A microscopic parasite is causing illness in thousands across the U.S., and investigators still haven't found the source.

Explosive diarrhea parasite cyclosporiasis is causing possible outbreaks in half of US states. See a map of the rising rates ...

Symptoms can come and go for weeks if left untreated.

The U.S. Centers for Disease Control and Prevention is working to find the source of a parasitic illness that's spreading ...

Hundreds of people in the U.S. have gotten sick so far from cyclosporiasis.

A parasitic infection causing severe diarrhea is surging in multiple states, with hundreds of cases reported. The illness, cyclosporiasis, is transmitted through food and water contaminated with feces ...