Pa. health officials monitoring cyclosporiasis cases
Public health officials in Pennsylvania and other states are on the lookout for cases of cyclosporiasis, a parasite that spreads through contaminated food and water and can cause severe diarrhea.
While there have been outbreaks in Michigan, Northwest Ohio and Illinois, the number of cases in the commonwealth have remained close to normal, according to the Pennsylvania Department of Health (DOH). So far this year, there have been 28 reported cyclosporiasis cases in Pennsylvania, with 11 of those cases coming from the southwest corner of the state. In 2025, there were 40 reported cases in Pennsylvania and 87 the year before.
This stands in contrast to Michigan, which has reported almost 1,000 cases, with about 40 hospitalizations, as of Wednesday. Most of the cases have been concentrated in the Detroit region. In Northwest Ohio, just across the border from Michigan, there have been more than 500 cases.
That being said, Melanie Firestone, a researcher on foodborne illnesses at the University of Minnesota, told the Associated Press that there is “a lot of underreporting when it comes to this,” because some tests for food poisoning are not designed to test for cyclosporiasis. Also, some cases end up not being reported because individuals recover without seeing a doctor.
Neil Ruhland, a spokesman for the DOH, said cyclosporiasis reporting is considered voluntary because it is not on the official list of reportable diseases in Pennsylvania, but the department still collects data on it and transmits it to the Centers for Disease Control and Prevention.
The primary symptom of cyclosporiasis is severe diarrhea. It is treated with antibiotics and is not typically life-threatening. Individual cases can last anywhere from a few days to a month or more. Outbreaks are most common in the late spring and summer. So far, the common denominator in the outbreak in Michigan and Ohio has not been determined.
People are most likely to come down with cyclosporiasis after eating fresh produce from tropical and subtropical regions. The DOH is advising people to wash their hands before and after handling raw fruits and vegetables, rinsing fruits and vegetables under running water and cutting away damaged areas. Also, consumers should scrub produce like cucumbers and melons, and refrigerate cut, peeled or cooked produce as soon as possible.
Officials in Michigan are also urging consumers to purchase whole heads of lettuce, instead of prewashed salad mixes or bagged lettuce, and to cook vegetables when possible.
The Associated Press contributed to this report.