The number of intestinal parasite cases causing explosive diarrhea is increasing rapidly in the U.S. In June, only a few dozen cases of cyclosporiasis were reported nationwide, but by July 9, Michigan alone had seen 1,251 cases, according to the state’s Department of Health and Human Services.
Cyclosporiasis is caused by a single-celled parasite called Cyclospora cayetanensis, which can spread through contaminated food or water. Although usually not deadly, it can cause severe diarrhea and “sometimes explosive bowel movements,” as the CDC notes.
The CDC hasn’t updated its national case count since June 16, when 145 cases had been reported from 17 states, with no cases in Michigan at that time. By June 30, Michigan’s health department had reported 170 cases, and that number has continued to rise.
On July 4, Michigan officials announced that no specific fresh produce supplier had been connected to the outbreak. When asked for additional comments, officials chose not to elaborate beyond the initial statement.
The release also urged residents and restaurants in southeastern Michigan to follow certain precautions to prevent further spread of the illness. These measures included buying whole heads of lettuce instead of prewashed bags or salad mixes.
Additionally, the state recommended discarding the outer two or three layers of lettuce and washing the remaining leaves under running water before use.
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Officials also advised washing leafy vegetables like cilantro and basil, as well as snow peas, and removing the outer layer of green onions. They recommended avoiding fresh, uncooked raspberries.
Michigan is not the only state recently affected; since May 1, New York has reported 394 cases, with 273 in New York City. This is an increase from 31 to 80 cases, according to CDC data as of June 16.
A spokesperson from the New York State Department of Health said there is no evidence linking the various outbreaks across the U.S. to a specific source.
They also noted that cyclosporiasis cases tend to rise in spring and summer, and the current case count in the state is consistent with previous years.