Michigan cyclosporiasis outbreak nears 1,000 cases

Michigan’s cyclosporiasis outbreak has climbed to 992 confirmed cases, according to state reporting cited by AP and local news outlets on July 8. Public health officials say they still have not identified the source.

AP reported that about 40 people have been hospitalized and that no deaths have been reported. The outbreak is now described as the largest cyclosporiasis outbreak in Michigan history.

Cyclosporiasis is an intestinal illness caused by the Cyclospora parasite. It can cause watery diarrhea, stomach cramps, nausea, fatigue and vomiting, and it is commonly linked to contaminated food or water, especially produce.

Officials have not identified a specific food item, grower, distributor or restaurant tied to the Michigan cases. A Huron County Health Department report said no specific produce grower, supplier or produce type had been identified.

How the outbreak grew

Michigan first alerted the public to the outbreak last week, when officials said they were aware of more than 170 cases in southeastern Michigan dating to June 22.

By July 4, state and local coverage said the count had reached 572. Reporting on July 7 said the outbreak was near 700 cases. The July 8 update moved the total to 992.

That jump underscores how quickly the investigation has expanded across southeastern Michigan. State officials said Michigan usually identifies about 50 cyclosporiasis cases each year, making this cluster far larger than a typical season.

Monroe County remains the hardest-hit county in the latest local reporting, with 173 reported cases. Washtenaw County followed with 95 cases.

Local reporting also said Mecosta, Osceola, Lake and Newaygo counties had no reported cases at that time.

What investigators know

Michigan officials have said the source remains unidentified. The outbreak’s size and lack of a confirmed source leave open the possibility that a contaminated food item could still be circulating.

The illness is not usually spread person to person because the parasite needs time outside the body before it becomes infectious. That makes a contaminated food or water exposure the main concern in most outbreaks.

Health officials are also watching other cyclosporiasis investigations in the U.S. CDC-linked coverage said at least 145 domestically acquired cases had been reported in 17 states through June 16, with 20 hospitalizations. At that point, officials did not see evidence of a single multistate outbreak tying all cases together.

What comes next

The biggest unanswered question is whether investigators can identify a common source before additional people are exposed. Officials are still looking at potential links involving produce, but no specific item has been confirmed.

Public health agencies in Michigan and elsewhere are expected to keep updating county and statewide totals as more lab-confirmed cases are reported. They are also watching for additional hospitalizations, spread into new counties or neighboring states, and any new guidance for food service operators and produce handlers.

For now, the outbreak remains a major public-health and food-safety concern because the source has not been found and potentially contaminated produce could still be in circulation.