The nationwide Cyclospora outbreak that has caused severe, sometimes "explosive" diarrhea appears to be easing slightly, but new cases and hospitalizations continue to rise. As of Aug. 11, the CDC reported 13,895 lab-confirmed infections across 47 states and Washington, D.C., with two deaths and 740 hospitalizations. Investigators have linked a large Michigan cluster to a Taylor Farms iceberg lettuce recall, but multiple clusters and sources remain under investigation. Officials warn consumers to keep exercising caution when buying and preparing produce until sources are clearly identified.
Cyclospora Outbreak May Be Easing — But Cases, Hospitalizations Remain High
Are cases of explosive diarrhea parasite slowing down? See the numbers.
New reports indicate the nationwide surge of cyclosporiasis — the intestinal parasite that can cause sudden, severe and sometimes "explosive" diarrhea — may be slowing slightly, but infections and hospitalizations are still rising as investigators work to identify all sources.
In its weekly update on Aug. 11, the Centers for Disease Control and Prevention (CDC) reported 13,895 laboratory-confirmed Cyclospora infections with onset on or after May 1 across 47 states and Washington, D.C. That total reflects an increase of more than 3,400 cases since the agency's Aug. 4 update. The CDC also reported two deaths and 740 hospitalizations, including 223 hospitalizations newly reported that week.
The CDC noted at least 10,455 additional probable cases are pending laboratory confirmation. The agency's national total typically lags state-level counts by roughly six weeks because of the time required for testing, verification and federal reporting. The CDC's public tally includes only lab-confirmed illnesses among people who did not travel internationally within 14 days before symptoms began.
Michigan remains the epicenter. State health officials reported 13,909 total cases as of Aug. 13, up from 12,485 on Aug. 6. The Michigan-centered cluster has been linked by the Food and Drug Administration (FDA) to a recall of iceberg lettuce produced by Taylor Farms in Mexico; illnesses tied to that lettuce have been confirmed in 15 states.
"Since we don't know the source or what the cause is, we don't know that it's not an ongoing problem. In fact, we don't even know for sure what fruits and vegetables are causing the disease," said Dr. Dana G. Mordue, associate professor of pathology, microbiology and immunology at New York Medical College.
Symptoms and Who Is Most At Risk
Cyclosporiasis is caused by the parasite Cyclospora cayetanensis and typically spreads through contaminated food or water. Symptoms resemble foodborne illness and can range from mild to severe. Common signs include:
- Watery, frequent and sometimes "explosive" diarrhea
- Vomiting
- Nausea and loss of appetite
- Bloating, gas or stomach cramps
- Extreme tiredness (fatigue) and fever
Many people recover at home and never seek medical care, so reported cases likely undercount the total number of infections. People with weakened immune systems or other serious health conditions are at higher risk for severe disease and complications.
Why Tracing Cyclospora Is Challenging
Investigators face several hurdles when tracking Cyclospora outbreaks: the parasite has a relatively long incubation period, obtaining diagnostic samples can be difficult, and public-health labs lack the rapid genetic-tracing tools used for bacterial outbreaks (for example, E. coli or Listeria). As a result, linking individual illnesses to a single contaminated source can take weeks or months, and multiple distinct clusters may be identified before investigators can connect them.
So far, the CDC and FDA have identified several separate case clusters, and the Taylor Farms iceberg lettuce has been tied to one major cluster. However, no single definitive cause has been identified for the entire multi-state outbreak.
What Consumers Should Do
Public-health officials advise people to continue practicing safe food handling: wash produce when appropriate, thoroughly cook foods when recommended, and follow recall notices. If you develop persistent or severe diarrhea, especially with dehydration, seek medical care and mention possible exposure to produce or travel history so clinicians can request appropriate testing.
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