Given that summer is somehow only a short while off for Americans, here’s a timely reminder courtesy of the Centers for Disease Control and Prevention: Please, we beg you, keep your disgusting butt away from the swimming pool or hot tub if you’re feeling the least bit like you might have diarrhea.
On Thursday, the CDC released a new report detailing exactly what happens when you don’t. From 2000 to 2014, it found, there were 493 recreational water-related outbreaks of disease scattered across 46 states and Puerto Rico. These outbreaks collectively sickened at least 27,219 people and even killed eight.
Of the nearly 400 outbreaks that could be traced to a specific source, 94 percent were caused by germs. The three most common culprits were the microscopic parasite Cryptosporidium (crypto, if you’re feeling friendly), Legionella, and Pseudomonas bacteria, respectively. Only 6 percent, or 22 outbreaks, were caused by chemical contamination (e.g., too much chlorine in the water).
From 2000 to 2006, the number of crypto cases increased by an average 25 percent each year but stabilized after 2006. Annual cases of Legionella steadily increased by an average of 14 percent every year from 2000 to 2014, and cases of Pseudomonas declined by an average of 22 percent each year during that time.
There are certainly other factors that contributed to these outbreaks, such as lackluster chlorination and decontamination, water used from a contaminated source, or recreational watering holes that were kept too warm, allowing the germs to grow and survive longer. But most cases can be traced to people who were knowingly sick and still decided to wade in, the authors say.
“This is more about people being sick [than anything else],” lead author Michele C. Hlavsa, a member of the CDC’s Division of Foodborne, Waterborne, and Environmental Diseases, told Gizmodo. “It’s important for the public or their kids to not swim if they’re sick with diarrhea.”
That’s especially true because the most common pool-related bug—and the one spread by poo-ridden water—is crypto, which isn’t easily defeated by chlorine. Responsible for 89 percent of all identifiable cases the authors found, crypto can survive as long as seven days even in a well-maintained pool. Legionella and Pseudomonas bacteria aren’t very resistant to cleaning chemicals, but can survive in hot tubs and spas that aren’t properly cleaned with disinfectants by accumulating itself into a thick biofilm.
Crypto causes your standard set of stomach bug symptoms, including diarrhea. Legionella bacteria are responsible for the sometimes deadly lung infection Legionnaires’ Disease, especially if inhaled through aerosol droplets loaded with the bacteria. More often, it causes a mild flu-like illness known as Pontiac fever. And Pseudomonas bacteria typically irritate the skin, causing what’s commonly referred to as hot tub rash. If contaminated water gets stuck in your ear, it can also cause a painful outer ear infection.
Aside from common decency on the part of sick would-be swimmers, there are other things we can do to ensure we stay healthy this pool season, Hlavsa said. For instance, we can check our local public pool’s inspection score, as well as making sure to regularly inspect and properly maintain our own pools.
“And, of course, not swallowing the water once you’re in the water,” she added.