US health officials report surge in cyclosporiasis cases across 31 states

The Centers for Disease Control and Prevention said on Friday that 31 states have reported cases of cyclosporiasis, a gastrointestinal illness caused by the Cyclospora parasite, and that 86 people have been hospitalized. State health departments have confirmed 843 cases, all acquired domestically, while more than 1,500 additional cases remain under investigation. No deaths have been reported.

Michigan accounts for the largest share of infections, with 1,562 confirmed cases and at least 36 hospitalizations. The outbreak has also been noted in Ohio, Colorado, Illinois, New York, North Carolina, Texas, Wisconsin and other states.

"The rapid rise is highly unusual," said Dr. Natasha Bagdasarian, chief medical executive of Michigan. She added that laboratories are sequencing the parasite’s genome to determine whether the isolates are closely related and to trace a possible common source.

"In an average year, there’s a small proportion of cases that actually get traced back to one particular food item," said Dianna Blau, acting chief of the CDC’s Parasitic Disease Branch. She noted that the incubation period can exceed a week, making source identification difficult.

The CDC indicated that fresh produce is the most common vector, as Cyclospora can adhere to fruits, vegetables and herbs and survive standard rinsing. While the Food and Drug Administration is working with state partners, no product recalls have been issued.

Cyclosporiasis typically presents with watery diarrhea, abdominal cramps, nausea and flu-like symptoms about a week after exposure. Treatment usually involves the antibiotic Bactrim, and about 10% of patients require hospitalization for dehydration. Public health officials continue to interview patients and examine grocery receipts to pinpoint potential sources.