The U.S. Centers for Disease Control (CDC) said this week that the majority of swimming pools across the country are contaminated by fecal matter.
Researchers with the government agency made the finding after testing a number of pools over the summer in 2012.
The researchers said that “swimmers frequently introduced fecal material into pools,” meaning that germs could spread to other people. E. coli is generally found in human feces.
They also found genetic material for the Pseudomonas aeruginosa bacteria that can cause rashes and ear infections.
The fecal matter, they said, comes from swimmers who do not take a shower or bath before entering the pool, as the average person has 0.14 grams of feces on their “perianal surface,” according to LiveScience.
Overall, it found that 58 percent of pool water has fecal matter in it.
“Escherichia coli, a fecal indicator, was detected in 93 (58%) samples; detection signifies that swimmers introduced fecal material into pool water. Fecal material can be introduced when it washes off of swimmers’ bodies or through a formed or diarrheal fecal incident in the water,” the CDC said on its website.
While E. coli was found in indoor and outdoor pools equally, the study found outdoor pools are more contaminated over all, according to the Atlantic Wire. It said that municipal pools were the worst-contaminated.
And pools where children are the main users were found to be the dirtiest.
The parasites Giardia and Cryptosporidium were found in less than 2 percent of pool samples, according to LiveScience.
“Swimming is an excellent way to get the physical activity needed to stay healthy,” said Michele Hlavsa, head of the CDC’s Healthy Swimming Program, in a release. “However, pool users should be aware of how to prevent infections while swimming. Remember, chlorine and other disinfectants don’t kill germs instantly.”
She added: “That’s why it’s important for swimmers to protect themselves by not swallowing the water they swim in and to protect others by keeping feces and germs out of the pool by taking a pre-swim shower and not swimming when ill with diarrhea.”
