seeds has withdrawn its mixed collections of "seed sandwich mix" and "salad sprouts mix" from hundreds of garden centers.
By the way, why do officials suspect fenugreek seeds or sprouts in particular? It's not entirely clear, and the new report notes there "is still much uncertainty about whether this is truly the common cause of all the infections."
But so-called trace-back investigations so far suggest that fenugreek seeds imported from Egypt in 2009 and/or 2010 by one or more British companies are implicated in both the German and French outbreaks.
So the plot thickens. The current vegetation-of-interest is a long way from the Spanish cucumbers that were erroneously blamed by Germans a month ago. In the tradition of all good detective stories, that turned out to be a red herring, as it were.