Issue: July 2016
July 15, 2016
10 min read

Pool maintenance violations put swimmers at risk for infections, injuries

Issue: July 2016
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One in every eight routine inspections of swimming pools and other aquatic venues conducted nationwide in 2013 resulted in immediate closure due to sanitation, maintenance, or safety risk violations, according to a recent data from the CDC.

H. Cody Meissner, MD, chief of the division of pediatric infectious disease at Tufts University School of Medicine, noted that chlorine-tolerant pathogens and asymptomatic infected swimmers contribute significantly to infectious disease spread via recreational water.

Photo by Tufts Medical Center

Poor sanitary and safety conditions at pools present a significant risk to pediatric patients, especially as families head to public swimming pools this summer. According to the CDC, an estimated 350 disease outbreaks linked to swimming facilities were reported between 2003 and 2012. Among these, the most common illnesses were gastrointestinal conditions and dermatological issues caused by waterborne pathogens. In addition, safety issues related to pools compound these risks for pediatric patients, as drowning is the leading cause of mortality among children aged 1 to 4 years.

To better understand how swimming pools affect public health, Infectious Diseases in Children spoke with pediatricians, infectious disease and public health experts about how pools contribute to the infectious disease and injury burden among children and how these risks can be mitigated to allow children to fully enjoy the health benefits of swimming.

Cryptosporidium and other waterborne bugs

“Swimming is a great exercise, and everybody should encourage participation in water activity,” H. Cody Meissner, MD, chief of the division of pediatric infectious disease at Tufts University School of Medicine and Infectious Diseases in Children Editorial Board member, said during an interview. “But parents think about the risk of sunburn, they think about the risk of drowning, but they tend to underestimate the risk from infectious organisms that are in swimming pools.”

The list of waterborne parasites, bacteria and viruses found in swimming pools is lengthy. In a 2015 report published in MMWR, treated recreational water-based outbreaks were caused by a spectrum of agents, including Escherichia coli O157:H7, Shigella sonnei, Legionella spp., Pseudomonas aeruginosa, norovirus, Giardia intestinalis and Cryptosporidium.

According to Meissner, the chlorine-tolerant parasite that most commonly causes issues for swimmers is Cryptosporidium. The report found that 52% of outbreaks associated with treated recreational water facilities during 2011 and 2012 were caused by Cryptosporidium.

“Caregivers worry most about diarrhea-related illnesses from pools, and in terms of the specific organisms, Cryptosporidium is one of the most troublesome,” Meissner said. “Cryptosporidium is the leading cause of diarrhea outbreaks from contaminated pools, and that’s because the organism is able to survive even with proper chlorination for a number of days.”

Timothy F. Jones

According to Meissner, Cryptosporidium is usually introduced into swimming pools by infected swimmers accidentally shedding fecal matter into the water.

“If someone with diarrhea has a bowel movement while they’re swimming, especially a young child, then that introduces billions and billions of organisms into the water,” Meissner said. “The bugs are in the perirectal area and under the buttocks, so if people don’t shower before they get into the pool, or if people still have a significant amount of fecal material on their buttocks, then that could spread the organism that had caused their previous episode of diarrhea.”

Meissner added that asymptomatic swimmers also can contribute to the spread of infectious diseases in pools. “People continue to shed these organisms, even after there is a resolution of symptoms, and that’s why the recommendation is to wait a week or more after someone’s gotten over their illness before they go swimming again,” he said.

According to Timothy F. Jones, MD, state epidemiologist for the Tennessee Department of Health, this recommendation can sometimes be difficult to enforce among children, requiring greater parental awareness.


“We think that this is common sense, but a little while back we investigated a Cryptosporidium outbreak involving a youth baseball tournament, and it was unbelievable how many of those kids admitted swimming while they were sick,” Jones, told Infectious Diseases in Children. “This is the kind of thing you would just roll your eyes and think it would never happen. But kids like being in the water, even if they’re having diarrhea.”

Jones said that symptoms caused by Cryptosporidium include vomiting and diarrhea. He noted that these illnesses tend to be fairly mild in severity, and they are usually self-limiting in healthy patient populations.

However, Cryptosporidium can be difficult to diagnose because it requires specialized testing that pediatricians may be unaware of, according to Michele C. Hlavsa, RN, MPH, chief of the CDC’s Healthy Swimming Program in the Domestic Water, Sanitation and Hygiene Team in the National Center for Emerging Zoonotic and Infectious Diseases.

