Holidaymakers warned about 'explosive diarrhoea' cyclospora parasite infection

UK tourists are being cautioned about a dangerous infection called cyclosporiasis, which can lead to severe diarrhea, following a surge in cases. The UK Health Security Agency (UKHSA) reported 67 instances since April, most of them among travelers from Mexico. This follows an outbreak in the US that has affected over 18,000 individuals across 45 states.

The source of the infection remains unidentified, and there have been no fatalities. The parasite responsible, cyclospora, can taint food such as salads, herbs, and soft fruits. The UK doesn't have this parasite, and there is no risk of person-to-person transmission, according to experts.

Between April 30 and July 15, 2026, 30 cases were reported in England, 27 in Scotland, and 10 in Wales, according to the UKHSA. Of the 52 cases with travel details, 48 involved Mexico, with many staying in the Riviera Maya beach resort area or Cancún. The affected individuals mentioned staying in various hotels and consuming different foods and drinks during their all-inclusive holiday packages. Ongoing investigations and monitoring of the situation are underway.

To protect themselves, travelers should follow good food and water hygiene practices, including drinking bottled water and eating fully cooked food, even in high-end all-inclusive resorts. They should also avoid certain foods like fresh uncooked berries and herbs, unpeeled fruit, and salad items. Symptoms of the intestinal illness include frequent, explosive watery diarrhea, which can be debilitating.

Some sufferers reported needing to use the toilet up to 20 times a day. While most cases resolve independently, antibiotics may be prescribed for severe or prolonged infections.

The UKHSA predicts more cases will emerge due to increased summer travel to Mexico and potentially the US. Dr. Philip Veal from the agency advised that if travelers develop symptoms like watery diarrhea, loss of appetite, weight loss, stomach cramps, bloating, increased wind, nausea, fatigue, or flu-like symptoms after returning from travel, they should seek medical attention and inform their healthcare professional of their travel history.