Indiana health officials said they are keeping a wary eye on a foodborne illness that causes a severe stomach bug, with a growing outbreak in Michigan and rising cases in the Indianapolis area.
As of Friday, Indiana had 122 cases of cyclosporiasis, caused by the parasite cyclospora, with 17 of those cases in Marion County, said Nicole Stone, epidemiology director of foodborne and enteric diseases with the Indiana State Department of Health.
Porter County had one case in June, said Dr. Rodney Guimont, the county’s public health officer.
“When we investigated with the state and our epidemiologist, it didn’t count” as part of the recent foodborne outbreak because the person had contracted the parasite while traveling outside the country, Guimont said.
Porter County didn’t have any cases last year, Guimont added.
According to the website for the federal Centers for Disease Control and Prevention, or CDC, symptoms of the parasitic illness include watery diarrhea, loss of appetite and weight loss.
Nearly 1,000 people in Michigan have been diagnosed with cyclosporiasis, making it the largest such outbreak in state history and one of the nation’s largest in years, the Associated Press reported.
Michigan officials first announced the outbreak last week, when they were aware of more than 170 cases — all in the southeastern corner of the state — since June 22. Michigan usually identifies only about 50 cases each year, according to the AP.
Illinois also is seeing a higher than usual number of cases this year, according to the Chicago Tribune.
Fresh produce, including herbs, salad greens and raspberries, can be the culprit for the illness, state and Porter County officials said, but no one has yet been able to pinpoint the direct source of the outbreak in Michigan or the uptick of cases in other places, including across the Michigan state line in Ohio, per the AP.
Indiana usually has 30 cases a year, Stone said, which typically occur in the late spring or early summer, since the illness tends to be seasonal. There are sporadic cases outside that window, usually from people who have traveled outside the country and picked up the bug overseas, she added.
The CDC site notes that as of Thursday, the U.S. had 843 cases in 31 states reported to the federal agency since May 1. The site also stated that the actual number of cases is likely higher.
“CDC is aware that states are likely to report higher case counts of cyclosporiasis than reflected in CDC data and is working closely with states to update numbers as additional cases are confirmed,” the agency said, adding it is aware of more than 1,500 cases that require further analysis to confirm the illness as domestically acquired cyclosporiasis.
“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 agency stated.
As far as the growing cluster of cases in Marion County and how the disease is spreading in Indiana, “We’re monitoring for that,” Stone said.
Fortunately, Stone said, cyclosporiasis doesn’t spread easily from person to person. “It doesn’t live very well outside of its host,” she said.
As with any stomach bug, she said, the best course of prevention is frequent handwashing and safe food preparation, including washing produce and cutting away bruised spots.
People also should consider cooking their produce or using frozen items, Stone added, and buying heads of lettuce and removing the outer couple of layers, rather than purchasing bagged greens.
Guimont added that the fast food chain Taco Bell has preemptively removed produce items susceptible to carrying the parasite from its offerings, including lettuce, onion and cilantro.
As far as treatment, Stone said that “generally, most people will get better on their own.” Hydration is important, especially with severe diarrhea, she said, and the bug is not particularly severe.
According to the CDC website, no deaths have been reported from cases this year, and there have been 86 hospitalizations.
If someone does seek out healthcare, Stone said, they should report their symptoms to their provider so they can be tested for the parasite. Some antibiotics can ease the illness, she said.
“It’s not an enjoyable thing to get but then again, it’s not that severe,” Stone said.
Tracking the illness, Guimont said, occurs when a patient provides a stool sample for testing by a lab. The lab is responsible for reporting cases to health authorities.
“That’s how all this happens,” he said, adding that the Porter County Health Department is watching the numbers in Indiana and Michigan as federal officials investigate the source of the outbreak.
Porter County put out a public service announcement on cyclosporiasis because officials knew people would ask about it, Guimont said.
“I think part of our responsibility as a health department is to pay attention to national happenings,” he said, including what’s going on in neighboring states.
alavalley@chicagotribune.com
