Key points
- CDC collects data on cyclosporiasis through routine tracking and monitoring of cases year-round to identify potential outbreaks.
- Like CDC, state and local health departments investigate cyclosporiasis cases. They notify CDC when they suspect clusters of cases or outbreaks.
- CDC works with state, local, and federal partners to find the source of outbreaks by interviewing patients, tracing food back through the supply chain, and conducting laboratory tests.
Why we collect data
Current outbreak
Cyclosporiasis is a gastrointestinal illness caused by the microscopic parasite Cyclospora. You can get cyclosporiasis from eating food or drinking water contaminated with human poop (feces) containing the parasite.
While cyclosporiasis is not usually life threatening and death from the illness is exceedingly rare in the United States, it can make some people very sick.
Cyclosporiasis is a nationally notifiable disease and is reportable in 47 states, the District of Columbia, and New York City. For the states and U.S. territories in which cyclosporiasis is not reportable, it is still important for healthcare providers and the public to inform local health departments about potential cases and clusters of cyclosporiasis. This helps health departments take appropriate action to prevent additional cases.
How we collect data
CDC collects data on cyclosporiasis through routine public health surveillance: clinicians and clinical laboratories report cases to local and state health departments based on their reporting practices. Health departments send case information to CDC through the National Notifiable Diseases Surveillance System (NNDSS) and outbreak-specific reporting channels.
State and local health departments also conduct case investigations using standardized questionnaires (capturing clinical, demographic, and exposure information) and notify CDC when clusters or outbreaks are suspected. Jurisdictions may request patient interviews, stool specimens, and detailed laboratory testing results to support epidemiologic analyses and any molecular or reference testing.
CDC further partners with state public health laboratories, FDA, and other agencies to integrate laboratory data and food traceback information to help identify outbreak sources and inform prevention efforts.
How CDC monitors cases
CDC, along with state and federal health and regulatory officials, monitors laboratory-confirmed cases of cyclosporiasis year-round to detect outbreaks potentially linked to a common food source in the United States. CDC uses molecular fingerprinting tools to help identify cyclosporiasis cases that may be part of outbreaks. Regular monitoring aids in swiftly identifying and investigating outbreaks in the United States.
Case counts of cyclosporiasis rise during the spring and summer months each year. The cyclosporiasis season in the United States is May 1 through August 31. Clusters of cyclosporiasis cases have been detected outside this range in some years.
CDC also monitors cases of people who became sick after eating food or drinking water while they were traveling outside the United States.
How CDC investigates outbreaks
CDC works with state, local, and federal partners to combine patient interviews, food traceback through the supply chain, and laboratory testing to find the source of multistate outbreaks. Many foods investigated in outbreaks have multiple produce ingredients, like salsa or salads, making it difficult to narrow down to a single food item.
In addition, the Cyclospora parasite is harder to track than many bacteria like Salmonella because whole genome sequencing isn't available for this pathogen. CDC uses genetic testing targeting specific markers on stool samples to group related cases. This helps prioritize traceback and other actions, including food recalls, to stop more illnesses.
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