Cyclosporiasis Cases Rise in Five Outbreak States
The CDC has reported 4,173 confirmed cases of cyclosporiasis in the U.S. between May 1 and July 20. Cases have now been reported in at least 41 states, with Michigan having the highest number of lab-confirmed domestic cases.
The Centers for Disease Control and Prevention (CDC) has reported 4,173 confirmed cases of cyclosporiasis in the U.S. between May 1 and July 20. This number is already higher than the total number of U.S. cases reported for all of 2025. The CDC has declared an outbreak in five states: Michigan, Ohio, Indiana, Kentucky, and West Virginia. Michigan has the highest number of lab-confirmed domestic cases, with an estimated infection rate of nearly 15 per 100,000 people.
Investigations are ongoing, but contaminated iceberg lettuce is currently being investigated as a source for the outbreak. The CDC is also aware of at least 7,400 cases that have not yet been lab-confirmed, many of which are from Michigan and Ohio. Additionally, some people who get sick may never get tested for cyclosporiasis, so the actual number of cases may be higher than reported.
The CDC and other health agencies are concerned about the growing number and concentration of cases this year. While cyclosporiasis cases occur every year, the increasing number of cases in 2026 is unusual and has led to the declaration of an outbreak.
Go Deeper
What is cyclosporiasis?
Cyclosporiasis is a food-borne parasitic infection that causes diarrhea and other symptoms. It is typically spread through contaminated food or water.
How many states have reported cases of cyclosporiasis?
Cases of cyclosporiasis have been reported in at least 41 states, with the highest number of cases in Michigan.
What is being investigated as a source of the outbreak?
Contaminated iceberg lettuce is currently being investigated as a source of the outbreak.
How many cases of cyclosporiasis have been reported in the U.S.?
The CDC has reported 4,173 confirmed cases of cyclosporiasis in the U.S. between May 1 and July 20.
Why are health agencies concerned about the outbreak?
Health agencies are concerned about the growing number and concentration of cases this year, which is unusual and has led to the declaration of an outbreak.
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