US health officials are investigating a sharp rise in cyclosporiasis, a food-borne intestinal illness caused by the Cyclospora parasite. More than 11,000 confirmed and suspected domestic cases have been reported across 41 states, making 2026 likely to be the country’s worst year for the infection and prompting investigations into several potential outbreaks.

The CDC had confirmed 4,173 cases between 1 May and 20 July, with more than 7,400 further reports awaiting confirmation; 308 people had been hospitalised and no deaths reported. Michigan and Ohio account for many of the additional reports, while one nine-state outbreak has been linked to iceberg lettuce and led to a Taylor Farms recall; officials caution that cases may rise further because reporting typically lags illness by about six weeks.