Federal health officials are investigating a new outbreak of Cyclospora infections that has sickened at least 72 people and is not currently linked to the large lettuce-associated outbreak already under investigation, according to the U.S. Food and Drug Administration (FDA).
The FDA added the new outbreak to its list of active foodborne illness investigations on Wednesday.
Officials said the source of the contamination has not been identified, and investigators are conducting traceback efforts to determine where the infections originated.
The newly identified outbreak is one of six active Cyclospora investigations currently being handled by the agency.
Among those investigations, only the largest outbreak has been linked to a specific food source.
Federal officials continue to trace that outbreak to Taylor Farms-branded iceberg lettuce sourced from central Mexico. The recalled products were distributed across dozens of states.
According to the FDA, the lettuce-associated outbreak has resulted in more than 4,000 laboratory-confirmed cases of cyclosporiasis in 41 states. Health officials have also identified approximately 7,400 additional suspected cases that have not yet been confirmed through laboratory testing.
Two smaller Cyclospora investigations involving two and eight illnesses, respectively, have been closed.
Cyclospora is a microscopic parasite that causes cyclosporiasis, an intestinal illness that commonly produces severe diarrhea and other gastrointestinal symptoms.
The Centers for Disease Control and Prevention says infections are most frequently reported between May and August. While travelers can contract the parasite through contaminated food or water overseas, domestic outbreaks are more commonly associated with fresh produce.
Last year, federal investigators linked a Cyclospora outbreak that sickened at least 69 people to contaminated parsley.
Health officials say identifying the source of Cyclospora outbreaks can be particularly difficult because symptoms may not appear for two days to two weeks after exposure.
Earlier this month, Gwen Biggerstaff, deputy director of the CDC’s Division of Foodborne, Waterborne, and Environmental Diseases, said Cyclospora investigations often require significant time because the parasite cannot be analyzed using whole genome sequencing, a technique commonly used to trace other foodborne pathogens.
Instead, investigators rely on targeted genotyping, which can help detect related cases but is generally less precise in identifying a specific food source.
The CDC also notes that many Cyclospora infections likely go undiagnosed because some people experience mild symptoms or do not seek medical care. Standard stool tests may also fail to detect the parasite, making diagnosis more difficult, per the Conservative Brief.
Federal health officials said confirmed infections linked to the lettuce outbreak have been reported in at least 34 states, with epidemiological evidence connecting cases in Michigan and Ohio to illnesses in West Virginia and Kentucky.
The FDA said its investigation into the newly identified 72-case outbreak remains ongoing as officials work to identify the contaminated food responsible.
Health authorities continue to advise consumers to thoroughly wash fresh fruits and vegetables, refrigerate cut produce promptly and discard damaged portions of produce to help reduce the risk of foodborne illness.
