Explosive diarrhea cases increase as mysterious parasitic outbreak spreads across US

A mysterious parasite outbreak that can trigger severe, "explosive" diarrhea is rapidly expanding across the United States, with Michigan emerging as the hardest-hit state after reported cases quadrupled in less than a week.

Michigan health officials reported 681 confirmed cyclosporiasis cases as of Monday, up dramatically from 170 cases just days earlier. The surge comes as federal investigators continue searching for the source of the outbreak, which has now been identified in at least 17 states. The Post Millennial reported last week that the illness is caused by Cyclospora cayetanensis, a microscopic parasite typically spread through contaminated fresh produce or water. Despite the spike in infections, the CDC says investigators have not linked the outbreak to a common food source, complicating efforts to contain it.

New York has reported 120 cases since May 1, while Texas has confirmed 48 infections. Illinois, Virginia, Florida, North Carolina, Pennsylvania, New Jersey, Connecticut, Massachusetts, Colorado, Ohio, Wisconsin, Georgia, Louisiana, Alaska and Tennessee have also reported cases. The CDC's most recent nationwide update, released in mid-June, documented 145 cases across 17 states, but those figures do not include Michigan's recent surge, suggesting the true national total is now substantially higher. At least 20 people had been hospitalized, though no deaths have been reported.

Symptoms range from mild illness to debilitating gastrointestinal distress. Patients can experience watery diarrhea, severe abdominal cramping, nausea, vomiting, fatigue, and low-grade fever. Health officials say some of the most severe cases involve frequent bouts of "explosive" diarrhea that can lead to dangerous dehydration, particularly among young children, older adults, and people with weakened immune systems.

One Michigan patient, 51-year-old Cristy Cooper, described the illness as worse than any flu she had experienced. Cooper, who is immunocompromised and receives dialysis treatment, told the New York Post she suffered severe diarrhea beginning June 25 before developing vomiting, intense cramping and fever. At the peak of her illness, she said she was using the bathroom more than 30 times per day.

Doctors say diagnosing cyclosporiasis can be challenging because routine stool tests do not detect Cyclospora. Instead, physicians must specifically request laboratory testing for the parasite, meaning some infections may go undiagnosed. The CDC and state health departments continue investigating the outbreak to determine which food item is responsible, as it does not spread from person-to-person.