Analyst warns of widespread E. coli contamination

Why is it so difficult to pinpoint the exact source of the deadly E.coli outbreak that has so far killed 17 people, 16 of whom live in Germany, and infected hundreds of others?

On Wednesday the European Commission lifted its warning against Spanish cucumbers.

Medical authorities in Hamburg, the epicentre of the outbreak, finally admitted that it wasn’t just cucumbers, and advised against eating and raw vegetables originating from Spain.

So how is an outbreak like this investigated? How serious is the current crisis?

Microbiologist Patricia Mariani, co-director of France’s National E.Coli Resear Centre, answers FRANCE 24’s questions.

Have cucumbers been definitively ruled out as the source of the outbreak? And why is it so difficult to pin down the source of the bacteria?

In principle, yes, cucumbers as a source of the outbreak have been ruled out. But tests are still ongoing and there are many other potential sources where E. coli can proliferate, including vegetables, meat, cheese and even water.

An investigation into an outbreak like this is a long and exhaustive process. For example, patients have to try to remember everything they have eaten in the last fortnight, where they have eaten, and where they did their shopping. It is extremely difficult.

There have been outbreaks of E. coli in the past. What makes this one different?

The outbreak in Germany is particularly alarming. We have never seen so many deaths due to E. coli. What is particularly worrying is the emergence of symptoms normally associated with childhood illnesses.

In Japan in 1996, radishes were infected by contaminated water and some 9,000 people were infected, with nine fatalities. There have been a number of outbreaks in the US, for instance in Washington in 1993 (undercooked hamburgers that had not been properly refrigerated) and in Ontario, Canada in 2000 (tap water was contaminated after heavy rain).

In France there were two outbreaks in 2005. One in the southwest came from undercooked minced beef and one in the Calvados region came from Camembert cheese. There have also been minor outbreaks linked to spinach and apple juice.

Normally only 1% of people who catch E. coli actually die from it. Until now E. coli infection has normally been confined to adults. This time however, symptoms have included bleeding from the digestive tract and in some cases kidney disorders (hemolytic- uremic syndrome, HUS) and severe neurological sequelae (a cerebral condition most often associated with malaria), ailments more commonly associated with children.  Those under fifteen and infants under three, are particularly vulnerable. 

What precautions can one take?

It is essential to peel and wash all vegetables before eating them. It is also important to do basic things such as washing one’s hands before cooking and again before eating. It is advisable to do this anyway, outbreak or not.

Children should not eat unpasteurised cheese or milk and all meat should be thoroughly cooked. Just one bacterium in 25g of meat is enough to contaminate a child.