Cryptosporidium danger in pools

womanownedAugust 26, 2013

There is an article published in the August 15th issue of Service Industry News (catered to the swimming pool industry) that I would like to make public. Without quoting the entire article, there are 748,000 cases of cryptosporidium infections transmitted through swimming pools. It produces flu like symptoms that can last from 2 - 4 weeks and represents a real threat to recreational swimmers. It is highly resistant to traditional chlorine disinfection methods. Cryptosporidium can lurk in a pool for 7 days, almost totally unaffected by chlorine. The sickness is transmitted when swimmers ingest the water, an inadvertent but normal swimming act. The EPA has found that adult swimmers typically swallow 24 milliliters of water per swim period. Children consume twice that much. The cryptosporidium is a result of someone being in the pool with diarrhea. Parents should take their children to the bathroom often and diapers checked regularly. Washing before getting into the pool is a great idea. Of course, this is another good reason to have your own pool instead of going to community pools or waterparks. You can regulate swimmers much more if you know who they are. Since chlorination is not particularly efficient in treating it, there are a couple of new studies that have shown ultraviolet radiation is effective at inactivating bacteria, viruses and other pathogenic organisms. UV offers no residual protection as it is only effective when passing through the UV light. This means that if you suspect your pool has been exposed to someone with diarrhea, then you should run the pump and the UV ozone system 24 hrs a day for at least 7 days to kill it. Normal cartridge, D.E. or sand filters are efficient at handling the smaller cryptosporidium organisms.

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This number seemed kind of outrageous, so I spent a few minutes trying to research where it came from.

Real numbers:
The CDC says that there were 7,656 cases in 2009 and 8,951 cases in 2010. These are confirmed cases from all sources, not just swimming pools.

There is also a page on the CDC website that gives the 748K number, although it also does not specify that these are just from swimming pools. Next to that number is a reference, and although the link doesn't work, it's not difficult to find the referenced study online. I can't see the enclosed tables for some reason, but the number "748,000" is nowhere in the study. It does say that of the 5.5 million foodborne illnesses annually, 2% are caused by parasites. The simple math means that 110,000 illnesses are caused annually by all parasites from all sources, which is not even close to 748K.

The sad thing is, that due to the internet, this number, which was probably a typo (probably supposed to be 7,480 I'd guess) has now been replicated over and over and if you google "748,000 cryptosporidium" there are over 500 hits. Ugh.

    Bookmark   August 27, 2013 at 9:55AM
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