Confirmed cases of cyclosporiasis, a parasitic infection known for causing explosive diarrhea, have surpassed 17,000 as federal health officials continue to investigate a series of outbreaks larger than any previously seen in the United States.
The Centers for Disease Control and Prevention said in its weekly update Aug. 24 that 17,180 infections with cyclospora, the parasite that causes the illness, have been confirmed across 48 states plus Washington, DC, since May 1 — an uptick of 1,464 since its last report on Aug. 18. While these numbers show that confirmed cases themselves are still rising, the overall trend is on a downward swing; previous weeks regularly saw increases into the 2,000 and 3,000 range.
There have been two deaths and 922 hospitalizations,
94 of which were reported since last week, according to the CDC. One state, New Mexico, was added to the list of states with confirmed cases.
Laboratories have yet to confirm at least 11,841 additional cases, the CDC said. The agency's case count lags about six weeks behind state-by-state numbers because of the process required to confirm and officially report an infection back to the federal level. This means states can report new cases that are not reflected in the CDC count until weeks later, and new illnesses may not be tracked until over a month after someone sees a doctor.
Michigan, which has been at the center of the largest case cluster, reported 14,277 total cases as of Aug. 20, up from 13,909 on Aug. 11. The state's health department updates its case numbers each week on Thursday.
The state's health department previously said in an Aug. 6 notice that the pace of new case reports and related emergency department visits was slowing and that residents could resume normal lettuce-eating habits. Some experts told USA TODAY, however, that caution may still be prudent in the produce aisle.
The FDA is also tracking at least six other cyclospora clusters that have yet to be linked back to a source.
See map of states with cyclosporiasis cases
New Mexico was the latest state added to the CDC's list of those with confirmed cases. Only two states, Delaware and Hawaii, still do not have federally confirmed cases. Michigan and Ohio remain the two states hit the hardest.
The CDC reports only lab-confirmed cases that occurred on or after May 1 in people who did not travel internationally within 14 days of illness onset. Its numbers often lag behind those cited by state health officials because of tracking, verification and reporting processes. There's typically a six-week reporting lag between an illness and the case being reported to the CDC.
What is cyclosporiasis? What are the symptoms?
Cyclosporiasis is a parasitic infection that causes gastrointestinal symptoms often associated with food poisoning, such as diarrhea, nausea and vomiting. It is caused by the parasite Cyclospora cayetanensis, also known simply as cyclospora, and is usually contracted through contaminated food or water.
Though unpleasant, it is not generally known to cause death, and in many cases it goes unreported because people recover at home without visiting a doctor. It can cause more serious complications in people with compromised immune systems or other underlying health problems.
The most common symptom is watery, frequent and sometimes "explosive" diarrhea that can go away and come back, according to the CDC and Cleveland Clinic, though other troubles can include:
- Vomiting
- Loss of appetite
- Bloating, including burping and gas, or stomach cramps
- Extreme tiredness (fatigue)
- Fever
- Nausea
Largest outbreak linked to lettuce accounts for more than 10,000 cases in 17 states
While the CDC is currently investigating multiple separate clusters of the gastrointestinal illness, only one source has been identified so far. According to the agency, it is unlikely that one common cause is behind all the outbreaks nationwide.
The largest outbreak, centered in Michigan, was tracked by the Food and Drug Administration back to recalled iceberg lettuce grown by produce giant Taylor Farms in central Mexico. This specific set of illnesses, first identified through traceback from fast-food chain Taco Bell, accounted for 10,930 cases and 454 hospitalizations across 17 states as of Aug. 20, per the CDC.
Health officials identified the 17 affected states by interviewing and testing sick people to determine whether their infections were related. Related confirmed cases are considered part of the same outbreak and likely stem from the same source. Thus far, these states are the only ones the CDC has confirmed as having cases related to each other and the lettuce.
Both deaths amid the ongoing outbreaks were associated with the lettuce-linked outbreak, according to the agency.
The source of a cyclosporiasis outbreak is harder to track than foodborne illnesses because of a long incubation period, difficulty obtaining samples and the inability to use the same genetic tracking tools available for pathogens like E. coli and listeria.
Some experts have also pointed to cuts to federal food and disease monitoring programs, though Health and Human Services Secretary Robert F. Kennedy Jr. has disputed these critiques.
Company at heart of lettuce-linked outbreak faces scrutiny
Taylor Farms itself has also come under increased scrutiny, especially after some of its products were included in a jalapeño recall initiated by Coast Citrus Distributors in August at the center of a still-growing, multistate salmonella outbreak.
In late July, California Rep. Robert Garcia, a top Democrat on the House Oversight Committee, sent a letter to the company's CEO Bruce Taylor, alleging that Taylor Farms had tried to influence or obstruct the FDA's investigation and mislead the public. The letter also pointed to the company's recent political donations, including one allegedly made to a Trump-associated super PAC.
"In 2025 alone, Taylor Farms donated more than $2 million to political action committees tied to President Donald Trump and other Republicans and spent over $810 million on lobbying related to food safety regulation," it reads.
Taylor Farms denied the allegations, saying in a statement shared with USA TODAY, "Taylor Farms categorically rejects any suggestion that the company has attempted or received favorable regulatory treatment as a result of political contributions or any other improper influence. These allegations are false.”
The company, which has been responsible for several major recallsover the last decade, also received criticism from the FDA for a since-deleted statement in which it said the FDA "apologized" for a "false positive" when testing its iceberg lettuce products for cyclospora. The FDA issued a statement shortly after clarifying that the lab sample finding "DOES NOT change the basis for FDA’s ongoing outbreak investigation or the overwhelming epidemiological data supporting the current voluntary recall by Taylor Farms."
A White House source familiar with the matter previously told USA TODAYon July 22 that "Taylor Farms’ intentionally misleading statements, including their now-deleted X post that falsely claimed the FDA ‘apologized’ to them, is actively aggravating administration officials, and reflect how Taylor Farms is not working in good faith to restore Americans’ confidence and trust in our food supply."
Taylor Farms again pointed to negative sample tests in its statement, saying there were no confirmed positive sample results for product testing for cyclospora as of Aug. 13.
Negative samples do not indicate that no pathogen is or was present in the case of cyclospora, as previously reported by USA TODAY.
"When questions were raised about the source of the recent Cyclospora outbreak, we immediately removed all potentially implicated product from the marketplace, and out of an abundance of caution we issued an even broader recall of all iceberg lettuce sourced from the region," the company said in a statement. "We have also voluntarily suspended all iceberg lettuce sourcing and production from central Mexico ... We are confident in our food and food safety systems and will continue to be transparent as more information becomes available."
Contributing: Swapna Venugopal, USA TODAY
This article originally appeared on USA TODAY: Confirmed cyclospora cases surpass 17,000. See map of affected states
