Oakland and Wayne counties have recorded more than 2,400 cyclosporiasis cases between them as Michigan's parasite outbreak, now the largest in the nation, surpassed 10,000 confirmed infections by Thursday, July 30.
Northville and Novi residents sit at the center of the outbreak's geographic footprint. Oakland County, which includes Novi, reported 1,043 cases. Wayne County, which includes Northville Township, leads the state with 1,379 cases, according to the Oakland Press. Metro Detroit as a whole accounts for 2,950 of the state's 10,386 confirmed infections.
The Michigan Department of Health and Human Services reported 193 hospitalizations statewide. No deaths have been reported.
Michigan typically sees about 50 cyclosporiasis cases per year. The 2026 outbreak has produced roughly 185 times that figure in about five weeks.
What residents should know
Cyclosporiasis is caused by the Cyclospora cayetanensis parasite, transmitted through contaminated food or water. It does not spread person to person.
Symptoms include frequent watery diarrhea, stomach cramps, bloating, nausea, and fatigue. They typically appear about one week after exposure but can emerge anywhere from two days to more than two weeks later. Without treatment, the illness can last for weeks and may recur, Wayne County Public Health warned. The disease is treatable with antibiotics, but severe dehydration poses particular risks for young children, elderly residents, and immunocompromised individuals.
The Taylor Farms recall and Taco Bell connection
On July 17, Taylor Farms voluntarily recalled all iceberg lettuce sourced from its Guanajuato, Mexico facility. The recall covers products distributed to 27 states, including Michigan, and includes two Walmart Marketside retail items: Iceberg Salad (12 oz. and 24 oz.) and Shredded Lettuce (8 oz. and 16 oz.) with best-if-used-by dates of July 18 through Aug. 3.
Taco Bell stopped using Taylor Farms iceberg lettuce nationwide and removed all affected product from its restaurants. The CDC linked a nine-state outbreak cluster to shredded iceberg lettuce served at Taco Bell locations, with 1,947 people in those states reporting illness after eating there. Michigan is among the nine affected states.
About 12% of Michigan patients have no clear link to lettuce or a fast-food chain, according to state Chief Medical Executive Dr. Natasha Bagdasarian, meaning the investigation remains open.
Local health response stretched thin
Oakland County Health Officer Kate Guzman is leading the county's response with a team of four communicable disease nurses and three epidemiologists serving nearly 1.3 million residents. The county lost four additional nurses in spring 2026 after federal COVID-era grant funding ended, Reuters reported.
"We have had to pull in dozens of staff from other areas, from hepatitis C and interns who are working on gun violence prevention," Dr. Bagdasarian told Reuters on July 25, describing the statewide strain on public health resources.
Dr. David Donaldson, Emergency Center Chief at Corewell Health Beaumont Troy Hospital in Oakland County, confirmed as of July 24 that clinics were seeing high volumes of diarrhea-related illness consistent with cyclosporiasis.
Wayne County Public Health announced July 30 that it is conducting a community survey and asked residents who are contacted to respond.
How to protect yourself
MDHHS recommends buying whole heads of lettuce rather than pre-washed bagged varieties, discarding the outer two to three layers of leaves, and washing remaining inner leaves under running water. Cooking greens to at least 158°F kills the parasite.
How to report illness
MDHHS advises anyone experiencing sudden, ongoing diarrhea to contact their health care provider and local health department.
Oakland County residents can reach the Oakland County Health Division at 248-858-1280 or the Oakland Connects Helpline at 800-848-5533 (Monday through Friday, 8:30 a.m. to 5 p.m.). Wayne County residents should contact their health care provider; updates are posted on the MDHHS Infectious Disease Outbreaks page.
The CDC expects cases to continue increasing possibly through the end of August.
