UK Travellers Warned About Cyclospora Infection

British holidaymakers were advised to watch for symptoms of Cyclospora infection after UK health authorities recorded 67 cases between April 30 and July 15, 2026.

Most patients had recently returned from Mexico, according to the UK Health Security Agency. Cyclospora is a microscopic parasite that causes an intestinal illness known as cyclosporiasis, usually after a person consumes contaminated food or water.

The most recognisable symptom is frequent watery diarrhoea. People may also experience stomach cramps, bloating, nausea, reduced appetite, weight loss and prolonged tiredness. Symptoms can improve and then return, making the infection easy to mistake for a shorter stomach illness.

When travellers should seek medical advice

Anyone who develops persistent diarrhoea after foreign travel should contact a healthcare professional and explain where and when they travelled. A specific laboratory test may be needed because Cyclospora is not necessarily included in every routine stool examination.

Treatment is available, but a clinician must decide whether it is appropriate for the patient. People should seek prompt advice if they cannot keep fluids down, show signs of dehydration, have blood in their stool or belong to a group at greater risk of complications.

Health agencies also investigate clusters to identify a shared food item, supplier or destination. The UK cases coincided with a separate US outbreak linked by the CDC to shredded iceberg lettuce sourced from Mexico, but each investigation follows its own evidence and distribution records.

Reducing risk while travelling

Cyclospora cannot be reliably detected by the appearance or smell of food. Travellers can reduce risk by using safe drinking water, washing hands, choosing food from hygienic premises and being cautious with raw produce where sanitation or water quality is uncertain.

Washing fruit and vegetables may reduce contamination but cannot guarantee removal of the parasite. Food businesses have a separate responsibility to maintain traceability, cold-chain controls and hygienic preparation.

The warning did not advise against all travel to Mexico. It was intended to help travellers recognise symptoms and obtain the correct testing after returning home.

Frequently asked questions

Can Cyclospora spread directly between people?

Direct person-to-person spread is considered unlikely because the parasite needs time outside the body before becoming infectious.

How long can symptoms last?

Without appropriate care, symptoms may continue for weeks and can follow a pattern of improvement and relapse.

What should returning travellers tell their doctor?

They should mention their destination, travel dates, foods eaten and the onset and duration of symptoms.

Why cases can be difficult to count

There can be a delay of about a week between exposure and symptoms, and some patients do not seek care or receive the specialised test needed for confirmation. As a result, an investigation may identify cases weeks after travel. Food traceback is also complex when fresh produce moves through several farms, processors and distributors. Public-health updates can therefore change both the case count and the suspected exposure. Travellers should check the latest UKHSA advice and should not use this dated July report as a substitute for current medical guidance.