A five-year-old boy has died while being treated for E.coli following last month's outbreak in south Wales.
Mason Jones, from Deri, near Bargoed, south Wales, was being treated at Bristol Children's Hospital.
It was confirmed on Tuesday that he had died on Monday evening. His family said they are "devastated" by his death.
Health officials admitted new cases were still being confirmed, with a total of 157 people and 42 schools affected since 18 September.
Mason, a pupil at Deri Primary School, was initially admitted to Prince Charles Hospital in Merthyr Tydfil but was transferred almost immediately to Bristol with renal problems.
He had been ill for more than a week before his death.
Mason's grandfather Lynn Jones said the family was "devastated".
'Lovely little boy'
Grandmother Mair Jones last saw him on Monday night and said the family had hoped he was improving, although he was still on dialysis.
She said: "I kissed him at 10.30pm and said 'Grandma will see you tomorrow', and then Sharon [Mason's mother] phoned at 11.30 to say that he was dying.
"We got into the hospital at 12.40 this morning into the intensive care unit and Nathan [Mason's father] came out to say that he had passed away 10 minutes before."
Family friend Muriel Thomas added: "He had woken up because they had kept him sedated. There was a slight improvement on the Friday - he fancied chips and he wanted his dinosaur book."
A cousin of the family, Chris Hebbard, told BBC Wales he was "lovely little boy" who had had been "very much loved".
She added: "We're a close knit community and everyone knows the children - it's the hardest part."
Mason's eight-year-old brother, Chandler, had also been treated for suspected E.coli and is recovering.
An inquiry is due to take place into the outbreak
Health minister Dr Brian Gibbons, in a statement to the assembly, expressed his sympathy to the family.
He added: "We can't just wait for the inquiry. We do need to be proactive in making sure that we do whatever we can do to stop this happening again".
Caerphilly Council leader Harry Andrews, said: "We will offer our every support to both the family and the wider community."
Health officials said that the outbreak was still "dynamic" with new cases being reported although some suspected cases had been taken off the total.
Two children are being treated at Alder Hey Hospital in Liverpool. Three are still being treated in Bristol.
Shortly after the first cases of E.coli were confirmed, the outbreak was linked with cooked meat from Bridgend-based food supplier John Tudor and Son.
It is considering challenging two prohibition notices issued by Bridgend Council, preventing it from trading.
The company said that two rounds of tests had proved negative.