Q: Hi Jason, I love your “Ask A Health Inspector” series, and I am a long time reader (since the very beginning!). I have a question… Since summer is upon us, my kid is dying to get to the swimming pool, but I’m worried about recreational water illnesses. Is there something you can tell me that will ease my mind?
A: Hi Rachael! There are few things quite as refreshing in the hot summer months as taking a dip in the pool. The sun beating down, the sound of children's laughter echoing through the park, Michael Jackson's "Beat It" on the teenagers radio, the cool drops spraying over you as that kid cannonballs into the deep end. Well you know what else could be spraying on you? Disease, that’s what.
Say hello to Cryptosporidium. (It's VERY pleased to meet you) Also known as "Crypto" (not to be confused with Superman's dog, Krypto…) this is a parasite that causes a disease known as cryptosporidiosis, and according to the CDC, it is the leading cause of waterborne disease among humans in the United States. In fact, in 2016, 32 cases of cryptosporidiosis were reported, which is double the number reported in 2014. In most healthy people, Cryptosporidiosis will produce a pretty significant bout of watery diarrhea, and will pass in a few weeks without medication. In immunocompromised individuals, and babies and the elderly, it can be a bit more threatening. Cryptosporidium has a tough, outer shell, and literally laughs at chlorine. OK, not literally, but normal concentrations of chlorine in most pools will not kill it.
So Jason, where does Crypto comes from?
Like many microorganisms, cryptosporidium occurs naturally, and enjoys the warm, comfy neighborhoods of animal and human intestines. Thick walled, sporulated oocysts (Sporulated means the undeveloped infective part of the organism is living inside the oocyst, and is waiting for the next victim...) exit the host through feces or sometimes through respiratory secretions (cough, cough), and typically hang around the pool like those kids whose parents drop them off in the morning and then pick them up in the evening…This is not a daycare, lady! Except crypto isn't scared of the lifeguards, and totally does not clean up after itself. Its outer shell makes it especially resistant to chlorine or other disinfectants.
Again, according to the CDC, the average swimmer has about 0.14 grams of feces on their ~ahem~ …person…at any given time. (Can you believe someone got paid to figure that out?) How much is 0.14 grams, you say? Well, let's put it into perspective. The average paper clip weighs about 1 gram, a pinch of salt weighs about one gram, and a stick of gum weighs about one gram. So figure 1/10 of a stick of gum, or the average size of a piece of Nerds candy, and that’s about how much feces you have on your body right now. And of course, babies could carry more than that…(speaking as a parent, I'm going to wager that it’s A LOT more…) so when you go swimming, you can pretty much plan on that rinsing off into the pool. Of course, not everyone is infected with crypto, but nobody is going to be wearing a swimsuit that says, "Hey, I had diarrhea last week, and I'm most likely still shedding!" (If you see this swimsuit, please leave the pool immediately.)
So how can Crypto be killed?
Well, there are a couple of different ways to kill Cryptosporidium, but boiling all the water in the swimming pool for one full minute is not usually the most feasible method, so chlorine is the way to go…Now, here is the problem. In North Carolina, swimming pools are required to maintain at least 1 ppm chlorine at all times. (That’s like one dollar out of one million dollars) That’s well and good for most microorganisms that get in the pool. For example, Chlorine at 1 ppm will kill E .Coli in less than one minute. Cool, huh? But let's think of a few other nasty little guys…Hepatitis A? 16 minutes at 1 ppm. Giardia? 45 minutes at 1 ppm. And our new friend Crypto? Well, he's going to need to sit there for 15,300 minutes…that’s 10.6 days (#theydidthemath). Do you think anyone wants to close their pool for 10.6 days? Not when its 95 degrees out and you’ve got your Sirius XM set to the Big 80s on 8. So the answer is super-chlorination (or hyper-chlorination). This involves raising the level of chlorine in the pool to levels that will kill the Crypto much quicker. And by quicker, I mean hours, not days. So, let's assume there is a diarrheal incident in a pool that is maintained correctly and is using a chlorine stabilizer. What happens next? First thing, of course, is to get everyone out (shouldn't be too hard to accomplish once they figure out what's happened), next the level of chlorine is raised to 20, 30 or 40 ppm. At 20 ppm, Crypto will be killed in 28 hours. At 30 ppm, 18 hours, and at 40 ppm, Crypto will be killed in 8.5 hours. Still, that’s a full Saturday that the kids won't be able to use the pool. And after the super-chlorination is complete, everything must be brought back to normal maintenance conditions. So, as you can see, a lot of work goes into maintaining a pool when a Crypto-incident is suspected, and everything must be considered Crypto, AND that’s in a pool where everything is maintained correctly.
Let's talk about things you can do to prevent a Crypto infection.
Make sure that the pool you are about to enter is well maintained.
Shower before entering, and after exiting the pool
Don’t swallow the water (Seems obvious, but if you have kids, you know what I'm talking about)
Pay attention to your surroundings. If you see something you are concerned about, let a person in charge know, and stay out of the water.
Keep your hands out of your mouth while in the pool and after exiting until you have washed.
Other things to watch out for when going swimming include the drains. Make sure that none are cracked or broken, or move. They are required to be securely attached to the bottom of the pool and be maintained in good repair. The drains can have an incredible suction, and without the drain covers, are a major hazard for children AND adults. Also, you want to make sure there are no openings or holes in the walls of the pool. Even a return inlet pipe (a return inlet is where water comes back into the pool from the pump, filter and sometimes the water heater) can be a hazard if it does not have a proper cover. Re-enforce to the kids that just because a hole is there, you don’t have to stick your hands, hair, skin, Nemo, Dory or anything else in there. Suction hazards exist all over pools, and it's going to be bad if something gets stuck in a pipe. It’s a good idea to look over the pool deck as well, to ensure that there are no trip hazards present. Cracks, settling, and water damage can lead to dangerous conditions. The environmental health department is responsible for issuing permits and conducting inspections on all year round and seasonal public pools, but we can't be there all the time.
Be safe, and have a great summer!