Public Pools - Cryptosporidium

• Cryptosporidium Protocol for Swimming Pools
• Criteria for Closing & Re-opening Pools
• Treatment Procedures Associated with the Removal of Cryptosporidium
• Cryptosporidium Testing Procedures
• Faecal Accident Standard Procedure
• Key Personal Hygiene Messages
• Public Awareness

Cryptosporidium Protocol for Swimming Pools

1. When a Cryptosporidium outbreak occurs in the community or cases are associated with a pool, the local Public Health Service will notify swimming pool managers of an outbreak, if there is concern about risks to pools.
2. During an outbreak you may be asked by the Public Health Service to test your water. Determine who pays for, and who is accredited to conduct the test.
   At this time if you are not in an outbreak area - do not test your pool for Cryptosporidium unless you are advised to by your Public Health Service.
3. If your test is positive, the Ministry of Health criteria for closing and re-opening swimming pools will be followed. This criteria includes consultation between pool managers, Public Health Service and Environmental Health Officers.
   If your pool is tested positive you are likely to be asked to close.
   If your pool is tested negative you may remain open, unless advised otherwise.
4. During an outbreak you should actively promote the key messages recommended by the Ministry of Health to your patrons.
5. Pool re-opening will be recommended in consultation with pool managers, Public Health Service and Environmental Health Officers. If there is still an active outbreak in the area, you may wish to reduce your risk of reinfection and avoid spreading infection to other pools by:
   a) Limit ‘at-risk’ groups, predominantly those under 8 years
   b) Limited opening options, only programmed session, no public recreational access
   c) Postponing any events, such as regional or national events
6. Open fully when recommended by the Public Health Service.

Criteria for Closing & Re-opening Pools

The following criteria has been established by the Ministry of Health, but will be administered by the Public Health Service and Environmental Health Officers (from your local council).

1. Criteria for closing a pool
   A pool may be recommended for closure by the Public Health Service if:
   
   
   1. There is an outbreak in the area, and:
      • the pool tests positive, or
      • the pool is linked to the outbreak, or
      • nearby pools test positive or are linked to the outbreak (this is in order to avoid the spread of infection)
      Note: Other factors such as the adequacy of treatment and filtration systems will be taken into account.
      
   2. A positive test result is obtained, but there is no outbreak.
   
   A low positive test result is less than 10 oocysts per 100 litres, a high result is greater than 10 oocysts per 100 litres.
   Any decision for closure will be in consultation with pool management, Environmental Health Officers and the Public Health Service, and must be considered on a case-by case basis.
   
   
2. Criteria for re-opening a pool
   
   • Pool decontaminated according to accepted methods and one clear test when the original positive test was less than 10 oocysts /100 litres.
   • Pool decontaminated according to accepted methods and two clear tests are taken at least 24 hours apart when the original positive test was 10 oocysts or more/100 litres and/or cases were associated with the pool.
   • Public Health Service recommendations are being followed regarding behaviour and personal hygiene while there is an outbreak in the community.

Treatment Procedures Associated with the Removal of Cryptosporidium

It is recommended that decontamination procedures are prepared and included in your pool operations manual, before you need to use them.

• If your pool is tested positive for Cryptosporidium inform the Public Health Service and close pool
• Filtration and/or dumping water are the only practical ways to remove oocysts.
• Decontamination procedure will depend on the number of oocysts per 100 litres and the type of filtration system. The longer the period of filtration, the greater the chances of removing the oocysts and getting a negative retest result. Filters should be effective to a level of 1 micron (i.e., DE filters). Filters which can not achieve this level will not reliably remove Cryptosporidium (i.e., sand filters on their own).
• Backwashing a sand filter or cleaning a DE filter close to the time of a retest is likely to increase the chances of a positive retest result.

A low test result (less than 10 oocysts per 100 litres) procedure

1. Implement decontamination procedure.
2. Increase chlorine to 20 mg/L for 20 hours. This will destroy other pathogens in the water (e.g., Giardia), and may assist in getting a negative retest result for Cryptosporidium.
3. For DE filters, allow a minimum of 3 pool turn-overs, and then dump DE, clean tank and replace DE. For sand filters, dump all pool water and backwash filters until clean with fresh non-contaminated water to remove oocysts from filter. Backwash may involve up to 25 times the normal cycle.
4. Further information on decontamination procedures is available from NZRA.
5. Retest
6. Inform Public Health Service of results. If a negative retest then reopen unless requested otherwise. If a positive retest then go to high level response

A high test result (greater than 10 oocysts per 100 litres) procedure

1. Implement decontamination procedure in consultation with your Public Health Service. See procedure for less than 10 oocysts.
2. Retest twice, 24 hours apart.
3. Inform Public Health Service of results. If both retests are negative then reopen unless requested otherwise. If either retest is positive then keep pool closed and recommence appropriate procedure.

Note: Pool managers should supervise the retesting arrangements.

Cryptosporidium Testing Procedures

At this time if you are not in an outbreak area, do not test your pool for Cryptosporidium unless you are advised by your Public Health Service. If a pool is identified as a common risk factor, you may be asked by the Public Health Service to test your water. Determine who pays for, and who is accredited to conduct the test.

