Bridgend County Borough Council,Civic Offices, Angel Street, Bridgend, CF31 4WB

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Cryptosporidium and swimming pools

Cryptosporidium (or Crypto) is a protozoan parasite which causes acute gastroenteritis and can often last up to two weeks. Cryptosporidium live in the human gut where they thrive and multiply. During their life cycle, dormant “spores” are formed which act as a protective shell. These spores (known as oocysts) are the mechanism for the transmission from one person to another. The mains symptoms are watery diarrhoea, abdominal pain, fever and vomiting. Infection commonly occurs through ingestion of contaminated drinking water, recreational and swimming pool water or contact with an infected person.

Since 2001, swimming pools have been the most common setting for outbreaks of waterborne, infectious intestinal disease in England and Wales, with Cryptosporidium as the leading cause. Cryptosporidium presents particular problems for swimming pools because the oocysts are resistant to normal chlorine levels used for pool disinfection. Oocysts can survive for months in moist environments with ambient temperature and will therefore survive in pool water and present an infection risk unless removed. Cryptosporidium is highly infectious and research indicates that it can survive in a swimming pool for over 10 days.

If these oocysts are introduced into the pool water through a faecal accident by infected individuals, the only method of removing these occysts is by optimal filtration. Filtration relies on good circulation of the pool water and should be undertaken with continual fine dosing of coagulant/flocculant.

Despite these measures, bathers in the vicinity of the faecal contamination by someone infected with Cryptosporidium, will still be at risk if they ingest the pool water. There is a video available on Youtube which explains these risks and advises bathers of measures they can take to reduce the chances of infection.

Bridgend County Borough Council’s Health and Safety Enforcement Team are partaking in an all Wales project into the effective management of Cryptosporidium in swimming pools.

The aim of the project is:

  • To raise awareness of Cryptosporidium with pool water users;
  • To raise awareness with pool operators of the controls required to minimise the spread of Cryptosporidium;
  • To assess management of Cryptosporidium in swimming pools across Wales; and
  • To gather information about swimming facilities which can be utilised in the event of an outbreak of infectious disease.

Swimming Pool


Last Updated: 10/10/2013
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