Parasites in Pools Are on the Rise

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June 03, 2017 | 121,216 views

Story at-a-glance

  • A parasite called cryptosporidium, or crypto, may contaminate pools and water parks and is spread by contact with the feces of an infected person
  • The number of outbreaks of a diarrhea-causing infection has doubled from 16 to 32 cases in the U.S. in just two years, from 2014 to 2016, records from the U.S. Centers for Disease Control and Prevention (CDC) show
  • Experts say hyperchlorination is required in pools contaminated by crypto, but chlorine poisoning from the liquid or gas form may cause other potentially toxic side effects

By Dr. Mercola

Sometimes the evening news reveals something that causes you to worry about that which you never worried before. Such may have been the case when news emerged recently of a huge uptick in the number of diarrhea outbreaks after people went swimming in a public pool and inadvertently swallowed the water. But that was just the beginning of their problem.

The U.S. Centers for Disease Control and Prevention (CDC's) Morbidity and Mortality Weekly Report (MMWR)1 noted that when they sought medical attention, the diarrhea sufferers learned the pool water they ingested contained parasites and that the parasites, known as cryptosporidium, or crypto, now resided in them.

Can it get worse? Well, yes: The diarrhea outbreaks have doubled in just a few years, as there were at least 32 known outbreaks due to crypto contamination in pools or water parks in 2016, while there were only 16 cases in 2014, the CDC reported. That's not 32 people infected; that's 32 outbreaks that affected multiple individuals. Reuters added:

"Arizona last year reported that 352 people became sick with Cryptosporidiosis from July through October, compared with no more than 62 cases per year from 2011 to 2015. Ohio reported 1,940 infections in 2016, compared with no more than 571 in any one year from 2012 to 2015."2

The Skinny on Crypto

Crypto is the most common cause of such diarrhea outbreaks, made worse because the parasite can survive for as long as 10 days even in chlorinated water and is "notoriously difficult to kill." It hasn't been just in the last handful of years that this problem seems to be multiplying. Since 2004, crypto cases have actually tripled. The CDC reports that the parasite is found in every region of the U.S. and throughout the world."3

Swallowing a single mouthful of water is all it takes for someone to find themselves knotted up with stomach cramps, nausea, vomiting and/or "profuse, watery diarrhea that can last up to two to three weeks," during which, not surprisingly, dehydration is common.

While some reports say crypto can spread when people come into contact with the feces of an infected person, the CDC asserts that it can also come from an animal, and that millions of cryptosporidium parasites can be released in a single bowel movement.4 Not just pools, but hot tubs, spas and other water venues can also pose a problem.

The only good news is that, in the U.S. at least, the CDC isn't sure if there are actually more parasite-driven diarrhea cases out there, or if states are simply reporting better since a new DNA-based tracking tool was introduced in 2010. However, states aren't required to report how many patients come in with such complaints.

Crypto Plagues Water Sources, Treatment Systems and Food Supplies

In seven countries in Africa and Asia, cryptosporidium is the most common cause of diarrhea in infants and toddlers, sometimes cutting off their ability to absorb nutrition, which can be fatal if left unchecked. In underdeveloped countries, crypto can cause chronic diarrhea in people who have HIV and other immunodeficiency problems.

Research published in the Asian Pacific Journal of Tropical Biomedicine reported that the prevalence of crypto illness in gastroenteritis patients is 1 percent to 4 percent in Europe and North America, while it's 1 percent to 37 percent in Africa, Asia, Australia and South and Central America.5

Not only water but food is also under threat of the pathogen. Milk, meat and vegetables, apple cider, fermented milk and salads have all been the source of outbreaks, and the threat is increasing. Here's how this parasite becomes so virulent, according to the CDC:

"Crypto may be found in water sources such as private wells that have been contaminated … Water can be contaminated through sewage overflows, sewage systems that are not working properly, polluted storm water runoff and agricultural runoff. Wells may be more vulnerable to such contamination after flooding, particularly if the wells are shallow, have been dug or bored, or have been submerged by floodwater for long periods of time."6

While the fact that crypto can contaminate swimming pool water is sobering enough, in many parts of the world the only drinking water available is contaminated with the parasite. The World Health Organization (WHO) reveals:

"Cryptosporidiosis was one of the defining illnesses for acquired immunodeficiency syndrome (AIDS) before the discovery of the human immunodeficiency virus (HIV). In 1993 in Milwaukee, Wisconsin, a Cryptosporidium outbreak resulted in 400,000 infections and 50 deaths.

A review of 46 studies of chronic diarrhea in people living with HIV in low-resource settings identified Cryptosporidium as the most common waterborne pathogen associated with chronic diarrhea and its increased risk of mortality. Most cases of HIV are in sub-Saharan Africa, the region that ranks last in sanitation coverage and next to last in safe drinking water coverage."7

Recommendations to Avoid Contracting — or Spreading — Crypto

According to Michele Hlavsa, chief of the CDC's Healthy Swimming Program, most healthy people recover from crypto contamination without treatment (and one wonders if some sufferers even realize what's wrong), but if diarrhea doesn't go away on its own within three days, she advises them to call their doctor. Additionally:

"Parents can encourage their children not to swallow the water when swimming. Also, take kids on bathroom breaks every hour, and check diapers in a diaper-changing area and not right next to the pool. We all share the water we swim in, but we don't want to share germs, pee or poop."8

The CDC also advises people to keep kids out of the pool if they have diarrhea and not to buy water toys that might encourage kids to drink pool water, such as a cup or anything that could be used like one. People who already have the parasite should wait two weeks after the diarrhea stops before they hit the water again.

