Nearly 1,000 people in Michigan have been diagnosed with a parasitic infection that causes watery diarrhea, marking the largest such outbreak in the state's history and one of the nation's largest in recent years. The parasite, cyclospora, has led to approximately 992 cases in Michigan as of Wednesday, including about 40 hospitalizations, according to state officials. Investigations into similar illnesses are underway in 28 other states.
Across the border in Ohio, Lucas County has reported 306 cases, with over 500 cases in the northwest Ohio region. Michigan initially announced the outbreak with more than 170 cases since June 22, a significant surge compared to the usual approximately 50 cases identified annually in the state.
"There is clearly a linked outbreak happening right now," Dr. Natasha Bagdasarian, Michigan's chief medical executive, told The Associated Press. The source of the infections has not yet been identified, and no deaths have been reported.
Cyclospora is a microscopic parasite that infects the bowels and commonly causes watery diarrhea. The illness, known as cyclosporiasis, is typically treated with antibiotics and is not usually life-threatening. Outbreaks tend to occur most frequently in the late spring and summer. Infection commonly occurs by consuming fruits or vegetables contaminated with feces.
While less common than illnesses like salmonella or E. coli, the number of reported cyclospora outbreaks has been rising over the past decade, with notable spikes in 2018 and 2019. Experts suggest that climate change and improved detection methods may contribute to this increase.
This undated photo provided by the CDC shows Cyclospora cayetanensis oocysts found in a stool sample. (CDC via AP)
Investigating cyclospora outbreaks can be challenging due to difficulties in detecting the parasite and identifying a definitive food source. Unlike some other foodborne illnesses, cyclospora cannot be easily grown in laboratories, complicating evidence gathering from produce. Furthermore, a contaminated single ingredient, such as basil or cilantro, might be present in multiple dishes, making it hard to pinpoint the exact common source among sick individuals.
While Michigan is experiencing the brunt of the current outbreak, officials do not consider it a national health emergency. There is no indication that the parasite has become more infectious. Current national CDC data, which lags behind state reporting, shows that the case total is four times higher than at the same point last year.
To protect against cyclospora infection, health officials recommend thorough washing of fresh produce. They advise consumers to remove the outer leaves of lettuce and wash the remaining leaves under running water, recommending whole heads of lettuce over pre-washed bagged varieties. Cooking vegetables when possible is also suggested to mitigate risk.