Swimming is one of the great summer activities. But before you head into the surf or dive into the pool, you should know what you might be jumping into. Oftentimes it’s what you can’t see — invisible but lurking bacteria, parasites, and viruses that cause recreational water illnesses (RWIs) — that can pose a threat to your health. What should you be aware of? Keep reading…
Pools, Kiddie Pools and Water Parks
According to a study by the Centers for Disease Control and Prevention, nearly 60 percent of public pools surveyed contain Escherichia coli (E. coli) from fecal matter. Given that stat, it makes sense that the most common water-related illness in the U.S. is infectious diarrhea caused by Shigella, Norovirus, Giardia, E. coli, and Cryptosporidium (crypto), all spread by fecal matter. The good news: Not all E. coli strains cause illness, and chlorine kills most germs in less than an hour.
Children are at higher risk for Shigella because they often play in untreated water in inflatable and plastic kiddie pools or fountains and in splash tables, where there’s no chlorine to kill the bacteria. Kids also tend to swallow pool water and put their fingers in their mouths. The main symptom of a Shigella infection is diarrhea, often bloody, accompanied by fever and stomach cramps. Though it typically clears up within five to seven days, antibiotics can shorten sick time.
Best ways to stay safe: Prevent contamination (and set a good example) by taking a shower before and after diving in. Wash your hands after bathroom breaks. Most of all, try not to swallow water while you’re swimming. (Blech.)
Rivers, Streams, and Lakes
In streams, ponds, and lakes, you are likely to encounter the microbial cysts of Giardia lamblia, a parasite that dwells in the small intestine and spreads among humans and animals, including deer, beavers, and sheep. These protozoan parasites can leave you laid out for weeks with nausea, diarrhea, gas, stomach cramps, and greasy-looking stools.
You’re also at risk for swimmer’s itch (also called lake itch or duck itch), caused by flatworm parasites that can live in snails and waterfowl. Humans aren’t suitable hosts, so the parasites soon die after burrowing into the skin, but not before inciting the body’s allergic reaction — hence, the itch.
Best ways to stay safe: To avoid Giardia, don’t swallow water during your dip, even if your surroundings look pristine. Also, keep your hands clean and bring some alcohol-based sanitizer when you’re out in nature, or on your camping trip. As for swimmer’s itch, there’s a water-resistant cream available that claims to block the parasite from entering the skin.
Oceans
One in ten U.S. beaches failed to pass the Environmental Protection Agency (EPA) standard for safe swimming water, according to an annual report by the Natural Resources Defense Council (NRDC). Coming in with the tide: trash, motor oil, fertilizers, pesticides, and human waste.
Gastroenteritis is the most common form of waterborne illness contracted in the ocean, according to the EPA, caused by the same bacteria, protozoa, and viruses that lurk in pools. While you’re often not in close quarters with your fellow swimmers at the beach, and the ocean is vast, it’s the runoff from overwhelmed storm and sewer systems that introduce pollutants and untreated sewage into the water.
Best ways to stay safe: The NRDC recommends swimming at beaches where the water is tested frequently — the organization has a database of water-quality reports on more than 3,000 beaches, as well as a list of superstar beaches. The Waterkeeper Swim Guide app uses simple green and red designations of water quality to help users find safe beaches, from city parks to remote lakes.
If possible, stay out of the water at least 24 hours after rainfall (72 hours after a heavy rain), when pollutants and waste runoff are at the highest levels. Also avoid any visible storm water drainage pipes; those who swim near these outlets are 50 percent more likely to come down with an illness.
All of that being said—don’t be scared away from swimming, which is of course part of summer’s fun, not to mention great exercise for everyone. Just take a few precautions to enjoy a safer swim season!
