Some 113 people have become ill with E. coli in recent weeks and experts believe it is most likely linked to a nationally distributed food item.
The UK Health Security Agency says testing of samples suggests all of the cases since 25 May are “part of a single outbreak”.
Based on the wide geographic spread, it is likely a contaminated batch of product that people can buy around the UK.
In December, a person in Scotland died from E. coli linked to cheese.
The source of this outbreak is not yet confirmed, but there is currently no evidence linking it to open farms, drinking water or swimming in contaminated sea, lakes or rivers, say the officials investigating it.
The number affected is expected to rise as more samples from patients get tested.
So far, there have been:
- 81 cases found in England
- 18 in Wales
- 13 in Scotland
- 1 in Northern Ireland
The youngest who has become ill is aged two and the oldest aged 79. Some have been in hospital.
Symptoms include severe and sometimes bloody diarrhoea, stomach cramps, vomiting and fever.
Most people usually recover well, but some – such as young children – can become very unwell. Call NHS 111 or contact your GP surgery if you are worried.
E. coli are a diverse group of bacteria that normally live in the intestines of humans and animals.
Although many are harmless, some produce toxins that can make you sick
This outbreak is a Shiga toxin-producing E. coli (STEC).
There are things people can do to reduce the risk of infection.
Trish Mannes, Incident Director at UKHSA, said: “Washing your hands with soap and warm water and using disinfectants to clean surfaces will help stop infections from spreading.
“If you are unwell with diarrhoea and vomiting, you should not prepare food for others while unwell and avoid visiting people in hospitals or care homes to avoid passing on the infection in these settings.
“Do not return to work, school or nursery until 48 hours after your symptoms have stopped.”
Alcohol-based hand gels will not stop E. coli.
In March, rowers taking part in the 2024 Boat Race between Oxford and Cambridge in London were told not to enter the Thames after high levels of E. coli were found.