More than 24,000 confirmed and potential cases of cyclosporiasis have been reported in the United States since May 1 amid several clusters, including a major outbreak connected to processed iceberg lettuce from central Mexico.
On Tuesday, the Centers for Disease Control and Prevention (CDC) announced it had received reports of 13,895 laboratory-confirmed cases acquired within the United States. The agency said it was also reviewing at least 10,455 additional cases that were either unconfirmed or required further investigation to determine whether they were acquired domestically.
The CDC said it began its annual surveillance period as infections increased during the warmer spring and summer months. Investigators later identified the lettuce-linked outbreak as a significant contributor to this year’s unusually high total.
The confirmed patients ranged in age from 1 to 98, with a median age of 45. Fifty-seven percent were female. Reported illness onset dates ranged from May 1 through Aug. 2, with a median date of July 7.
Officials cautioned that the total will likely continue to rise because an estimated six weeks can pass between the onset of illness and a case being reported to the CDC. The agency also said the true number of infections is probably higher because some patients recover without seeking medical care or being tested.
Among domestically acquired cases, 740 patients were hospitalized and two died. Cases were reported by 47 states, plus the District of Columbia and Puerto Rico. State totals may exceed federal figures because local agencies can include illnesses that do not meet the CDC’s national reporting criteria.
An additional 1,530 laboratory-confirmed infections were acquired during international travel. Those cases involved residents of 46 states and included 58 hospitalizations and no deaths.
On Aug. 5, the Food and Drug Administration said the lettuce-specific outbreak had caused 6,358 illnesses across 15 states, including 278 hospitalizations and two deaths. Investigators initially connected illnesses to shredded lettuce served at Taco Bell before tracing the product to Taylor Farms de Mexico.
“This increase in cases is due, in part, to the inclusion of people who reported exposure to Taco Bell or recalled Taylor Farms de Mexico iceberg lettuce and the identification and addition of six new states that are now linked to this outbreak,” a statement read.
Taylor Farms voluntarily recalled all iceberg lettuce sourced from central Mexico on July 17. The recall included certain Marketside-brand iceberg salad and shredded lettuce products sold at Walmart, as well as products supplied to restaurants and other food-service customers.
Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora. People can become infected by consuming food or water contaminated with the parasite. Common symptoms include watery diarrhea, fatigue and loss of appetite, and symptoms typically begin about one week after exposure.