Health
State officials say the next update of reported cases — which currently sits at 18 from May 1 to July 1 — will be available in the first week of August.
Past cyclospora outbreaks in the U.S. have been linked to fresh produce, including raspberries, DPH says. Kelsey McClellan/The New York Times
Significant buzz has built up since the cyclospora parasite, known to cause explosive diarrhea, was officially detected in Massachusetts this summer. While Midwestern states are currently dealing with an outbreak of the parasite, state officials say Massachusetts is not seeing a surge of reported cases.
“There is no evidence currently that the outbreak of Cyclospora affecting multiple Midwestern states is affecting Massachusetts,” a state Department of Public Health spokesperson told Boston.com Wednesday. “We are seeing a normal seasonal amount of cyclosporiasis so far this year.”
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Cyclospora, the explosive diarrhea parasite, has reached Mass. Here’s what to know.
Between May 1 and July 1, 18 cases of cyclosporiasis — the infection caused by cyclospora — were reported in Massachusetts residents, according to DPH.
“This is in line with the normal number of cases seen in Massachusetts during this time frame,” the spokesperson said.
According to DPH data, the parasite was detected 74 times in Massachusetts residents in 2025, following 84 reported cases in 2024. During a spring and summer outbreak in 2019, Massachusetts documented more than 100 cases of cyclosporiasis.
While seasonal increases in cases are typical at this time of year, DPH officials said they expect to see additional cases because diagnosis does not always happen promptly after symptoms begin.
State officials will update Massachusetts’ online surveillance database in the first week of August to reflect cases reported from May through August, DPH said.
The parasite is spread through contaminated food or water and treatable with antibiotics. Its symptoms include watery diarrhea, weight loss, bloating, cramps, nausea, vomiting, exhaustion, and a fever. Some infected with cyclospora do not experience symptoms, according to DPH.
To investigate outbreaks, DPH works with local health boards, which receive individual reports based on residency and interview patients about their food history. DPH epidemiologists continuously review this data to identify clusters linked to common exposures, officials said.
Information from the Centers for Disease Control and Prevention regarding the Midwestern outbreak show that more than 400 cyclospora infections have been reported as of Monday across four states: Kentucky, Michigan, Ohio, and West Virginia.
CDC noted further cases remain under investigation, though the agency did not specify where they were located. A particular food source has not yet been identified.
Previous outbreaks in the U.S. have been linked to fresh produce, such as raspberries, fresh basil, cilantro, scallions, snow peas, and bagged salads. DPH officials recommend washing fresh produce before eating to help avoid infection, but they caution that doing so might not fully prevent contracting the disease.
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