A community outbreak of echovirus infection associated with an outdoor swimming pool

Forty-six people became ill with vomiting, diarrhoea and headache within days of an outdoor swimming pool opening for the summer season in a small seaside village. During the weekend of the outbreak, 185 tickets to the pool had been sold. It was found that 34 bathers were ill, and one subject had vomited into the pool. All other cases arose after this incident. The risk of infection was greatest among those who swallowed pool water (24/28 versus 10/17, p = 0.07). Echovirus 30 was isolated from the case who vomited into the pool and from six other cases. Normal chlorine levels had not been adequate to contain the infection risk from vomitus, and, in future, pool attendants witnessing such incidents should consider closing the pool to the public and seeking advice on superchlorination.