What is cyclosporiasis, the parasitic illness causing ‘explosive’ diarrhea?

The CDC is investigating a surge of cyclosporiasis, a parasitic illness causing explosive, watery diarrhea, across 18 US states. Over 1,600 cases are linked to lettuce served at Taco Bell in Indiana, Kentucky, Michigan, Ohio, and West Virginia. Michigan experienced an abnormally large outbreak with nearly 1,000 cases, the largest in its history. Ohio also reported a sharp increase with 177 cases. While rarely life-threatening, the illness can cause severe effects for those infected.