Suspected cases of cyclosporiasis, a parasitic infection causing severe gastrointestinal distress, have surged to nearly 600 in Michigan, prompting state health officials to issue new warnings and intensify investigations into the outbreak's source. The Michigan Department of Health and Human Services (MDHHS) is working to identify the cause, which is believed to be food-related, though no specific food item or supplier has been identified.
As of July 4, Michigan reported 572 cases, a significant increase from previous days. The Centers for Disease Control and Prevention (CDC) reported 145 cases across 17 states as of July 1, with 20 hospitalizations. However, the CDC's update did not list any Michigan cases at that time, highlighting the rapid escalation within the state.
The outbreak is concentrated in Southeast Michigan, with cases reported in Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland, and Livingston counties. Patients range in age from eight to 84, with an average age of 44. Cyclosporiasis symptoms typically appear about a week after exposure and can include sudden, severe diarrhea, cramping, nausea, vomiting, and fatigue. The infection can last for more than a month, with symptoms recurring.
To reduce the risk of exposure, MDHHS has advised restaurants, particularly in affected areas, on specific food preparation techniques. For produce like lettuce and leafy greens, the agency recommends purchasing whole heads instead of pre-washed bagged products, discarding the outer leaves, and thoroughly washing inner leaves under running water. Cilantro and basil should also be washed separately, and green onions should have their root ends trimmed and outer layers removed before washing. Raspberries and snow peas are also highlighted as items requiring thorough washing due to the parasite's ability to hide in crevices or on surfaces.
Heating foods to 158 degrees Fahrenheit (70 degrees Celsius) can kill the cyclospora parasite. MDHHS also emphasized that all fresh produce should be washed under running water, even if it is to be peeled.
The CDC is investigating clusters of cases in multiple states and is collaborating with state and federal agencies. Cyclosporiasis is typically acquired through contaminated food or water, often originating from feces, and human-to-human transmission is rare. While most healthy individuals recover without treatment, the antibiotic trimethoprim-sulfamethoxazole is prescribed for those who require it. Individuals experiencing gastrointestinal illness are encouraged to contact their healthcare providers and local health departments.
Cases of cyclosporiasis commonly increase between May and August, and are often associated with foreign travel. In the current outbreak, New York has reported the highest number of cases outside of Michigan, between 31 and 80, according to the CDC. Texas and Illinois follow with 11 to 30 cases. An additional 45 cases have been reported in individuals who consumed food or beverages while traveling internationally, with three hospitalizations but no reported deaths.
Previous outbreaks have been linked to bagged salad kits, cilantro, basil, and other leafy greens, though the specific source in the current outbreak remains under investigation. MDHHS stated it would provide updates as more information becomes available through its collaboration with local health departments and the Michigan Department of Agriculture and Rural Development.