More than 10,000 Americans have been infected with the parasitic illness cyclosporiasis since May, with iceberg lettuce imported from Mexico identified as a culprit, according to the US Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA).
Outbreak Statistics and Symptoms
As of 4 August, there were 10,468 laboratory-confirmed cases of cyclosporiasis in the US, with an additional 12,255 cases under investigation, and two deaths reported. Symptoms include vomiting, watery diarrhoea, and, as the CDC describes, “frequent and sometimes explosive bowel movements.”
The outbreak has drawn attention to the risks of salad consumption. While salad is often considered a healthy choice, the recent surge in cases highlights potential dangers. The FDA has pointed to iceberg lettuce imported from Mexico as one source of contamination.
Global Context and UK Concerns
Cyclosporiasis is not endemic in Europe, but UK health officials have noted an increase in cases among travellers returning from the US and Mexico. Meanwhile, the UK Health Security Agency reported a sharp rise in shiga toxin-producing E coli cases last year, with symptoms including vomiting, diarrhoea, stomach cramps, and fever.
The largest E coli outbreak in the UK in 2024 affected more than 250 people, 86 of whom were hospitalised, and was thought to be caused by prepacked sandwiches containing contaminated lettuce.
Expert Warnings on Bagged Salad
Dr Primrose Freestone, an associate professor of clinical microbiology at the University of Leicester, told the Times that she “wouldn’t touch a bagged salad in a million years.” Her research indicates that the moist environment inside salad bags is a breeding ground for bacteria and pathogens, with pathogens growing more than 1,000 times better in a salad bag than on loose leaves.
Freestone advises washing all salad leaves thoroughly, refrigerating bagged leaves promptly, and eating them soon after purchase. She warns, “Salad, lettuce and side salad infections can kill.”
The outbreak has also been a subject of late-night commentary, with host Ike Barinholtz referring to it as “Trump diarrhoea,” though the president is not directly responsible for this outbreak.
