The United States is experiencing its largest known outbreak of and other gastrointestinal illness, with thousands of infections reported across more than 30 states.
The US Centers for Disease Control and Prevention (CDC) has confirmed 1,645 cases of and is investigating more than 5,100 additional possible cases in 34 states. State-level data suggests 2026 has already surpassed the previous national record set in 2019, making it the worst year on record for reported infections.
Here’s what you need to know.
What is cyclospora?
that infects the small intestine and causes an illness known as cyclosporiasis.
People usually become infected after consuming raw fruits, vegetables or water contaminated with feces containing the parasite. Unlike many other infections, cyclospora is not commonly spread directly from person to person because the parasite requires time in the environment before it becomes infectious.
What are the symptoms?
Symptoms can appear two days to more than two weeks after infection and may last for weeks if left untreated.
Common symptoms include:
-Frequent watery diarrhea, sometimes described as “explosive”
-Nausea and vomiting
-Loss of appetite
-Stomach cramps
-Bloating
-Fatigue
-Weight loss
-Low-grade fever
While most people recover, severe diarrhea can lead to dehydration and hospitalization, particularly in vulnerable individuals.
Who is most at risk?
The illness can affect anyone, but serious complications are more likely in:
-Young children
-Older adults
-People with weakened immune systems
-People living with HIV
-Individuals with chronic medical conditions
Which states are most affected?
The CDC says cases linked to the current outbreak have been identified in 34 states.
The hardest-hit areas include:
Michigan: More than 3,300 cases
Ohio: More than 1,100 cases
New York City: More than 400 cases
Illinois: More than 200 cases
Federal investigators believe cases in Michigan, Ohio, Kentucky and West Virginia may be linked to the same outbreak, although other infections may have separate sources.
What is causing the outbreak?
Investigators have not yet identified a single source.
However, Michigan officials say interviews with more than 1,000 patients suggest lettuce or salad greens may be a common factor.
The US Food and Drug Administration (FDA) is conducting traceback investigations involving multiple produce items to identify where contamination occurred.
Past have been linked to:
-Bagged salad mixes
-Fresh cilantro
-Basil
-Raspberries
-Snow peas
-Green onions
How is the FDA investigating?
The FDA is tracing foods eaten by infected people back through the supply chain—from restaurants and grocery stores to distributors, processors and farms—to determine where contamination may have occurred.
Officials stress that no single grower, supplier or produce item has yet been confirmed as the source.
How can you protect yourself?
Health experts recommend:
-Wash hands thoroughly with soap and water before handling food.
-Wash fresh fruits and vegetables under running water.
-Scrub firm produce with a clean brush.
-Consider buying whole heads of lettuce instead of bagged salads until more information is available.
-Avoid consuming produce that appears spoiled or improperly stored.
Because cyclospora can survive on fresh produce, washing may reduce—but not completely eliminate—the risk.
Why are cases increasing?
Health experts say several factors may be contributing to the rise in infections:
-Improved laboratory testing and detection
-More widespread surveillance by public health agencies
-Increased consumption of fresh imported produce
-Climate conditions that may favor the parasite’s survival
(With Reuters, AP inputs)
