Cyclospora Outbreak May Have Peaked in Michigan as US Cases Top 18,000

There are tentative signs that the cyclosporiasis outbreak may be slowing in Michigan — the epicenter of the nation’s worst cyclospora surge in recorded history — but health officials caution the outbreak is far from over and other food sources beyond iceberg lettuce are still under active investigation.

18,000 Cases Nationwide, Michigan Hardest Hit

The CDC reported Tuesday that more than 18,000 confirmed or suspected cases of cyclosporiasis have been recorded nationwide this season. Michigan alone has tallied more than 9,500 cases with approximately 160 hospitalizations over the past two months. In nine states, most illnesses have been traced to shredded iceberg lettuce sourced from Taylor Farms de Mexico, which was recalled more than a week ago after the FDA linked it to Taco Bell restaurants in Indiana, Kentucky, Michigan, Ohio, and West Virginia, as well as grocery and food service suppliers.

Signs of a Peak — With Caveats

Dr. Natasha Bagdasarian, Michigan’s chief medical executive, said roughly 475 cases reported since Friday were the result of a reporting backlog at one healthcare system rather than new infections — a positive sign. She also noted that the percentage of emergency department visits with diarrhea as a primary complaint has begun to decline.

However, Bagdasarian added significant caveats. Some health systems have begun limiting cyclospora testing to severely ill or immunocompromised patients due to lab backlogs and supply constraints — meaning milder cases are going undetected and the true trajectory of the cyclospora outbreak Michigan peak 18000 US cases picture remains uncertain.

“I don’t know if a single product recall is related to the slowdown that we’ve seen,” Bagdasarian said. She credited both the Taylor Farms recall and public health guidance — encouraging consumers to peel, cook, and remove outer layers of produce — as potential contributors to the decline.

Michigan has seen two distinct waves of illness this season. The first peaked June 21 through June 28, and the second ran July 5 through July 12, a pattern food safety expert Barbara Kowalcyk of George Washington University said may indicate the contaminated product was supplied in two separate batches. She raised the broader question of whether ongoing contamination of irrigation or processing water at the Taylor Farms site in central Mexico could be affecting multiple crops and product batches.

Multiple Food Sources Still Under Investigation

Officials are increasingly clear that iceberg lettuce from Taylor Farms is not the only culprit. Frank Yiannas, former FDA deputy commissioner for food policy, said explicitly that more than one product is causing illness this season.

Cilantro and parsley have emerged as suspects in separate clusters. North Carolina, which has reported 561 cyclospora cases, said its preliminary investigation points to cilantro and parsley as possible sources. An earlier cluster in New York was traced to cilantro served at a Brooklyn restaurant, though it was never definitively confirmed. Neither the North Carolina nor New York cases have been linked to Taylor Farms.

Dr. Stephen Ostroff, a former acting FDA commissioner, said illnesses could also be stemming from other lettuce grown in the same Mexican region as Taylor Farms, which may have entered the US supply chain through different distribution channels. “If, in fact, all the lettuce is pulled from the market, consumers should not be surprised that they continue to see states report illnesses,” Yiannas said.

Systemic Weaknesses Exposed

The outbreak has also highlighted structural vulnerabilities in the US food safety and public health system. Health officials lack access to real-time genetic sequencing that would allow faster matching of contaminated products to specific cases. The complex, multi-step food supply chain — in which products change hands many times and move through multiple distribution centers — makes traceback investigations slow and often inconclusive.

“We still need increased capacity. We aren’t investing enough in science. We’re not investing enough in research,” said Kowalcyk, whose institute focuses on food safety and nutrition security. “This goes back to the need for better laboratory methods in terms of detecting cyclospora in the environment.”