Thousands of cyclosporiasis cases, a parasitic illness causing prolonged diarrhea, have been reported across several U.S. states, primarily in the Midwest and on the East Coast. While California has recorded some cases, none are currently linked to the ongoing national outbreak, though public health officials are urging residents to adopt preventive measures.
Cyclosporiasis is an intestinal infection caused by the parasite Cyclospora cayetanensis, which spreads through contaminated food or water originating from human feces. Infection occurs through the consumption of contaminated items, and the illness is not transmitted directly from person to person. Michigan has emerged as the epicenter of the current outbreak, with over 1,000 cases reported since June, including 44 hospitalizations, a significant increase from its typical annual count of approximately 50 cases. Seventeen states have reported numerous cases, with officials estimating the actual number of infections to be higher due to individuals recovering without seeking medical attention or testing.
In the United States, previous cyclosporiasis outbreaks have been associated with imported fresh produce from Latin America, such as raspberries, cilantro, and basil. The current outbreak's affected individuals reported falling ill after consuming food within the U.S. and did not report travel to affected regions within the two weeks preceding their illness. The age range of those infected spans from 5 to 86 years. Federal health agencies, including the CDC and FDA, are collaborating with local authorities to investigate the cases, noting that there is no current evidence of a single, unifying multi-state outbreak or common source linking all infections.
California has reported 41 provisional cases of cyclosporiasis between January and June of the current year, compared to 80 cases during the same period last year. Most of these cases are linked to international travel. State health officials will closely monitor for any cases potentially associated with travel to outbreak regions and for clusters within California that might indicate local transmission. Since May 1st, four domestic cases have been reported in California, with two individuals having traveled to the Midwest; investigations into these cases are ongoing.
Symptoms of cyclosporiasis typically appear between two days and two weeks after exposure and can include watery diarrhea, loss of appetite, nausea, fatigue, and stomach cramps. Less common symptoms may involve vomiting, body aches, and fever. While some infected individuals, particularly those from endemic areas, may remain asymptomatic, symptoms can persist for weeks or months if left untreated, with intermittent relapses being possible. Treatment usually involves a course of antibiotics.
To prevent infection, especially when traveling to tropical or subtropical regions where cyclosporiasis is endemic, authorities advise avoiding tap water and ensuring hot foods are served hot and cold foods are kept chilled. Given the historical link to imported produce, California and other affected states recommend thorough washing of all fresh fruits and vegetables before consumption, particularly those from potentially contaminated sources.
