Michigan health officials reported a dramatic spike in laboratory-confirmed infections of cyclosporiasis, a diarrheal illness caused by the parasite Cyclospora, saying the state is tracking more than 3,309 cases as of July 14. State leaders warned the figure could make this outbreak the largest recorded in U.S. history.
Scope of the outbreak
The Michigan Department of Health and Human Services (MDHHS) said the number of cases in the state is roughly 10 times higher than it was on July 2 and more than 65 times Michigan’s usual annual average. The Centers for Disease Control and Prevention (CDC) reported it has received 1,645 confirmed domestic cases since May 1 and is aware of more than 5,100 additional reports that require further analysis to determine whether the infections were acquired in the United States.
Possible sources and early investigational findings
MDHHS investigators are focusing on leafy produce after collecting exposure histories from more than 1,000 people with confirmed infections. Officials said early patterns point toward lettuce and other salad greens as potential common exposures.
"In Michigan alone, with more than 3,300 cases, this already makes this likely the largest cyclosporiasis outbreak in U.S. history," MDHHS Chief Medical Executive Dr. Natasha Bagdasarian said.
Bagdasarian also noted that interviews with patients — documenting where they dined, which restaurants and fast-food chains they visited, and specific menu items ordered — have started to reveal signals implicating leafy greens.
Geographic distribution and severity
While Michigan leads the nation in reported cases, health officials said more than 30 other states have reported infections that may be linked to the same period. The CDC cautioned that state and local case counts often outpace the agency’s national totals because of reporting and confirmation timelines.
As of Monday, Wayne County reported nearly 340 cases, and almost all counties in Southeast Michigan now have more than 100 confirmed infections. The CDC has reported no deaths associated with this outbreak to date.
What investigators are doing
State and federal health agencies are pursuing epidemiologic interviews, trace-back investigations and laboratory testing to identify the contaminated product or distribution pathway. Officials said they are analyzing where affected individuals shopped or ate and are working with suppliers and retailers to trace fresh produce origins.
- Michigan cases (MDHHS): 3,309+
- CDC confirmed domestic cases since May 1: 1,645
- CDC reports pending further analysis: 5,100+
- Wayne County cases: ~340
- Suspected vehicles: lettuce and salad greens
| Jurisdiction | Reported cases |
|---|---|
| Michigan (MDHHS) | 3,309+ |
| CDC (confirmed domestic since May 1) | 1,645 |
| CDC (pending analysis) | 5,100+ |
| Wayne County | ~340 |
Federal and state officials advise the public to follow routine food-safety guidance and to stay informed through official public health channels. Investigations of outbreaks involving fresh produce can be complex and time-consuming, as trace-back must link affected people to common suppliers and specific lots.
Health departments are continuing interviews and laboratory work to narrow potential sources and distribution patterns. Because reporting and confirmation lag differently across jurisdictions, the totals are likely to change as more data are processed and shared.
News Block will monitor official updates from MDHHS and the CDC and report new findings as investigators release them.
