Warning: If you’re eating dinner, please consider finishing your meal before reading this article. A new study from the Centers for Disease Control and Prevention (CDC) found the poop contaminates 58 percent of public swimming pools. That, according to a news release from the CDC, is the percentage of the pool filter samples that tested positive for E. coli. To conduct their study, the researchers collected samples of pool filter water from public pools.

E. coli bacteria typically reside in the intestines of people and animals. While most E. coliare are not dangerous, some E. coli can cause diarrhea or illness outside of the intestinal tract. According to the U.S. National Library of Medicine, the worst type of E. coli causes bloody diarrhea, and can occasionally result in kidney failure and sometimes death. You can get E. coli illnesses by consuming foods containing the bacteria.

The researchers posit that their discovery of a high percentage of E. coli-positive filters in public pools across the United States suggests several unsanitary practices are at fault: First, swimmers are pooping in the pool and, second, fecal matter is being washed off of swimmers’ bodies because they fail to adequately shower before entering the water. Fortunately, the CDC says that no pool filter samples tested positive for a toxin-generating E. coli strain that brings about illness.

However, the researchers discovered Pseudomonas aeruginosa in 59 percent of the samples. While serious Pseudomonas infections typically take place in people in the hospital, healthy people can experience mild illnesses due to Pseudomonas aeruginosa, especially after being in the water. Ear and eye infections, as well as skin rashes, may be caused by exposure to poorly chlorinated swimming pools. The researchers detected Cryptosporidium and Giardia in less than two percent of samples.

The researchers collected samples from indoor and outdoor pools but didn’t look at water parks, residential pools or other types of recreational water. Thus, the study doesn’t allow the researchers to draw conclusions about all pools in the U.S. However, the CDC notes that the problems with swimmer-introduced contamination or swimmer hygiene practices are probably widespread and not limited to their study.

According to Michele Hlavsa, the boss of the CDC’s Healthy Swimming Program, swimming is a great way to stay healthy. However, swimmers need to be aware that chlorine doesn’t kill germs instantly. She reminds swimmers to take a pre-swim shower and to avoid pools when ill with diarrhea or any other intestinal disease.

The CDC has several recommendations to prevent infections while using indoor and outdoor swimming pools:

• Keep poop out of the water.
• Verify the chlorine level and pH before entering the water.
• Do not swallow the water you swim in.

You can read more about these steps and other ways you can prevent the spread of illness here.

What do you think of the CDC’s findings? Are you grossed out by this information or is this common knowledge among pool goers? Have you ever been stricken with E. coli? Will you still visit public pools? Share your thoughts in the comments section.