E.coli: Is it safe to eat salad? And can the bacteria be passed between people?

Q&A

How many people have died in the current outbreak of E.coli?

There have been 18 deaths and 1,823 people infected in 12 countries since the outbreak began. Victims have been identified across Europe and in the US who are suffering severe diarrhoea and in some cases life-threatening complications. It is already the deadliest outbreak involving E.coli in recent history.

Why is it so serious?

A rare strain of E.coli has appeared that is extremely virulent. It belongs to a type of the bug called enteroaggregative E.coli which is a common cause of diarrhoea all over the world. Unusually, however, this strain has acquired the capacity to produce Shiga toxin, which makes it particularly dangerous.

How did the bug get into Britain?

It hasn't – yet. Although 11 people have fallen ill from the bug in this country, including three Britons, all had recently travelled to Germany.

What is the source of the outbreak?

That is the question scientists are desperate to answer. It involves asking the people infected what they ate, identifying the common foods and then testing these for the presence of the bacteria. It is a hugely complex task and the answer may never be known. E.coli is usually linked with meat products but in this case, it is salad vegetables that are under suspicion, possibly through being watered with contaminated water or from manure in the soil.

Is it safe to eat salad?

In England – yes. There is no sign that the deadly E.coli strain identified in Germany is present in the environment beyond its borders. The UK Health Protection Agency says there is "no evidence that produce from possible sources identified so far has been distributed to the UK". However, it is always advisable to wash or peel fruit and vegetables before eating them, especially if they are to be eaten raw. Cooking destroys E.coli.

Can the bug be passed from person to person?

Yes – if someone infected does not observe basic hygiene, eg by washing their hands after going to the toilet.

What happens when people become infected?

The bacteria become established in the gut and release the Shiga toxin into the intestine. The toxin is absorbed into the blood stream and attacks the kidneys and the small blood vessels causing a life-threatening condition called haemolytic uraemic syndrome which can lead to kidney failure. Damage is also likely to the blood vessels supplying the gut causing bloody diarrhoea.

How do you know you have got it?

Pretty unmistakeable – E.coli infection is marked by severe diarrhoea. Most people get better within seven days but some strains can cause serious kidney and blood complications. If you develop bloody diarrhoea, see a doctor immediately.