Additional Coverage:
A widespread outbreak of cyclosporiasis, a parasitic infection that causes severe gastrointestinal distress, has now been reported in 47 states across the U.S., reaching record-high numbers this season.
According to the Centers for Disease Control and Prevention (CDC) update released on August 4, there have been 10,468 laboratory-confirmed cases of cyclospora infections since May 1. This marks an increase of more than 3,700 cases compared to the agency’s last report on July 28. Additionally, at least 12,255 more cases are currently under investigation but have not yet been confirmed through laboratory testing.
The outbreak has resulted in 517 hospitalizations and two reported deaths. Health officials are actively investigating multiple separate outbreaks, with the largest cluster centered in Michigan. The state has reported over 11,000 cases and the two fatalities linked to the outbreak, though these figures have not yet been fully verified by the CDC.
Federal authorities have connected the most significant outbreak to iceberg lettuce produced by Taylor Farms in central Mexico. The company initiated a recall of the implicated lettuce on July 17 as a precautionary measure.
Currently, only Delaware, Hawaii, and Montana remain free of reported cases. Michigan and Ohio are the hardest hit, with Washington, D.C. also reporting a few infections.
The CDC notes that its data only include laboratory-confirmed cases occurring in people who did not travel internationally within 14 days prior to illness onset, which may explain some discrepancies compared to state-level reports. Reporting delays typically result in a six-week lag between the onset of illness and CDC confirmation.
Understanding Cyclosporiasis and Its Symptoms
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis and is typically contracted through ingestion of contaminated food or water. The infection primarily affects the gastrointestinal tract, producing symptoms such as watery and frequent diarrhea, which can sometimes be described as “explosive.” Other common symptoms include nausea, vomiting, loss of appetite, stomach cramps, bloating, fatigue, and fever.
While most individuals recover without complications, the illness can be more severe in people with weakened immune systems or underlying health conditions. Deaths from cyclosporiasis are rare.
Scope of the Lettuce-Linked Outbreak
The outbreak linked to iceberg lettuce from Taylor Farms has been identified as the largest in the country, with Michigan alone reporting 11,508 cases and two deaths as of early August. Confirmed cases tied to this lettuce have been reported in nine states: Illinois, Indiana, Kansas, Kentucky, Michigan, Ohio, Oklahoma, Pennsylvania, and West Virginia.
Health officials have traced these cases through epidemiological investigations, including identifying genetic markers in the parasite, to confirm that the infections are connected to the same source. However, tracking cyclosporiasis outbreaks is challenging due to the parasite’s long incubation period and the difficulty in obtaining samples. Unlike other foodborne pathogens such as E. coli or listeria, there are currently no rapid genetic tools available to trace cyclospora infections with the same precision.
The CDC and the Food and Drug Administration (FDA) have also identified several other clusters of cyclosporiasis cases in different regions, but no common sources have yet been determined for those outbreaks.
Public health officials continue to monitor the situation closely and advise consumers to be cautious with fresh produce, particularly iceberg lettuce, while investigations remain ongoing.