Cyclospora infections spread among US patients and travellers returning to Britain

Updated: 17 August 2026

LANSING, Michigan, 3 August 2026 — Michigan health authorities recorded the first two US deaths associated with this year’s sharp rise in cyclosporiasis, the Associated Press reported, as British officials investigated 67 infections among travellers returning mainly from Mexico. The US Centers for Disease Control and Prevention was aware of more than 18,000 confirmed or suspected cases nationwide when the deaths were announced, according to AP.

The UK Health Security Agency said on 30 July that England, Scotland and Wales had recorded 67 cases between 30 April and 15 July. Travel information was available for 52 patients; 48 had visited Mexico, particularly Cancún and the Riviera Maya, UKHSA said. One had also visited the United States, while another reported US travel only.

Cyclospora cayetanensis is a microscopic parasite transmitted through contaminated food or water. UKHSA says it does not naturally occur in Britain and does not spread directly from one person to another. Infection causes frequent watery diarrhoea, cramps, bloating, nausea, fatigue and weight loss; illness is normally mild but can persist or become serious in people with weakened immune systems.

The American outbreak is larger and includes several clusters. The US Food and Drug Administration linked one nine-state cluster to shredded iceberg lettuce served at Taco Bell restaurants. By 24 July, the CDC had counted 1,947 cases and at least 98 hospital admissions in that cluster, AP reported. The FDA’s investigation traced the implicated supply chain to Taylor Farms de Mexico, although laboratory experts withdrew an initial positive lettuce result after concluding that it was false.

Mexico’s health and agriculture authorities said their subsequent tests had not detected Cyclospora in lettuce or water from the facility. That result does not overturn the US epidemiological and supply-chain findings, but it leaves the precise point and mechanism of contamination unresolved.

No Belgian cluster connected with these outbreaks has been announced. The direct relevance for Belgium is travel-related: residents returning from Mexico or the United States should tell a doctor about their journey if prolonged watery diarrhoea develops. Sciensano’s historical surveillance reports say Belgian infections are generally imported and can be missed unless clinicians request parasite-specific testing.

UKHSA expects further travel-associated reports during the summer and is working with Mexican authorities. US agencies are continuing to trace contaminated produce and separate lettuce-linked patients from unrelated clusters. Those investigations will determine whether the outbreaks share a wider source or represent several distinct contamination events.