Mountain bikers and cross-country runners are at risk from the deadly stomach bug E. coli if they get splashed with mud, doctors warned today.

Medics at Aberdeen Royal Infirmary say they treated a 23-year-old cyclist for an E. coli O157 infection after he was admitted to the hospital suffering from vomiting, abdominal pain and bloody diarrhea.

The man – a vegetarian – said he had not eaten undercooked meat or vegetables, nor had he spent time with livestock or visiting farms before falling ill.

But eight days before his symptoms began the man had competed in a cycling event along wet, muddy tracks in eastern Scotland.

He, along with other competitors, had removed the mudguards from his bicycle to reduce weight, and mud and water had splashed on his face during the race. 

It is thought this was how he became infected with the bug, which can be found in animal feces and farm slurry.

The man said he had taken part in a ‘Tough Mudder’ event, which involves a 10 -12 mile race with obstacles such as climbing vertical walls and plunging through ice pools.

The cyclist, who has not been identified, recovered – but the doctors have highlighted his case in the Journal of Infection Prevention.

Writing in the research paper, the doctors warned: ‘Sporting endeavours such as cycling and cross-country running events often take participants through such high-risk areas and may be an important cause of contact with E. coli O157.

‘This case highlights such exposure and should alert clinicians to the possibility of E.coli O157 infection and the importance of individuals presenting with bloody diarrhea with a history of participation in similar sporting or other events.’

In 2012, three people contracted E.coli 0O57 infection following a 12-mile ‘Tough Mudder’ event at Drumlanrig Castle, Dumfriesshire, which involved immersion or contact with mud.

Also in 2012, a study of one of the world’s largest mountain bike races, the 95k Birkebeinerrittet in Norway, which annually attracts 19,000 participants, found that when mudguards were attached to bikes, there were fewer cases of gastrointestinal illness.