Michigan sees 170+ cyclosporiasis cases in weeks, tripling annual average

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Michigan Case Counts and Regional Spread

The spike in Michigan is significantly outside the norm. According to a spokesperson for the Michigan Department of Health and Human Services (MDHHS), the state typically identifies 50 cases per year. By July 1, that number had more than tripled compared to 2025, with over 170 cases reported in just a few weeks. The outbreak is concentrated in southeast Michigan. Wayne County health officials are currently tracking 27 potential cases as part of the wider surge. The infections have been detected across seven specific Michigan counties:

• Wayne
• Monroe
• Lenawee
• Washtenaw
• Livingston
• Shiawassee
• Jackson

State officials noted that the increase in reports may be partially driven by heightened public awareness of the outbreak.

National Trends and CDC Surveillance

While Michigan is facing a localized cluster, the U.S. is seeing a broader seasonal rise in the parasite. Between May 1 and June 16, the Centers for Disease Control and Prevention (CDC) reported 145 cases across 17 states. New York reported the highest number of cases in that window, followed by Illinois and Texas. The CDC’s data indicates that those infected range in age from 5 to 86, with a median age of 42. While 20 people have been hospitalized nationwide, no deaths have been reported. However, the agency warns that the official count is likely an underestimate. “The true number of people sick with cyclosporiasis was likely higher than the number reported,” the CDC notes. The current national situation is fragmented. Despite the surge, federal investigators have not found a single common link for every patient. “CDC has no evidence of a single, multistate Cyclospora outbreak linking cases happening right now and being reported in press,” the agency said in a June 2 statement to USA TODAY. “The data currently found on CDC’s website is a surveillance count of cases across the United States of people with cyclosporiasis. This number includes clusters of cases currently under investigation by FDA and cases that have not been linked to a common source.” CDC, via USA Today

Identifying the Parasite and Its Symptoms

Cyclosporiasis is caused by Cyclospora cayetanensis, a microscopic parasite found in human feces. It is primarily contracted through the fecal-oral route, most commonly via contaminated fresh produce or water. Unlike some gastrointestinal illnesses, it is not typically transmitted from person to person. The illness is known for its delayed onset. Symptoms typically appear about a week after exposure, though the window can range from two to 14 days.

• Primary Symptom: Watery, frequent, and sometimes explosive diarrhea.
• Secondary Symptoms: Loss of appetite, abdominal cramps, nausea, vomiting, fatigue, and low-grade fever.
• Duration: Without treatment, the illness can last several days to over a month.

Most infections are treatable with prescription antibiotics. Because the illness is seasonal—typically peaking between May 1 and the end of August—health officials are urging vigilance during the summer months.

Prevention and Food Safety Measures

Because the parasite is frequently linked to fresh produce, health officials recommend specific cleaning and handling protocols to reduce risk.

• Wash hands thoroughly before preparing or eating food.
• Rinse fresh fruits and vegetables under running water.
• Use a clean produce brush to scrub firm produce.
• Discard any damaged portions of fruits and vegetables.
• Refrigerate cut produce promptly.

Wayne County Public Health is currently collaborating with the Michigan Department of Agriculture and Rural Development and the MDHHS to identify the specific food or water source driving the southeast Michigan cluster.

Comparing the 2026 Surge to Historical Data

The current activity in Michigan represents a sharp departure from the state’s baseline. While the U.S. generally sees several hundred cases annually, the 2026 Michigan spike has already exceeded the total annual cases from the previous year. The 2019 spike of 4,703 cases serves as a historical benchmark for how severe these outbreaks can become when a widespread contaminated product enters the supply chain. Currently, the CDC and FDA are continuing to investigate whether the Michigan cluster and other state cases share a common throughline or remain isolated seasonal events. Individuals experiencing severe or persistent diarrhea should consult their healthcare provider for diagnosis and treatment.

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