Updated 10:01 31 Jul 2026 GMT+1Published 09:58 31 Jul 2026 GMT+1

Brit holidaymakers now being warned about ‘explosive diarrhoea’ infection spreading across US

The UKHSA has released new data for the number of cyclosporiasis cases in the UK and many travellers had visited similar areas

Greg Harris

British travellers with holidays booked to visit the US and Mexico in the coming weeks are being warned after cases of a highly infectious stomach bug that can cause ‘explosive diarrhoea’ have surged.

Health experts are urging visitors to take extra precautions as outbreaks of the illness continue spreading, raising renewed concerns ahead of the busy summer travel season.

Cyclosporiasis is an illness caused by the parasite cyclospora, which can contaminate foods such as uncooked salads, herbs and soft fruits. There is no risk of it spreading from person to person and it does to naturally occur in the UK, the BBC reports.

The UK Health Security Agency (UKHSA) said 67 cases have been reported since April, with many cases linked to travel to Mexico.

Between 30 April and 15 July, 30 cases were reported in England, 27 in Scotland and 10 in Wales, according to data from the UKHSA.

Of the cases reported in the UK, 48 had travelled to Mexico. Some travellers said they stayed in the area of Riviera Maya or Cancún.

British travellers are being warned ahead of their summer trips to Mexico and the US (Getty Stock Image)

The holidaymakers had all-inclusive holiday packages and consumed a variety of food and drink as part of their deals.

The warning follows news of an outbreak in the US that has infected more than 18,000 people across 45 states. There have been no reported deaths and the source is still being investigated.

In Michigan alone, 1,000 people were diagnosed in just a two-week period. The US Centers for Disease Control and Prevention (CDC) has been monitoring the situation and has shared that it received reports of 145 cases of cyclosporiasis acquired in the United States in people who became sick from May 1, 2026, through June 16, 2026.

Symptoms can include frequent watery diarrhoea, stomach cramps, nausea, bloating, loss of appetite and extreme tiredness.

Holidaymakers can protect themselves by following food and hygiene measures, such as choosing bottled water and eating food that has been thoroughly cooked.

Salads and uncooked fruit and veg have been mentioned in warnings from health experts (Getty Stock Image)

Experts have previously advised people to avoid foods such as fresh uncooked berries, herbs, unpeeled fruit, and salads during outbreaks.

The UKHSA said it believes there will be more cases linked to summer travel to Mexico and the US in the coming weeks.

CBS reported that the US Food and Drug Administration remained confident its traceback investigation pointed towards iceberg lettuce grown by Taylor Farms in central Mexico, despite an earlier test result being deemed a false positive.

Taylor Farms previously said the FDA had not identified a single positive product test result for Cyclospora, while Mexico's health minister has reportedly disputed claims that the outbreak originated at a lettuce farm in the country.