Cases of cyclosporiasis, a parasitic infection known for causing “explosive” diarrhea, have now reached 47 states as the illness hits unprecedented numbers. According to the Centers for Disease Control and Prevention (CDC) in its weekly update on August 4, there have been 10,468 laboratory-confirmed cases since May 1. This figure marks an increase of more than 3,700 cases since the agency’s previous report on July 28.
The geographic reach of the illness has expanded to 47 states, an increase from 45 states just one week prior. Beyond the confirmed laboratory counts, the CDC noted that at least 12,255 additional cases have not yet been verified by clinical testing. To date, the agency has recorded 517 hospitalizations and two deaths associated with the infection.
Federal health authorities are actively investigating what they believe to be multiple separate outbreaks. The largest of these is centered in Michigan, where state officials reported 11,508 cases and two deaths as of August 4. These state-level figures often exceed federal counts due to the time required for tracking, verification, and reporting processes. The CDC typically experiences a six-week reporting lag between an illness occurring and its formal inclusion in federal data.
The Michigan-centered outbreak has been linked by the Food and Drug Administration to recalled iceberg lettuce produced by Taylor Farms in central Mexico. This discovery prompted the company to initiate a recall on July 17. Illnesses associated with this specific lettuce outbreak have been confirmed in nine states: Illinois, Indiana, Kansas, Kentucky, Michigan, Ohio, Oklahoma, Pennsylvania, and West Virginia.
Health officials identified these states after testing sick individuals and tracing the genetic “DNA” of the infections. Cases that are found to be related are considered part of the same outbreak, likely originating from the same source. Thus far, these nine states are the only ones the CDC has been able to confirm as related to each other and trace back to the contaminated lettuce.
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis and is typically contracted through contaminated food or water. While the infection is unpleasant, it is not generally known to cause death, and many cases go unreported because individuals often recover at home without seeking medical attention. However, it can lead to serious complications for those with compromised immune systems or other underlying health conditions.
The most common symptom is watery, frequent, and sometimes “explosive” diarrhea, according to the CDC and the Cleveland Clinic. Other symptoms include bloating, burping, gas, and stomach cramps, as well as nausea and vomiting. The CDC only reports lab-confirmed cases that occurred on or after May 1 in people who did not travel internationally within 14 days of the onset of their illness.
Tracking the source of a cyclosporiasis outbreak is notoriously difficult compared to other foodborne illnesses. Challenges include a long incubation period, the difficulty of obtaining viable samples, and the inability to utilize the same genetic tracking tools available for pathogens like E. coli or listeria. Currently, only Delaware, Hawaii, and Montana have been spared from the outbreaks, while Michigan and Ohio remain the most heavily impacted states, with a small number of cases also reported in Washington, D.C. Several other separate case clusters remain under investigation by the CDC and FDA, with no common cause yet identified.
The state reported more than 11,000 cases of cyclosporiasis and the first two U.S.
