A parasitic infection that causes miserable bouts of “explosive” diarrhea is surging across the United States. Meanwhile, public health authorities are racing to identify the
As of July 10, over3,100 cases of cyclosporiasis have been reported in 31 states, according to NBC News’ latest tally
Michigan, New York, Ohio, Illinois and North Carolina are among the states hit hardest by the parasitic stomach bug, which usually increases during the warmer months in the United States, according to the U.S. Centers for Disease Control and Prevention
The infection is caused by the Cyclospora cayetanensis parasite, which spreads through food and water contaminated with feces from an infected person, also known as the fecal-oral route. In the U.S., it’s commonly linked to fresh fruits and vegetables
When ingested, cyclospora infects the small intestine and leads to watery, uncontrollable diarrhea and other gastrointestinal symptoms. Person-to-person spread is uncommon
Cyclosporiasis is usually not life-threatening, per the CDC. However, it is extremely unpleasant, and the episodes of severe diarrhea can last for several weeks — which can put a real damper on vacation plans. Some patients report relapsing symptoms, meaning they stop and then return
Amid peak summer and fresh produce season, cyclosporiasis is surging in multiple states. There’s no evidence these clusters are related so far, the CDC says, but investigations are ongoing
“When we started seeing cases of persistent diarrhea showing up, we knew there’s something going on,” Dr. Brian Kaminski, vice president of medical affairs at ProMedica Health System, which sees patients living Michigan and Ohio, told NBC News. “I would say that trend continues.”
Where Are Cyclosporiasis Cases Rising?
Nationally, cyclospora infections have been ramping up since spring
According to the latest surveillance data from the CDC, at least 843 cases of cyclosporiasis have been reported in 31 U.S. states since May 1. (This data does not include all the latest case counts reported by state health departments.)
Among those sickened, at least 86 have been hospitalized
In a July 10 update, the CDC said “it is aware of more than 1,500 cases that require further analysis to confirm the illness as domestically acquired cyclosporiasis.”
The true number of people infected with cyclospora in the U.S. is likely higher than the numbers being reported “because some people recover without medical care and are not tested for cyclospora,” the CDC said on its website
Several states’ health departments have told TODAY.com and NBC News directly about recent cyclosporiasis spikes
Michigan
In Michigan, health officials are seeing an unprecedented “sudden and large” increase in infections with the diarrhea-causing parasite, TODAY.com reported previously
As of July 10, Michigan has reported 1,562 cases of cyclosporiasis since the end of June, according to the Michigan Department of Health and Human Services. That’s nearly 25 times higher than the annual average for the state, which records about 40-50 cases a year, a spokesperson for MDHHS told TODAY.com
The majority of cases are in Southeast Michigan in the following counties: Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland and Livingston
As of July 10, the Ohio Department of Health has reported at least 397 cyclosporiasis cases in 2026 — of those, 171 occurred since late June, a spokesperson for the Ohio Department of Health tells TODAY.com
The recent surge in cases in Michigan and bordering Ohio may be part of an “epidemic cluster,” Kaminski said
New York
New York state has recorded approximately 394 cyclosporiasis cases since May 1, a spokesperson for the state health department told TODAY.com in a July 9 statement. Typically, the state records 500-700 cases a year
“New York’s current case counts do not represent a major de
Illinois
The Illinois Department of Health told NBC News that the state has seen 141 cases this year, a “higher than average” number, with no single potential cause identified
North Carolina
As of July 6, North Carolina has reported at least 110 cyclospora infections since May, according to a statement from the North Carolina Department of Health to NBC News
Colorado
Colorado has reported 90 cases of cyclosporiasis so far, a public health spokesperson for the state told NBC News
Indiana
Some 72 cases have been reported in Indiana since May 1, a state spokesperson told NBC news
Texas
Texas has reported 48 cases between May 1 and July 6, resulting in five hospitalizations and no deaths. No commonrtment of Health
Is There a Cyclosporiasis Outbreak in the U.S.?
It’s not out of the norm to see cyclospora infections increase around this time of year. In the U.S., cyclosporiasis season usually lasts from May to August, per the CDC
“So far this year, multiple states have reported an increase in cases in the last two weeks compared to the same period in 2025,” the CDC says on its website
However, the agency clarified that it “has no evidence of a single, multistate Cyclospora outbreak linking cases happening right now and being reported in the press,” a spokesperson told NBC News in an email
The CDC and FDA are currently monitoring clusters of cases in multiple states. “We are not in a position at this time to characterize the current numbers as definitively unusual pending the completion of that investigation,” a U.S. Food and Drug Administration spokesperson told NBC News
The massive increase in cyclosporiasis in Michigan and other states has prompted investigations into a potential common
The current hypothesis is that contaminated fresh produce is driving the surge, Dr. Natasha Bagdasarian, chief medical executive for the state of Michigan, told NBC News. In the past, cyclosporiasis outbreaks have been linked to salad greens, raspberries, basil, cilantro, green onions and snow peas
Health officials are urging people to seek treatment if they experience cyclosporiasis symptoms
Cyclosporiasis Symptoms
The most common symptom of cyclosporiasis is sudden, watery diarrhea. According to the CDC, these bowel movements are often frequent and “explosive.”
In addition to diarrhea, people may experience severe stomach cramps, bloating, vomiting, nausea, loss of appetite, and fatigue, per the Cleveland Clinic
These can last for several days to several weeks or longer. The bouts of diarrhea may occur in cycles and “relapse” after you seem to feel better, the CDC says
It can take up to 14 days after ingesting food or water contaminated with cyclospora for symptoms to start
Compared to norovirus, another common illness that causes GI upset, cyclosporiasis typically takes longer to show symptoms and is more likely to cause diarrhea and cramping than vomiting, Bagdasarian said
Most healthy people will recover on their own, per the CDC, but the infection can be treated with a combination antibiotic. People with weak immune systems are at higher risk for recurring symptoms and may require more extensive treatment
If you develop signs of cyclosporiasis or sudden bouts of severe gastrointestinal illness, contact your health care provider
How to Prevent Cyclosporiasis
The only way to prevent cyclosporiasis is to avoid food or water that may be contaminated with feces
Cooking food to at least 158 degrees Fahrenheit is the most effective way to destroy the parasite, per the MDHHS
The New York State Department of Health also offered a few more tips to prevent the spread of cyclospora:
- Wash hands with soap and water before and after handling raw produce.
- Thoroughly wash all fresh produce under running water before eating it.
- Scrub fruits and vegetables with a produce brush when possible.
- Cut away any damaged areas on fresh produce before eating.
- Refrigerate fruits and vegetables (cooked or fresh) within two hours of preparing it.
