Michigan Cyclospora Outbreak: Nearly 1,000 Cases Reported
Almost 1,000 individuals in Michigan have been diagnosed with a parasitic infection that leads to prolonged watery diarrhea. This marks the largest outbreak of its kind in the state’s history and is among the biggest in the country in recent years.
So far, there have been no reported fatalities, and the source of these cyclospora infections is currently unknown. Health officials are also investigating similar cases in 28 other states, including Ohio, where residents near Michigan have shown signs of illness. According to the U.S. Centers for Disease Control and Prevention (CDC), 17 states confirmed cases between early May and June 16, including Illinois, Maryland, Massachusetts, New York, and Texas.
The outbreak was first disclosed by Michigan officials last week, noting that there were over 170 cases reported in the southeastern part of the state since June 22—a significant increase compared to the typical annual average of about 50 cases.
As of Wednesday, the state confirmed that the number of cases had reached 992, with around 40 individuals hospitalized. Just across the border in Lucas County, Ohio, 306 cases were reported as of the same day, and northwest Ohio has seen more than 400 instances.
Dr. Natasha Bagdasarian, Michigan’s chief medical executive, remarked, “There is clearly a linked outbreak happening right now,” indicating the complexity of tracing cyclospora sources. The FDA has acknowledged that their investigation is ongoing, emphasizing that both the FDA and CDC are actively monitoring the situation.
Understanding Cyclospora
Cyclospora is a tiny, round parasite that often leads to watery diarrhea, characterized by frequent or intense bowel movements, according to the CDC. While the illness, called cyclosporiasis, isn’t generally life-threatening, outbreaks tend to occur mostly in the late spring and summer months. This heat-loving parasite infects the digestive system and can be spread through feces, particularly when fruits or vegetables come into contact with contaminated irrigation water.
Past outbreaks in the U.S. and Canada have been traced to bagged salad mixes, cilantro, basil, raspberries, snow peas, and scallions. Currently, the cause of this particular outbreak remains unknown.
Although cyclospora is less common than other foodborne ailments like salmonella and E. coli, reports of its outbreaks have been on the rise—especially noticeable since about a decade ago, peaking sharply in 2018 and 2019. Experts attribute this trend to climate change and improved detection methods.
Comprehensive statistics on cyclospora outbreaks are sparse, but not many in the last 20 years have exceeded 1,000 cases. Some notable incidents include a 1997 outbreak linked to Guatemalan raspberries and another in 2019 connected to Mexican basil—both resulting in significant numbers of illnesses across the U.S. and Canada.
The difficulty in tracking these outbreaks often comes down to limitations in reporting mechanisms, according to Melanie Firestone, a foodborne illness expert. Certain tests are not designed for detecting cyclospora, leading to underreporting. Moreover, the inability to cultivate the parasite in laboratories complicates efforts to trace contamination back to specific foods. Sometimes, a single shared ingredient in multiple dishes makes it hard to identify common links.
While cases are surging in southeastern Michigan, health officials have stated that it doesn’t constitute a national health emergency.
There is currently no evidence suggesting that the parasite has evolved to become more contagious, according to Dianna Blau, acting chief of the CDC’s parasitic diseases branch. Thousands of cyclospora cases are recorded annually, and although this year’s numbers are significantly higher compared to last year, it’s still uncertain how this year will trend overall.
Symptoms of Cyclosporiasis
Health officials advise individuals who experience persistent diarrhea for several days to consult a healthcare provider about the possibility of cyclospora. Most people recover without treatment, but hydration is essential, and antibiotics can help if an infection occurs. It’s important to note that cyclospora is not transmitted from person to person.
Common symptoms of cyclosporiasis include diarrhea, loss of appetite, weight loss, cramping, bloating, nausea, and fatigue. In rarer cases, symptoms may extend to vomiting, body aches, headaches, low-grade fever, and flu-like issues.
To minimize the risk of infection, it’s best to avoid potentially contaminated food and water. Fresh produce should be washed thoroughly, though cyclospora can cling to some foods, meaning washing might not eliminate all risks. Michigan officials recommend opting for whole heads of lettuce instead of prewashed bagged varieties and to remove the outer leaves before rinsing the others. Cooking vegetables when possible is also advised.
