(WSIL) � Before you head to the pool, you’ll want to know about something in the water that could make you sick.
It’s a parasite called cryptosporidium or "crypto" for short.
It’s spread by feces and the Centers for Disease Control and Prevention (CDC) says they’re seeing more and more people come down with it.
In fact, a  shows a nearly 13 percent increase every year between 2009 and 2017.
The CDC says it can cause "profuse, watery diarrhea" for as long as three weeks. It can be worse for kids, pregnant women and anyone who has a compromised immune system.
Chlorine and filters aren’t enough to keep "crypto" away, so if you go to the pool, shower after. And if you know anyone who’s had diarrhea recently, don’t let them in the pool.
Most people who get "crypto" get it from the pool but you can also get it from lakes and cattle.
