Travelers warned of cyclospora infections after holidays abroad

On July 30, the UK Health Security Agency issued an alert about a sharp rise in cyclospora infections among holidaymakers returning from Mexico, a parasitic illness that can cause severe stomach cramps and prolonged diarrhea.

Cyclospora is different from the short-lived stomach bug many travelers assume they have. The parasite often takes about a week to cause symptoms, which makes it harder to connect the illness to a meal, drink or destination. For healthy adults it is not usually life-threatening, but it can be miserable and disruptive, leaving people dehydrated and unable to travel or work normally for days or even weeks.

Cyclospora is not found in the UK, but travelers can pick it up in parts of the world where food and water safety vary. It is common in Central and South America, south and southeast Asia, the Middle East and Africa. Infection can come from unclean water or from food that has been contaminated, undercooked or washed with unclean water.

Fresh produce is a common route, especially salads and fruit. Travelers may not think twice about washed leaves, fruit plates or ice made from contaminated water. The infection does not spread through close contact with someone who has it, which means households do not face the same transmission risk as with ordinary gastroenteritis.

Cyclospora is a summer travel issue, and the incubation period is typically about one week. Public Health Scotland's cyclospora travel-associated outbreaks page was last updated on May 22, 2025. Travelers with diarrhea, dehydration, stomach cramps or fatigue after a trip should seek medical attention, because doctors may need to test specifically for cyclospora instead of treating it as a routine stomach infection.