Parasite Outbreak Tied to Two Deaths in Michigan, CDC Says

Two people have died in Michigan from the severe diarrhea-causing parasite that has sickened thousands across the US, according to the Centers for Disease Control and Prevention.

Both had underlying health conditions, the agency said in a statement Monday. The cyclosporiasis infections and dehydration may have exacerbated their existing, significant health conditions, Michigan’s health department said in a statement.

They’re the first deaths in a growing US outbreak of cyclosporiasis, a disease caused by eating food contaminated with a microscopic parasite. The CDC has recorded 6,707 infections across 45 states this year. State health departments have recorded even higher numbers — the largest cluster in Michigan has infected 11,234 people as of Monday.

Many sick people had eaten iceberg lettuce from producer Taylor Farms, which makes 40% of bagged or packaged salads in the US. Taylor Farms recalled products from 27 states, including lettuce sent to Taco Bell, after being linked to the outbreak. It said it no longer sources from a Mexico farm that provided the lettuce.

The widening outbreak prompted Taco Bell to pull some lettuce from its stores last month and led some Americans to shun salads. It’s not clear whether the deaths were linked to specific products or restaurants. The CDC and US Food and Drug Administration continue to investigate other outbreaks.

Shares of Sweetgreen Inc. fell as much as 5.7% in New York, while Taco Bell parent Yum! Brands Inc. fell as much as 1.8%.

Taylor Farms, Sweetgreen and Taco Bell didn’t immediately respond to requests for comment. Sweetgreen has said it’s not affected by the outbreak.

It’s rare for someone to die from a cyclosporiasis infection. Symptoms — including watery diarrhea and nausea — can appear as long as two weeks after ingesting the parasite and potentially last for as long as two months. Treatment can include prescription antibiotics and supportive care, including plenty of fluids.

Around 22% of people with confirmed cyclosporiasis infections visited the emergency room within two weeks of being diagnosed, and 12% were hospitalized, according to an analysis by Truveta, a health data firm. Just under 10% of patients younger than 65 were hospitalized, compared to 19.4% of patients 65 and older.

Last month, the rate of diagnosing cyclosporiasis was more than 11 times the average July rate between 2018 and 2025, according to Truveta.

The parasite responsible for the disease, called cyclospora, is difficult to track. It’s hard to replicate and study the parasite in a lab, and the short shelf life of the produce where it typically lives complicates the process. Typically, it thrives on leafy greens like lettuce and basil, or fruits like raspberries.