(CNN) – The Centers for Disease Control and Prevention warn people before going out to the pool to bathe after swimming.
There may be a parasite in the water that could literally turn your stomach. 19659004] It's called cryptosporidium or short crypto.
The parasite is scattered by faeces, and the CDC says they are getting more and more people to come down with it.
In a report that came out Friday, the CDC says they have experienced an increase of almost 13 percent every year between 2009 and 2017.
Most people who get crypt get it from the pool but you can also get it from lakes and cattle.
CDC says it can cause "vigorous aqueous diarrhea" for as long as three weeks.
It can be worse for children, pregnant women and anyone who has a compromised immune system.
Chlorine and filters are not enough to keep the crypt away, so if you go to the pool, soda after your swim.
And if you know someone who has had d Iarrhea recently, don't let them in the pool.