Michigan cyclosporiasis outbreak tops 1,500 cases, health department says

Michigan’s cyclosporiasis outbreak has reached 1,562 reported cases, including 44 hospitalizations, according to the Michigan Department of Health and Human Services.

MDHHS says the source of the outbreak still has not been identified. The agency is posting case totals daily on weekdays and updating hospitalization figures weekly on Thursdays as it works with local health departments and the Michigan Department of Agriculture and Rural Development.

Case counts rose quickly

The latest total marks a sharp rise over the past two weeks. On June 30, MDHHS said Michigan had 170 reported cases. By July 4, the total had climbed to 572, prompting the agency to issue recommendations for preventing foodborne illness and to warn restaurants and other commercial kitchens that handle raw produce to take extra precautions.

On July 9, the Associated Press reported 992 confirmed Michigan cases and about 40 hospitalizations, citing state officials. AP quoted Michigan chief medical executive Dr. Natasha Bagdasarian as saying there was “clearly a linked outbreak happening right now.”

MDHHS’s outbreak page then listed 1,562 total cases on July 10, along with 44 hospitalizations. The state says the largest increase has been in Southeast Michigan.

Where the outbreak is concentrated

MDHHS said the highest county counts were in Monroe, Lenawee, Washtenaw, Wayne, Shiawassee, Jackson, Oakland and Livingston counties. The state has not identified a single food, grower, distributor or exposure setting tied to the outbreak.

The agency continues to investigate with local health departments and MDARD. For now, the case pattern suggests the outbreak is still active and expanding, but the source remains unclear.

Guidance for food handlers

Cyclospora is a parasite that can spread through contaminated food or water. Illness can cause watery diarrhea and may last from days to more than a month.

Because the parasite can be difficult to detect in food and outbreaks can take time to trace, MDHHS has urged food-service operations to treat raw produce as a possible exposure point while investigators work.

Its July 4 guidance told restaurants and other commercial kitchens to buy whole heads of lettuce when possible, wash leafy greens under running water and cook produce when it can be cooked.

Why it matters

The outbreak raises concerns for fresh produce supply chains and for restaurants and commercial kitchens that handle vegetables in bulk. It also poses added risk for older adults, young children and immunocompromised people, who are more vulnerable to dehydration and hospitalization.

The main open questions are whether investigators can identify a contaminated produce item or a common supplier, and whether the outbreak stays concentrated in Southeast Michigan or spreads more widely.

MDHHS says daily case totals will continue to be updated Monday through Friday, with hospitalization information updated on Thursdays.