It seems incredible, but the fact is, people who hit water parks and the like too soon after suffering a bout of diarrhea — or even before they've recovered — continue to spread the parasite in public pools, hot tubs and any other water-related venue people frequent. The MMWR report adds:

"Young swimmers aged under 5 years are more likely to contaminate the water because they are more likely to have inadequate toilet­ing and hygiene skills; therefore, prevention efforts should focus on their parents (because) as the Arizona outbreak investigation demonstrated, patients continue to swim while symptomatic."9

NBC News reported that in Alabama, at least 35 people were sickened from a single venue. In Phoenix, 51 Little League players, their families and a total of 352 people had confirmed crypto cases from one pool. NBC News added a little-known recommendation from the CDC: "All swimmers should shower and use soap before going in any swimming pool. Toilet paper alone does not remove disease-causing germs.10

Increasing Levels of Pool Chemicals Could Lead to 'Something Worse'

When there's a crypto outbreak linked to a certain pool or water park, Reuters said the CDC recommends the facility be closed so the water can be zapped with especially high doses of chlorine, called hyperchlorination.11 Chlorine use is not something that should be messed with without oversight, as human error and equipment failure can produce toxic chlorine gas.

CNN reported 156 incidents where people were exposed and noted that for properly treated pools, "upping" the levels of chlorine is not recommended because "that might lead to something even worse."12 An example of such an emergency occurred when about 34 of the 50 people in an outdoor pool in Contra Costa County, California, began experiencing eye irritation, coughing or vomiting.

A chemical controller malfunction had allowed the release of sodium hypochlorite, which reacted with muriatic acid and the release of toxic chlorine gas. You'd like to think that was an isolated incident, but since then the CDC has reported that more than 4,800 people throughout the U.S. visited emergency rooms for similar chemical-related health issues in 2012 alone.13 

Symptoms, CNN reports, depend on whether the chlorine poisoning involved the liquid or gas form, the amount, how long the exposure took place and how close the individuals were to the source. Many scenarios can cause a toxic level of exposure.

You may remember that chlorine gas was used as a chemical weapon during World War I. Exposure can cause skin redness, burning pain and blisters, blurred vision, a burning sensation in the nose, throat and eyes, difficulty breathing, coughing and/or fluid in the lungs. The CDC report on chlorine adds, "When chlorine gas comes into contact with moist tissues such as the eyes, throat and lungs, an acid is produced that can damage these tissues."14 The CNN report says in order to prevent such accidents:

"Pool chemicals need to be properly handled, stored and monitored. Pool operators and staff must be trained in pool chemical safety as well as appropriate operation and maintenance of equipment.

It is also important to follow standard pool policies, including evacuating bathers before a recirculation pump is restarted. State and local jurisdictions write, implement and enforce public water venue regulations, with no federal agencies overseeing facility design, construction, operation or maintenance."15

Measures Taken (or That You Can Take) to Disinfect Water

The CDC has developed an "all-inclusive" Model Aquatic Health Code as a "voluntary guidance document" to help federal, state and local health officials collaborate and share efforts to help make swimming, spas and other water-related activities safer and healthier.16 Crypto, as stated, is notorious for being impervious to chlorine. The CDC's advice for people wanting to kill or inactivate crypto entails bringing your water to a rolling boil for one minute. At elevations above 6,500 feet, boil for three minutes. 

Water should then be allowed to cool and stored in a clean, sanitized container with a tight cover and refrigerated. When using water from a stream on a camping trip, for instance, a point-of-use filter is a good thing to have. Keep in mind, however, that not all home-use water filters eliminate cryptosporidium, so the CDC recommends only one of the following, listed on its A Guide to Water Filters page:17

With all that, I believe an explanation is in order: Pure Water Gazette18 explains that ANSI, the American National Standards Institute, is the official certifying agency in the U.S., but the NSF (National Sanitation Foundation, or NSF International), is not a government agency.

The U.S. Environmental Protection Agency (EPA), as well as all U.S. states, the Standards Council of Canada (SCC,) Health Canada and all of Canada's provinces rely on ANSI and SCC to determine the standards accepted for third party product certification. Again, the CDC notes:

"Alternative disinfection processes to consider include systems that utilize ultraviolet light or ozone. Contact your local health department for recommended procedures. Remember to have your well water tested regularly, at least once a year, after disinfection to make sure the problem does not recur."19

Protect Yourself, Your Family and Your Community

Of course, crypto isn't the only threat for contamination in pools. Norovirus, giardia, E. coli and shigella are other illness-causing microbes that may be found in public pools. Symptoms and problems can range from allergies to asthma, sinusitis to DNA damage.

If you suspect there's a problem with a drinking water source, the EPA requires laboratories to obtain certification for analyzing drinking water.20 You can find a certified laboratory to have your drinking water tested via the EPA's Office of Ground Water and Drinking Water.21 And if you swim in a pool or visit a water park, don't drink the water.

[+]Sources and References [-]Sources and References

  • 1, 9 MMWR May 19, 2017
  • 2, 11 Reuters May 18, 2017
  • 3, 4, 6, 19 CDC Diseases and Contaminants July 1, 2015
  • 5 Asian Pac J Trop Biomed. 2013 November;3(11):916-924
  • 7 Bulletin of the World Health Organization 2013;91:238
  • 8, 12, 15 CNN May 19, 2017
  • 10 NBC News May 19, 2017
  • 13 CDC MMWR 2008-2015
  • 14 CDC Chlorine April 10, 2013
  • 16 CDC Model Aquatic Health Code March 8, 2016
  • 17 CDC A Guide to Water Filters April 3, 2015
  • 18 The Pure Water Gazette September 12, 2013
  • 20 EPA: Learn About Laboratory Certification for Drinking Water
  • 21 U.S. EPA, Certification of Laboratories for Drinking Water