Health officials are continuing to investigate as cases of cyclosporiasis, an intestinal illness caused by a parasite, spread across the United States. Health officials are continuing to investigate as cases of cyclosporiasis, an intestinal illness caused by a parasite, spread across the United States. Health officials are continuing to investigate as cases of cyclosporiasis, an intestinal illness caused by a parasite, spread across the United States. Health officials are continuing to investigate as cases of cyclosporiasis, an intestinal illness caused by a parasite, spread across the United States. Cases of cyclosporiasis, an intestinal illness caused by a parasite, have topped 18,000 in 45 states, according to updated data Wednesday from the Centers for Disease Control and Prevention (CDC).