Cyclospora: Explosive diarrhoea infection spreads to UK as officials issue holiday warning

A parasite outbreak linked to explosive diarrhoea has spread to the UK, after leaving thousands sick in America.

The UK has seen a rise in cyclospora infections among travellers returning from Mexico, according to figures published by the UK Health Security Agency (UKHSA) today.

Cylosporiasis infections lead to nasty but non-life-threatening symptoms, such as ‘explosive diarrhoea’ and vomiting. “You’re barely able to make it to the toilet,” Dr. Alejandro Macías, an epidemiologist and physician at the University of Guanajuato in central Mexico, told The New York Times.

The latest data shows that 67 cases reported in the space of two and a half months, a sharp rise on previous years, when an average of 93 cases was recorded across the whole year.

The stats published today, shows that 67 cases have been reported in returning travellers in England (30 cases) Wales and (10 cases) Scotland (27 cases) between 30 April and 15 July 2026.

A total of 48 cases reported are from people who traveled to Mexico, with one also reporting travel to the USA. One further case reported travel to the USA only, and one to Kenya.

Among those who travelled to Mexico, cases reported staying at hotels in the Riviera Maya and Cancún regions and consuming a variety of food and drink as part of all-inclusive holiday packages.

UKHSA is now telling all travellers to take precautions when abroad including maintaining good food and water hygiene to reduce their risk of infection.

Dr Philip Veal, Consultant in Travel Health at UKHSA, said: “We have recently detected a rise in Cyclospora infections among travellers returning from Mexico. These infections are caused by a parasite and can affect the stomach and intestines.

“Travellers to Mexico and other areas where the infection is more common can reduce their risk by following good food and water hygiene measures, including drinking bottled water and eating thoroughly cooked food, even when staying in high-end all-inclusive resorts. We also advise avoiding certain foods such as fresh uncooked berries and herbs, unpeeled fruit and salad items.

“If you develop symptoms after returning from travel, such as watery diarrhoea, loss of appetite, weight loss, stomach cramps or pain, bloating, increased wind, nausea, fatigue or other flu-like symptoms, please seek medical attention and inform your healthcare professional of your travel history.”

What are the symptoms of cyclospora?

Symptoms of infection can include frequent watery diarrhoea, abdominal cramping, bloating, nausea, flatulence, low-grade fever, loss of appetite and weight loss. While cyclosporiasis is usually mild and most people improve typically in a few days without any treatment, infections can be more serious or prolonged in people who are immunocompromised and antibiotics may be prescribed.

What is cyclospora and how does it spread?

Contaminated food specifically herbs, salad and soft fruit are common sources of outbreaks and infections. Infection is acquired via consumption of contaminated food. Cyclospora doesn’t naturally occur in the UK and there is no risk of spread from person to person.

The outbreak has spread across the US in recent weeks making it now one of the nation’s largest known outbreak of the parasitic illness.

There are now nine states that have been affected, updated data from federal health agencies shows.

Trump health officials had previously identified Indiana, Kentucky, Michigan, Ohio and West Virginia as the main states with cases tied to iceberg lettuce from central Mexico contaminated with the parasite cyclospora.