Pools can be inviting for families to cool off from the heat during summer vacations. However, a recent CDC report demonstrates that many swimming-related disease outbreaks occur at hotel pools or hot tubs.1,2 Pharmacists can play an important role in educating patients regarding healthy swim habits, and outbreak prevention strategies.
There have been 493 outbreaks associated with treated recreational water during 2000-2014, which caused at least 27,219 illnesses, and 8 deaths.2 Outbreaks associated with pools and hot tubs are determined when similar illnesses occur in 2 or more individuals linked to the same location and time of exposure to pathogens or chemicals. Hotels were found to be the leading setting, associated with 157 (32%) of the outbreaks. About 50% of the outbreaks occurred June-August, the peak swimming season.2
Outbreak Causes and Treatment Options
The most common infectious cause (58%) of the outbreaks in pools, hot tubs, and water playgrounds was Cryptosporidium, which causes gastrointestinal adverse effects including diarrhea.2 Other outbreak causes include Pseudomonas, and Legionella. Cryptosporidium symptoms usually occur around 7 days after becoming infected, and generally include the following:
- Watery diarrhea
- Stomach pain
- Weight loss
Cryptosporidium spreads in pools when someone sick with the parasite has diarrhea in the pool, and other swimmers swallow the contaminated water. In heathy patients, Cryptosporidium generally resolves on its own, and is diagnosed through stool samples. Educate patients to manage the diarrhea by drinking plenty of fluids to prevent dehydration. Oral rehydration solutions, such as Pedialyte® for infants and children, and Gatorade for adults, should be used to replenish electrolytes lost through diarrhea. Alinia (nitazoxanide) is FDA approved for the treatment of diarrhea caused by Cryptosporidium.3 Individuals with severe dehydration may need to be hospitalized and receive intravenous fluids.
Prevention is key to reduce the risk of pool-related outbreaks. The CDC has a national campaign known as Healthy and Safe Swimming Week, which occurs May 21-27, 2018. This encourages swim related activities for physical fitness, and health benefits, while minimizing the risk of illness. The CDC provides a useful map with state specific healthy swimming resources that include pool code information, beach monitoring, facts on outbreaks, and public health contact information. Pharmacists can encourage parents to follow these prevention strategies:1
- Adults and children with diarrhea should not swim.
- Individuals infected with Cryptosporidium should wait to swim until 2 weeks after diarrhea has stopped.
- Check the pool inspection scores.
- Use a test strip from a pool supply store to check if the water’s pH and bromine or free chlorine level are correct.
- Avoid swallowing the water. Swim lessons can help prevent children from swallowing water.
- Children should be taken on bathroom breaks regularly, and diapers should be changed away from the pool.
- Children that are not toilet trained must wear a swim diaper in the pool and water playground.
- Rinse off the pool water immediately after swimming.
- Centers for Disease Control and Prevention. 1 in 3 swimming-related disease outbreaks occur at hotels. https://www.cdc.gov/media/releases/2018/p0517-swimming-related-diseases.html. Accessed May 18, 2018.
- Hlavsa MC, Cikesh BL, Roberts VA, et al. Outbreaks Associated with Treated Recreational Water-United States, 2000-2014. MMWR Morb Mortal Wkly Rep 2018;67:547-551.DOI:http://dx.doi.org/10.15585/mmwr.mm6719a3.
- Centers for Disease Control and Prevention. Parasites- Cryptosporidium. https://www.cdc.gov/parasites/crypto/. Accessed May 18, 2018.