Federal health officials are monitoring a growing number of cyclosporiasis cases this summer, with 145 infections reported across 17 states as of mid-June 2026.
The Centers for Disease Control and Prevention released updated surveillance data showing that all 145 domestic cases involved people who became sick between May 1 and June 6, 2026 — and none had traveled internationally in the two weeks before falling ill.
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What is cyclosporiasis?
Cyclosporiasis is a gastrointestinal illness caused by Cyclospora, a microscopic parasite.
The illness is a nationally notifiable disease, meaning healthcare providers are required to report confirmed cases to local health departments. It is reportable in 47 states, the District of Columbia and New York City.
If a patient shows symptoms of cyclosporiasis, health officials urge providers to test and treat accordingly — and to notify local health departments of confirmed cases.
2026 by the numbers
The CDC’s fast facts for the 2026 season paint a clear picture of the outbreak’s scope so far:
- 145 cases acquired in the United States
- 20 hospitalizations
- 0 deaths
- 17 states reporting cases
Sick individuals ranged in age from 5 to 86 years old, with a median age of 42. Roughly 61% of domestic cases were female. The median illness onset date was May 13, 2026.
Investigations ongoing
Local, state and federal authorities — including the CDC and the U.S. Food and Drug Administration — are actively investigating several clusters of cases spanning multiple states. Officials have not yet identified a confirmed food source linked to the current outbreak.
The cyclosporiasis season runs May 1 through Aug. 31, though clusters have been detected outside that window in some years. Case counts historically rise during the spring and summer months.
Travel-related cases also reported
Beyond domestic infections, 45 additional cases involved people who became ill after eating or drinking contaminated food or water while traveling outside the United States.
Those individuals ranged in age from 17 to 89, with a median age of 43, and 62% were female. Three of the 45 were hospitalized. No deaths were reported in this group.
What to do if you’re sick
Anyone experiencing symptoms consistent with cyclosporiasis is encouraged to contact a healthcare provider. The illness is treatable, and early reporting helps officials detect and contain outbreaks more quickly.