An outbreak of E. coli that occurred in the UK between December last year and July has just been revealed despite hundreds of people falling ill and one dying.

The UK’s Health Protection Agency announced yesterday that an outbreak of E. coli O157 started in December and lasted until July. The outbreak caused one fatality and left 250 ill.

The unusual strain of E. coli O157, a bacterium that can cause bloody diarrhoea, dehydration, and in the most severe cases, kidney failure, is believed to have been present in soil on vegetables, including leeks and potatoes.

This outbreak was not related to the outbreaks in Germany or France earlier this year, which were caused by a different strain of E. coli.

A spokesperson for the HPA said the cause of the outbreak had proved difficult to identify.

When asked whether the HPA should have signalled a warning when the outbreak started, the spokesperson said the procedures used to find the cause “takes a period of time”. With the cause of the outbreak uncertain, health officials developed several questionnaires and case control studies to try to identify its origin.

The HPA said the person who died had “underlying health problems”. Of the 250 people who fell ill, 74 people were assessed in hospital and four developed Haemolytic Uraemic Syndrome (HUS), which can cause acute kidney failure in children. The HPA said 193 cases were reported in England, 44 in Scotland and 14 in Wales. It added that 40% of cases were in children under 16.

This year’s E. coli outbreak in Germany hit produce sales in a number of European countries, including the UK.

The disclosure that there had been a separate outbreak in the UK could affect consumer confidence again.

A spokesperson from the Fresh Produce Consortium refused to comment on the UK outbreak but urged consumers to wash the vegetables they buy.