Key Takeaway:
- Nearly 4,000 U.S. cases of cyclosporiasis have been reported this year, with investigators still working to identify the contaminated produce responsible for the multistate cyclospora outbreak.
- Health officials advise washing fresh produce thoroughly, cooking foods when possible and seeking medical care for severe diarrhea or dehydration symptoms.
- The parasite spreads through contaminated food, not person-to-person contact, and tracing cyclospora outbreaks is challenging because symptoms can appear up to two weeks after exposure.
A multistate outbreak of cyclosporiasis has sickened nearly 4,000 people across the United States this year, prompting health officials to urge consumers to wash produce thoroughly and seek medical care for severe symptoms as investigators work to identify the contamination source.
Health officials are investigating a widespread Cyclospora outbreak, a foodborne illness caused by the Cyclospora parasite, after thousands of infections were reported nationwide. No deaths have been reported, but dozens of people have required hospitalisation. The CDC’s involvement here mirrors a similar CDC-led multistate outbreak investigation earlier this year, which also left health officials racing to pin down a contaminated food source.
Michigan has reported 3,762 confirmed cases as of July 15, a sharp increase from about 1,500 cases reported late the previous week. State officials said 44 people had been hospitalized as of July 9. Ohio has reported at least 364 cases, while nearly every state has identified at least one infection this year, according to compiled state health data. For the latest official case counts and updates, see the CDC’s outbreak investigation page.
Cyclosporiasis spreads through contaminated fresh produce rather than person-to-person contact. Common symptoms include watery diarrhea, stomach cramps, bloating, nausea, and vomiting. Illness typically begins between two days and two weeks after eating contaminated food and may last up to a month without treatment.
Investigators search for contamination source
Officials have not identified the specific food products responsible for the Cyclospora outbreak. Michigan health authorities said lettuce or bagged salad products remain possible sources, but no grower, supplier, or brand has been linked conclusively to the illnesses.
“At this time, no specific produce grower, supplier, or type of produce has been identified as the source,” Michigan Department of Health and Human Services spokesperson Laina Stebbins said in a statement.
Health experts said tracing cyclospora outbreaks is difficult because contaminated produce may travel through complex international supply chains before reaching consumers. The parasite is also difficult to detect, and infected people often struggle to remember what they ate one or two weeks before symptoms appear.
Dr. Kathleen Linder, a hospital epidemiologist at the Veterans Affairs hospital in Ann Arbor, Michigan, said investigations are further complicated by delays in reporting. She said reduced national surveillance has left states taking a larger role in tracking cases, making it harder to assemble a complete national picture.
Experts recommend extra precautions with produce
Previous U.S. outbreaks have been linked to bagged salads, basil, cilantro, peas, and berries. A large 2018 outbreak associated with contaminated restaurant salads sickened more than 500 people, while another investigation in 2020 examined bagged salad products without conclusively identifying the source. This year’s Cyclospora outbreak is already on pace to surpass those earlier events in total case count.
Experts recommend washing all fruits, vegetables, and herbs under running water before eating them. Firm produce should be scrubbed with a clean produce brush, and damaged portions should be discarded. Consumers may also consider purchasing whole heads of lettuce instead of prepackaged salads and rewashing produce labeled as prewashed.
Heat effectively destroys the parasite, making cooked produce safer than raw items during outbreaks. Health officials also advise refrigerating leftovers within two hours and considering locally sourced produce when possible.
People experiencing severe diarrhea should drink plenty of fluids to prevent dehydration. Those who develop dizziness, cannot keep fluids down, or notice signs of severe dehydration should seek medical attention promptly and notify their health care provider.
Health authorities said investigations continue as they work to identify the contamination source and prevent additional illnesses.