Michele C. Hlavsa

Cryptosporidium is very under-diagnosed,” Hlavsa said during an interview. “I think a lot of health care providers believe that when they order routine ova and parasite testing it includes Cryptosporidium testing, but oftentimes it does not. Health care providers need to request Cryptosporidium testing when they suspect that a patient is infected with Cryptosporidium.”

Hlavsa said the antiviral drug Alinia (nitazoxanide, Romark Laboratories) is FDA-approved for the treatment of Cryptosporidium in patients aged older than 1 year.

Keeping the water clean

Based on data presented at a CDC press briefing in May, Michael Beach, PhD, the CDC’s associate director for Healthy Water, said Cryptosporidium causes an estimated 75% of swimming pool outbreaks each year. The remaining outbreaks are usually caused by chlorine-susceptible pathogens, including Shigella, Campylobacter and E. coli, and are indicative of very poor pool management.

Research by Hlavsa and colleagues reported that disinfectant violations were identified in 11.9% of routine swimming pool inspections, which indicated a risk for outbreaks of infectious diseases. Hlavsa said that maintaining proper disinfectant levels within pools is vital to curbing the spread of infectious diseases.

“To prevent the transmission of infectious disease, it’s important to look at the disinfectant level — the chlorine or bromine level — and look at the pH,” Hlavsa said. “The pH is important because it’s going to determine how effective the chlorine or bromine are at killing germs and how comfortable swimmers are in the water.”

According to Francesca Gallè, PhD, hygiene researcher at the Parthenope University of Naples in Italy, special disinfectant procedures are necessary to protect swimmers from Cryptosporidium.

“A lot of measures can be applied to the control of microbial contamination and the prevention of waterborne illnesses in swimming pools, including the replacement, filtration and disinfection of water and the periodical maintenance and sanitization of pool surfaces and systems,” Gallè told Infectious Diseases in Children. “However, due to its resistance to disinfectants, Cryptosporidium can be removed by water only through filters with a porosity less than 4 m.”

Furthermore, research by Hlavsa found that one in five routine inspections of kiddie pools resulted in immediate closure, representing an increased risk for children due to poor water sanitation.

“We need to do a better job with our kiddie wading pools,” Hlavsa said. “It is hard to maintain the chlorine levels in kiddie wading pools because the water is shallow, so the chlorine is likely to be used up by the sun.”

According to Meissner, hot tubs and Jacuzzis present a similar risk to children because of their smaller size. “If you go into hot tubs, you have to be particularly careful because the warm water inactivates the disinfectant, and the bacteria like to grow in the warmer waters,” he said.


Using common sense to battle illness

According to Gallè, the best infectious disease prevention strategy is to educate swimmers about appropriate hygienic behaviors in and around swimming pools. Meissner agreed that education is critical to waterborne disease prevention.

“Pediatricians must remind parents to tell their children not to swallow the pool water, because if you do that, then you swallow whatever bacteria or parasites or viruses are in the water, and they gain entrance into your body,” Meissner said. “This is important because chlorine or bromine doesn’t work immediately, it takes awhile before the parasite or the bacteria are killed. Or some pools have filtration systems and that means that all the water has to go through the filter before the infectious organism is removed.”

Children represent an increased risk for both infectious disease transmission and infection, because they are more likely to swallow water and release fecal matter into the pool, according to Hlavsa. As a result, parents must be keenly aware of their children’s health and hygiene before allowing them to swim, she said.

“There was a study out of the University of Arizona that showed that children can have as much as 10 grams of feces on their perianal surface,” Hlavsa said. “It doesn’t sound like very much, but if we think about a water park where you have 1,000 diapered children potentially going into the water, we’re now talking about 10,000 grams, which is 10 kilograms or 22 pounds.”

Hlavsa also recommended that parents take their children to the bathroom at least once per hour while they are swimming in public pools.

“We recommend hourly bathroom breaks to check diapers and to take older little children and remind them that they have to get to the toilet because sometimes they get so involved in what they’re doing that they forget,” Hlavsa said. “It’s better that they do what they need to do in the restroom vs. in the water or in the pool.”

Meissner added that healthier hygienic behaviors at the poolside can significantly help to prevent pathogens from getting into the water. “Parents, when they change a diaper of a young child, should do it in the bathroom, or in some changing area. They shouldn’t do it at the poolside because feces may leak back into the pool” he said.

Julie Gilchrist

Scan the pool before swimming

Hlavsa also recommended that parents conduct a multipoint inspection of public facilities before allowing their children to swim.

“Parents should check the disinfectant level and the pH using testing strips before getting in,” Hlavsa said. “The second step of the inspection is to make sure you see the bottom of the pool especially in the deep end. The clear water allows lifeguards and swimmers to see if someone underwater needs help. The third step is to check that the drain cover looks to be secured and in good repair. If they’re not, someone can get trapped underwater. And the fourth step, especially if you’re at a public pool, is to make sure there is a lifeguard with safety equipment.”

