Wild swimming has been linked to an increased risk of stomach bugs and skin rashes, according to the largest controlled study of illnesses associated with bathing in rivers and lakes. The research found that swimmers at locations in Hungary were more than twice as likely to develop skin problems.
The risk of contracting a stomach bug rose significantly in water with higher concentrations of E coli and other bacteria linked to faecal pollution. About 2.1% of swimmers reported gastrointestinal illness, compared with 1.9% of non-swimmers.
Skin complaints, such as a rash, ulcer, or itching, were reported by 2.7% of swimmers and 1.3% of people who stayed out of the water. These skin problems were not associated with faecal contamination markers, suggesting other organisms or pollutants may be responsible.
Professor Paul Hunter of the University of East Anglia, who led the study, stated that the findings support retaining E coli in freshwater monitoring. He suggested that somatic coliphages could also help identify unsafe conditions.