Some US states are facing a large and growing outbreak of diarrhea caused by cyclospora, a microscopic parasite that can contaminate fresh food or water, reports BritPanorama.
Iceberg lettuce supplied by Taylor Farms has been recalled, and it’s likely that contaminated products have already been eaten or removed from shelves. “We do have the outbreak under control,” US Health and Human Services Secretary Robert F. Kennedy Jr. said Tuesday, noting the recall. However, illness can take a while to appear, and the epidemiological curve of new cases hasn’t yet slowed.
Health officials are racing to trace the details of cases in an ongoing investigation, but the parasite is notoriously difficult to find. Testing produce can be challenging, and people who are sick may be asked to remember what they ate weeks earlier to help identify a common thread. Cases of cyclosporiasis are known to rise during spring and summer months in the US, with a typical season running from the start of May through the end of August, according to the US Centers for Disease Control and Prevention. However, case counts are particularly high this year.
As of last week, the CDC has identified nearly 7,000 cases of domestic cyclosporiasis this season, including 1,645 cases confirmed, with about 5,100 others undergoing further analysis to determine whether the illness was acquired in the US. Multiple “subclusters” of cyclosporiasis cases have been investigated this year by the US Food and Drug Administration in collaboration with the CDC and state partners. Two investigations remain ongoing, including a particularly large multistate outbreak centered in the Midwest. The CDC has linked 1,644 cases to this specific outbreak.
However, CDC data includes only confirmed cases and hasn’t been updated since last week. Data from individual states shows much higher case counts. The CDC has identified five states with cases linked to the ongoing outbreak: Indiana, Kentucky, Michigan, Ohio, and West Virginia. As of Tuesday, the Michigan Department of Health and Human Services has reported 6,571 cases of cyclosporiasis during the investigation timeframe. The state health department has indicated that while they “cannot say with certainty that every illness is linked to the same source of exposure,” the concentrated increase in cases “strongly suggests that the vast majority of these illnesses are associated with the same outbreak.”
Ohio has reported at least 1,244 cases, Indiana has reported 511 cases, West Virginia has reported 195 cases, and Kentucky has reported 192 cases. Michigan and Indiana update data daily on weekdays, while West Virginia reports new totals twice a week, and Ohio and Kentucky update data weekly. “The true number of sick people in this multistate outbreak is likely higher than the number reported, and the outbreak may not be limited to the states with known illnesses,” according to an update from the CDC. Overall, 34 states have reported at least one domestically acquired cyclosporiasis case this season, with some states — including California and New Jersey — noting that their case counts are in line with typical seasonal trends.
Health officials in Michigan have conducted more than 2,000 interviews of people sick with cyclosporiasis and noted “very strong” evidence linking the outbreak to one product in particular: shredded iceberg lettuce supplied by Taylor Farms, which was served at some Taco Bell locations. The CDC advises against consuming any shredded iceberg lettuce from Taylor Farms de Mexico served at Taco Bell locations in states associated with the outbreak: Indiana, Kentucky, Michigan, Ohio, and West Virginia.
The FDA is working to determine whether contaminated shredded iceberg lettuce went to other locations. Taco Bell has confirmed that it has removed Taylor Farms lettuce from its restaurants and nationwide supply chain, while supplier Taylor Fresh Foods has begun withdrawing all iceberg lettuce from central Mexico from the US market. Taylor Farms has also recalled iceberg lettuce shipped to 27 states, with some distributed to Walmart, Jack in the Box, and other food services.
The investigation remains ongoing, but no other foods have been identified as part of this outbreak. Foods historically linked to cyclospora outbreaks include basil, cilantro, berries, and snap peas. Illnesses associated with the current outbreak started in mid-May, with new cases reported as recently as last week, according to the CDC. Symptoms of cyclosporiasis may take days or up to two weeks to appear after consuming contaminated food or water and can include watery diarrhea, loss of appetite, weight loss, cramping, bloating, increased gas, nausea, and fatigue. Individuals who become ill may experience symptoms for weeks.
At least 94 people have been hospitalized in relation to the current outbreak, according to the CDC. States linked to the outbreak have reported hundreds of cyclospora hospitalizations, with Michigan reporting 102, Ohio 88, Kentucky 9, and West Virginia 15, while data for Indiana has not been disclosed. No deaths have been reported.
Compared to other outbreaks, this current situation is notable. The largest cyclospora outbreak on record in the US led to approximately 1,500 cases and involved raspberries. Other significant outbreaks typically haven’t surpassed 1,000 cases. This ongoing outbreak is likely the largest cyclospora outbreak in the US to date. If confirmed, it would also represent the largest foodborne illness outbreak tracked in the US. There were more than 4,500 cases in 2023 and over 3,500 in 2024, but this year has seen thousands more reported with at least a month remaining in the season.
Current trends in gastrointestinal pathogens also highlight cyclospora’s rising prevalence in the US, which has surged from less than 3% in early June to more than 18% recently. Nevertheless, E. coli continues to be a more common cause of stomach issues, present in over 19% of tests during the same period, with viruses detected in around 14% of tests.
The story continues to evolve, underscoring the challenges of managing foodborne illnesses in a complex and interconnected food supply chain.
