Hospitals and doctors' offices in Michigan ran out of Cyclospora tests during the worst weeks of this summer's outbreak, according to the state's chief medical executive, and the state had no authority to trace the contaminated lettuce through the supply chain.
Those two capacity failures sit underneath every case number published this summer. A test that is unavailable produces no case, and an outbreak that nobody can trace stays open longer.
Michigan's health department reported 13,909 cyclosporiasis infections, 314 hospitalizations, and two deaths as of mid-August, the highest total of any state, and publishes updates on its state health department's outbreak page. For households, the useful takeaway is not the total. It is that some people who were sick in June and July were never tested, will never appear in any count, and may still be carrying a treatable infection.
The Tests Ran Out Before the Cases Did
Natasha Bagdasarian, MD, MPH, Michigan's chief medical executive, described the shortage directly. As cases rose, some hospitals and doctors' offices ran out of supplies.
"They simply couldn't keep them in stock long enough," because of the sheer volume of cases, Bagdasarian told CIDRAP News, adding that it was challenging for health systems to keep up.
The shortage compounded a reporting lag that was already built into the disease. Symptoms begin one to two weeks after someone eats contaminated food, and people often wait before seeking care. Laboratory backlogs then added time on top of that. Bagdasarian said the state initially was not experiencing such delays, and that longer delays emerged as health systems worked through testing backlogs.
The consequence of the numbers is that a case reported in August frequently describes an illness that began in early summer. Bagdasarian said the vast majority of recently reported cases had symptom onset before July 16.
MedicalDaily has reported that the cases being logged now are mostly older infections rather than evidence of new transmission. The test shortage is the mechanism that produced much of that backlog, and it is the part that has consequences for individual patients rather than only for statisticians.
Cyclospora is not detected by a routine stool culture. A clinician has to specifically order testing for the parasite. When that test is out of stock, the alternative is not a slower diagnosis. It is often no diagnosis, an untreated infection that can cycle for weeks, and an illness that never enters surveillance. Food Safety News has reported that for every confirmed patient, as many as 83 can go undiagnosed.
A State That Could Investigate but Could Not Trace
The second gap Bagdasarian described is structural rather than logistical.
Michigan's outbreak team spotted the signal early. Bagdasarian said staff was quick to recognize something outside the norm as reports came in during June, that the state notified federal agencies immediately and urged them to begin national investigations, and that early case interviews led Michigan to flag lettuce to the CDC and FDA and ask them to prioritize it. She said those early, swift actions likely saved the state from thousands of additional cases and that every licensed health care provider in the state received an early bulletin on who to test and how.
What the state could not do was follow the product. Bagdasarian said Michigan does not have the mechanisms to conduct that traceback or to examine harvesting and processing of products outside its jurisdiction, and that strong federal systems are needed to visit factories and processing plants.
She also described a blind spot in the other direction, saying it would have been helpful to hear what other states were seeing early on, and that it has never been entirely clear whether a single contaminated product explained Michigan's cases or whether overlapping issues were occurring simultaneously.
That is a state health official describing the limits of state authority in a national food supply. A jurisdiction can interview patients and warn its own residents. It cannot inspect a farm in another country. The traceback that eventually implicated iceberg lettuce from central Mexico required federal investigators, and the FDA began an on-site inspection at the Mexican facility on August 13, nearly four weeks after the recall.
The People Still Owed a Diagnosis
The practical consequence of a test shortage lands on a specific group: people who were sick during the peak weeks, sought care, and were sent home without a Cyclospora test because none was available.
Cyclosporiasis does not reliably resolve on its own. Untreated, it can cause watery diarrhea that comes and goes over weeks, along with cramping, bloating, nausea, loss of appetite, fatigue, and weight loss. It is treatable with antibiotics once identified.
Anyone who has had prolonged or relapsing diarrhea dating to late spring or summer and never received a specific answer should contact a clinician and ask specifically about Cyclospora testing. Supply pressure has eased as case volume has fallen, so a test that was unavailable in July may now be available. Bringing a rough symptom timeline and any record of restaurant meals or bagged lettuce purchases helps, because state investigators use those interviews, and confirmed illnesses reported to a local health department are what eventually feed the national surveillance figures.
Older adults, people with weakened immune systems, and anyone unable to keep fluids down face the highest risk of complications and should seek care rather than waiting the illness out. Both deaths in this outbreak were attributed to cyclosporiasis-induced dehydration in patients with underlying health conditions, not to the parasite directly.
For uninsured patients, federally qualified health centers can order the testing.
Michigan has told residents they can return to routine precautions around leafy greens, and Bagdasarian was explicit that the guidance applies to Michigan, not nationally. The state has also stepped back from daily case updates as the pace slowed. Whether federal agencies expand traceback capacity in response to this outbreak is an open question, and Congress is now asking. MedicalDaily will report the findings from the FDA inspection in Mexico and any federal response on surveillance capacity.
Key Questions Answered
What is new in this report? Michigan's chief medical executive says hospitals and doctors' offices ran out of Cyclospora tests during the peak, and that the state lacked the mechanisms to trace the contaminated product itself.
Why does a test shortage matter? Cyclospora is not found on a routine stool culture. Without the specific test, many people went undiagnosed and untreated, and those illnesses never entered the case counts.
Does that mean the real number is higher? Almost certainly. Confirmed counts capture people who sought care and were successfully tested, which the shortage limited during the busiest weeks.
Should someone who was sick in June still get tested? If symptoms are ongoing or keep returning, yes. Ask a clinician specifically about Cyclospora testing, since availability has improved as case volume has dropped.
Is cyclosporiasis treatable? Yes, with antibiotics once it is identified. Untreated, it can cycle for weeks.
Why could Michigan not trace the lettuce? State health departments have no authority to inspect harvesting or processing operations outside their jurisdiction. Traceback across state and national borders requires federal investigators.
Is lettuce safe in Michigan now? State officials have told residents to return to routine precautions around leafy greens and were explicit that the advice applies to Michigan rather than to other states.
