The Centers for Disease Control and Prevention is publishing cyclosporiasis surveillance updates more frequently this season after multiple states reported increases in cases compared with the same period in 2025. According to the agency, it has received reports of 1,645 laboratory-confirmed domestically acquired cases since May 1, 2026, and is aware of more than 5,100 additional reports requiring further analysis to determine whether they represent domestically acquired cyclosporiasis.
As of July 13, 2026, laboratory-confirmed domestically acquired cases had been reported from 34 states. The CDC cautions that state totals may be higher than its national surveillance count because states may include both probable and confirmed cases, whereas CDC surveillance updates include only laboratory-confirmed cases reported to the agency.
The agency also assumes an approximately 6-week lag between illness onset and case reporting and therefore expects reported case counts to continue increasing as additional data are received. The surveillance figures are preliminary and subject to change.
Cyclosporiasis is a gastrointestinal disease caused by the microscopic parasite Cyclospora. It is nationally notifiable and reportable in 47 states, the District of Columbia, and New York City. The CDC advises health care providers to report confirmed cases to their local health departments.
Among the 1,645 patients with laboratory-confirmed domestically acquired cyclosporiasis, none reported travel outside the United States during the 14 days before illness onset. Patients ranged in age from 2 to 95 years, with a median age of 44 years, and 56% were female. The median illness onset date was June 22, 2026, with onset dates ranging from May 1 to July 9. A total of 141 patients were hospitalized, and no deaths were reported.
The CDC also reported 440 travel-associated cases from 35 states. These patients reported eating or drinking food or water while traveling outside the United States during the 14 days before illness onset. They ranged in age from 14 to 89 years, with a median age of 45 years, and 59% were female. Twenty patients were hospitalized, and no deaths were reported.
The CDC states that it is working with state, federal, and regulatory partners to investigate several cyclosporiasis outbreaks. The agency, the US Food and Drug Administration, and jurisdictional partners are also investigating a multistate outbreak, and efforts to identify and confirm the source or sources remain ongoing.
The CDC notes that cyclosporiasis case counts typically rise during the May 1 through August 31 season. Because of the recent increase in reported cases, the agency says it will issue surveillance updates more frequently than in previous seasons.
