Four people fell ill with E. coli linked to a music festival held in Aberystwyth during the summer.
Big Tribute Festival confirmed the cases after 5,000 people attended the event, held between Aberystwyth and Capel Bangor.
Public Health Wales (PHW) said the outbreak, which can be declared with as few as two cases, closed in October with no evidence of onward transmission and no ongoing risk to the public. It said it continued to explore the source of the infection.
Big Tribute Festival said it had met all environmental health requirements, including council-led water testing and the removal of livestock ahead of the event.
PHW said it had contacted people who had purchased tickets to the festival to complete a survey.
It added a report into the outbreak would be published in due course.
What is E. coli?
According to PHW, the O26 shiga toxin-producing E. coli (STEC) is a bacterial infection that can cause serious complications.
It is often transmitted via consumption of contaminated food but can also be spread by close contact with an infected person, as well as direct contact with an infected animal or its environment.
What are the symptoms of E. coli?
Symptoms include:
Severe and sometimes bloody diarrhoea
Stomach cramps, vomiting and fever
It usually takes a few days from being infected for symptoms to show.
E. coli are a diverse group of bacteria that normally live in the intestines of humans and animals.
Big Tribute Festival said it continued to support PHW fully in their work, adding: “The festival met all environmental health requirements, including council-led water testing ahead of the event, the removal of livestock more than 30 days before the festival and ensuring all food vendors complied with the legal standards required to operate.”
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