Health authorities are scrambling to identify the source of a parasitic outbreak that has sickened hundreds across the United States, with victims reporting severe, sometimes explosive diarrhea. The Centers for Disease Control and Prevention (CDC) first flagged large clusters of cyclosporiasis in early May, and as of its latest update on July 1, had recorded 145 cases across 17 states. But the numbers have since climbed sharply.
As of Monday, the illness has spread to at least 18 states, with Michigan reporting 572 cases as of July 4 and New York tallying more than 100. Illinois and Texas have not released exact figures. Health officials caution that current counts likely understate the outbreak, as many infected individuals do not seek medical attention unless symptoms become severe. Other states affected include Alaska, Colorado, Connecticut, Florida, Georgia, Louisiana, Massachusetts, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, and Wisconsin.
The CDC and the U.S. Food and Drug Administration have not yet pinpointed a specific produce item, product, or supplier responsible for the outbreak. Cyclosporiasis typically spreads through food or water contaminated with feces, and previous outbreaks have been linked to bagged salad mixes, fresh cilantro, basil, raspberries, snow peas, and green onions. The last major outbreak in 2019, which sickened at least 2,400 people across 37 states and the District of Columbia, was traced to basil imported from Mexico.
While cyclosporiasis is rarely life-threatening, it can cause debilitating symptoms including watery diarrhea, cramps, nausea, fatigue, and vomiting. The CDC notes that the most common symptom is watery diarrhea with frequent, sometimes explosive bowel movements. Other symptoms include loss of appetite, weight loss, increased gas, body aches, headache, low-grade fever, and flu-like symptoms. Without antibiotic treatment, the illness can last from a few days to over a month, and symptoms may recur.
The parasite responsible, Cyclospora cayetanensis, is more common in tropical and subtropical regions, raising the risk for travelers and those living in such areas. For context, the current outbreak emerges amid broader public health concerns, including a recent surge in West Nile virus cases to a 22-year high, underscoring the ongoing challenges in infectious disease surveillance and response.
To reduce the risk of cyclosporiasis, the CDC recommends washing hands before and after handling raw produce, thoroughly washing all fruits and vegetables, scrubbing firm produce with a clean brush, cutting away damaged areas, refrigerating cut or peeled items within two hours, and cooking raw foods to at least 158°F to kill the parasites. These precautions are especially relevant given that previous outbreaks have been tied to fresh produce, highlighting the need for vigilance in food safety.
The outbreak also raises questions about the adequacy of food safety regulations and import inspections, a topic that has drawn scrutiny from lawmakers and public health advocates. As the CDC and FDA continue their investigation, the public is urged to stay informed and take preventive measures to avoid infection.
