Nurses Chase Cyclospora, Aided by Interviews, Fast-Food Receipts — And the Messy Details

In the summer of 2025, more than 900 residents of Washtenaw County, Michigan, were struck by cyclosporiasis, a condition leading to severe gastrointestinal symptoms. Linda Kim, a public health nurse, conducted more than 100 interviews with those affected, discovering that nearly everyone described the illness as excruciating and one of the worst they had ever experienced.

On a Wednesday in July, however, Kim interviewed a man who expressed a preference to contract the disease again, remarking on the weight loss it had caused. This marked a stark contrast to her earlier experience with a measles outbreak in March, where people were initially reluctant to disclose personal information. The measles outbreak had ended in late May, but cyclosporiasis cases began to surge in mid-June, with over 11,000 reported cases in Michigan by August, including two deaths.

Both fatalities were attributed to underlying health conditions that may have been exacerbated by the parasite and dehydration. Cyclosporiasis generally is not life-threatening, though deaths from it are rare in the U.S. Kim noted that contact tracing for cyclosporiasis is vastly different from measles, as symptoms can take up to two weeks to manifest and people often struggle to recall their food intake from that period.

To identify the source, Kim and her colleagues requested detailed information from patients, including restaurant receipts, grocery store app purchases, and specifics about contaminated food items. This process, she said, can often extend beyond an hour. The county's health department has been grappling with staffing shortages due to federal funding cuts, which have also impacted disease surveillance labs and outbreak response capabilities.

Despite these challenges, the health department continues to work tirelessly to trace the origins of the cyclosporiasis outbreaks and contain the spread.