Iowa has been added to the list of states with confirmed cases of a parasite-caused gastrointestinal disease linked to contaminated iceberg lettuce, the FDA confirmed Wednesday in an update on the ongoing cyclosporiasis outbreak. The New York Times and the Washington Post had already reported on Tuesday that Iowa was one of six states with newly confirmed cases in the outbreak. Both newspapers based their reports on statements from CDC officials granted anonymity because they weren’t authorized to speak publicly about the cyclosporiasis outbreak.
Cyclosporiasis is caused by Cyclospora cayetanensis, a microscopic, single-cell parasite.
“People can become infected when they drink water or eat raw food, usually raw produce, that is carrying the parasite,” the Johns Hopkins School of Medicine explains on its page about the outbreak. “Food picks up the parasite most often through water supplies that are infected with human feces.”
“Cyclosporiasis is not transmitted via person-to-person contact.”
There is a latency period after a person consumes contaminated food or water. Symptoms may not appear for up to two weeks. The main symptom is severe, even explosive, diarrhea. Other symptoms include abdominal cramping, bloating, fatigue, nausea, vomiting, loss of appetite and weight loss. The disease can be relatively mild and brief, but it can also be protracted with the diarrhea resulting in severe dehydration, which is particularly dangerous for infants and older adults, as well anyone who is pregnant or immunocompromised.
On Monday, the Michigan Department of Health and Human Services disclosed two people suffering from cyclosporiasis had died. They were the first confirmed deaths related to the current outbreak. According to the health department, both individuals had underlying health conditions. Cyclosporiasis typically does not result in fatalities.
The current outbreak has been traced to shredded iceberg lettuce distributed by Taylor Farms, a company that describes itself as “America’s favorite maker of salads and healthy, fresh foods.” According to the CDC, the contaminated lettuce was grown in central Mexico and was sold as bagged lettuce and in bagged salad mixes in supermarkets, and also supplies lettuce to restaurants, including national chains like Taco Bell. On July 17, Taylor Farms announced it was recalling all its bagged iceberg lettuce from Mexico, sold in 27 states.
Although cyclosporiasis is often caused by lettuce that has been irrigated using water contaminated with fecal matter containing the parasite, previous outbreaks have been linked to other leafy greens, fresh basil, fresh cilantro, snow peas, green onions and raspberries.
Because water sources used in commercial farming are often contaminated with fecal matter, cyclosporiasis is a common foodborne disease in the United States. Cases usually peak during summer months, but are often underreported as people frequently don’t seek medical attention for mild cases. When medical attention is sought, doctors treat cyclosporiasis with antibiotics and antidiarrheal medications.
Over the last decade, the CDC has reported an average of approximately 2,800 laboratory-confirmed cases of the disease each year. This year it has confirmed more than 10,400 cases in 45 states since May 1, and is investigating another 11,500 potential cases. The first cases linked to Taylor Farms lettuce outbreak were reported on June 22.
The CDC first confirmed cases of the lettuce-related outbreak in Michigan, Ohio, Indiana, Kentucky and West Virginia. On July 24, it confirmed cases of the outbreak in Illinois, Kansas, Oklahoma and Pennsylvania. This week, Iowa, Arkansas, Missouri, Nebraska, New Hampshire and North Carolina were added to the list, bringing the total number of states affected so far to 15.
The CDC reports that 6,358 people have been sickened by cyclosporiasis in the current outbreak, including 278 who were hospitalized. The CDC only reports cases in which the disease has been confirmed through laboratory testing, and its reporting of cases is usually slower than reporting coming from state health agencies.
According to the Iowa Department of Health and Human Services (IHHS), there were 226 cyclosporiasis cases reported in 48 counties as of July 30 this year. That is a substantial increase from 2025, when a total of 69 cases for the entire year. IHHS said not all this year’s cases were related to the 15-state outbreak, but did not provide any information on how many were. It did say that 47 of the cases involved people who recently returned from international travel and may have been infected abroad.
The ongoing Taylor Farms-related outbreak is the largest outbreak of cyclosporiasis on record in the U.S.
“We’ve never seen anything like this,” Susan Mayne, an adjunct professor at the Yale School of Public Health, told CBS News. “This is just an astonishingly large outbreak, record-setting outbreak.”
Mayne, who was in charge of the FDA’s food-safety department from 2015 to 2023, made her comments in late July, when the CDC had only confirmed cases of the outbreak in nine states.
Since President Trump returned to the White House in January 2015, both the FDA and CDC have had massive cuts to their budgets and staff. The FDA has lost about 20 percent of its staff and the CDC has had its staff reduced by 25 percent. Under the Biden administration, the CDC had 11 scientists dedicated to tracking foodborne illnesses, but the CDC under HHS Secretary Robert F. Kennedy Jr. cut that number to three.
“We had a national advisory committee, a committee that advised FDA and USDA on how to prevent microbial contamination in food,” Mayne said. “That advisory committee was disbanded. We used to convene meetings with our Mexican counterparts on how we can work together to improve food safety. That entire team was let go.”
Trump administration cuts have also affected how states are able to deal with the outbreak. Food safety programs and public health programs that deal with problems like the cyclosporiasis outbreak are largely funded through FDA and CDC grants. Last year, the administration cut $5.8 billion from the CDC’s state grant program, which was a 40 percent reduction in funding.
To prevent a cyclosporiasis infection, public health experts recommend thoroughly washing all fruits and vegetables under running water, and washing hands and food preparation surfaces with warm, soapy water. Fruits and vegetables that can be peeled should be to reduce the possibility of contact with the microscopic parasite. Cooking is also an effective means of killing the parasite, as long as the food is heated to 158 degrees.