An outbreak is defined as more cases than is normally expected for that region. Remember, Cryptosporidium has been in New Zealand for a number of years, it is not a new communicable disease, but it has only recently been listed as a notifiable disease (these are diseases which medical practitioners are required to notify to the Public Health Service).

The Ministry of Health has advised that they currently recognise the following laboratories for testing Cryptosporidium.

Samples are often taken by a separate organisation therefore care should be taken to ensure the pool manager and laboratory are satisfied that correct sampling procedure is followed.

Pool managers are advised that the internationally recognised test for Cryptosporidium is APHA 9711B. The sampling procedure should be provided by the laboratory carrying out the test. It is accepted that 380 litres (100 US gallons) is the standard minimum quantity to be collected at a prefereable flow rate of 4 litres per minute.

It is important that pool managers ensure sampling equipment is cleaned thoroughly before each test, as specified by the accredited laboratory and or according to APHA 9711B test method.

Faecal Accident Standard Procedure

A standard procedure for dealing with faecal accidents has been established. This procedure differentiates between Cryptosporidium outbreak areas, and non-outbreak areas, as well as “floaters/sinkers” and diarrhoea. These procedures aim to provide pool managers with adequate and practical measures to reduce the risk of pathogen contamination (whether Cryptosporidium, Giardia or other micro-organisms).

Floaters/sinkers

Standard procedure

1. Evacuate and isolate immediate area
2. Remove solids
3. Spot superchlorinate (in excess of 100 mg/l) using a water can or similar
4. Keep area clear for 30 minutes
5. Ensure chlorine is adequately dispersed before allowing people to reenter area - spot test area to check chlorine dilution

Diarrhoea

Standard procedure

1. Evacuate and isolate immediate area
2. Remove any solids, vacuum to waste
3. Increase FAC to no less than 5 mg/l
4. Keep area clear for long enough for faecal matter to be removed by vacuum or turn-over (pool specific)
5. Ensure chlorine is adequately dispersed before allowing people to reenter area

Cryptosporidium Outbreak procedure

1. Evacuate and isolate whole area
2. Close pool
3. Remove any solids, vacuum to waste
4. For pools with d.e. filters add 20 mg/l of chlorine then allow 3 turn-overs
5. For pools with sand filters, flocculate and dilute heavily (dump approximately 90% of water), then add 20 mg/l of chlorine
6. Advise Public Health Service

Key Personal Hygiene Messages

These messages should be promoted at all times. During an outbreak they should be particularly emphasised and there may be additional advice (e.g., immunocompromised people avoiding swimming).

1. Don’t go swimming if you have had diarrhoea within the last two weeks.
   (According to a number of customer surveys in Wellington, it appears that the common understanding is that if you shower you can go swimming. This is not the case, if you are unwell - stay away from the pool.)
2. Don’t allow your children to go swimming if they have had diarrhoea within the last two weeks.
3. Encourage personal hygiene at all times, namely washing hands after going to the toilet, after changing a nappy, before handling food, before entering the pool.
4. The greatest ‘at-risk’ group in the Wellington outbreak were children under 8 years, ensure parents and caregivers are aware of the child’s hygiene
5. Ensure children swim in tight fitting togs, not nappies.
6. Make customers aware that they need to report any faecal accidents immediately.
7. Encourage customers to shower, using soap around the anal area, before entering the pool. Ensure parents and caregivers take responsibility for children.

Public Awareness

Appropriate and accurate public awareness is necessary with respect to the Cryptosporidium issue, or for that matter any public health issue which affects pools.

Please note: a negative result does not indicate your pool is “crypto clear”. Do not place public notices indicating this as it is both misleading to the customers and inaccurate. A negative result is not 100% conclusive and only represents a single point in time.

If there is an outbreak in the community which is not related to a pool (e.g., a crèche) and you are notified by the Public Health Service, you may wish to notify your customers of this. It is recommended you use the Key Personal Hygiene Messages.

If you choose to restrict access by the ‘at-risk’ group, please clearly inform customers that there is an outbreak in the community and to avoid the spread of the disease the pool has taken a pro-active stance to close the children’s pool to protect everyone’s health. Contact schools, crèches etc. in your area and explain the closure, they will probably be supportive of the position.

Remember: Cryptosporidium IS NOT A POOL BUG. It is a community disease which is brought into the pool by the community. Your role as a pool manager, in an outbreak, is to reduce the risk of spreading the disease. This will be done in consultation with the Public Health Service and the Environmental Health Officer.

Do not accept liability for the spread of the disease unless there is an established link with your pool by the Public Health Service. However, take a responsible position to assist public health by limiting the spread of the disease through your pool.

Some groups in the community need to be very careful to ensure that they do not become infected (e.g., people who are HIV positive, people on medications which affect their immune systems). If there is concern about Cryptosporidium in an area or in a pool these people should seek medical advice before swimming.

Lets collectively educate the community that the safety of pools is the responsibility of the community. By swimming while ill, people are endangering everyone’s health and safety.