United States -- July 20, 2026: The investigation into the nationwide Cyclospora outbreak has taken an unexpected turn after the U.S. Food and Drug Administration (FDA) announced that a laboratory test previously believed to confirm the parasite in shredded iceberg lettuce was actually a false positive.
Federal and state health officials continue gathering evidence while trying to determine whether they are dealing with a single nationwide outbreak, multiple unrelated outbreaks, or several contamination events occurring during the same growing season.
Current Numbers
• The Centers for Disease Control and Prevention (CDC) has confirmed 1,645 domestically acquired laboratory-confirmed cases of cyclosporiasis in 34 states.
• The CDC is also reviewing more than 5,100 additional reports to determine whether they meet the criteria for confirmed cases.
• North Carolina has reported 307 confirmed cases and 13 hospitalizations between May 1 and July 14.
• No deaths have been reported in connection with the current outbreak.
These numbers continue to change as investigators review new reports and complete additional laboratory testing.
What Changed?
Earlier this month, the FDA announced that a sample of shredded iceberg lettuce associated with Taylor Farms de Mexico had tested positive for Cyclospora cayetanensis, the parasite that causes cyclosporiasis.
After additional laboratory review, FDA scientists determined that the laboratory result was a false positive and officially withdrew that finding.
As of this writing, the FDA has not confirmed Cyclospora in any food product through laboratory testing.
Despite the withdrawal of the laboratory result, the FDA continues investigating shredded iceberg lettuce because epidemiological evidence—the food histories reported by people who became sick—continues to point investigators toward lettuce as one possible source.
The voluntary recall associated with the investigation also remains in effect while additional testing, environmental sampling, and supply-chain tracing continue.
What Is Cyclospora?
Cyclospora is a microscopic parasite that causes an intestinal illness known as cyclosporiasis. People become infected by consuming food or water contaminated with the parasite.
Symptoms often include prolonged diarrhea, stomach cramps, nausea, fatigue, loss of appetite, weight loss, bloating, and low-grade fever. Illness can last for weeks and sometimes longer if left untreated.
Unlike viruses such as norovirus, Cyclospora is not typically spread directly from person to person. Most outbreaks are linked to contaminated fresh produce or contaminated water.
North Carolina Investigation Continues
North Carolina is also experiencing a significant increase in Cyclospora cases during the same time period.
According to the North Carolina Department of Health and Human Services, 307 confirmed cases and 13 hospitalizations have been reported between May 1 and July 14.
State health officials have stated that, based on the evidence currently available, they have not linked North Carolina's increase in cases to outbreaks in other states.
However, investigators have not identified the source of North Carolina's illnesses.
That means no one can say with certainty whether the outbreaks are connected or completely unrelated.
Both the North Carolina investigation and the federal investigation remain active, and health officials may revise their conclusions as additional evidence becomes available.
Can Multiple Outbreaks Occur at the Same Time?
Although uncommon, the answer is yes.
Cyclospora has caused multiple simultaneous outbreaks in previous years. During earlier investigations, health officials eventually traced illnesses to different foods, including:
• Bagged salad mixes
• Fresh cilantro
• Basil
• Vegetable trays
• Other fresh produce
Because fresh produce is grown, harvested, processed, and distributed through many different supply chains, more than one contamination event can occur during the same growing season.
What makes the current investigation unusual is the combination of factors:
• Cases have been reported across 34 states.
• The CDC has confirmed 1,645 laboratory-confirmed domestically acquired cases while reviewing more than 5,100 additional reports.
• No food product has been laboratory-confirmed as the source.
• One of the FDA's most significant laboratory findings was later determined to be a false positive.
• Investigators are evaluating whether multiple outbreaks may be occurring at the same time.
Why Is This Investigation So Difficult?
Cyclospora is one of the more challenging foodborne parasites to investigate.
By the time patients become ill and seek medical care, the contaminated food has often already been consumed or discarded, making laboratory confirmation extremely difficult.
Investigators must combine several different types of evidence, including:
• Patient interviews
• Purchase records
• Restaurant distribution records
• Farm traceback investigations
• Environmental inspections
• Laboratory testing
No single piece of evidence is usually enough to identify the source.
Instead, investigators build the case by combining information from all available sources.
The CDC and FDA work together throughout these investigations. The CDC focuses on identifying illness patterns, interviewing patients, and determining whether cases are related, while the FDA focuses on tracing foods through the supply chain, inspecting facilities, collecting samples, and determining whether a particular food product is responsible. Information is continuously shared between federal, state, and local health agencies as the investigation progresses.
Federal Staffing Is Also Part of the Story
Another important factor is the condition of the federal public health workforce. During the past year, both the FDA and the Centers for Disease Control and Prevention (CDC) experienced significant staffing reductions as part of broader federal workforce changes. The FDA has since begun hiring again. The CDC has also experienced staffing reductions affecting specialized scientific programs, including laboratories involved in Cyclospora investigations. Public health experts have noted that fewer inspectors, investigators, and laboratory specialists can make complex foodborne outbreak investigations more challenging and potentially slower to complete.
What We Know Today
• The CDC has confirmed 1,645 domestically acquired laboratory-confirmed cases in 34 states.
• More than 5,100 additional reports are still under review by the CDC.
• The FDA withdrew its original positive lettuce laboratory finding after determining it was a false positive.
• No food product has yet been confirmed positive for Cyclospora through FDA laboratory testing.
• The FDA investigation remains active.
• The lettuce recall remains in effect while investigators continue their work.
• North Carolina has reported 307 confirmed cases and 13 hospitalizations.
• North Carolina officials have not linked the state's increase in cases to outbreaks in other states, but the source has not yet been identified.
• Investigators continue tracing farms, processors, distributors, restaurants, and additional produce items.
• The investigation remains active, and conclusions may change as additional evidence is gathered.
The Bottom Line
Today, there are still unanswered questions.
The CDC continues reviewing thousands of additional reports, the FDA continues tracing food products through the supply chain, and North Carolina continues investigating its own increase in cases.
At this point, investigators have not identified a definitive food source, and they continue following the evidence wherever it leads.
WNC Times will continue monitoring both the federal investigation and North Carolina's investigation and will provide updates as new facts—not speculation—become available.