Safety measures reduce drowning risks

Safety violations, such as unkempt fencing or missing lifesaving flotation devices, represent a significant risk for drowning and other serious water-related injuries among children, according to Hlavsa. Research by the CDC found that safety violations were identified during 12.7% of routine aquatic facility inspections.

According to Julie Gilchrist, MD, pediatrician and medical epidemiologist with the CDC’s National Center for Injury Prevention and Control, these violations pose an even more significant threat to younger children.

“The most shocking data point, for a lot of people, is that for children 1 to 4 years old, drowning kills more kids annually than anything else except birth defects,” Gilchrist told Infectious Diseases in Children. “If you think about all of the things that could kill your kids, if your child does not have a congenital anomaly, the most likely thing to kill them is drowning.”


According to data provided by Gilchrist, between 2001 and 2006, there were an estimated 30,000 swimming-related injuries requiring use of the ED among children aged younger than 9 years. She noted that 6.6% of these injuries were drowning-related. Gilchrist said that drowning prevention strategies are not unlike those for infectious disease prevention: They too require greater parental awareness.

“Parents need to realize that water is a dangerous environment,” Gilchrist said. “One of the things parents don’t realize is that drowning happens very quickly and very, very quietly. There is no splashing, there is no calling out. So, if you’re just keeping your ear toward the pool, you’re going to miss it.”

Gilchrist said drowning most often occurs as a result of two preventable scenarios: lack of supervision when children are in the water and lack of proper barriers to keep them out of the water when they are not supposed to be swimming.

“Constant undistracted supervision is key,” she said. “You need someone there with their eyes on the child, acting like a lifeguard — not on their phone, not reading a book, not grilling out, not mowing the lawn, but ... actually watching the kids. The scary thing is sometimes parents are standing there watching as their children drown, they don’t realize what’s happening.”

Gilchrist stressed that preventing swimming-related injuries is crucial mainly because of the severe consequences associated with submersion and drowning.

“For the people who make it to the emergency department, half require transfer for further care or hospitalization, compared to about 6% of all unintentional injuries,” she said. “Ultimately, the most severe aspect of drowning is the brain injury. It’s a very severe global hypoxic brain injury. That’s not something that you come back from very well; unlike, if you break a leg, or pull a muscle.”

Treat pool chemicals cautiously

According to research by Hlavsa, additional pool closures happened as a result of pool and chemical-associated safety violations. While these chemicals are critical for preventing the propagation of infectious diseases, they also pose a serious safety risk when handled or stored improperly. These injuries most commonly result from chemical inhalation, ingestion, and eye or skin contact.

“We really need our pool chemicals to stop the transmission of pathogens in the water,” Hlavsa said. “Chlorine and bromine are primary barriers to preventing germs from spreading in the water amongst swimmers. It’s really important that we use pool chemicals to keep the pool safe, but at the same time we have to handle them safely.”

Ensuring healthy swimming

To minimize swimming-related illnesses or injuries, the CDC developed and released the Model Aquatic Health Code (MAHC) in 2014. These guidelines provide national guidance for ensuring that public swimming areas meet proper safety and sanitary standards. However, the health code requires that local and state governments voluntarily participate. Current recommendations from the CDC suggest expanded use of the MAHC throughout the country.

While pools present a potential risk to the health and safety of children, Jones said the benefits of swimming far outweigh those risks.

“These things get a lot of attention because kids are involved, but given the number of pools that are out there, and the number of kids and people that are spending time in the water all summer, the chances of getting ill ... in general, are really, really low,” he said. “We still want people to be careful, but we would never recommend that people avoid swimming. I think the benefits to being out, getting exercise and enjoying the environment far outweigh the risk as long as people use common sense behavior.”

Gilchrist agreed that swimming is an important part of healthy childhood development.

“I am a huge advocate for learning to swim and spending time in and around the water,” Gilchrist said. “I think the water is a wonderful place to be, but like everything, there are hazards that are associated with it.”

Hlavsa emphasized that the key to maximizing the benefits of swimming during the summer, is simply to take a moment to assess the safety and sanitary conditions before anyone gets in the water.

“Swimming is a great way to spend time with family and friends, and it’s a great way to get physical activity,” Hlavsa said. “We’re just asking the public to do it in a healthier, safer way.” – by David Costill

Disclosures: Gallè, Gilchrist, Hlavsa, Jones and Meissner report no relevant financial disclosures.