Cyclospora Outbreak in Michigan: What You Need to Know

Michigan is currently dealing with a significant cyclospora outbreak. Nearly 1,000 individuals have been affected by this parasitic infection known for causing extended periods of watery diarrhea. While no fatalities have been reported, the origin of these infections remains unidentified. Moreover, similar health issues are being investigated in 28 other states, including Ohio, where residents close to the Michigan border are also experiencing symptoms.

Michigan officials made the initial announcement of the outbreak last week, having identified over 170 cases concentrated in the southeastern region since June 22. Typically, Michigan reports about 50 cases annually. As of Wednesday, the number of reported cases increased to 992, with approximately 40 hospitalizations. Lucas County in Ohio reported 306 cases by Wednesday, and northwest Ohio has experienced more than 400 cases in total. Cyclospora outbreaks are particularly challenging to pinpoint, as food poisoning sources are often elusive. However, Michigan’s chief medical executive, Dr. Natasha Bagdasarian, affirmed the clear connection between cases in both states.

Understanding Cyclospora

Cyclospora is a spherical, microscopic parasite known for causing cyclosporiasis, characterized by watery diarrhea with frequent bowel movements. Although not usually life-threatening, cyclosporiasis is generally treated with antibiotics. Outbreaks tend to arise in late spring and summer. The heat-tolerant parasite infects the digestive system and spreads via feces, often through foods like fruits or vegetables that have been exposed to fecal-contaminated water. Cyclospora infections are less common than other foodborne illnesses, such as salmonella and E. coli.

The frequency of U.S. cyclospora outbreaks began increasing roughly a decade ago, notably peaking in 2018 and 2019. Experts attribute these rises to climate change and improved detection of the parasite.

A Comparison with Past Outbreaks

Data on cyclospora outbreaks is somewhat scarce, though records reveal only a few outbreaks in the past 20 years have exceeded 1,000 cases. Notable examples include a 1997 outbreak linked to Guatemalan raspberries affecting over 1,000 people in the U.S. and Canada, and a 2019 incident associated with Mexican basil that sickened over 2,400 individuals.

Melanie Firestone, a foodborne illness researcher at the University of Minnesota, notes various reasons for the underreporting of infections. Standard tests do not target cyclospora, contributing to underreporting. Additionally, lab technicians cannot cultivate the parasite, which complicates efforts to gather evidence from contaminated produce. Identifying common food items among infected individuals is difficult, especially when single ingredients like basil or cilantro are involved. Food distributors may also unknowingly deliver contaminated products to both grocery stores and restaurants, complicating source determination. Investigations often take months and sometimes fail to identify a definitive source.

Current Developments in Michigan

Cases are currently surging in southeastern Michigan, though it is not regarded as a national health crisis. Dianna Blau, acting chief of the CDC’s parasitic diseases branch, affirmed no evidence of increased pathogen infectivity. Thousands of cyclospora cases are reported annually in the U.S., though the numbers are four times higher than this time last year according to current CDC data.

Melanie Firestone suggests Michigan’s proactive approach in investigating and reporting cases may contribute to the perception of a localized issue.

Prevention Measures Against Cyclospora

If diarrhea persists for several days, consult a healthcare provider and discuss the potential of cyclospora infection. Prevent infection by avoiding potentially contaminated food and water. Thoroughly wash produce before consumption, though cyclospora may still adhere to food items, negating complete risk elimination. Consumers are advised by Michigan officials to purchase whole heads of lettuce instead of prewashed and bagged versions, removing a few outer leaves before washing thoroughly under running water. Cooking vegetables when possible is also recommended.

The Associated Press Health and Science Department is supported by the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. All content is the sole responsibility of the AP.