Rise in Cyclospora Infections in the U.S.

Infections from the parasite cyclospora are rapidly increasing across the United States, with 2026 already marked as the worst year for reported cases. Over 30 states have recorded infections, and current data indicates the number exceeds the previous record of approximately 4,700 cases in 2019.

Identifying the Source

Although cyclospora infections rarely pose life-threatening risks and are primarily treated with antibiotics, the exact cause of the surge remains unidentified. On Tuesday, federal health officials noted variations in infection patterns across different regions. However, there are indications that cases in Michigan, Ohio, Kentucky, and West Virginia might be interconnected.

In Michigan, where over 3,300 cases have emerged, officials suspect that lettuce or salad greens could be the source. Natasha Bagdasarian, the chief medical executive of the Michigan health department, stated that lettuce frequently appears in discussions during investigations following interviews with more than 1,000 patients.

Safety Measures and Industry Responses

Given the association between produce and past cyclospora outbreaks, Michigan authorities recommend consumers purchase whole heads of lettuce, discard the outer layers, and thoroughly wash the remaining parts. They advise against bagged lettuce and pre-mixed salad kits.

On Tuesday, Taco Bell announced a temporary withdrawal of certain ingredients from select locations as a preventive step. The company’s move is aligned with guidelines from public health agencies.

The U.S. Food and Drug Administration (FDA) continues its traceback investigation of several produce items and locations linked to reported cases. Donald Prater, Acting Deputy Commissioner for Food, stated that the investigation remains ongoing.

Cyclospora Infection Characteristics

Cyclospora is a microscopic, spherical parasite predominantly causing watery diarrhea characterized by frequent and severe bowel movements. The U.S. Centers for Disease Control and Prevention (CDC) highlight that outbreaks primarily occur in late spring and summer.

The parasite, thriving in warm conditions, infects the intestines and spreads through feces. Past infections have been linked to consumption of fruits or vegetables contacting contaminated irrigation water.

Cyclosporiasis is relatively less common compared to foodborne illnesses like salmonella and E. coli. Traditional testing methods often overlook cyclospora, leading experts to believe historical cases were underreported. The increasing cases are attributed to climate change and advancements in detection methods.

The Rising Trend

2019 marked the worst year for cyclospora infections in the U.S. with around 4,700 reported cases. Federal data on confirmed and suspected cases are maintained by the CDC, who issue health alerts based on state reports.

Since May 1, the CDC acknowledged 1,645 confirmed domestic cases and more than 5,100 needing further analysis to determine the source of infection. Reports span 34 states, yet no fatalities have been recorded.

The actual number of cases could be higher, as individuals with milder symptoms may refrain from seeking medical care, according to Gwen Biggerstaff, Deputy Director of the CDC’s Division of Foodborne, Waterborne, and Environmental Diseases.

Symptoms may develop days to weeks post-exposure, leaving the current infection rate unclear. However, Biggerstaff anticipates case numbers to rise through August.

Specific State Information

Statistics from individual states are not detailed in federal alerts. Michigan reports over 3,300 cases, northwest Ohio accounts for over 1,100, New York City records more than 400, and Illinois lists over 200.

Officials believe cases in Michigan are primarily due to a domestic outbreak. The CDC did not elaborate on the rationale for connecting Michigan, Ohio, Kentucky, and West Virginia cases to a single outbreak.