Michigan Cyclospora Cases Reach 2,640 as Officials Focus on Lettuce

No specific product, grower or supplier has been identified.

Michigan health officials are investigating lettuce and salad greens as a possible source of the state’s cyclosporiasis outbreak, which has grown to 2,640 reported cases, including 290 in Washtenaw County.

Early findings point to lettuce or salad greens, although other foods have not been ruled out, the Michigan Department of Health and Human Services said Monday, July 13. Officials have not identified a specific product, lettuce variety, grower or supplier.

“Early information has shown lettuce as a common product that regularly comes up during the investigation,” said Dr. Natasha Bagdasarian, Michigan’s chief medical executive.

The statewide total is up from 572 cases reported July 4. Monroe County has recorded 258 cases, and 44 people had been hospitalized statewide as of July 9. Michigan typically records about 40 to 50 cases in an entire year, according to MDHHS.

While the investigation continues, the state recommends buying whole heads of lettuce rather than prewashed, bagged lettuce or salad kits. Consumers should discard the outer two or three layers and thoroughly wash the remaining leaves under clean running water.

Washing produce can reduce exposure but cannot guarantee the parasite has been removed. Cooking greens to at least 158 degrees is the safest option when practical.

Cyclospora is a microscopic parasite that infects the intestines and can cause frequent watery diarrhea. Other symptoms include stomach cramps, nausea, fatigue, loss of appetite and weight loss. Symptoms may take up to two weeks to develop.

Officials also clarified that swimming in lakes and other recreational water exposure are not recognized risk factors for cyclosporiasis. Investigators have found no evidence connecting recreational water to the outbreak. Foodborne exposure remains the primary focus.

People experiencing sudden or persistent diarrhea should contact a health care provider about testing and treatment. Cyclosporiasis can be treated with antibiotics, along with rest and fluids to prevent dehydration.