Swimming pools are a major source of injury and death for children in the U.S., but they are also responsible for many outbreaks of waterborne disease, government health officials warn.
One-third of all recreational waterborne disease outbreaks from 2000 through 2014 occurred in hotel pools and hot tubs, the U.S. Centers for Disease Control and Prevention (CDC) says in a new report.
The pathogens Cryptosporidium (also known as “Crypto”), Pseudomonas, and Legionella were responsible for the largest number of outbreaks in swimming pools throughout the U.S. during the 14-year time period analyzed, according to the CDC report.
The Crypto parasite is tough enough to survive even in properly maintained pools, the CDC warned, while the Pseudomonas and Legionella bacteria can survive disinfectants in the slimy areas of pools, hot tubs, and water parks and playgrounds.
Crypto causes 58 percent of outbreaks linked to pools but accounts for 89 percent of the illnesses. Crypto spreads in pools when someone sick with the parasite has diarrhea in the water and other swimmers swallow that contaminated water, the CDC says, adding that parents of young swimmers play a key role in preventing these outbreaks.
“Swallowing just a mouthful of water with Crypto in it can make otherwise healthy kids and adults sick for weeks with diarrhea, stomach cramps, nausea, and vomiting,” said Michele Hlavsa, R.N., M.P.H., chief of CDC’s Healthy Swimming Program. “Chlorine cannot kill Crypto quickly. We need to keep it out of the water in the first place. Don’t go into the water, and don’t let your kids go into the water, if sick with diarrhea.”
The bacteria Legionella and Pseudomonas are the next most leading causes of these outbreaks. Legionella caused 16 percent of the outbreaks and Pseudomonas caused 13 percent Legionella can cause severe respiratory distress and pneumonia with symptoms similar to the flu. Pseudomonas can cause hot tub rash and swimmer’s ear, the CDC says.
If a pool, hot tub, or water playground is not cleaned properly, bacteria can grow and form a slime called biofilm on wet surfaces. Legionella and Pseudomonas can live in this biofilm, and it is harder for disinfectants to kill these bacteria when they are protected by biofilm.
The CDC says it’s up to pool operators to properly clean and disinfect the pools to prevent bacteria from growing and causing illness.
Some people are more likely to get sick from Legionella, including people 50 years or older, current or former smokers, people with chronic lung disease, and people with a weakened immune system. These people should see a doctor right away if they develop pneumonia symptoms and let the doctor know about any possible exposures to Legionella, including recent hot tub use, the CDC advises.