A parasitic infection called cyclosporiasis has triggered concern across several US states after health officials reported a rise in cases linked to severe gastrointestinal symptoms, including prolonged and sometimes intense diarrhea.
Michigan has reported one of the largest clusters, with hundreds of infections recorded in recent weeks. While officials suspect contaminated fresh produce may be behind the outbreak, investigators have not yet identified a specific food item, brand or supplier responsible.
What is cyclosporiasis?
Cyclosporiasis is a foodborne illness caused by the parasite Cyclospora cayetanensis, according to the Centers for Disease Control and Prevention.
The infection occurs when people consume food or water contaminated with the parasite, which is usually spread through contact with feces. It commonly affects the intestinal tract and can cause symptoms that last for weeks if untreated.
The CDC says symptoms generally appear two days to 14 days after exposure. The most common symptom is “watery diarrhea with frequent, sometimes explosive, bowel movements.”
Other symptoms may include stomach cramps, nausea, vomiting, fatigue, loss of appetite, weight loss, increased gas, body aches and low-grade fever.
Although cyclosporiasis is not usually life-threatening, untreated infections can continue for several weeks, with symptoms sometimes disappearing and returning.
Why are US health officials investigating an outbreak?
Health officials have reported cases of cyclosporiasis across multiple states, including Michigan, Illinois, New York and Texas.
In Michigan, the Michigan Department of Health and Human Services (MDHHS) said cases have climbed rapidly, reaching at least 700 infections. Monroe County has reported the highest number of cases in the state, followed by Washtenaw, Lenawee, Shiawassee and Wayne counties.
Officials believe contaminated fresh produce is the leading possible source, but no specific product has been confirmed.
Michigan Chief Medical Executive Dr. Natasha Bagdasarian said the growing number of cases has made tracing the source more challenging.
“So we have 700 people who need to be interviewed, which makes things significantly more complicated. But I can tell you that our main hypothesis right now is contaminated produce,” Bagdasarian said.
How does cyclosporiasis spread?
The parasite is often linked to fresh fruits and vegetables because these foods may become contaminated during growing, harvesting, processing or handling. Officials said identifying the source can be difficult because food supply chains often involve multiple states.
“There is food that is grown in one state, that is packaged and processed in another state, and then sent out to a variety of states,” Bagdasarian said.
Previous cyclosporiasis outbreaks have been associated with foods including bagged salad mixes, fresh herbs such as cilantro and basil, raspberries, snow peas and green onions.
How can people prevent cyclosporiasis?
Health officials recommend taking precautions while preparing fresh produce.
The CDC advises people to wash their hands before and after handling fruits and vegetables, thoroughly rinse produce before eating, and scrub firm items such as cucumbers and melons with a clean brush.
People should also refrigerate cut or cooked produce promptly. For foods that can be cooked, heating them to at least 158°F (70°C) can help kill the parasite.
Anyone experiencing persistent diarrhea, severe abdominal pain, dehydration or worsening symptoms should seek medical advice, as cyclosporiasis may require treatment with antibiotics.
