Not to dampen your weekend plans, but the CDC is warning people about parasites that can thrive in swimming pools.

Cryptosporidiosis is a gastrointestinal illness which can leave people suffering from diarrhea for weeks.

The CDC says the parasites that cause the illness can spread even in chlorinated water.

The agency is now calling for additional water treatments to try to fight the illness, such as extra chlorine and ultraviolet radiation.

In the meantime, CDC officials recommend people shower before and after getting into pools, avoid swallowing pool water, and wait at least two weeks after bouts of diarrhea to get back in the water.